ITB - what a bunch of crap

[Knestis]

Kirk,

See IT-07-051 on our site.

Thanks, Andy - I stand corrected, as is often the case when I rely on my memory.

I know that this isn't just supposed to be about the VWs but they are a natural point of comparison, since as Chris points out, they share a lot of the same technology over 3 generations and multiple generations of specification decisions. This factor isn't going to make the math closer, I don't think.

K

[dickita15]

I think the process is the most important thing that has made IT what it is today. I think the ITAC need to keep working on the process until vehicle classification really is formulamatic and then every car should be classed based in the process exactly. Ok you can round to the nearest pound.
Has any good efforts been made to come up with a way to use torque in the process, anything close?

[shwah]

We can debate VW's all day. The bottom line here for this group is that half the ITAC would like to run every car through the process and reset it's weigh +/- ZERO, the other half thinks what we have is 'good enough' given the inherent guesses in the developed process.

And obviously the former half is right

I think IT has never been healthier in terms of what can win.

Here here.

It is good, and you can continue to make it better.

[tom91ita]

Your right Andy. I mis-read your post mentioning the -50 for the rear beam. Sorry about that.

At the end of the day, the Golf III and Golf II are the same car in terms of chassis. If the Golf III is spot on then the Golf II should be speced at 2145 (20.4lb/stock hp). That's not going to happen, whether because the Golf III is light, or folks don't want to reduce the weight of one of the more highly developed ITB cars out there (speaking on aggregate here, not about one specific car). Of course the Golf III having that exact same chassis, more torque and less lb/hp is why it has not taken long at all for them to gravitate to the front of the grid in every division that they are competing within a year or two. I welcome the compeition, but the Rabbits, Sciroccos, Golfs and Civics certainly deserve an equal opportunity within the system to get off the corner and down the straight.

three quick questions:

what is IT-07-051? i looked at scca's website and did not get any hits on the search.

what is the -50 for the rear beam? does the golf have a rear beam axle like my crx?

and the 20.4 # / stock hp is interesting. my crx is 2130 #'s and 91 hp stock which works out to 23.4 #/hp.

just trying to understand. tia, tom

[Knestis]

From my corner, Dick - I *think* that maybe what we lack is a theoretical basis on which we might base a process that more effectively considers torque. My admittedly lacking understanding is that "horsepower" is in most cases a derived value for work, that results from math applied to what is actually a torque measurement taken by the mechanical bits of a dyno.

Further, if one buys the old saw that "horsepower sells engines, torque wins races," AND we understand that some of the issues we deal with as we look at the "formula" behind the process (e.g., how the torqueless wonders struggle compared to where they "should be..."

...then maybe we're missing a bet by ignoring torque. Again - if some smart someone could say, "Here's what really matters, and here's how torque/HP relate to one another," and maybe help with some peripheral issues like the influence of gearing, I have a little hope that we might be able to come up with adjustments to the math that improves the entire deal.

K

[Knestis]

Tom - IT-07-051 is the internal designation of a request submitted by a member, that made it to the ITAC for review and recommendation. Those aren't in the searchable content and the number doesn't follow the request all the way through to a Fastrack announcement of action, if any.

K

[seckerich]

From my corner, Dick - I *think* that maybe what we lack is a theoretical basis on which we might base a process that more effectively considers torque. My admittedly lacking understanding is that "horsepower" is in most cases a derived value for work, that results from math applied to what is actually a torque measurement taken by the mechanical bits of a dyno.

Further, if one buys the old saw that "horsepower sells engines, torque wins races," AND we understand that some of the issues we deal with as we look at the "formula" behind the process (e.g., how the torqueless wonders struggle compared to where they "should be..."

...then maybe we're missing a bet by ignoring torque. Again - if some smart someone could say, "Here's what really matters, and here's how torque/HP relate to one another," and maybe help with some peripheral issues like the influence of gearing, I have a little hope that we might be able to come up with adjustments to the math that improves the entire deal.

K

Torque is the only quantity you can actually measure Kirk. HP is just the equation of the work possible. HP is actually a time, force, distance calculation. Gearing can change HP slightly due to different driveline losses but torque is always the constant. There is a reason we use a torque rather than a HP wrench. I hope you will set goals within the ITAC to work towards refining the process over time to include Torque. Having this discussion is a good start.

