The new Camaro will likely bring an end to.......

......160+ mph top speeds.

Ungoverned 3700 pound 400 horse GTOs can approach 170, and LS1 Camaros can go about 162-165 depending on who you believe. But the new one is hardly likely to approach those speeds.

4th gen Camaros aerodynamics wasn't nearly as great as you'd expect, but the new Camaro has a blunt full width grille, doesn't have it's wintunnel developed fastback hatch, has it's wheels pulled out to the body, & has a less radical rake to the windshield.

Alot can be countered by attention to underside aerodynamics, but looking at the CAD of the the underbody, there isn't that much to look forward to.

In the translation from concept to production, there will be alot of aerodynamic "tuning" of Camaro, but like was stated in another thread by another member, blunt nose Mustangs (the last SN95 editions as well as the new current version) begin to hit an aerodynamic wall under 140, and forcing the car through the air beyond that makes the car "squrrelly".

The 4th gen, while not really aerodynamic, was designed in the wind tunnel for decent stability at high speeds. The 5th gen is designed to look great, but it's likely going to lose top speed.

but how many people actually hit 160 anyways? most guys dont build them fast enough to hit that in the 1/4, the highways are no place to hit those speeds, and I don't think too many people have access to the talladega track.
If you're looking in the future to a nascar vehicle, the bodies are so far modified that it doesn't matter what the car looked like to begin with. The same goes for NHRA, the bodies on those cars don't resemble the actual car one bit. I bet if you took all the stickers and paint off of those top fuel funny cars and put every body next to eachother, you'd hardly be able to tell the difference.

The 4th gen, while not really aerodynamic, was designed in the wind tunnel for decent stability at high speeds. The 5th gen is designed to look great, but it's likely going to lose top speed.

The gearing of the 5th gen will also measure heavily in its top speed. I don't know about the Cd numbers for the 4th gen, but with its last minute styling alterations I doubt it has as much time put into high speed, wind tunnel testing.

Of course, everyone could debate just how important a 150/160/170 mph top speed is for a Camaro. I understand Corvette seeking such heights for world credibility, but I'm not so sure it'll weaken the image of a Camaro if it's not there.

I'm not too worried about it. Only ricers seem to care about top speed anyway.

The cure is more HP, though the faster you are going the exponentially more HP you need to continue accelerating.

Aerodynamics are essentially made up of 1) drag and 2) frontal area. I imagine although the 5thgen's CD will be up vs. the 4th gen, the frontal area will be similar as the overal height and width are about the same.

I don't think it will drop off as much as you think Guy. A lot of the Mustang's issues were due to its overall height (high frontal area) exposed wipers and things like that as well as a lack of HP and slightly steeper gearing.

Even an LT1 f-body was said to be able to hit 150+

I agree with shock. Top speed is an interesting data point, sort of a "bragging rights" thing, but in terms of everyday life, simply irrelevant. 1/4 times, 0-60, stopping distances, lateral g's, etc. all seem to apply more to most guy's driving experiences.

Top speed doesn't matter, really. If the 5th gen can hit 150, that's enough.

If you want top speed, get a car designed to go that fast. Get a vette, to be honest.

I've been in a few friends stangs at 125+...its almost like turbulence...well i guess thats what it is, its scary either way.

Whats the CD on a 4th gen...anyone know?
the 3rd gen was somewhere between .32 .34 i think.

So the Z/28 won't be able to take on Ferraris on the top end?

If the aerodynamics are as bad as you say they are, GM better make 1-5 some really really agressive gears with 6 being a heavy heavy overdrive.

I think the 4th gens were .34 cd.

The 3rd gen was the first F-body designed with aero in mind IMO. Particularly before the days of overdrives, top speed was much more mechanically limited than aero limited.

Eithre way I hope they clean up the Aero's.. When/If I get a 5th gen, I'll probably follow the trend of my 4th gen.. Drive it around and have some fun with it the first 3 years... Then after warranty is done, and loans are paid off, bring it to the open track days at the roadcourse... I don't want the car to fall flat or feel wierd going down the front and back straights at well into triple digits.

camaro
LS1 .34
LT1 .32

LT1 firebird .34
convertible .36

third gens have around the same #'s both camaro and firebird.. can't find any hard details on that though (firebird and camaro about the same).. the newer the lower the CoD, though.

C6 is .28

mustangs:
94/95 is .37
whereas the late 80s'/early 90s Mustangs are about .41


Those are from google searching, and those numbers appear quite a few places.. take them with a grain of salt, though, to get the taste you want

The only things that worry me about it really are Perception and bragging rights for the car.

I mean i'm at the track a lot, i used to race a lot on the street when i was a little younger(stuupidder), but my car has only seen 160+ maybe twice that i can remember.

I imagine the average person...hitting 100mph once, feeling like they just killed someone and never thinking about it again.

If the 2 ton 425 hp blunt nosed charger SRT8 can hit 160 the Camaro should have no problem.

Whenever you refer to Cd, you have to also consider the frontal area. But I agree with Falchuck, if the chubby, flat-faced Charger can do 160, the Camaro should, too. At least the Camaro LOOKS way better.

Though not the most important aspect of the car by any means...I like knowing I 'could' go XXXmph if I wanted to / had to.

Top speed isn't a big deal to me. I expect it to hit 150mph, but anything over that is just for bragging on message boards. I'd like the car to get good milage at 85mph though, that is important.

The fastest I've ever gone was 130mph for a few seconds and that was enough for me. I'd feel safe setting the cruise at 100mph, but not much over that.

It's no biggie as to the top speed in my book, but rather how long it takes to hit it. If a car took 20 minutes to hit its top speed, would you really want it?

......160+ mph top speeds.

Ungoverned 3700 pound 400 horse GTOs can approach 170, and LS1 Camaros can go about 162-165 depending on who you believe. But the new one is hardly likely to approach those speeds.

The speed limiter on an F-Body with z rated tires is 162 mph. With the limiter removed, the 4th gens were good for around 170 flat out. At least, that is what SLP got stock ones to do.


The 4th gen, while not really aerodynamic, was designed in the wind tunnel for decent stability at high speeds. The 5th gen is designed to look great, but it's likely going to lose top speed.

I don't understand this statement at all. Not really aerodynamic reference to what? A Corvette? Because then I might agree with you. The 4th gens had a Cd of .34, and although I am unsure of its exact frontal area, its probably with a few square feet of the Vette. That Cd number isn't going to blow anyones mind, but is still better than many of the sedans (or cars period) out there. I don't know how often you have done triple digit speeds in any of your 4th gens, but mine feels fine up to 140. Never gone much faster than that. Saying the 4th gen had poor aero is ridiculous. It could have been better, but it certainly isn't bad.

About the 5th gen's top speed, I am left to assume that this all on your on presumption, unless you have actually been doing aero testing in some way or another for it. Aero is a tricky thing, cars that don't look like they should be very aerodynamically clean can often be just that, so I won't go making observations based on a concept until there is actual hard info and data to back up an assumption like that.

I've taken my 99 up to about 135 once but wouldn't do it again as the flashing lights kind of scared me straight. I like knowing that I can do 150+ but as long as the fifth gen gives me room to about 125 I'm not worried about it.

...sounds like it'll be a good drafting partner, lol.

