I came across a thread late last night that was on a GTI forum and saw this one poster going on about torque, and how important it is. But I felt like he was speaking for all the wrong reasons.

I tried to talk a little bit of sense into him with a quick breakdown IMO, but all he does is refute with insults, and more false information (for the most part).


Cheers fellas

 

What's important is 1) effective torque at the wheels (determined by engine torque, gearing, tire size) and it's integral over time, 2) tires (obviously, if your tire is only capable of handling .8g under acceleration your car is going to be slower than one capable of handling 1g under acceleration assuming both are capable of producing enough power to exceed that), and 3) slip ratio. The optimum slip ratio is going to depend on the tire, but it basically depends on wheel spin, contact patch movement relative to the rim, and longitudinal deformation of the contact patch. Keeping the car at the optimum slip ratio is up to the driver (so yes, you actually need the wheels to slip a little in order for them to have traction).

In regards to number one, horsepower is a much better indicator of effective torque at the wheels than engine torque because it takes into consideration gearing (by multiplying times rpm, you get more if the torque at a higher rpm where higher gearing can be used to get the same torque at the same speed). It's not absolutely right, but it's a better indicator than engine torque alone.

 

I'm sure most people on here have seen this article from Bruce Augenstein. I had a link saved from where Andy Baritchi posted it year ago (some folks might know Andy from his finishes in the One Lap in his Supra).

http://www.boostaholic.com/hptq.html

 

Listen to some of what this guy says...

"Gees im glad you realised torque is the twisting force or as you anally put it as the rotational force... and what does that rotational force do care to answer that???? and what happens when you have have more torque??? it has a far greater ability to move an inert object .. so a vehicle with more torque like a truck/tractor etc has far greater ability to pull\push\move things due to its greater torque force. so as far as any one is concerned that torque is the force that push, pulls.. moves the inert object and i dont give a shit what fancy physics you wanna spout. im putting it in lamens term.


-I have explained in pure physical sense how torque and power are relational in a motor vehicle and how it behaves and where torque is utilized by a vehicle and where power is utilized.. thats why you hear the expression TOP END POWER you dont hear Top End Torque.


This is his definition: "torque is the pulling power and gets you moving and is the shoving force that pulls your car and helps you accelerate .. power comes into play and keeps things moving well after torque has lost its affect and gravity has been over come and when pulling torque is no longer in required and where inertia and power will continue to help you maintain speed"


-i never said power has nothing to do with it and I NEVER said that TORQUE IS the only factor that affects acceleration. I said torque is one of the mahjor factors in a cars ability to accelerate not POWER and I stand by that. You only need to look at diesel cars with buckets of torque and not much power yet they can accelerate so quickly. WHY?? Answer me oh clever one. you truely need to learn to read

-and on yeh im glad you realise that race cars have high horsepower at high rpm.. and not high torque.. cos it literally pisses all over your STUPID statement that torque should be at HIGH RPM and where it is "best" in your exact words

-Find me one dyno chart where Peak Torque should be at its high RPM range.. because based on your bullshit logic thats how all car tuners and manufacturers should be tuning their cars..

-yet if you look at most production high performance vehicles... what do you find .. wow high torque is produced very early on at 2000 rpm and peaks at 5500-6000 rpm before they start tailing off at the red line rpm range..

why is that Einstein????? better call all the car manufacturers and tell them torque is useless and it means nothing and oh yeah stick all your peak torque at the highest rpm range .

if you want to go on and continue making a complete retard out of yourself go for it buddy. but any tool who makes a stupid comment like torque has nothing to do with a cars ability to accelerate its all horsepower is ****** stupid and completely kidding themselves"

 

That RobbyJai guy has the right idea but has severely distorted view of it. The idea that "torque wins races" is a very very misleading saying and its like he heard this and ran with it...with no clue what it really meant or without giving it any thought since the common understanding of this saying is...well, wrong.

When it comes down to it, of course, torque is what matters - it is the measure of twisting force required to actually move the car and furthermore, hp is calculated from it. Furthermore, torque is very helpful for road racing situations where the thrust out of corners allows quicker acceleration out of the corner and less concern over optimal gear selection vs a car with the same horsepower but less torque.

However, taking this idea to create a accurate picture of a car's acceleration, takes more work and simply saying "this car makes more torque and therefore is faster"

1. multiply torque x gear ratio (starting with 1st) x final ratio (and secondary ratio) and make a line graph with the vertical line being torque produced at the wheels and the horizontal line being speed. Do this for each gear. Remember since speed is the horizontal axis, we are in essence ignoring any part of powerband which falls below the RPM in the next gear after an optimal shift point, which is why torque at low RPMs does very little aside from the launch, which can be made up by giving the car some revs at launch. (However, my statement of course ignores the usefulness of low rpm torque in daily driving situations).

(Side note: to determine when to shift, see where the torque at the wheels (i.e. post gear multiplication) becomes lower than the torque produced at the wheels post-shift; one of my pet peeves is when people say "there's no need to rev past X RPM b/c the car doesn't make anymore horsepower/torque drops off")

2. Then comparing both cars on the same graph, the car with more area under the curve will be the faster car, ASSUMING equal grip, equal weight and equal times between shifts.

As a result, while torque is what matters, in the real world (without doing these calculations and simply using numbers given by a manufacturer or dyno), horsepower ends up being the more accurate measure of a car's performance since it partially reflects powerband, which a torque figure alone does not do, by incorporating revs in its calculation.

That's not to say that the torque figure is not useful. By looking at torque number (and at which rpm) and comparing with the horsepower number, you can paint a rough sketch of the type of powerband (peaky or whether torque falls off at higher rpms, or hopefully, neither).

 

You just gotta let it go, man. You just get yourself worked up over nothing. (Unfortunately, that's a lesson I still haven't fully learned.)

 

Haha, wow. I can't believe people need to resort to name calling. I didn't even see anything that could have offended the retard (lol)
Hopefully thats not the norm on GTI forums.

And I agree with above, give up OP.

 

This reminds me of a old saying that goes something like, "Don't get into a pissing match with an idiot since even if you win, you'll still be covered in piss."

 

I wish I had the link still, but there was a great article that was circulating the internet for a while where it breaks down hp, torque, etc. The part that I found to be interesting was that when you use radians instead of degrees of crank rotation and you use metric numbers, horsepower equal torque. This involves math and physics beyond my own understanding so I'm sure I'm shitting the bed on the explanation. The concept of torque having one curve and hp having another is more an issue of the ways we choose to quantify the two rather than some indication that they are separate forces

 

One is a measurement of power. One is a measurement of torque. They're very different things.

@ITR#203: You forgot tire radius.