Revisiting Torque

[Knestis]

The ITAC continues to noodle over how to equitably consider what we all seem to think of as "torque" in our specification math, and I have a question: Without getting bogged down in math, can I sample your first principles on the issue...?

Some questions for consideration...

** When you say "a Mustang has a lot of torque" or "Hondas don't have any torque," what do you mean? Drill into your own language and try to be as explicit as possible about what you are thinking when you say that.

** How would you compare these four cars, in terms of their "torque" relative to one another, AND how would you expect them to compete against one another (there no "right" answers, so far as I know)...

Car 1 - 150 hp, 150 lb-ft of torque

Car 2 - 110 hp, 190 lb-ft of torque

Car 3 - 190 hp, 110 lb-ft of torque

Car 4 - 170 hp, 170 lb-ft of torque

** If they were all otherwise the same, which of those cars would you choose to race against the others? Why?

** (The first hard one) - How is it that you think "torque" makes a difference in competitiveness? If we all have different conceptions of the mechanism by which it matters, we'll probably never get anything like a consensus answer re: how to manage this variable - or variables.

** (The second hard one) - The ITAC can really only control a very few factors, in terms of specifications we can set, the key one of course being weight. How do the factors that we MIGHT control bear on torque, to your way of thinking? Is it safe to say for example that more weight mitigates against a "torque" advantage?

** Finally (and this is kind of an easy one, since it's about philosophies) - Do you even think we should try to accommodate torque in the processes we use? One philosophy says, "We don't try to control a lot of the variables that make a difference to competitiveness, and since we don't have a very good grasp on torque, we should ignore it." Another would suggest that "mathematical models are good enough that a digital car on a digital track can reasonably approximate the real thing, so we should try to take any and all variables that we can into consideration, to make the cars as equal as possible." Where are you on these issues?

THANKS!

K

PS to ITAC members. I'd be interested to hear from the membership before we dive into the conversation ourselves.

[Ed Funk]

I'd choose car # 4, because it's numbers are almost the same as my "C" car!
Seriously, it has the best of both worlds, should come out of the corners hard and wind tighter than the low hp high torque example.

Question 1, sure take torque into consideration, but it's going to make the "napkin" math more "interesting". Add weight, but then take it off for bad brakes? Where does it stop?

Maybe it wasn't politically correct back in the beginning when we raced at our manufacturers "curb" weight, but it did let those that could read specs pick the right car. The old "we'll give you a place to race, but your car may not be competitive" has been replaced by "no car left behind".

Just my opinion, yours may be wrong!

[chuck baader]

I would prefer a similar hp/tq because the curves will be flatter making a wider power band and easier to drive fast. However, you left the most important variable out of the equation....RPM. Torque only works at the wheels. Applied torque is what moves the car. The 190/110 example, if it turns 9k, will easily out run the 170/170 that turns 7k beacuse it can run a much shorter gear.

I don't think tq is a consideration above what is currently given based on the parity of the top running cars in SEDIV. (clevat: that would be a most biased comment although I am researching the rpm route rather than torque.) Of more concern to me is the ability to generate grip, and the fully independent cars seem to have a better handle on that than the strut cars. As more of the fully independent cars are classified/built, consideration should be given to the older strut cars. Jes Sayn Chuck

[Andy Bettencourt]

Don't we need to know the applicable minimum weights before we can make a decision?

[Knestis]

Assume that the minimum weights are the same for the purposes of this discussion. Since we're talking about figuring out how to consider torque (or if we should), don't presume that given whatever the final process might be, the result would be that they are different.

We have WAY too many of these conversations that get all tangled up because we're all talking about different things. All I want to understand from this is how people understand this torque thing, and generally how (or if) we should tackle it.

K

[pfcs]

Looking at torque w/o rpm is senseless.
Engines that develop torque at much lower rpm than their peak horsepower peak are potent because they neccessarily develop good torque across a relatively large (rpm) band. This implies good airflow design and somewhat agressive cam timing or variable cam timing. The allowed IT prep and their pre-existing advantages will make them competetive.
Engines that develop torque at low speeds and rpm at conservative speeds, (often more torque than hp), imply airflow restricted engines. Often they are on the large end of the displacement spectrum for their #of cyls. Their response to IT tunes will depend on how much that restriction responds to IT prep. If the airflow restriction is due to conservative cam timing/lift and/or restricitve cylinder head design, then they likely won't respond as well to IT prep-and they will be toads.
V8s that have well seperated torque and hp peaks-look out! phil

[rx7chris]

Torque makes all the difference in the world. HP is just a figure derived from a torque reading. For example, gonna use motorcycles cause i can speak from experience. Say Bike 1 makes 52lbs of torque and 120HP Bike 2 makes 47lbs of torque and 130hp. Bike 1 and 2 are otherwise equal. Both bikes come out of a turn at the exact same time, Bike 1 will win the race to the next turn given that it's not at such a distance that the added hp of bike 2 allows it to catch up. Say if this turn is the bus-stop at daytona. By the time both bikes reach start finish they should be about equal again. If the turn was the carousel at sebring bike 1 would have a definitive lead by the time they reach the short-course start finish. Each side has it's pro's and con's and you can have a different advantage depending on track lay-out.