The speed limiter on an F-Body with z rated tires is 162 mph. With the limiter removed, the 4th gens were good for around 170 flat out. At least, that is what SLP got stock ones to do.


.

I'm not sure where you're getting your info but the Z rated G92 cars didn't have a speed limiter at all. Fuel cutoff at 255mph only.

The 235/55-16 cars got the 115mph speed limiter. The Z rated cars were aero limited.

Fastest i have gone is 150 in a '01 Mustang GT Bullitt (only because it wasn't mine, and have never put much value into Fords), and it was very nerve racking. Both hands making dents in the steering wheel. I had my '93 Z28 going about 140 chasing some punk on a crotch rocket and it was stable as hell. Setting the cruise at 110 on squirly northern missouri roads felt like 70 in the 4th gen.

I'm not sure where you're getting your info but the Z rated G92 cars didn't have a speed limiter at all. Fuel cutoff at 255mph only.

The 235/55-16 cars got the 115mph speed limiter. The Z rated cars were aero limited.

Nope. At least not on the LS1 cars.

http://www.ls1tech.com/forums/showthread.php?t=469199&highlight=162+mph+speed+limiter

http://www.ls1tech.com/forums/showthread.php?t=471695&highlight=speed+limiter

http://www.ls1tech.com/forums/showthread.php?t=440206&highlight=speed+limiter

http://web.camaross.com/forums/showthread.php?t=105483&highlight=162+speed+limiter

There used to be a site where a guy took some pretty decent videos of both an A4 and M6 F-Body out on a desert road in Nevada, both cars bone stock, and ran them both to the limiter. You can sort of hear it (there is alot of wind noise even with the windows shut), and he remarks on when he has hit it. Both cars it was at 162. I will see if I can find the videos, but it has been awhile.

I also remember someone telling me that he was suprised GM put a limiter as harsh (not sure what he meant by that) on the F-Body, because he said when he nailed it at those speeds it unsettled the car more than he would have liked. I honestly am suprised at how many people don't actually know this about the 4th gens, on an enthusiast website.

Fastest i have gone is 150 in a '01 Mustang GT Bullitt (only because it wasn't mine, and have never put much value into Fords), and it was very nerve racking. Both hands making dents in the steering wheel. I had my '93 Z28 going about 140 chasing some punk on a crotch rocket and it was stable as hell. Setting the cruise at 110 on squirly northern missouri roads felt like 70 in the 4th gen.

My 01 GT definetly didn't have much pull to it anymore at around 130. It would have gone faster, but I am questionable as to exactly how much faster it would have gone.

There is a video of some dumbass hitting 160 in his cobalt. At least make the camaro slightly faster than the cobalt. Otherwise the ricer crowd will never let us hear the end of it.

Top Speed isn't as important as acceleration beyond bragging rights. My purpose is to bring attention to the one area of Camaro that was world class and noteworthy. Camaro (and Firebird) were probally the world's FASTEST cars that carried more than 2 people and cost under 100 grand when they were discontinued!

Wanna talk about bragging rights?! :D

GTO is governed at 155mph, and I believe the title now belongs to the Magnum SRT8, with the 300 SRT-8 and the Charger SRT-8 close behind.


I don't understand this statement at all. Not really aerodynamic reference to what? A Corvette? Because then I might agree with you.

In general. When Camaros were doing .32cd 24 years ago, and 11 years later, doing worse, then 5 years later, doing worse still, seems like it's going in the wrong direction.

....Aero is a tricky thing, cars that don't look like they should be very aerodynamically clean can often be just that, so I won't go making observations based on a concept until there is actual hard info and data to back up an assumption like that.

A correct assesment, and probally a wise decision. years ago I had the areo numbers of a group of cars, and they weren't what you'd expect. The thing that surprized me was Camaro's. But unless GM has plenty of tricks up their sleeve, I'm guessing the 5th gen is going to be worse than the 4th aerodynamically.

If the 2 ton 425 hp blunt nosed charger SRT8 can hit 160 the Camaro should have no problem.

One difference. Charger is pretty smooth up front save the grille opening. The Camaro doesn't even have headlight covers. It could probally be made more aerodynamic up front with them though.

I'm not too worried about it. Only ricers seem to care about top speed anyway.

Some of us westerners also care. Not because we routinely run top speed, but because it's easier to do sudden bursts of to 130 from 90 or so if your car is capable of 150 or more. There are some places in Arizona I run a steady 120 (no exaggeration).

Then there's the "Autobaun" on that stunningly long & straight streach of Interstate 15 going into the Neveda state line on the way to Vegas where I first hit 140 mph and years later witnessed my 1st 18 wheeler doing over 120. :eek:

Even an LT1 f-body was said to be able to hit 150+

A loaded 1997 LT1 6 speed Z28 with 255 series tires tops out at a notch past it's 155mph marking on the speedometer............ ;)

...As a side note, I have zero intentions of running that fast off track ever again. As smooth as the roads were where I ran, the tiniest dips and road imperfections have a way of scaring the living daylights out of you at that speed. My B4C will be the 1st car I ever owned that I never ran it flat out on the highway. It already was involved in a shootout (still has a bullet hole), so it has enough history already. )

The 3rd gen was the first F-body designed with aero in mind IMO. Particularly before the days of overdrives, top speed was much more mechanically limited than aero limited.

You're right. The '82 Trans Am was the world's most aerodynamic car when it came out. Even by today's standards, it's insanely low (those wheelcovers helped).

The 4th gen of both Camaro & Firebird had worse aerodynamics than the 3rd gens.

About the 5th gen's top speed, I am left to assume that this all on your on presumption, unless you have actually been doing aero testing in some way or another for it. Aero is a tricky thing, cars that don't look like they should be very aerodynamically clean can often be just that, so I won't go making observations based on a concept until there is actual hard info and data to back up an assumption like that.
Definitely true. I remember the Eagle Premiere (square, blocky, Renault-derived thing) had a lower Cd than the much-hyped Taurus back in the late-80s. I don't think there's too many armchair quarterbacks that can just look at a car and accurately evaluate its aerodynamic performance.

We have had two huge threads in the Advanced Tech and Longe of LS1TECH on this. The 3rd gens ran from .299-.33 Cd based on model with about 22 sq/ft of frontal area. All info for 4th gens quote a .34 Cd, and I am unbale to find frontal area however it has to be close. Just as a side not the 300C has a Cd of .35. Aerodynamics is not intuitive.

Aerodynamics is not intuitive.

This is probably the most important statement to focus on when discussing aerodynamics. The 3rd gen was more aerodynamic then the 4th, but I wonder what kind of lift or downforce was generated with each model as the speeds increased. I seem to recall that the 4th gen z28 spoiler is better than the 4th gen SS spoiler at high speed, because the SS spoiler actually creates lift. I think the Formula spoiler actually creates downforce, although I don't remember for certain. Gimmicks like the SS hoods, although nice looking, probably do little for high speed aerodynamics (although like I said earlier, aero is tricky, so maybe I wrong).

......160+ mph top speeds.

Ungoverned 3700 pound 400 horse GTOs can approach 170, and LS1 Camaros can go about 162-165 depending on who you believe. But the new one is hardly likely to approach those speeds.

