I don't see how it is a joke it a $25K car. 99.999% of the people driving those cars can't tell the difference anyways. I'm sure most would rather save a few grand and get the HV with more low end torque and better gas milage thanks to VVT and DoD.

 

Well, first, the correct term you're looking for between the transmissions is not rotating mass, it's moment of inertia, moron.

In the absence of data to show the relative efficiencies of the two drivetrains, 15% is a pretty good number to use.

The difference here is, yet again, you don't know what the hell you're talking about and are attempting to educate some who does.

Now, go take a regular old algebra-based physics class and learn something.

Alternately, if you don't like the "rule of thumb" number we could power the two drive trains with an electric motor and get an efficiency percentage that way... but that'd be a little bit expensive (two drivetrains, instrumentation, etc...).

So, when did ya run this test Booby? Until you do, we'll just have to take the 15% and go with it.



There are about a half a dozen variables that could effect those times that I can think of off the top of my head - DA, warm-up technique, wind, track temperature, Cd, etc....

Now Booby, since you actually wouldn't know me from Adam, I suggest you either turn on your frontal lobe, or find someone else to play with. If you need to be stroked Booby, I imagine you could pay someone to do it for you - as long as she had LOW standards...

 

I'm sorry sir, I did not use the correct term. Thanks for correcting me.

Do you get a kick out of calling people "morons"? Bet you're quite the asset your company....being the intellectual you are.

And you base this on....what? Internet gossip? Such poor standards for such a respected injuneer. This is especially true after said injuneer makes statements such as....

E-gads, shouldn't you should be ashamed, making such an assumption with no data, yet expecting those that work for you to do exactly what you did not? Wow.

I can show you back to back dyno's of two different street trannys that showed a ~4% difference in RWHP. Guess real world doesn't count? Unless it's your real world, perhaps?

Those who believe themselves to be superior are typically the last to find out how much they lack, but I digress.

Regardless, if you wish to believe incorrect assumptions because they help you make a silly point on the internet, that's your problem, not mine.

No thanks. I'll leave textbooks to folks like you. In the meantime, I present actual, verifiable data.

Or use test data from real racers (vice the magazine/internet types) that have done actual testing.

Here you go, kind sir:

Street Tranny A
Street Tranny B

Same car. No changes except swapping a T45 for a 3550/TKO. The T56 is heavier than the 3550 - wonder what it would do? Has a different design, too. A T5 (like I currently have) is lighter than the T45, and showed a 4 RWHP increase over that tranny. Do some math (no injuneering algebra required) and you can easily get a 5% difference - with the same car, by only changing the tranny.

Great rule of thumb you got there Mr Pacer sir. I suggest that you continue to use it.

No kidding? But your statement was blanket. Shall I repeat it? Sure....let's repeat it....

"Spot any driver worth a damn 40hp in basically equivalent weight cars and you'll lose."

BTW, the "top of your head" missed the two most important factors (directly related to each other), but surely you know....being superior and all....you just didn't type it out. Share em with us some time, if you decide to stoop to such mere mortal levels again.

Hey, that's original! Did you think of that one all by yourself? Does doing that make you feel big? Smart? I bet it does. Congratulations. You deserve a brownie.

I shall take your suggestion under advisement.







No. Next.

Wow - you're on a roll! Perhaps you can teach the boys over at ricer.com a thing or two about witty comebacks?

You have a wonderful day, and kindly continue to race the internet and magazines, and continue to talk down to those of us that don't meet your high standards. I enjoy the fodder it provides.

 

Welp, seems you need the help since it's pretty easy to design two objects with the same rotating MASS, but one is TWICE as hard to accelerate as the other. Betcha I could make you faster Booby, just by designing your driveshaft to within a hair's breadth of failure.

The mass may not go down, but the diameter will - and your drivetrain will get more power to the ground.

The problem with your point wasn't that you used the wrong term. The problem is that you don't know what the correct term IS and MEANS, and how to apply the concept. Yet you want to argue about it...


Just you.


Awwww, thanks. I appreciate your concern for my employer.


Lots of stuff to base it on, and never stated it was a hard and fast rule, but an ASSUMPTION - a "Rule of Thumb". I also INTENTIONALLY used the more conservative method of calculating it than the other one available.

Now, your proposed test method has flaws, which is why an ELECTRIC motor would be used, since it is far easier to instrument and eliminates variables. All you need is current draw and RPM as long as voltage is held constant by the power supply. You'll get a repeatable number then.

