you will not accelerate faster if you dont increase torque, thats all there is to it (assuming we arent throwing traction, weight, etc into this) the turning force which pushes you forward is torque, at low and high RPMs.
pushing the power into a higher RPM will NOT make you faster unless somehow torque to the wheels is increased, it may let you hold a gear longer by increasing the redline, but you wont accelerate at any better rate.
the reason the infiniti accelerates so fast is because of GEARING, it has very short gears which increase RW TORQUE, it has nothing to do with the HP.

D'oh, thats true, you have to be able to rev fast otherwise alot of torque won't make you fast, diesels proved this, i can't really compare the LS1 to the 350Z because i've never driven one but i'm sure the extra torque will overcome any of the speed advantage the 350Z has.
yes the smaller pulley would cause it to lift faster, but it can't produce as much force. also the reason the larger wheel can't lift it faster, even though it has ample force to do so, is because it's being limited by the RPM it can spin, this isnt the case with a car engine. spinning more RPM may mathematically add more HP but thats not the force thats doing the work, the torque is still lifting that weight, just at a higher RPM. It's a matter of making the driveline spin up to its max RPM as fast as possible, and ensuring your tire size and gearing is big/wide enough to spin it high enough for a good amount of MPH.

 

I agree with a lot of what you are saying, I'm not saying that HP is more important than torque or vice versa...they are both important in acceleration. I know that torque is what you feel.. but when you make the same torque at higher RPMs you go faster even though you don't "feel"it. Yes, gearing is very important here also. Read this http://vettenet.org/torquehp.html
it was written by a vette owner.

 

I guess I'm still not explaining it very well, but FYRHWK1 you did touch on it in your last post.

"the reason the infiniti accelerates so fast is because of GEARING, it has very short gears which increase RW TORQUE, it has nothing to do with the HP."

GEARING has EVERYTHING to do with HP and the redline. The only reason a car can have short gearing is with a high redline, otherwise you would have to shift a crapload of times and your top speed would be really low.



Then you touch on it again when you say this,

"the reason the larger wheel can't lift it faster, even though it has ample force to do so, is because it's being limited by the RPM it can spin, this isnt the case with a car engine. spinning more RPM may mathematically add more HP but thats not the force thats doing the work"

It is EXACTLY the same with a car engine. All car engines are limited to certain engine speeds, so by increasing the engine speed (and therefore HP, as long as you maintain torque) you can adjust your gearing to increase the torque to the wheels. Even if you don't adjust your gearing, you will be able to stay in a lower gear (with a greater torque multiplication) for a longer period of time. Also, when you are talking about acceleration, top speed, etc., you want to talk power, not work.

Finally you say,
"i can't really compare the LS1 to the 350Z because i've never driven one but i'm sure the extra torque will overcome any of the speed advantage the 350Z has."

It isn't the extra torque, but rather the extra 50 or so HP that is what makes the F-body's so damn fast. Give the Z a similar PWR/Weight ratio, and no matter what the torque is, as long the curve is fairly flat, the cars will be very close.


Anyhow, we are very close to talking about the same thing, but I guess I can't really explain the differences between all the components very well. Sorry 'bout that.

-D'oh!

 

my point is this, HP does not accelerate you, a higher redline (and thus more HP) means you can run shorter gears, but what shorter gears get you is more effective torque. the only force that the gears can multiply is the engine torque, having a good torque band in whatever range your engine operates will make you fast, if geared properly.
But i suppose using either peak HP or peak torque to measure an engines performance is misleading.

 

Ahh, the good old torque VS horsepower argument...

 

Ahhh, here's the thing.

The higher HP engine with equivalent gearing (by that, I mean gearing that will make the car go the same speed at its redline as the lower HP motor at its redline) will always put down more torque to the road than the lower HP car (even if the lower HP car has more engine torque). If the high HP car has a peaky engine, it may produce an average HP lower than the average of the low HP car, but the most well known high revving engine (S2000) has a very flat torque curve, plus, with 6 speed transmissions, sequential shifters, etc, the peaks aren't as much of a factor as they used to be.

Anyhow, that's the last I'll say on the matter, since I think that's the clearest I can be (good thing I'm not a writer).

So all I'm saying is that if I were forced to choose between a 225 HP, 235 Trq engine, and a 240 HP, 150 Trq engine, I'd take the horsepower every time.