4th gen Camaros aerodynamics wasn't nearly as great as you'd expect, but the new Camaro has a blunt full width grille, doesn't have it's wintunnel developed fastback hatch, has it's wheels pulled out to the body, & has a less radical rake to the windshield.

Alot can be countered by attention to underside aerodynamics, but looking at the CAD of the the underbody, there isn't that much to look forward to.

In the translation from concept to production, there will be alot of aerodynamic "tuning" of Camaro, but like was stated in another thread by another member, blunt nose Mustangs (the last SN95 editions as well as the new current version) begin to hit an aerodynamic wall under 140, and forcing the car through the air beyond that makes the car "squrrelly".

The 4th gen, while not really aerodynamic, was designed in the wind tunnel for decent stability at high speeds. The 5th gen is designed to look great, but it's likely going to lose top speed.

Cant imagine its going to be as bad as you say. The rake of the 4th gen window is much more aggressive than GTO which you said has a higher top speed. Cant the back pressure of the grille be relieved against the windshield out the back of the Cowl? Thats all they need is to go back to that windshield and cover the motor again...

I can see you guys are worrying about the nose of the car, with the grill almost cuping the air.
This can be solved by placing a vent on the sides of the grill, that exit right in front of the tire.
I made a chop using paint on my computer. Its not as good as some of you guys can do with photoshop, but I'm sure you will get the idea.

http://img97.imageshack.us/img97/7215/venter2qr.jpg (http://imageshack.us)
....almost looks exotic. :eek: :bow:

Aerodynamics is not intuitive.

I'll be happy to lend my Fundamentals of Aerodynamics book to anybody who disagrees. Let them see just how counter-intuitive it can be.

Drag coefficient is effected by so many little things its almost impossible to estimate just by looking for anything other than VERY simple bodies like flat plates and cylinders. The Reynolds number you're operating at has a huge effect. Depending on the specific shape of the body, drag coefficient can change depending upon your velocity because it shifts to a different Reynolds number regime. Thats all not to mention vortex effects, flow separation, boundry layer separation and any number of strange and unusual aerodynamic effects that may be going on.

I'll be happy to lend my Fundamentals of Aerodynamics book to anybody who disagrees. Let them see just how counter-intuitive it can be.

Drag coefficient is effected by so many little things its almost impossible to estimate just by looking for anything other than VERY simple bodies like flat plates and cylinders. The Reynolds number you're operating at has a huge effect. Depending on the specific shape of the body, drag coefficient can change depending upon your velocity because it shifts to a different Reynolds number regime. Thats all not to mention vortex effects, flow separation, boundry layer separation and any number of strange and unusual aerodynamic effects that may be going on.

So can the back pressure from the front grille be channeled through the engine bay then out the back of the cowl and over the windshield?

So can the back pressure from the front grille be channeled through the engine bay then out the back of the cowl and over the windshield?

The base of the windshield is a high pressure area (take a look at where nascar cars breathe from). Even worse so with a steeper windshield. You can't vent to a high pressure area (well, you can, if you're venting even higher pressure, but...)

As people are trying to explain, aerodynamics is counter intuitive. Want a great example. Modern trucks are designed to be more aerodynamic with the tailgates UP than down. The bed holds air, which creates a nice big boundary layer (i know, not quite teh right application of the term) so air coming over the cab smoothly exits back. Open the tailgate and you create a low pressure area in the bed since air coming over the top spills down to the floor of the bed.

Aero is way too complex to estimate by looking, as some in this thread have already said. Sometimes adding a vent (like dropping the tailgate) costs you more energy in air movement than just letting the air build pressure and create a cushion that keeps more air from coming in. That air cushion becomes you 'grille cover'

While I wouldn't say aerodynamics aren't important, I wouldn't place as much emphasis on them as some others. There seems to be a tradeoff between, aero, design, and cost. They could make it a bulbous car with a wonderful Cd, but who would want to buy that? They could use a number of solutions like the plates under the Corvette, but they might add cost.

I'm sure the aero wizards will gin up some good ideas to help. I've seen a couple areas on the 4th gen cars where that was done. In the end appearance counts for a lot as well. Mustang has been getting worse figures for a while now. It hasn't seemed to make a dent in their sales.

The base of the windshield is a high pressure area (take a look at where nascar cars breathe from). Even worse so with a steeper windshield. You can't vent to a high pressure area (well, you can, if you're venting even higher pressure, but...)

As people are trying to explain, aerodynamics is counter intuitive. Want a great example. Modern trucks are designed to be more aerodynamic with the tailgates UP than down. The bed holds air, which creates a nice big boundary layer (i know, not quite teh right application of the term) so air coming over the cab smoothly exits back. Open the tailgate and you create a low pressure area in the bed since air coming over the top spills down to the floor of the bed.

Aero is way too complex to estimate by looking, as some in this thread have already said. Sometimes adding a vent (like dropping the tailgate) costs you more energy in air movement than just letting the air build pressure and create a cushion that keeps more air from coming in. That air cushion becomes you 'grille cover'

Even better!

I love the dialogue about areodynamics and I do not have the tools to argue it...you guys seem to be doing great.

I will say this; I hit 160MPH once in my 02 SS Coupe and all I can say is...




STUPID STUPID STUPID

I'd prefer an all attitude 12 sec quarter mile car that handles twisties like it was on rails (I've heard that before:) ) and I'll settle for a little less top speed.

Give me handling and torque, save the aerodynamics for the Air Force.

...which brings up and interesting point. I was reading an article somewhere recently about the design of the 5th gen. One of their inspirations was modern military aircraft like the B2, and F22 Raptor. Anugular beasts that excude function over form.;) ;)

I'm a noob at this aerodynamics stuff but it fascinates me.
I was under the impression that higher drag is good for making a car stable at highspeeds, that it works kinda like downforce, and a high power car that has a lot of drag would be more stable than a low powered very "slippery" car because of the extra drag.

I'm a noob at this aerodynamics stuff but it fascinates me.
I was under the impression that higher drag is good for making a car stable at highspeeds, that it works kinda like downforce, and a high power car that has a lot of drag would be more stable than a low powered very "slippery" car because of the extra drag.
Well downforce creates drag, but drag does not necessarily create downforce.

The speed limiter on an F-Body with z rated tires is 162 mph. With the limiter removed, the 4th gens were good for around 170 flat out. At least, that is what SLP got stock ones to do.

IIRC, the actual number was 172 mph. I have the video somewhere. It was a 99 Firehawk with the speed limiter removed.

...which brings up and interesting point. I was reading an article somewhere recently about the design of the 5th gen. One of their inspirations was modern military aircraft like the B2, and F22 Raptor. Anugular beasts that excude function over form.;) ;)

They are that angular shape to reduce their radar signature. Wouldnt it be sweet if 5th gen reduced that radar signature when smokey was waiting for you behind his favorite tree radar in hand at the end of the month? I know its rediculous but I can dream cant I?

IIRC, the actual number was 172 mph. I have the video somewhere. It was a 99 Firehawk with the speed limiter removed.

I don't think that is the video I was thining of, but if you have the video on your hard drive I would love to see it. I have heard about a none limiter car hitting just over 170. The videos I saw were of 2 4th gen LS1 cars hitting there stock 162 mph limiters. I don't know as much about the LT1 cars as I do the LS1 cars, but I know most definelty that that is exactly where the governor sits on the LS1 cars; 162.

