BIGRED1, I didn't say that his times or dyno numbers were bull. The whole point of what I'm saying is that I doubt that the internals are stock.

About Chuck Yeager's supersonic flight: I guarantee you that more than half of the government's scientists and engineers agreed that it could be done, and done safely, otherwise they would not have built the plane or allowed him to fly it.

I just choose not to blindly accept everything that people tell me.

I know that TurboSpeed is not going to drive his car down here, run it, and tear it apart. That's why I said he "can not practically prove to me" that what he is saying is true, so don't offer up bets.


About the Turbo vs. Supercharger debate:

Turbo's have more ultimate torque potential and superchargers have more ultimate hp potential. Many drag cars are quicker with turbochargers because the motor spends alot of time below peak hp rpm.

Mike

 

At one point is was thought that the stresses of going of 67 miles per hours were too much for the human body to handle. You are right, I'm not going to drive it to Louisiana to prove to you that my engine is internally stock. But I'm not the one calling somebody a liar either. You can come up here and I'll tear it down. It's not a bet, in racing circles it's called a tear down fee. I don't have to bet you my car has a stock LT1 minus the mods listed in previous posts. I know what the car is. You can come up, I'll demonstrate my cars performance, then tear it down. Tear down fee, 10 thousand dollars. Anything less is a waste of my time. But if you are confident enough to flame someone whom you have never met, with whom you have had no previous interactions with, you have no risk then do you? Seems to me you stand to loose credability either way. If you don't like being called out, perhaps you should consider taking people at their word especially when they have nothing to gain by lying to you.

BTW, as previously stated, my calculations are based on 10lbs not 11lbs of boost.

How do you figure this? First of all, it's not superchargers vs turbochargers, it's centrifugal compressors vs positive displacement compressors. Turbochargers as well as all superchargers commonly used on 4th gen Camaros are of the centrifugal variety. How you drive the same compressor does not change it's efficiency. It is also known that positive displacement superchargers are significantly less efficient that the centrifugal types. Less efficiency means less density which means less horsepower and torque.

NHRA banned turbochargers for the same reason they limit the CID of the engines; to keep the cars slower. They can't use the power they are making now which is why they have I believe 6 clutch discs designed to slip during the first 2.8 seconds on the run. Beyond simple efficiency, they stand to gain 600+ horsepower by using turbochargers vs superchargers simply by taking the load off the crank. If you've ever seen them run under the lights, you will see there is plenty of exhaust energy to spin the turbochargers.

The same compressor on a turbocharger will make more peak horsepower than on a supercharger because there is no drag on the crank. Turbo lag can be all but nullified on a well designed system especially on a 5.7lt engine.

 

ok, i'm no enginneer or huge math guru

BUT

that doesn't make sense above for a few reasons to me. 1) is that hp is just a mathematical equation driven from torque at a certain RPM. So if turbos are going to create more torque they will in turn (because of the formula) make more horsepower. 2) you have to lose horsepower from driving the blower, you lose VERY little from driving a turbo.

but thats just my humble opinion

 

like i said.......if turbos had been allowed the whole time, they would have spent just as much time advancing the capabilities of turbos, and they would be supporting way more power.


building boost exponentially is better than boost linearly

 

LOL...maybe, but not for traction hehehe

 

TurboSpeed, if we're going by dirt track rules, let's make it a claimer fee. I'll pay you $500 and you give me your motor.

If we're comparing centrifugal compressors to PD compressors, then I'll be the first to agree that the adiabatic efficiency of the centrifugal is far greater than PD. As part of my senior design project, I measured the efficiency of a B&M 144 PD blower and found it to be a lowly 38%, compared to 70+% for centrifugals. I'm sure, though, that the larger PD blowers have higher efficiencies, but I doubt they get up as high as 70%.

As far as losing hp to drive the blower -- that's not entirely true. It does take hp to drive any compressor, however, that hp is put back into the crankshaft in the form of positive cylinder pressure on the intake stroke. This positive pressure helps drive the crank. But, on a turbocharged motor, there is positive pressure in the cylinder during the exhaust stroke also (at least as much as on the intake side). So, if you're running 10 psi boost, then there is at least 10 psi in the cylinder on the exhaust stroke working against the crankshaft.

Mike

 

89ProchargedROC, the equation for hp includes rpm. A turbocharged engine will make a larger peak torque number in the mid-range because it will make full boost at a very low rpm. The '86-'87 Buick 3.8 turbo motors made peak torque at 2000 rpm since they would build 12 psi by this time. At 2000 rpm, a centrifugal supercharger is doing little or nothing.

However, at, say, 6000 rpm, a centrifugal is making full boost. And, as I stated above, parasitic crankshaft losses are a moot point. A centrifugal supercharged motor benefits from better exhaust scavenging since it's not working against the high header pressures in a turbo motor.

Don't get me wrong, if it weren't for the complicated plumbing associated with a Turbocharger, I'd prefer that over my Vortech T-trim. If you set up a turbo and a supercharger to both run 12 # of boost, the turbo will make 12 from one end of the strip to the other and the supercharger will only see 12 psi for a few moments inbetween. My T-trim makes 9 psi peak, but spends alot of time at 7 - 8 psi.

Mike

 

from what i understand.....the issues with exhaust pressure can be almost made non-existant by properly matching the exhaust turbine and to the engine/setup.


bwahaha.....traction....whats that?