[lateapex911]

Trust me Steve, there is a LOT of discussion within the ITAC regarding improving the process. And by that I mean the "process" as you know it, as well as the greater process that surrounds the "process".

Again, it seems to me that it's better to take aim, shoot for your target, accept that you might not be dead on, but shoot for every target that you are given using the same methods. AND, if you are asked to shoot for a certain target that has already been shot at (that didn't have the same methods used), that you apply the consistent methods you've been using, you take your shot, then you use the result, without discarding the results, whether they are "within a range" or not, regardless if it's within your shooting confidence window.

You do your best, and you take the results, and you live with them. Simple, right?

[shwah]

three quick questions:

what is the -50 for the rear beam? does the golf have a rear beam axle like my crx?

and the 20.4 # / stock hp is interesting. my crx is 2130 #'s and 91 hp stock which works out to 23.4 #/hp.

just trying to understand. tia, tom

The Golf has a twist beam rear axle - imagine a giant sway bar serving as the rear axle.

The 20.4 was just a simple 2350 / 115 (stock Golf III hp). Your comment is exactly why I tossed the Honda into my list.

I don't want to start that debate up as well, BUT, I do understand that there could be cars with 'x' factors that change how they respond to the process. The rotary RX7 is a good example. I concede that there may be a need to treat some cars uniquely in the process, but I don't think there is agreement about how to determine if or how a car would end up with a 'process modifier'. I was starting to wonder if there was a process modifier for my car that assumed more power gains than typical when I first started looking at this stuff, and I would also wonder if that were the case with the Honda sitting at 23.4#/stock hp. <------ If we want to go way down the road of this debate we should probably start a new thread (or resurrect the last one) ((heck we should probably take this whole discussion to another thread)).

[tom91ita]

not really wanting to hijack the thread. it was just interesting numbers. and i will admit that the coefficient of drag is likely less on my car, etc., etc.,

but it is most interesting to have these discussions with folks i have raced with on various tracks because then we have some idea of what is going on.

and then there is the new tires, etc.

the weight difference might be valid or not. i know that my laptimes at the ARRC were far from consistent. i did not mean to be complaining. just trying to better understand.

back to your regularly scheduled programming....

[pfcs]

the torque vs hp question is a slippery slope. The concepts can be very confusing.
A car will have it's max accelleration at it's torque peak-period. But horsepower being a function of rpm (angular velocity) and torque, is more expressive of the ability of the engine to accellerate the vehicle (do work). If 2 otherwise equal cars generate the same torque, the one that generates that torque at higher rpm will accellerate faster. Consider the VW Cup TDI jettas: sub 1 minute lap times @LRP, 2880lb cars, 119hp, but torque is HUGE. If they developed that torque at 5000 rpm, they'd probably be making 300hp and going several secs faster.

[Andy Bettencourt]

the torque vs hp question is a slippery slope. The concepts can be very confusing.
A car will have it's max accelleration at it's torque peak-period. But horsepower being a function of rpm (angular velocity) and torque, is more expressive of the ability of the engine to accellerate the vehicle (do work). If 2 otherwise equal cars generate the same torque, the one that generates that torque at higher rpm will accellerate faster. Consider the VW Cup TDI jettas: sub 1 minute lap times @LRP, 2880lb cars, 119hp, but torque is HUGE. If they developed that torque at 5000 rpm, they'd probably be making 300hp and going several secs faster.

They make 170hp and 300ft/lbs.

http://www.vw.com/vwhype/motorsport/...p/tdi_racecar/

[seckerich]

They make 170hp and 300ft/lbs.

http://www.vw.com/vwhype/motorsport/...p/tdi_racecar/

Run that car through the process and see what we get. I also disagree with the blanket statement about peak torque. The torque band is much more important as is the power band. Next time you go to the dyno look at the spread sheet on elapsed time and distance. I bet the guys beating you are. Good debate.