They are that angular shape to reduce their radar signature. Wouldnt it be sweet if 5th gen reduced that radar signature when smokey was waiting for you behind his favorite tree radar in hand at the end of the month? I know its rediculous but I can dream cant I?

That would definetly help me out alot with the local law enforcement.

That would definetly help me out alot with the local law enforcement.

Speaking of which, I need to get to bed so I can get up for community service. Yeah Id say that a stealth Camaro just MIGHT pique my interest! lol :D

I have no plans on driving 150+ mph down the interstate. I'm more interested in the acceleration. The "gitup n go" factor.

Aerodynamics matters far more than just to top speed. It can affect performance long before top speed is reached, not to mention gas milage, wind noise, etc.

There's a reason why GM is so proud of the .36 coefficient of drag that the GMT-900 SUVs have... and no, it's not top speed.;)

The 4th gen of both Camaro & Firebird had worse aerodynamics than the 3rd gens.


Hmm, I can't find a source that will verify that statement.. both 3rd and 4th gen seen to be in the .34 cd with the 4th gen's having a slightly lower frontal area than the 3rd gens....

The blunt nose is not the issue so much... a blunt nose (depending on the aero efficiency) can actually improve front end stability... it's more the rest of the car's body where gains in aero efficiency is achieved.

Qualifier: I'm no aero dynamicist but I'm only going by what I've read on recent designs like Cadillac's 'Art and Science' theme and how GM's designers were commenting on how they could still achieve good aero efficiency with that chiseled blunt nose.

Ok...Here's info from the "1982 Camaro Product Specialist Manual". The Z-28 figure is also in the '82 Camaro brochure.

Cd figures:
Egg .030 (yes, this is quoted as well)
'82 Camaro Z-28 .369
'82 Camaro Coupe/Berlinetta .374
'79 Camaro sport Coupe .412
'80 Corvette .443

Target for '82 Camaro was .380

I don't know where the .32 is coming from, but it also makes me wonder about the .34 of the 4th gen.

My 01 GT definetly didn't have much pull to it anymore at around 130. It would have gone faster, but I am questionable as to exactly how much faster it would have gone.

The top speed of the GT and the bullit is actually about 145. Some claim 147 though.

I'll be happy to lend my Fundamentals of Aerodynamics book to anybody who disagrees. Let them see just how counter-intuitive it can be.

Drag coefficient is effected by so many little things its almost impossible to estimate just by looking for anything other than VERY simple bodies like flat plates and cylinders. The Reynolds number you're operating at has a huge effect. Depending on the specific shape of the body, drag coefficient can change depending upon your velocity because it shifts to a different Reynolds number regime. Thats all not to mention vortex effects, flow separation, boundry layer separation and any number of strange and unusual aerodynamic effects that may be going on.


These are the same kind of concerns that the mustang guys had before the 05 debuted. I guess its normal:)

They are that angular shape to reduce their radar signature. Wouldnt it be sweet if 5th gen reduced that radar signature when smokey was waiting for you behind his favorite tree radar in hand at the end of the month? I know its rediculous but I can dream cant I?

The angular parts reflect the radar away from the source. Thats why the signature is reduced. They are also covered with a composite skin (which the camaro will not have:( ) to absorb the waves. An angular chape could theoretically introduce errors into the returning wave that would make it read incorrectly.................

The blunt nose is not the issue so much... a blunt nose (depending on the aero efficiency) can actually improve front end stability... it's more the rest of the car's body where gains in aero efficiency is achieved.

Qualifier: I'm no aero dynamicist but I'm only going by what I've read on recent designs like Cadillac's 'Art and Science' theme and how GM's designers were commenting on how they could still achieve good aero efficiency with that chiseled blunt nose.


People worry about the blunt nose because of the frontal area it presents. Reducing frontal area reduces drag. But there are other ways to compensate.

Ok...Here's info from the "1982 Camaro Product Specialist Manual". The Z-28 figure is also in the '82 Camaro brochure.



I don't know where the .32 is coming from, but it also makes me wonder about the .34 of the 4th gen.


I dont see how it could be either. Starting to think its one of those myths like the 3rd gens easily out handleing the 4ths. I know they did a lot of aero work on the 4th gens to get the gas milage as high as possible.

People worry about the blunt nose because of the frontal area it presents. Reducing frontal area reduces drag. But there are other ways to compensate.

I thought frontal area was the "shadow" of car from straight on. In otherwords a 2D representation of the surfaces that hit the air.

If that's accurate,then sloped vs. flat nose is irrelevant to a measurement of frontal area. It would definitely factor into CD, but frontal area is only concerned with the total square feet of area that sees air hit it from straight on.

So as long as the nose isn't taller than the windshield or wider than the rest of the car its really not a factor in the measurement of frontal area.

I have all my fun in the first 3 gears, not enough open road for anything else. Fastest I've ever gone is 125, and can't say I'd ever need more than that again.

As far as the aero, I'd gladly give up some aero for a well styled package. Look at the butt of the C5, thats what happens when aero takes higher priority than styling. They improved it greatly w/ the C6, but for me, I don't want a design dictated solely by the wind tunnel. I want as slick a car as I can get so long as it still has attractive styling. An example for me would be the 4th gen LS1 Firebirds. I thought their styling was much more interesting than the Camaros, but I think they were a notch or 2 higher in .cd.

My 01 GT definetly didn't have much pull to it anymore at around 130. It would have gone faster, but I am questionable as to exactly how much faster it would have gone.

It was a downhill on the interstate, bigger throttle body, and i just wanted to max out the speedo, it probably wouldn't have done it on flat ground, i am just talking about the stability at that speed.

I thought frontal area was the "shadow" of car from straight on. In otherwords a 2D representation of the surfaces that hit the air.

If that's accurate,then sloped vs. flat nose is irrelevant to a measurement of frontal area. It would definitely factor into CD, but frontal area is only concerned with the total square feet of area that sees air hit it from straight on.

So as long as the nose isn't taller than the windshield or wider than the rest of the car its really not a factor in the measurement of frontal area.

Even in terms of Cd, the shape of the front of the vehicle is nowhere near as important as the after run.

It's not really the way you hit the air, it's the way you leave it that matters.

Btw - if you really want to go faster than 165ish mph, there are MUCH MUCH more cost-effective ways to do it.

Bias the gearing towards fuel economy/quarter mile/road course - leave the top speed contests to Corvettes and hyperbikes.

If that's accurate,then sloped vs. flat nose is irrelevant to a measurement of frontal area. It would definitely factor into CD, but frontal area is only concerned with the total square feet of area that sees air hit it from straight on.
That was my understanding, but I don't do aero for a living or anything.

Regarding the Stealth Camaro, you need to make all the body panels out of radar absorbent material, and then use RAM paint, and then the glass would need to be tinted with gold too. ;)

The top speed of the GT and the bullit is actually about 145. Some claim 147 though.
I was thinking the same thing, maybe he was going downhill with a tailwind?:rolleyes:

People shouldn't worry about the top speed, look at the Chrysler 300 SRT-8 it does over 170mph and it weighs 2 tons and definitely isn't aerodynamic. I agree on the Mustang comments about stability. My old GT would start to get squirrely around 130 and it probably couldn't go much faster anyway(97GT, don't laugh) it felt like air was getting under the backend and trying to lift it or something. My 02 Z28 never had that problem but I was too scared to try and run aver 140mph because of the cops around here.