 

Mike, I am curious. What internals do you claim he must have? Lower C/R pistons? Different Cam? Ported heads? Where does it stop? If he takes the heads off, and they are stock, then would you claim the cam? Ok, he removes the cam and its stock, then what, it must be a stroker? I know for a fact my friends stock internal (NO HEADS/CAMS) 96 Slowbra put down 499.6 on an s-trim w/15psi, non-intercooled. He eventually cracked the block, but it did it. Those cars make about 230 rwhp stock. Guess he's a liar too, huh? I don't see why its so hard to believe, unless you are just dissapointed in the performance of your car. I don't blame you, because after we cracked the block in that cobra, we put in a 94 5.0 stroker motor. A4 block, ported canfields, forged everything, huge intercooler, ATI D1, etc. etc. Guess how much power? A whopping 590 rwhp. Woo hoo. All that money and work for 90 rwhp? It should be making 750 at least, but the D1 is just too small. I think you would pick up a good bit of power if you switch to a YS-trim. Isn't that a bit bigger than a t-trim?

 

The post that spans two years (and it really feels like it). It just keeps going and going. Might wanna lock this one and post more on the set-up later. This post is getting less and less productive. And I didn't hear anyone say this was about dirt tracking, but then again I may have missed it. I think if it was torn down, and everything looked stock, we'd still have people say it's impossible. We'd have to measure the track to see if it's a true 1/4 mile, recalibrate the dyno, check for hidden nitrous set-ups, see if the car was acid dipped for lighter weight, check the backyard for an exact look-a-like of TurboSpeeds car hidden under a tarp, guarded by ill tempered sea bass, motion detectors and furbie with fazers set on stun. The truth is out there... It may not be exactly as we imagined it, but it's far from impossible.

 

got_hp,

the exhaust backpressure on a turbo motor IS ALWAYS greater than the intake boost level. It is physically impossible to produce 10 psi boost with <10 psi exhaust backpressure. Most turbo-knowledgable sources (David Vizard, for one) say that actual backpressure is roughly double the boost level. For instance, it will take 20 psi exhaust header pressure to produce 10 psi boost. You can minimize this by properly matching the turbine to the motor, but, at best, backpressure will be more than the boost level.

Big Red,

You're right about the productivity of the thread, so I'll stick to the science (as I have been) and leave the mud-slinging to others.

brain,

I may gain peak horsepower with the YS, but I'd sacrifice some low-rpm boost. And since I am only running a 2800 stall, I need all the low-end I can get, hence the small cam. I carefully analyzed the compressor maps on Vortech's website before selecting the T-trim.

Mike

 

Then why do I see that turbo's are getting more horsepower capabilities than superchargers lately...

A long time ago, I always noticed that boost for boost, the supercharger yielded higher horsepower than turbo.

I do understand that you get full boost sooner with a turbo than a supercharger so the turbo will leave you with a faster feeling that supercharger, but when you are racing, you are almost always under full boost??

I remember I saw on my crapxton 5psi from 4000rpm up to 6000...

 

Wrong again. You considering the pressure in the cylinder to be linear. It is not...
To quote Hugh MacInnes...

Many People think this exhaust-gas energy is not free becaue the turine wheel causes back pressure on the engine exhaust system. This is true to a certain extent, but when the exhaust valve first opens, the flow through it is critical. Critical flow occurs when the cylinder pressure is more than twice the exhaust-manifold pressure. As long as this condition exists, back pressure will not affect flow.

When an engine is running at wide-open throttle with a well-matched high-efficiency turbocharger, intake manifold pressure will be considerably higher than exhaust manifold pressure. This intake manigold pressure will drive the piston down during the intake stroke, reversing the process of the engine driving the gases out during the exhaust stroke.

During the overlap perioud when both valves are open, the higher intake-manifold pressure forces residual gases out of the clearance volume, scavenging the cylinder. Intake-manifold pressure as much as 10 psi higher than exhaust manifold pressures have been measured on engines running at about 900hp. Good scavenging can account for as mch as 15% more power than from the increase in manifold pressure of the naturally aspirated engine.

I guess I am thankful I didn't have your instructors while in pursuit of my engineering degree. I've never known someone calling themselves an engineer to have such of an "it can't be done" attitude. I guess that's the difference between success and failure.

The science has proven this correct several times. Less we forget the scientific method. Also, if I recall, you were the one on here saying I'm lying about this. Without refreshing my memory by reading my first post, I believe I was posting the results of further testing of the car. Yes, in fact it was you who started the mud slinging.

Oh and btw, in dirt track circles, if you called BS on someone, then told them you were going to give them 500 dollars for their engine, they would either laugh at you or knock that "engineers" hat off your head. In the two years I raced on dirt tracks, you didn't call BS on someone unless you damn well could back it up. I've found you greatly amusing which is why I offered you a tear down. Come on up, unless you don't want to loose any more credability than you already have.

Amusing as it has been, I've lost interest as it has become repetitive. You are going to just keep repeating your fuzzy and incomplete mathematics that prove nothing. There are a few of you that want to call me a liar and I guess that's your right but I also have the right to overlook you. I can see that those interested in following how this system progresses are getting tired of the flamers and my responses to them. The supercharger vs turbocharger debate is an issue worthy of it's own thread. So I have some more testing to do on some bug fixes. As I get results, I'll let those interested know how things came out!

 

I was gonna post, but turbospeed took care of it

 

so i was right?.......having a properly matched exhaust turbine helps negate the backprese issue?