All that being said, there ARE drivetrain experts out there, and you aren't one of them. Alternately, neither am I. So, in the absence of their input, I'll stick with the 15% for now and call it exactly what it was - a RULE OF THUMB.

Do you think dynos are accurate to +/- 1%? Do you think you can hold all of the variables present to within that tolerance. +/- 1% on a 400hp motor is 8hp... Now, you can statistically get a trend by continuing to A/B the test, but the precision and accuracy of the test rig used is such that any gain that small HAS to be questioned.

Furthermore, I highly doubt your ability to hold those variables constant and run the test in question. ESPECIALLY since within your OWN CURVES, run BACK TO BACK, the hysteresis is pretty considerable. At 5000rpm on the second run (roughly 2 minutes after the first run), you've got better than 5 rwhp difference WITH NO CHANGES WHATSOEVER.

Do the two transmissions in question use the same driveshaft?


Dynos vary, even from running the SAME car back-to-back. What's the hysteresis of the dyno in question? I'll bet that alone eats up a large part of your 4% number.

Go look up hysteresis in the dictionary and get back to me.


Blah... knowing WHY something is happening is far more important that WHAT happened. Which is the step you missed.


I stand by that statement. Eliminating the variable of the driver, that horsepower difference is enough to require vast differences in other parts of the equation to overcome.

Tell me, in your type of racing, would you surrender 40hp to every person you run against and expect to win? No. In certain racing classes with far more horsepower on the table than yours, folks spend VAST amounts of money to make 5hp more - let alone 40.

From your site, look at the mess you went through debating over 13rwhp:

"Once back home, I decided to put the car back on the Dyno with the T45. The results were not good - on the same dyno that I had run with the TKO, I picked up 13 RWHP over that tranny. What does that mean? I have choice - the reliablity of the TKO, or the extra 10-15 HP of the T45. I chose the T45. However, knowing that the input shafts WILL break, and likely sooner vice later, I have taken steps to prevent that. First, I installed an aluminum flywheel, hoping to reduce the initial shock on the driveline. Second, I had 2 input shafts modified. Ian Mullane polished the area where the splines neck down to the smaller diameter of the shaft. This was to remove the 'stress risers', which is about the place that each of my driveshaft failures had occured. Next, they were shipped off to 'Extreme Thermal Cycling' in Michigan for heat treating. I just got them back and installed yesterday. The NMRA Reading event in a few weeks will be the first test. Hopefully, things will come together, and I can put on a good show."

That was only 13rwhp and look at the expense. Heat treatment, special machining, an aluminum flywheel...

Now, you're claiming you'll spot the folks you run against regularly regularly 40???? Tell us, what did that ~13rwhp cost you?


Hold the nuts please - and I prefer frosted.

 

The 4.6 Dohc is up there with the big blocks in size and weight, even with all the aluminum. The all-iron 5.0 is a small lightweight in comparison. I too was blown away after seeing the pics. The Dohc 4.6 makes the 5.0 look like it came off a midjet car.

I can't come up with a good reason to kill the windsor engines, but it looks like they're begining to put out some killer numbers withg the modulars. I'm sure the next Cobra will be monstrous, and the little GT's 3v'er looks to be impressive. I just want them to get a 350-400hp N/A 5.4 Dohc into the lineup. Given the right power/tq, i can overlook their size and weight.

 

You do a good job of quoting only selected pieces of my reply. However, even then it is simply a poor attempt at trying to convince somebody else (obviously not yourself) that you have some fabulously extensive and obviously far superior knowledge of everything (or at least this thing) automotive. Nice try. Once again though, I'm going to ignore your advice to "find someone else to play with" and have a little more fun with you. Ok? Cool. Let's go....

BTW...this will be in two replies.....just one is too long to answer all your jibberish.

Who said anything - at all - about twice as hard? I was simply pointing out - correctly - that your blanket use of 15% was easily disputed and proven to be quite inaccurate. I further explained that an injuneer with such high credentials as yourself, who obviously holds his/her employers to such hard standards, such as having actual data to back up their assumptions, does not look too good when they then make baseless assumptions.....ooops...I mean "rules of thumb" to back up their assertions.

Tisk tisk.

You, make me faster? Bahahahahahahahahahahahahahahaha. That has to be the funniest thing you've said in this post.