I thought frontal area was the "shadow" of car from straight on. In otherwords a 2D representation of the surfaces that hit the air.

If that's accurate,then sloped vs. flat nose is irrelevant to a measurement of frontal area. It would definitely factor into CD, but frontal area is only concerned with the total square feet of area that sees air hit it from straight on.

So as long as the nose isn't taller than the windshield or wider than the rest of the car its really not a factor in the measurement of frontal area.


Think about an airplane with a long pointed nose. The frontal area is small. Now chop the nose off about 5 feet back and now its flat instead of pointed. It presents more frontal area for air to effect. The same with a car. With a car, there are ways to channel the air so that it does not make that much of an impact.

Think about an airplane with a long pointed nose. The frontal area is small. Now chop the nose off about 5 feet back and now its flat instead of pointed. It presents more frontal area for air to effect. The same with a car. With a car, there are ways to channel the air so that it does not make that much of an impact.


I'm no engineer but that's not how frontal area is measured. Its just a footprint of the width and height....3D has nothing to do with it. Its obvious a curved pointed nose is more beneficial, but the issue is what is the definition of "frontal area".

Frontal area is a 2D cross section http://www.v8sho.com/SHO/FrontalAreaCalculationsCd.htm

I've been in a few friends stangs at 125+...its almost like turbulence...well i guess thats what it is, its scary either way.

Whats the CD on a 4th gen...anyone know?
the 3rd gen was somewhere between .32 .34 i think.

4th gen CD was .33 - interestingly enough, so was the '03/04 Mustang, which I wouldn't have thought by the looks of it. C5 is .29 and C6 is .28, for comparison.

Think about an airplane with a long pointed nose. The frontal area is small. Now chop the nose off about 5 feet back and now its flat instead of pointed. It presents more frontal area for air to effect. The same with a car. With a car, there are ways to channel the air so that it does not make that much of an impact.

This is wrong.

Frontal area as he described it is correct.

It is the MAXIMUM 2D area seen from the front view as projected orthographically.

Frontal area DOES NOT describe the first surface that the object comes in contact with, but the entire area of air that the object must push out of the way - which is the 2D "shadow" he described.

Furthermore, aircraft have lifting surfaces and are much, MUCH faster, so the comparison sort of breaks down there some more. The most aerodynamically efficient shape for a car would be a tear drop, where the blunt end is facing the wind and the after run is long and gradual. Making it pointy is WORSE for a car than the teardrop shape.

And again, the front of the vehicle is never as important as the after run.

To use a double entendre where air is concerned:
It ain't the way you first poke her, it's the way you leave her when you're done.

I dont see how it could be either. Starting to think its one of those myths like the 3rd gens easily out handleing the 4ths. I know they did a lot of aero work on the 4th gens to get the gas milage as high as possible.

For the Third Gen early Z28's were .36, IROC-Z's were .34, early TA's got .29, the last TA's got .31. The handling thing is no myth, but I wouldn't say they can do it easily.

Great thread. I like just sitting back and letting the experts on this chat. Learning quite a bit here. :)

For the Third Gen early Z28's were .36, IROC-Z's were .34, early TA's got .29, the last TA's got .31. The handling thing is no myth, but I wouldn't say they can do it easily.

The 3rd gen handling myth comes from GM taking out the harshness of the F-body's suspension when they did the 4th gen. Because the 4th gen rides smoother, feels much wider, and the steering picked up some weight to it's feel, the 3rd gen feels much snappier and quicker.

Put a stock version of both on the same course, and the 4th gen is actually better handling, though by comparison it doesn't feel like it.

The top speed of the GT and the bullit is actually about 145. Some claim 147 though.

My boxy '85 Special Service Mustang notchback topped out at 136 with just 210 horsepower. 145 with 70 more horses, and the same aerodynamics of the latter 4th gen Camaro sounds perfectly reasonable. But the USE of that wind makes you far more comfortable taking the Camaro to 140 than the Mustang.

On a sidenote (which I find facinating) my current '89 Supercoupe which has the same horsepower as my '85 Stang had & weighs about 600 pounds more tops out 10 mph faster. It also feels far more stable than even my Camaros around 140.

This is wrong.

Frontal area as he described it is correct.

It is the MAXIMUM 2D area seen from the front view as projected orthographically.

Frontal area DOES NOT describe the first surface that the object comes in contact with, but the entire area of air that the object must push out of the way - which is the 2D "shadow" he described.

Furthermore, aircraft have lifting surfaces and are much, MUCH faster, so the comparison sort of breaks down there some more. The most aerodynamically efficient shape for a car would be a tear drop, where the blunt end is facing the wind and the after run is long and gradual. Making it pointy is WORSE for a car than the teardrop shape.

And again, the front of the vehicle is never as important as the after run.

To use a double entendre where air is concerned:
It ain't the way you first poke her, it's the way you leave her when you're done.

I never said that was correct, just that is why people worry about it. Frontal area is the outline of the car as it heads towards you. The air it displaces can be reduced by the shap of the front of the car. Thats why people assume blunt cars have trouble attaing higher speeds.

Nobody liked my solution? I thought it looked pretty snazzy for something made in MSpaint. :(

Even in terms of Cd, the shape of the front of the vehicle is nowhere near as important as the after run.

It's not really the way you hit the air, it's the way you leave it that matters.

Yep, flow separation is a big component of drag. The longer you can keep flow attached to a body the less drag you will have. Its the same reason golf balls have dimples. The dimples induce high energy turbulent flow which keeps the flow attached further back along the body and the energy lost due to inducing the turbulent flow is much less than what would be lost to air, hence the ball fly's farther.

I would be willing to bet that whatever the drag coefficient of the 5th gen is, you could probably drop it by 0.2 or so just be redesigning the back end so that there's both a smooth transition back to free stream and a favorable pressure gradient over the length. Looking at the cars profile it looks like there might be an adverse pressure gradient along the back window which could cause premature flow separation. Course doing this redesign would make it terribly ugly for a car.

This is wrong.

Frontal area as he described it is correct.

It is the MAXIMUM 2D area seen from the front view as projected orthographically.

Frontal area DOES NOT describe the first surface that the object comes in contact with, but the entire area of air that the object must push out of the way - which is the 2D "shadow" he described.


Right again. People need to understand how drag force is calculated. D = 0.5*Cd*rho*S*V^2 where S is a reference area, rho is the air density and V is velocity. That reference area varies depending on the vehicle you're talking about and is usually the prevalent area. Airplanes use the wing planeform because its the dominant area whereas cars use frontal area.


Furthermore, aircraft have lifting surfaces and are much, MUCH faster, so the comparison sort of breaks down there some more. The most aerodynamically efficient shape for a car would be a tear drop, where the blunt end is facing the wind and the after run is long and gradual. Making it pointy is WORSE for a car than the teardrop shape.


