Guys, it's simple...in a race car, it's all about hp...torque isn't even a consideration. Ask Warren Johnson how much torque he makes and he'll laugh...he may not even know.

F1 cars make maybe 300 lb ft of torque but over 800 hp from something ridiculous like 2.5 liters...they also turn over 18000 rpms. A motor is just an air pump...and the more explosions, the better. For you to prove me wrong would mean proving every top race engine builder in the world wrong too. They all build motors for hp and not torque.

 

3 liters Patrick, and the top teams are going over 19k now with bore:stroke ratios near 3:1 <img src="gr_eek2.gif" border="0"> If you only run 18k you'll probably finish between 10th and 5th in an average race.

J.

 

With only the info provide, if your concern is 1/4 then torque is the winner. If your interested in top end,then Hp is the victor.

 

That's a ridiculous statement to make. Torque does not win you the quarter mile. If it did, we'd all be racing turbo diesels making 800 lb ft of torque and 150 hp to win the 1/4. <img src="images/icons/rolleyes.gif" border="0">

I'll state it again:
440 hp at 6500 rpms beats a 440 hp motor making peak power at 6000 rpms providing you gear both to make the best use of maximum horsepower over the 1/4 mile. It's simple...when given the same peak hp, he who makes the most explosions by the end of the 1/4 mile wins the race.

 

http://www.speeddemonmotorsports.com...torquevsHP.htm

 

Patrick,

Warren Johnson would NEVER run the 346 inch with 440 hp he would run the 400 inch with 440 hp because it would almost certainly average more power and he could run a more efficient clutch, and he'd have more hp with the 400 like any good engine builder would as well. I agree with you that all else equal hp always wins or at least average hp. The fact is that the larger engine will have more hp almost every time as well. Warren Johnson doesn't run a 450 inch pro stocker so he can turn it 10,500 but rather runs a 500 incher at 9,500 so that should answer your question. You neevr give cubic inches away! There's also NO 2.5 liter Formula 1 engines they're ALL at the MAXIMUM cubic inches because in ALL racing CUBIC INCHES RULE, even F1. This is a fact. <img src="gr_images/icons/cool.gif" border="0">

The only exceptions are bracket racing where it doesn't matter and they usually run huge engines as well for reliability and in COMP or other HP per cubic inch classes where you have to carry more weight if you have a bigger engine. In these COMP classes you will see tiny high rpm mini mee turd engines that would get their *** whooped if they had to run with the big ones at the same weight but they get huge weight breaks so there still fast. I respect these builder immensely but the engines can't compete with the larger ones. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

 

"if your concern is 1/4 then torque is the winner."

No, think again. AVERAGE HP TO THE GROUND over the course of 1320 ft is what wins races. That doesn't necessarily mean who has the highest peak TQ.

 

[quote]Originally posted by Crazyquik:
<strong>Yup, definently LS1 oriented. Trust me, I am far from wrapped up in peak numbers (I would have got an M6 if I were <img src="gr_images/icons/wink.gif" border="0"> )

J.</strong><hr></blockquote>

Just curious, is this purely theoretical, or is drivability a factor in your choice of engine & drivetrain combos. In an unconstrained set-up, I agree that HP rules. For a daily driven LS1 with constraints on the maximum stall and gearing, a torquier combination may be faster because of its 60' ability.

 

COLONEL, your explanation about high Hp needing more gear multiplication isnt exactly true.
Testing on the same vehicle, more hp means more mph, which in turn means gear selction is limited to max rpm at end of 1/4 mile. Example: 4.10 best gear for no adder car ,add NOS and rpms go too high when extra mph is reached in 1/4.

 

For this discussion I am talking purely 1/4 mile, with no regards to streetability.

I do think (maybe wrongly) there would be a point of dimishing returns with added hp though. With a very narrow powerband (lots of revs, not much torque) you might need 6 or 7 gears to make the most use of it. Even the 500 CI Pro Stock cars use 5 spds. Wouldn't it be better to make less hp, have a flatter curve, and have 1 or 2 less shifts to make (since you aren't accelerating during the shifts) instead of having 6 or 7 speeds?

[ February 02, 2002: Message edited by: Crazyquik ]</p>

 

[quote]Originally posted by Patrick G:
<strong>That's a ridiculous statement to make. Torque does not win you the quarter mile. If it did, we'd all be racing turbo diesels making 800 lb ft of torque and 150 hp to win the 1/4. <img src="images/icons/rolleyes.gif" border="0"> </strong><hr></blockquote>

Ok then why do A4's buy torque converters? Knowing we lose 5 - 10 horsepower but we gain nearly 80 ft pds of torque. Doing this we gain 5 tenths to a full second of E.T., and we have not increased the horsepower in fact we lost some. Torque is what E.T. is dependent on, and how it is distributed throughout the run. Horsepower gives you that trap speed, Horsepower maintains the car's velocity and acceleration.

[ February 02, 2002: Message edited by: BigBake ]</p>

 

CrazyQuick, this basic concept was tested in early 90's in ProStock, Wayne county was doing the broader torque curve thing with less gears, with good results against The Professor. Unfortunately with there NOS cheating we dont really know the results for comparison. In a Fbody comparison i think a peaky m6 would beat up on a broader A4 except on the starting line.
What do you think?