BTW....the driveshaft is a very small part of the rotating mass in my car. Good luck picking up any measurable HP. Been there, done that, got the test results (vice physics books). Go look up "class racing" for a clue.

See above, please.

I'm quite familier with what it is that I'm argueing, and I think my "terms" did fine in stating my results and conclusions.

Assuming is not a real good thing to do sometimes...your assumption that I don't know what something "IS" or "MEANS" might make you feel better, but it is quite foolish. I'll let you find out how.

Ah. Isn't that special. Thanks.

LOL. I have little concern for you or your employer. Sorry.

Hmmm.....and you know it is more conservative because........what? More internet gossip? Show some data, or your 15% is worthless - or worse.

Proposed? Bzzzzzzzzt. Wrong answer - there is nothing "proposed" about it. I've offered data - verifiable data. You've offered a baseless assumption. Amazing.

I have no issues with that. Got the data?

Cool. Got the data?

Never claimed to be. If I did, please go back and quote me. However, unlike you, I back up my claims and assertions with data. Know what I mean, Vern?

Good for you, and when the opportunity presents itself, I'll repute such "RULE OF THUMB" assumptions, and then provide the evidence to back it up.

If one is careful, 1% - on the same dyno - isn't out of the realm of possibility. Seen it many times. I've dyno'd within 2 HP several times, back to back, within minutes of each other. Usually less than 1 HP. With ~300 HP, how many percent is that? Bueller?

Ya, I think we can. In fact, we have.

Come again? 8 hp is 1% of 400 hp?

I question everything. I class race - I HAVE to question everything if I wish to go faster.

This is a direct contridiction to what you have displayed...ie..."rules of thumb".

And it bothers me that you doubt something that I do? LOL. Ya.

Quite true - which is a bit over 1%. See statement above.

Yup. But you know what, magazine-racing internet boy? I've dyno'd different driveshafts (ie...different weights and diameters), back-to-back, with virtually no changes in documented RWHP.

Perhaps you can show data that shows something different? If so, please do. Please.

Continued below....

 

No arguement there. However, much of that variance can be mitigated by using the same dyno, with the same instruments, the same operator, and the same procedures.

Have you ever dyno tested a car? More than just watching someone spin the rollers? Ever done any real dyno testing? I doubt it - but who knows.

Eeewww....Mr Injuneer picks out the big words from his book and tries to make himself look big and superior. Must be the type of car you drive. Yup, that's it. Let's see....

Hysteresis - The lagging of an effect behind its cause, as when the change in magnetism of a body lags behind changes in the magnetic field. www.dictionary.com.

I'm sure a "lagging of an effect" has a lot to do with this case, being a mechanical, direct linkage and all.

Ya, that's it.

LOL. Know both is even better. So tell me, why is it that one tranny ate up more power than the other? I know what happened, and have a pretty fair idea of the why, too. You can only assume on both issues, as you've never conducted the test, nor do you likely have much insight into the inner workings of the TTC 3550 or T45.

BTW....TTC sponsors my car. Great guys. Why don't you go ask them?

No surprise there. The statement is false and baseless, but one must stand behind something.

You don't do much drag racing, do you? Bet you consider it a 'redneck' thing, or something similar? Far below you, no doubt.

If it were that easy and black and white, many other things that you fail to mention come into play.

ROFLOL. Do you have any idea how funny that is, coming from you and pointed towards me? I race in a HP restricted class, Mr Injuneer. 5 HP is a HUGE gain in my class. Tell you what...turn on ESPN2 at 11 am (EST) on May 2nd and get a very small education on what I do.

It's called class racing on my part, and being clueless on your part. That fact is likely lost on you, however (go look up 'clueless', as you are likely too high and mighty to have ever been labeled such).

Bzzzzzzzt. Incorrect assumption. In my first post, I refuted your claim with examples. Those two cars are both LS1s...I'm afraid I don't "regularly regularly" race them.

A bit over a tenth and 1 mph - on average. But if you're talking cost, well, that is why TTC was a sponsor. Know what I mean, Vern?

Got a mirror? All your requests wil be answered.



Appreciate the reply. Great fun. Kindly forgive me if it takes a while to get back with you on your next diatribe. I have to fly across the country this afternoon.

 

Nice novel Bob

 

Oh man, I cant believe Bob took the time to write that response. I believe this one is done...

 

1) Do I own a dyno? No.