Aircraft are a whole different ballgame. You have to start taking into account effects from tilted lift vectors, induced drag from vortexes from producing lift and a ton of other factors. Chopping an airplane off 5 feet from the nose will produce increased drag but not because it increased the frontal area. I would explain but it would take a lot more time than I have at the moment and its further complicated by the fact that after studying aerospace engineering for 5 years I still don't completely understand it.

I never said that was correct, just that is why people worry about it. Frontal area is the outline of the car as it heads towards you. The air it displaces can be reduced by the shap of the front of the car. Thats why people assume blunt cars have trouble attaing higher speeds.


The air displaced is fixed by frontal area, velocity and density. How EFFICIENTLY IT IS DISPLACED is represented by Cd. A better way to describe it might be "how little the air is disturbed during displacement" my old fluid dynamics prof used to describe this disturbance of the air as "making the fluid angry" (air is a fluid, btw...).

That's the whole point.

How much air I gotta move is the S (frontal area for a car) * V^2 (velocity squared) * rho (density).

How efficiently I displace it is Cd.

Great thread. I like just sitting back and letting the experts on this chat. Learning quite a bit here. :)

The 3rd gen handling myth comes from GM taking out the harshness of the F-body's suspension when they did the 4th gen. Because the 4th gen rides smoother, feels much wider, and the steering picked up some weight to it's feel, the 3rd gen feels much snappier and quicker.

Put a stock version of both on the same course, and the 4th gen is actually better handling, though by comparison it doesn't feel like it.


Oh I agree it's really close in stock form even if Thirds feel better. But if you evened it out and gave the Third a manual (and maybe an LS1) and the same wheels/tires as the 4th, it would be a sight to see.

The top speed of the GT and the bullit is actually about 145. Some claim 147 though.

I thought that was kind of odd because even the 32 valve Cobras weren't able to go 150 back then.

A word about limiters, there are Speed limiters and then there are RPM or rev limiters

I don't think there are speed limiters on the Z-rated 4th gen F-Bodies, but there are rev limiters, and rev limiters will keep you from going faster when you reach the upper limit of RPMs. For instance top speed on 6-speed cars is attained in 5th gear, and the top speed point is the point of which the rev limiter kicks in and safeguards the engine from destruction. LS1 have a much higher rev limiter than the ole LT1. Rev limits can be changed with a programmer. The talk of a 162 mph limter on stock LS1s is probably the rev limiter in 5th gear.

Speed limiters are set at a certain speed, usually the speed rating of the factory tires. My old Caprice LT1 had a speed limiter set at 108 mph, and didn't take long to hit it if you kicked down on it on the interstate. After I reprogrammed it I ran into another problem at WOT the transmission would not shift out of 3rd gear so it would hit the rev limiter at 128-129 mph. To go faster I would have to let off half way let it shift into 4th then get back on the gas.

You can really tell/feel the difference in a speed limiter vs.rev limiter. A speed limiter when you reach that terminal speed kills the gas for several seconds, until the car has slowed by at least 5 mph then resumes gas.
A rev limiter when hit is very fast off and on again with the gas. Some of you may have heard people hit the rev limiter at the drag strip doing burn outs, the same goes for top speed runs if you get the RPMs high enough.

Would adding cowl induction and hood vents help with aero any?

Would adding cowl induction and hood vents help with aero any?
Did you see my post?

A word about limiters, there are Speed limiters and then there are RPM or rev limiters

I don't think there are speed limiters on the Z-rated 4th gen F-Bodies, but there are rev limiters, and rev limiters will keep you from going faster when you reach the upper limit of RPMs.

Z-rated LS-1 F-bodies were speed-limited not rev-limited. For reference a 3.23 A4 will do 155mph at 4900RPM that is nowhere near the 6200 LS-1 rev-limter or its 5800RPM HP peak.

As for the Aero argument, yes it's impossible to eyeball Cd. But assumimg similar shapes will yield similar Cd results is reasonable given that both shapes operate in the same flow regime.

A comparison of Frontal Area, length, and surfaces (likely to trip the boundary layer, i.e. grille dimensions) will show that the Camaro and Mustang have ALOT in common. Expecting similar #s for the two isn't a stretch by any means. I still can't find an 05+ Mustang's Cd anywhere.


Oh yeah and I too have that Anderson book.

If you've ever looked at the OBDII you'd know they have rev limit (by gear) and max speed limit.

LS1 cars were factory set at 6200 rpms with a max speed of 160mph (might have been 162, I'll have to go look again.)

Did you see my post?
I like what you did there... doesn't look half bad really

If you've ever looked at the OBDII you'd know they have rev limit (by gear) and max speed limit.

LS1 cars were factory set at 6200 rpms with a max speed of 160mph (might have been 162, I'll have to go look again.)

Well I know the 3800 has a rev limiter because it hits it in park. Its violent too. I doesnt just hit it and top off. It knocks it well down only for it to come back up to be knocked down again. Like whack a mole rev limiter...

Did you see my post?
yea i did and it's unrealistic. Your vent is blocked by the headlight, and at such an angle that it wouldn't let the air "flow" out, as much as have to be pushed out by more air entering the front.

Fascinating thread!

I have but one point to add in reference to the third gen's aerodynamics. I remember that the third gen firebird has been the darling of the Bonneville top speed crowd for a long time due to its aerodynamics at speed. I seem to remember a record being set in one.

Fascinating thread!

I have but one point to add in reference to the third gen's aerodynamics. I remember that the third gen firebird has been the darling of the Bonneville top speed crowd for a long time due to its aerodynamics at speed. I seem to remember a record being set in one.

John Lingenfelter tried to go 300mph in one, but only got 298. He also built an 86 Corvette that did 264.

yea i did and it's unrealistic. Your vent is blocked by the headlight, and at such an angle that it wouldn't let the air "flow" out, as much as have to be pushed out by more air entering the front.
I completely disagree....many super cars, and race cars use the exact same principle...

... Its the same reason golf balls have dimples. The dimples induce high energy turbulent flow which keeps the flow attached further back along the body and the energy lost due to inducing the turbulent flow is much less than what would be lost to air, hence the ball fly's farther.


OK, who's got the balls (no pun intnended) to photoshop a dimpled finish on a 5th gen concept?:eek:

It is a true statement though, the dimples also keep make the ball much more accurate...as long as I'm not swinging the club.:rolleyes:

Car & Driver hit 160 mph in a Camaro SS, and 163 mph in Trans Am WS6 and both were convertibles!, that was back in 1999.

Yet another reason to model it after the Ferrari 612 and go with a strong 2nd/third gen influence. Splash in some Corvette blood, and you have yourself a fantastic looking Camaro.

Yet another reason to model it after the Ferrari 612 and go with a strong 2nd/third gen influence. Splash in some Corvette blood, and you have yourself a fantastic looking Camaro.

If you do a modern 2nd you might as well say 2nd 3rd and 4th because all the 4th was is a modern 2nd gen.


The 612 looks like cross between a Miami Vice Ferrari, a 4th gen with 50's Vette Door C indents anyway.