-D'oh!

 

yes, if thats the case then you're right, but it still proves my point, torque is what moves you, shorter gearing = more torque

 

Hehe, wiseguy!

-D'oh!

 

Torque vs. Horsepower? Give me both.


Mantaining torque output into the higher RPM's= Horsepower, all horsepower is is a measurement of how fast you're delivering torque.

HP= (TQ*RPM)/5250

Then you can take advantage of gearing to make up for any lack of low end by getting the motor up in the RPM's where it is making torque faster, ie. making horsepower. Great for small displacement, high revving engines like the S2000. Or, you can have a bigger engine, an LS1 for example, and only turn the motor to 6000 RPM but make a broad torque curve so you don't need the agressive gearing like an S2000. You can do it either way, its more about results than methods IMO.

 

Do you remember the old F1 cars? They got like 1000+ hp out of 1.5 liters. Reved to like 17,000 or something (I know the 3.0 honda does). But they had like 2 ft lbs of torque. Horsepower means alot when you have the ability to rev.

 

Doesnt mean **** if you have the ability to rev. Means alot if the car is an F1 car that weighs absolutely nothing though. Ill race in my 3 ton car and show you what torque does.

 

if you drive a domestic, shut your mouth, you're making the rest of us look bad. Are you incapable of reading this thread? D'oh just explained torque and horsepower better then I've seen it in a long while. Not that i'm going into this, but the weight of an F1 car is not the sole reason it's as fast as it is either.

 

I would like to hear more about this 6000lb car that doesn't need to rev.

Sounds like its powered by a 10 liter 1 cylinder engine that makes 800 lb-ft of torque @30 rpm and 5hp @35rpm

0-60 in 5 miles

 

Correction, I didnt mean if you have the ability to rev. I mean if you have the ability to rev with no torque. Of course revving is extremely important, I was just trying to point out that revving to 17,000 RPM wont do a damn thing in a car that weighs much. Im sorry for the misunderstanding. Dang people are jumpy on this board. And yes I drive a domestic, as well as several foreign cars. How would a stupid statement out of a solitary domestic drivers mouth make a group look bad?

 

because people work like that, they see a few domestic people openly talking down on their cars and they start to believe they all think like that, unfortunatly thats how it happens.
and revving to 17,000 RPM would allow you to run F1 style gearing, you can turn 100 ft lb into 3-4 thousand ft lb @ the rear wheels with that much redline.

 

I added a Yank Torque Converter to my FireHawk and it dropped my RWHP numbers by 20!

But it raised my TQ by 40 with the TC locked!

So I lost HP but gained Torque.

Result?

Took off .4 from my 1/4 mile! Higher stalls from Yanl promise up to a full second off your 1/4 but lower your HP!

Wierd eh?

Just thought I would chime in with some real life experience, all science aside (which admittedly is over my head but interesting to read!)

 

MaxHax,

Do you have a dyno chart from before and after that mod? Maybe we could see something in the curve that would explain why you could cut your times with less HP. Or maybe the improvements came because of an improved launch? Any ideas based on your times?

-D'oh!

 

did you check your HP witht he converter locked? gaining 40 ft lb would increase your HP by quite a bit, to drop 20 would be some severe topend problems. also what other mods did you include? a converter wouldn't add power, they do have torque multiplication but that happens for the first ~5 feet or so, great for getting off the line but i can't say i've ever seen power from one on a dyno.
The 1/4 mile gains are in the launch with a converter, but .4 off is impressive, congrats

 

Here is a Dyno page on verters but they don't show any loss but incredible TQ gain.

link

This is the brand I used. I had a 3200 Stealth Thruster that was later discontinued for some reason.

 

I bet that mod really improved your 60' time a lot to get you a better 1/4 mile. How did it affect your trap speed though?

I had a similar experience but because of opposite factors. I used to own a 91 Sentra SE-R with a few bolt-on mods and it would run high 14s. It dynoed at 139hp and 125tq. I got some JWT cams and my power went to 147hp but my torque stayed the same at 125 lb-ft but the max moved up 1000rpm. I was dissapointed because as a Nissan guy I can appreciate torque not found in Hondas. The cams really brought the top end to life though and knocked .3 secs off my 1/4 mile time, and 3mph to my trap.