Torque can also be massaged with dyno time as well.

Don't try to measure it, you'll go insane with 300+ cars at an event.

[Andy Bettencourt]

Torque makes all the difference in the world. HP is just a figure derived from a torque reading. For example, gonna use motorcycles cause i can speak from experience. Say Bike 1 makes 52lbs of torque and 120HP Bike 2 makes 47lbs of torque and 130hp. Bike 1 and 2 are otherwise equal. Both bikes come out of a turn at the exact same time, Bike 1 will win the race to the next turn given that it's not at such a distance that the added hp of bike 2 allows it to catch up. Say if this turn is the bus-stop at daytona. By the time both bikes reach start finish they should be about equal again. If the turn was the carousel at sebring bike 1 would have a definitive lead by the time they reach the short-course start finish. Each side has it's pro's and con's and you can have a different advantage depending on track lay-out.

Torque can also be massaged with dyno time as well.

Don't try to measure it, you'll go insane with 300+ cars at an event.

But in IT things aren't otherwise equal. You can run a R&P that helps your problems and exploits your strengths.

[pfcs]

"You're right, Josh. As soon as I posted the comment about HP/torque peak RPM variation being higher in lower rev engines, I looked back and realized that it wasn't much of a correlation at all. I think I got focused in on the S2000 and V6 Mustang and didn't do a proper analysis. Sorry."
It's more illustrative to look at this by % of rpm difference than rpms difference. And the relative numbers (ft/lbs and hp). They reveal a whole lot about the area under the curve and the ballistics of said engine. Engines with more torque than hp will have the hp peak nearer the torque peak and are stones, running out of torque quickly, they generate little hp because hp is a product (in the math sense) of torque and rpm. There's little area under this curve.
Imagine other scenarios and you can imagine the neccessary tq curves and the implications.
AB: "But in IT things aren't otherwise equal. You can run a R&P that helps your problems and exploits your strengths."
And if the %difference between peak tq and hp is less than the %difference between 2 transmission gears you use, you're screwing the pooch-when you're out of torque, you're better drinking beer.

[JoshS]

Engines with more torque than hp will have the hp peak nearer the torque peak and are stones, running out of torque quickly ...

There's lots of conventional wisdom like this, but IT JUST ISN'T TRUE, at least for the fairly random sampling of cars I ran. There seems to be very little correlation between these factors.

[JoshS]

Torque makes all the difference in the world. HP is just a figure derived from a torque reading. For example, gonna use motorcycles cause i can speak from experience. Say Bike 1 makes 52lbs of torque and 120HP Bike 2 makes 47lbs of torque and 130hp. Bike 1 and 2 are otherwise equal. Both bikes come out of a turn at the exact same time, Bike 1 will win the race to the next turn given that it's not at such a distance that the added hp of bike 2 allows it to catch up.

Please prove it with math.

[lateapex911]

Found it.
Read this:
http://www.yawpower.com/tqvshp.html

[pfcs]

The point I keep trying to make is so easy to miss, and I'll bet people like Bill O'Reilly wouldn't admit they got it if they did!
Horsepower is a FUNCTION of TORQUE and VELOCITY (rpm in a crankshaft). To make a lot of horsepower, you need to have good torque at higher rpm. (Xtorque@4000rpm =Yhp; Xtorque@8000rpm=2Yhp). Understanding their interelatedness, and how their relative amounts and %rpm-spreads describe the area under the curve in question tell a lot about the dynamics of the engine and its likely response to tuning. (an airflow restricted engine [high tq/lowhp/small rpm-spread] is unlikely to respond much to IT tuning unless the restriction is in the exhaust system). Yes, you need a lot of horsepower to go fast but hp is still determined by torque AND-torque is what accellerates the car, even at 10,000rpm, hp simply describes how well it makes that torque at high rpm. Get it? You need to know BOTH to describe the dynamics of an engine. If you only know one parameter, hp is more informative; if you know both (tq@rpm/hp@rpm), you have much clearer info.
On another front-I actually heard Rush Limbaugh suggest that what killed Detroit was trial lawyers. Turn you r radios off please.

[ekim952522000]

Found it.
Read this:
http://www.yawpower.com/tqvshp.html

Best article I have ever read on TQ and HP.

[chuck baader]

I would guess that the consensus it that those of us with the 50# torque adder should have that removed post haste. Chuck