 

Just give you a little more food for thought. I have worked on turbo prop aircraft for quite a few years. This is a jet engine hooked up to a prop. The jet egnine turns at a 100% RPM at all times and produces 5,000 shaft horsepower at all times. But we only worry about 2 indications for flight, RPM and Torque. With the aircraft turning at 100% and all 5,000 shaft horsepower on tap we let go the brakes and the aircraft will get to a speed of 20 knots and that is it. But as soon as we apply the full torque which is 2300 ft pds the aircraft will accelerate to 325 knots, and then once we reached cruising speed you reduce torque and let the 5,000 horsepower maintain the speed. The device that is applying the torque is the variable pitch Propeller. Much like a troque converter except better, because we can vary the pitch of the blades, which varies the amount of torque applied.

 

BigBake,

Clearly you don't understand what high stall torque converters do for automatics. Basically, they slip the engine into a higher power range so they make more explosions for the same mph. It's the same as running more gear, but you are multiplying torque (and horsepower) with a fluid coupling and not gears. More power is put to the pavement.

Torque doesn't get you down the track because torque does no work. Horsepower does the work. An LS1 with an A4 and a high stall torque converter will spend a much greater time above 5000 rpms than an equally geared LS1 with a low stall converter. In a nutshell, you are putting down more average hp down the entire run of the 1/4 mile. You put down more hp by making more explosions from the starting line to the traps.

If torque got you down the quarter mile faster, we'd all be short shifting and allowing our motors to drop back to peak torque (4500-5000 rpms in most heads/cam LS1s). If you ever try this, you will find that you go a lot slower. Why? Because you were not maximizing the most of the hp band the engine makes. In most heads cam LS1s, that means keeping the motor between 5800-6800 rpms. If torque ruled, we would want to keep our motors between 4500-5500 rpms. Try both and see which one brings you a faster ET.

Repeat after me: High stall torque converters are there to slip the motor into a higher powerband quicker than a low stall torque converter. More rpms equals more power. Of course, you need the most efficient fluid coupling you can find to achieve this. That's why some converters lose more hp than others (when transferring power from the motor to the transmission). They are less efficient. Find a converter that will slip your engine into it's best power band while maintaining good efficiency and you will go faster.

 

"COLONEL, your explanation about high Hp needing more gear multiplication isnt exactly true."

I don't think I ever said that high HP needs more gear multiplication.

"a numerically higher gear than with the others, presumably,"

Here I was stating that I was presuming that a numerically higher gear would be used if geared perfectly.

"With the HP being made at a higher RPM you will be using a numerically higher ratio rearend gear"

Here again, I'm presuming that since we have less TQ but more HP, that it's being made at a higher RPM. I think it's very reasonable to presume that.

What I mean is that more RPMs enables us to use more gear so long as the increase in MPH doesn't outweigh the increase in RPM which shouldn't be the case in similar engines...one with higher TQ but making less HP and the other with lower TQ making more HP. You take two similar LS1s but one is making 20 more HP at a higher RPM and it will make better MPH (just as you stated) but not by enough to not justifiy more gearing.

Maybe I could sum it up to say that IN GENERAL a higher HP engine will make it's power at a higher RPM if it has a lower peak TQ. This will generally mean that more gear will be needed despite the higher trap speed.

Fair enough? <img src="gr_stretch.gif" border="0">

[ February 02, 2002: Message edited by: Colonel ]</p>

 

BigBake,

Your turboprop analogy is just like a torque converter analogy. When you flatten the blades on the prop, you have a very inefficient way of transferring power from the jet engine to the thrust generated by the prop blades. The most efficient prop blade angle is the one that produces the most thrust (which would also give the aircraft its maximum speed). A flat bladed prop would be analogous to a poorly designed torque converter...really bad efficiency. The reason for the variable pitch prop is to allow the jet engine to allow the jet engine to maintain peak horsepower at all times. Without it, a fixed blade prop would bog a jet engine down to a much less powerful powerband and acceleration would suffer greatly.

That's why cars need gear reduction (same reason).

 

"Torque doesn't get you down the track because torque does no work."

How many times do we have to say this??? If ya'll don't listen to anything else I've said in this thread, please understand this absolute F-A-C-T!

TQ DOES NOT move your car in itself! You can have 1,000,000,000,000,000,000,000,000,000 ft lbs of TQ, but if you don't have ANY HP to go with it, YOUR CAR WILL SIT STILL! Yes, that's right, even with all of the TQ in the world, you can't so much as move something one single inch if you don't have HP taking place.

 

Colonel, ok thats fair. <img src="graemlins/gr_cheers.gif" border="0" alt="[cheers]" />

 

"The car that has the 400/380 would have a higher trap speed as opposed to the 380/400 car which would have a lower E.T."

So you would think that with my car if I installed a cam that gave me 50 less HP but 50 lbs more TQ that I would have a quicker ET but with less MPH? So I could maybe run a 9.7 but at only 132 MPH?

No, that definitely wouldn't happen. I would run a faster MPH AND a quicker ET with the cam that I have. Why? It goes back to that average HP to the ground over the course of the 1/4 mile that I keep preaching about. You take that extra HP you have and channel it via the converter and overall gearing.

[ February 02, 2002: Message edited by: Colonel ]</p>

 

HP is just a way to talk about the cars power band. High HP cars put down good torque over a broad range. That is what makes you run faster at the track, not good torque at only a specific RPM.