2) Have I done dyno testing? I've had my car tested repeatedly, and been there for it, and know enough that it takes considerable effort to ensure repeatability from run to run ON THE SAME CAR WITH NO CHANGES. Mine has run from baseline with no mods up to the bolt-ons. The latest round of mods will be tested again when finished.

I've also conducted tests using other types of dynomometer on my own (electric motors), same concept, but far less complicated.



That's good Booby, you can use a dictionary. So, what's the hysteresis on the dyno you're using?


Not knowing the design of either, I'll decline that one. Feel free to educate me here.



Wipe your chin. You'll mess up your keyboard if that stuff hits it.


Actually, it's the only type of racing I do. As I actually have a job, I'm precluded from doing it as often as I like, but still do it. Best time while dead stock was a 13.1@108 at M7 - not a bad time for a full book SS with 1400 miles on the clock. Proceeded to the low twelves last year on the stock rear end and tires with bolt-ons, and am rebuilding the machine as we speak... considerably more powerful than low 12's this time around, and no "glass-jaw" 10-bolt to worry about.

Am I a professional? God no. I do enjoy it though. Will I ever be? God no. Do I want to be? God no. Won't take the pay cut.

Having just bought a decently fast motorcycle, I'll run that around the twisty tracks and see if I enjoy it this summer while the SS works it's way down the mod path.


Booby, I've already seen at least one of your wins mentioned on Speed - saw the film of it too. Great. Have a cookie. Being a class-winning idiot makes you no less of an idiot.

The question still exists:

Is 40hp enough to allow someone in your class to dominate everyone else? And the answer would be "YES". Spot your competition 40hp if you think otherwise and let's see how you do.

Either do that, or shut up. You know the answer, and so do I. 40hp, all other things being equal, would allow someone to dominate your class.

 

*grabs popcorn* .

 

I was reading Motor Trend or C&D and there was an editorial on Pushrods vs OHC. The author interviewed a drivetrain engineer at GM about the advantages and dissadvantages. In a pony car or sports car where NVH is less of a concern the pushrod engine won 99% of the time. It's only when you need a really smooth engine is DOHC really needed on a 2V engine. On a 4V engine it had some more benifits but not many due to the packaging and weight penalties.
The fact is it takes less hp to turn a pushrod OHV 2 vavle engine vavletrain than it does to push the vavletrain on a 2 vavle OHC engine. The packaging is a lot better, it weighs less and there's really no advantage other than smoothness to OHC.
The 4.6L ford is a square engine meaning the bore and stroke are the same. The 5.4L ford is a tall deck 4.6L essentially with a taller deck so it can have a longer stroke meaning it's under square. That's a bad design even on a 4V engine since it shrouds the valves and decreases maximum rpm, which is one of the things a 4V DOHC engine should take advantage of. The mod motor is a disaster of an engine if you ask me. The physical dimensions, weight, efficency, are all compromises on the DOHC's design strengths. Sure the engine has proven itself, but you can overbuild almost any engine to endure race conditions. Like the moutain motors that have huge stokes, it can work but takes a lot of over building. It's strange that Ford went with DOHC since their engines don't take advantage of the benefits of DOHC like extended rpm. The LS6 revs to 6600rpm, while the Cobra only USE to rev to 7200rpm. Most performance DOHC engines in other cars rev much higher than that, especially small displacement engines like the 4.6l.

GM also built a 4.6L V-8 called the Northstar that was making the same hp long before the 4.6L came to the Mustang. It also did it hooked up to an automatic which is a little harder to do since Ford had to detune their 4.6L DOHC when coupled to an automatic. GM was smart though and only made the engine for customers so that their cars would have "precieved" refinement and luxury. They kept the real OHV engines for their true performance cars.
It's worth noting also that the DOHC design was actually invented before the OHV design. So technically OHV is newer technology and DOHC is the old technology.

 

Halfway through mine!

 

Stop the fighting, boys!

to PacerX, I like his method of thought.

Though I don't think anyone has earned the right to throw the: flag just yet...

 

I would like to point out that when Dave Hill came over to Team Corvette from Caddilac he wanted to use the N* in the C5 but he got convinced for the C5 Corvette that the LSX based Pushrod motors were better for the car. He did kinda get his way with the XLR since it is Corvette based and has the N* motor.

BTW the N* did almost have to go into the C5 because the aluminum LSx series motors weren't being produced correctly because of all the new technologies. The C5 had the N* as its contention plan just in case the LSx motors weren't ready. As it turned out the N* wouldn't have fit without major reworking, it was just to darn big.