A word about limiters, there are Speed limiters and then there are RPM or rev limiters

I don't think there are speed limiters on the Z-rated 4th gen F-Bodies, but there are rev limiters, and rev limiters will keep you from going faster when you reach the upper limit of RPMs. For instance top speed on 6-speed cars is attained in 5th gear, and the top speed point is the point of which the rev limiter kicks in and safeguards the engine from destruction. LS1 have a much higher rev limiter than the ole LT1. Rev limits can be changed with a programmer. The talk of a 162 mph limter on stock LS1s is probably the rev limiter in 5th gear.

Speed limiters are set at a certain speed, usually the speed rating of the factory tires. My old Caprice LT1 had a speed limiter set at 108 mph, and didn't take long to hit it if you kicked down on it on the interstate. After I reprogrammed it I ran into another problem at WOT the transmission would not shift out of 3rd gear so it would hit the rev limiter at 128-129 mph. To go faster I would have to let off half way let it shift into 4th then get back on the gas.

You can really tell/feel the difference in a speed limiter vs.rev limiter. A speed limiter when you reach that terminal speed kills the gas for several seconds, until the car has slowed by at least 5 mph then resumes gas.
A rev limiter when hit is very fast off and on again with the gas. Some of you may have heard people hit the rev limiter at the drag strip doing burn outs, the same goes for top speed runs if you get the RPMs high enough.

Thanks for the 4th gen lesson. Did you bother to read any of the links I posted? The 4th gen LS1 f-bodies with z-rated tires had a 162mph speed governor on them straight from the factory. Not all z-rated are created equally, and the stock GSCs are only good for 162, hence the limiter at 162.

If you do a modern 2nd you might as well say 2nd 3rd and 4th because all the 4th was is a modern 2nd gen.


The 612 looks like cross between a Miami Vice Ferrari, a 4th gen with 50's Vette Door C indents anyway.

Uh...as an owner of a 2nd gen, It sure doesnt look like those catfish.
And the 612 mimics a lot of the 60s and 70's front engine Ferrari GT cars, and that is where the 2nd gen got most of its design influence from. The 612 looks very close to a modern 70-73 Camaro, complete with circular tail lights.

And I like that quote in your profile ;)

From everything I have read the 4th gens had a 162 limiter for cars with Z-rated tires. They usually have a margin of error +/- 3 mph. A little tuning, and that is no longer an issue. Mine is set at 255 mph now (or whatever arbitrary number tuners use, basically somewhere your car will never obtain).

Uh...as an owner of a 2nd gen, It sure doesnt look like those catfish.
And the 612 mimics a lot of the 60s and 70's front engine Ferrari GT cars, and that is where the 2nd gen got most of its design influence from. The 612 looks very close to a modern 70-73 Camaro, complete with circular tail lights.

And I like that quote in your profile ;)

But 98-02 does look like a 79 with the Open grille that hints of the 70-73 I think. But no its not just like the catfish, I never thought of them that way before.

Thanks on the quote. It was an old slogan people used where I work internally to remind everyone that the way clients see you if only a short while is their reality of the way your company is. It can make or break you. It stuck with me. I dont know where it came from but I like it and thought it appropriate.

I'll be the upmteenth person to confirm that the LS1 Z rated tire cars do have a 160soemthing speed limiter in addition to their 6200rpm rev limiter.

Top speed isn't an exact science because the speedo isn't quite dead on accurate at those speeds so sometimes you'll see 159, 163, etc....


I THINK the LT1 z-rated cars had no top speed limiter.

The story I've heard as to why the LS1 cars were limited to 160something is because the driveshaft was only capable of that speed before it hit "critical speed" and was at risk of causing all sorts of problems. It certainly wasn't the tires, they were the same GS-Cs that were on unlimited C4 Vettes which ran faster than 160.

Of course, now that I've got my LPE driveshaft with a 200mph critical speed, it's time to clip that 160 limiter and open her up looking for 170+!

I agree with everyone that says aerodynamics are WAY to complex to judge by eyeballing this concept. If the brick looking 300C SRT8 can run 170+ with 425 hp, it's entirely possible that the 5th gen will be able too. Can't judge it on looks.

they were the same GS-Cs that were on unlimited C4 Vettes which ran faster than 160.


Are they? Don't the RSAs on the 3rd gen Mitsu Eclipses and the RSAs on the 4th gen fbodies carry a different speed rating? At least I thought they did, but I could be wrong. Tires on both cars are still Goodyear RSAs.

FWIW, I remember back in 1999, a Canadian publication (Canadian Motorist? - I honestly can't remember... and the article isn't available online any longer) had a top speed shootout on the banked oval at Blaineville, Quebecl between a Ford Lightening and a Firehawk. Umberto Bonfa, who was the Canadian Sales Mgr. for SLP at the time told me that the Firehawk that he brought to the shootout had the [B]speed[B] limiter removed and that car managed to pull an honest 170+mph on that banked track.

best regardSS,

Elie

I really wish I could get a copy of that article. Not on the net anymore huh? I wonder if someone has it and could scan it?

Are they? Don't the RSAs on the 3rd gen Mitsu Eclipses and the RSAs on the 4th gen fbodies carry a different speed rating? At least I thought they did, but I could be wrong. Tires on both cars are still Goodyear RSAs.


All Goodyear GSCs are Z-rated, RSAs can be H-rated or V-rated.

FWIW, I remember back in 1999, a Canadian publication (Canadian Motorist? - I honestly can't remember... and the article isn't available online any longer) had a top speed shootout on the banked oval at Blaineville, Quebecl between a Ford Lightening and a Firehawk. Umberto Bonfa, who was the Canadian Sales Mgr. for SLP at the time told me that the Firehawk that he brought to the shootout had the [B]speed[B] limiter removed and that car managed to pull an honest 170+mph on that banked track.

best regardSS,

Elie

I have a Road & Track video tape from 1995 that is called Fastest Cars in America. They tested 5 completely stock cars, and then 5 of the same models that tuners sold as pkgs. The Lingenfelter Firebird 383 NA had the fastest top speed of the test. I believe it was 196 mph, which even beat the Lingenfelter Corvette ZR1.

Off the top of my head other cars that were tested: Camaro Z28, Vortech Camaro Z28, Mustang GT, Saleen S351, Viper and Hennessy Viper

Are they? Don't the RSAs on the 3rd gen Mitsu Eclipses and the RSAs on the 4th gen fbodies carry a different speed rating? At least I thought they did, but I could be wrong. Tires on both cars are still Goodyear RSAs.

You could order the "Z rated" option and get GSCs, or the "Z Rated All Season" option and get RSAs. They are both Z rated tires. Goodyear makes a lot of other RSAs with other speed ratings, but the ones that came on the camaro were Z rated.

The Z rating has been subdivided in recent years. Z was just 149+, and that was it for a while. There's W and Y now. W = 168 and Y = 186.

In any event, the driveshaft was a limiting factor, the stock LS1 shaft can't handle much more than 162mph according to LPE.

All Goodyear GSCs are Z-rated, RSAs can be H-rated or V-rated.

Correct, and RSAs can also be Z rated.

I hate to get into the middle of a rev vs. rpm limiter argument but wanted to share something I've always thought strange.

I used to have a 1994 Lumina Z34. It was an automatic and once hitting around 120mph the car would shift into fourth gear and stay at the same rpm & speed no matter how much you pushed down on the gas pedal.