[CRallo]

the torque vs hp question is a slippery slope. The concepts can be very confusing.
A car will have it's max accelleration at it's torque peak-period. But horsepower being a function of rpm (angular velocity) and torque, is more expressive of the ability of the engine to accellerate the vehicle (do work). If 2 otherwise equal cars generate the same torque, the one that generates that torque at higher rpm will accellerate faster.

half right / half wrong

you have the right definitions, but your evidence/data does not support your hypothisis...

Basically: Torque is the force applied to the drivetrain by the engine and Horsepower is the ability of the engine to do work. (accel the vehicle) Therefore peak acceleration will be at peak horsepower. If peak accel were at peak torque, we wouldn't be winding our engines so tight lol just think about it for a minute...

the fact the car that makes a higher peak torque at a higher RPM will accel faster is true, but only because that means it makes more horsepower also because, as you said, horsepower is a funtion of torque and RPM.

[Andy Bettencourt]

Run that car through the process and see what we get. I also disagree with the blanket statement about peak torque. The torque band is much more important as is the power band. Next time you go to the dyno look at the spread sheet on elapsed time and distance. I bet the guys beating you are. Good debate.

Luckly, we don't have too...turbo!

[CRallo]

Run that car through the process and see what we get. I also disagree with the blanket statement about peak torque. The torque band is much more important as is the power band. Next time you go to the dyno look at the spread sheet on elapsed time and distance. I bet the guys beating you are. Good debate.

You are (almost) right on the money here.

Peak Torque has very little to do with it. Nor does peak horsepower. It is the Horsepower band that matters here. Specifically "the area under the curve" or the average HP generated within the useful powerband.

For example: a car that has little midrange torque will have even less midrange hp while an engine that makes good mid range torque will tend to have a much wider "powerband" and more average horsepower even if the peak horsepower is less.


"peak hp wins dyno days, average hp wins races"


Here I tried to keep it short and to the point, but I'll explain more if anyone doesn't understand the concept.

[CRallo]

Has any good efforts been made to come up with a way to use torque in the process, anything close?

In my eyes, the most accurate way to take "torque" into account, is to use an average horsepower number and not a peak horsepower number. This however would not be simple...

a few possible issues that come to mind:
-where would the data come from??
-different cars/engines use different RPM bands...
-certain cars may have very different average hp numbers and or operate in a different rpm band in IT trim vs stock due to certain limitations that modifications permitted by the IT ruleset negate.

I'm sure that someone more experienced with this stuff could add more... or maybe come up with an idea to handle the already mention issues...

somebody chew on that and see what you can come up with

[JoshS]

In my eyes, the most accurate way to take "torque" into account, is to use an average horsepower number and not a peak horsepower number. This however would not be simple...

a few possible issues that come to mind:
-where would the data come from??

This is by far the biggest problem. Solve that and the rest will follow.

[JeffYoung]

And that is my personal "ME" problem. If you go to a average hp number, I've got a ton of torque below 3500 RPM or so that just isn't usable. I get killed. 325e gets killed with weight.

The average hp numbers reward high revving cars that make peak power in a narrow band.

Someone above posted something along the lines of "IT is working really well right now, why monkey with it?" That I agree with. No overdogs in S, A, or B that I can see.

-certain cars may have very different average hp numbers and or operate in a different rpm band in IT trim vs stock due to certain limitations that modifications permitted by the IT ruleset negate.

[pfcs]

"you have the right definitions, but your evidence/data does not support your hypothisis...

Basically: Torque is the force applied to the drivetrain by the engine and Horsepower is the ability of the engine to do work. (accel the vehicle) Therefore peak acceleration will be at peak horsepower. If peak accel were at peak torque, we wouldn't be winding our engines so tight lol just think about it for a minute..."
Sorry Ralph but you're wrong. Torque is force and that's what accellerates a anything.
By changing gearing, you can skew that relationship but in ANY gear, the vehicle will have the greatest accelleration as it passes thru the torque peak. Period!
Because of that confusing relationship between HP & torque there is much misinformation. One fairly true rule is that you will get the best use of the package if you arrange gearing so that if you shift @max hp, the rpm falls back to max torque (torque peak). Most racer's, especially those with fairly stock engines, mistake noise for accelleration and use a higher rev range than is ideal, myself included!