I eventually discovered that if I put the car back into third gear, I could run all the way up to redline until fuel cut off which was so obvious around 135mph. A few mph drop and the engine would turn back on but shift into fourth at any point and the car would slow down to 120mph . . .

I've never understood limiters because of this. Stuck at 120ish in overdrive but fuel cut off deep into redline around 130s? Was this drag/gearing or rev/speed limiting?

I hate to get into the middle of a rev vs. rpm limiter argument but wanted to share something I've always thought strange.

I used to have a 1994 Lumina Z34. It was an automatic and once hitting around 120mph the car would shift into fourth gear and stay at the same rpm & speed no matter how much you pushed down on the gas pedal.

I eventually discovered that if I put the car back into third gear, I could run all the way up to redline until fuel cut off which was so obvious around 135mph. A few mph drop and the engine would turn back on but shift into fourth at any point and the car would slow down to 120mph . . .

I've never understood limiters because of this. Stuck at 120ish in overdrive but fuel cut off deep into redline around 130s? Was this drag/gearing or rev/speed limiting?

You couldn't go faster than 120mph in 4th gear because you simply didn't have enough gear to keep the rpms higher in the powerband, so the car couldn't fight the aerodynamic drag. When you held it in 3rd gear manually, your car had the benefit of better torque multiplication at the wheels due to the direct drive property of 3rd gear as opposed to the overdrive property of 4th, and the rpms were at a better point in the powerband to fight the force of the air. When you would wind the car out in third gear to redline, that is rev limited. When you couldn't pull any further in 4th gear, that was drag limited.

I hate to get into the middle of a rev vs. rpm limiter argument but wanted to share something I've always thought strange.

I used to have a 1994 Lumina Z34. It was an automatic and once hitting around 120mph the car would shift into fourth gear and stay at the same rpm & speed no matter how much you pushed down on the gas pedal.

I eventually discovered that if I put the car back into third gear, I could run all the way up to redline until fuel cut off which was so obvious around 135mph. A few mph drop and the engine would turn back on but shift into fourth at any point and the car would slow down to 120mph . . .

I've never understood limiters because of this. Stuck at 120ish in overdrive but fuel cut off deep into redline around 130s? Was this drag/gearing or rev/speed limiting?

I think what RussStang said is correct.

Now for some random Lumina/Grand Prix/Cutlass 3.4 DOHC trivia: I had a 95 Cutlass Supreme Coupe 3.4 "Twin Dual Cam" (pretty much the same as your Lumina Z34) - and I recall it having a speed limiter somewhere around 130 to match the H rated tires it came with - as well as a rev limiter. I don't know if you remember this, but if it was like my 3.4 cutlass, it also had a unique, lower rev limiter in park - of something like 2500 or 3000 rpm. Interestingly, not in neutral. And, it had a speed limiter in reverse - you could only go about 20 or 25 mph in reverse before you hit it.

You couldn't go faster than 120mph in 4th gear because you simply didn't have enough gear to keep the rpms higher in the powerband, so the car couldn't fight the aerodynamic drag. When you held it in 3rd gear manually, your car had the benefit of better torque multiplication at the wheels due to the direct drive property of 3rd gear as opposed to the overdrive property of 4th, and the rpms were at a better point in the powerband to fight the force of the air. When you would wind the car out in third gear to redline, that is rev limited. When you couldn't pull any further in 4th gear, that was drag limited.

Its hard to imagine that is true. My civic, while not a chevy was limited to 100mph in 4th gear. The RPMs would stop increasing, but if you knocked it down to 3rd you overcame the speed limiter. Once past the 110 mark then back to 4th and the RPMs would now increas in 4th and keep going to 125 130 if you had the road, but thats usually when I ran out of road. But the limiter was completely overcome. I think what is more likely is that the programming for the computer is that if the car is in fourth AND once you hit 120 you get no more fuel. Especially if you step down more on the gas and arent getting more RPMs.

So it sounds like my Z34 had no limiter at all. Fuel cut off point and rev limiter are two different things right? I know what it's like to bounce off the rev limiter in my 6-speed Camaro but I've only had the fuel cut off a couple times. When fuel cut off in my Lumina it was deep into redline way past normal shift point.

hmm.. the rev limiter works by cutting off the fuel.. i don't think there are two different things.

Speed limiter cuts off the fuel, too

Guess I don't know what to call the difference but when I think of rev limiter I think of bouncing between a couple hundred rpm constantly hitting that 'limit' until you let off the gas. When I think of fuel cut off, I think of the engine shutting off entirely for a few seconds before coming back on at least a thousand rpm lower.

So it sounds like my Z34 had no limiter at all. Fuel cut off point and rev limiter are two different things right? I know what it's like to bounce off the rev limiter in my 6-speed Camaro but I've only had the fuel cut off a couple times. When fuel cut off in my Lumina it was deep into redline way past normal shift point.

If your car had a speed governor, it sounds like you never reached it. In third gear you were bouncing off of the rev limiter, and in 4th gear your car couldn't fight the wind with the power it had.

CD is a strange thing, because you can't look at something anymore and tell how aerodynamic it is. I was shocked when the last generation Seville came out in 98 and it's CD was .30, i believe. How could it be lower than the 4th gen Camaro? It was just as shocking how little the aero was improved from the 3rd gen to 4th. That stupid windshield for nothing! Although the 4th didn't blow around as much on the highway. As far as the handling, I owned two Irocs and they felt much lighter, better handling than the 4th gen, but eventually i realized i was taking curves just as fast in the 4th gen, but with more body roll and a smoother ride. So although the 5th gen doesn't look real aerodynamic, with wind tunnel work it might be. It does look more aero than the new Mustang.

camaro
LS1 .34
LT1 .32

LT1 firebird .34
convertible .36

third gens have around the same #'s both camaro and firebird.. can't find any hard details on that though (firebird and camaro about the same).. the newer the lower the CoD, though.

C6 is .28

mustangs:
94/95 is .37
whereas the late 80s'/early 90s Mustangs are about .41


Those are from google searching, and those numbers appear quite a few places.. take them with a grain of salt, though, to get the taste you want


I thought 3rd GEN camaro's and Firebird had the BEST aero for top speed?? You see them on the salt flat races alot. Of course the camaro has the headlight cover to AID in Aero

I thought 3rd GEN camaro's and Firebird had the BEST aero for top speed?? You see them on the salt flat races alot. Of course the camaro has the headlight cover to AID in Aero

I would think one of the main reasons you might see a third gen out on the salt flats is because third gens can be had for so cheap nowadays. Save money on the car, and put it into the drivetrain.

IIRC, Irocs were .34

I'm no expert, but, it isn't just the "frontal area" alone that affects drag. The shape of the frontal area, slightly rounded from top to bottom, and from side to side, will change numbers quite a bit. As well as being longer, or a length to height ratio, lowers drag a little too. Even the width of the tires...from what little I've read.
Most of us will never top 150, even at the strip, so I think it's not much to worry about. Hardcore speed-junkies will probably do a lot more mods to run high speeds, so some body reworking wouldn't worry them either.

Since this argument is still going, here's some more information for those of you curious about high top speeds. From what I understand there are many more complications to increasing a 4th generation Camaro's top speed than there are to the 3rd generation.

http://racingarticles.com/article_racing-21.html