So, what TRULY matters...?
- Thread starter Knestis
- Start date
Maybe I should stop posting this because no one seems to listen...
A single torque value is not a good indication of the potential of an engine. The power transmitted to the ground at that instantaneous engine speed is what makes the car go. Horsepower is basically torque multiplied by RPM. Many of the cars with low torque are also turning higher revs, so they're still putting good power to the pavement.
What is really important is the full dyno plot combined with the transmission ratios, so you can see the actual power through the RPM range used on the track. One torque value doesn't come close to representing this. The max torque value may give some insight into the shape of the curve however. The hp curve on a high torque engine (TR-8 for example) may be very flat, while a low torque motor (S2000) has a relatively peaky power curve. What nearly everyone is missing here though is the transmission. Most of the cars with very peaky power curves also have much closer ratios in the transmission, so they still put similar power to the pavement.
Kirk mentions the adder for transmission. Has this ever been used? I see five cars in ITR with 6-speed transmissions, none show evidence of added weight because of better transmission ratios.
Acura RSX: 150 lbs subtracted (FWD and low torque?)
Honda S2000: 100 lbs subtracted (low torque)
Mazda Rx-8: 100 lbs subtracted (low torque)
Porsche 968: no adders
Toyota Celica GTS: 150 lbs subtracted (FWD and low torque?)
I'm ok with the subjective adder for torque as currently applied. It should not be used in the formula without the full power curve combined with the transmission ratios.
A single torque value is not a good indication of the potential of an engine. The power transmitted to the ground at that instantaneous engine speed is what makes the car go. Horsepower is basically torque multiplied by RPM. Many of the cars with low torque are also turning higher revs, so they're still putting good power to the pavement.
What is really important is the full dyno plot combined with the transmission ratios, so you can see the actual power through the RPM range used on the track. One torque value doesn't come close to representing this. The max torque value may give some insight into the shape of the curve however. The hp curve on a high torque engine (TR-8 for example) may be very flat, while a low torque motor (S2000) has a relatively peaky power curve. What nearly everyone is missing here though is the transmission. Most of the cars with very peaky power curves also have much closer ratios in the transmission, so they still put similar power to the pavement.
Kirk mentions the adder for transmission. Has this ever been used? I see five cars in ITR with 6-speed transmissions, none show evidence of added weight because of better transmission ratios.
Acura RSX: 150 lbs subtracted (FWD and low torque?)
Honda S2000: 100 lbs subtracted (low torque)
Mazda Rx-8: 100 lbs subtracted (low torque)
Porsche 968: no adders
Toyota Celica GTS: 150 lbs subtracted (FWD and low torque?)
I'm ok with the subjective adder for torque as currently applied. It should not be used in the formula without the full power curve combined with the transmission ratios.
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Bill Miller
New member
Kirk,
I'm not sure I see much of a difference in these two positions. One of the things I see here, is really a case of granularity. In the Prod world, they do it to a given make/model/engine. On the IT side it's based on physical attributes, and is not marque-specific. Only in very rare cases, can I see the need for anything down to the model-specific level of granularity, in IT. We do have something close though, in the fact that the rotaries can't port-match.
Kirk,
I'll submit this, there wasn't something about a given physical attribute that was perceived to be a competitive advantage/disadvantage, there would be no need for an adder/subtracter for it. Case in point. I seriously doubt any consideration is given to the difference between 2dr and 4dr cars.
I guess I'm falling into my old trap of slicing it a bit too fine. As I said, I'm all about the objectivity, repeatability, consistency, and transparency. I'd like it to just come down to a difference in driver ability, but I know that's a bit on the optimistic side.
JeffYoung
New member
Yeah, cars like mine and Chuck Baaders (325e) that make a ton of torque at low rpm get killed by the "power factor." The real reason is that on my motor anyway, a lot of that torque simply isn't usable.
The last dyno run I did I got nearly 200 ft lbs (198 I think) but it was DECLINING already at 3500 rmp or so when the dyno operator started the run. I may have as much usable torque in the actual racing rpm band as a Z car, or in the 150-170 range. Still a lot, but if you use my peak torque number, it's a bit misleading because, in fact, I never get to use it. Peak hp is a different story of course.
All of that said, I agree wtih Ron and Steve E. that a project for the ITAC in the future is a better torque model. If the work that I am doing with exhaust development and the FI setup does what I hope it to do -- move peak hp and tq up the rpm band -- then my car is probably going to need some process weight simply because the process (using my stock hp number of 133) doesn't account for what development does on this fairly quirky (for IT) motor.
As always, I'll post dyno numbers as soon as I get them.
The last dyno run I did I got nearly 200 ft lbs (198 I think) but it was DECLINING already at 3500 rmp or so when the dyno operator started the run. I may have as much usable torque in the actual racing rpm band as a Z car, or in the 150-170 range. Still a lot, but if you use my peak torque number, it's a bit misleading because, in fact, I never get to use it. Peak hp is a different story of course.
All of that said, I agree wtih Ron and Steve E. that a project for the ITAC in the future is a better torque model. If the work that I am doing with exhaust development and the FI setup does what I hope it to do -- move peak hp and tq up the rpm band -- then my car is probably going to need some process weight simply because the process (using my stock hp number of 133) doesn't account for what development does on this fairly quirky (for IT) motor.
As always, I'll post dyno numbers as soon as I get them.
Ron Earp
Administrator
I agree with you and also suggested a sum of torque over the RPM range used. This won't account for gearing and so on, but it'll give you a good idea of what the motor is capable of doing.
Getting this sort of data is another story. Probably available for most all ITR cars, but beyond that it'll be a crap shoot. Good luck finding factory Datsun torque curve data from 3000-7000 RPM for a 260Z.
Jeff, your old torque plot looked like this - drops like a rock:
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lateapex911
Super Moderator
Hey, I'm listening!!!
I've looked at and tried several models, but as you point out, it's not that simple. And we do currently look at, and try to account for the torque/trans situation, so any further mods to the process have to be bullet proof... and lacking the full data, that's a tall order.
it sounds like the level of detail people want in the classification process is moving too far away from the KISS principle to me. we're not recreating the Black-Scholes model for racing here. i think if you try and fine tune it too much, people's expectations change, and you will get many more requests for this or that in order for them to be competitive.
we're throwing darts, and as long as we hit the board everything is A-OK with me. it doesn't have to be a bulls-eye.
we're throwing darts, and as long as we hit the board everything is A-OK with me. it doesn't have to be a bulls-eye.
lateapex911
Super Moderator
Travis, I agree.
But. The issue at play in my mind is the adders, and the consistent application of them.
Lets say there's a car spec'ed at 2500. We run the process on it, (Let's say it never was carefully scrutinized in the GR), and the process spits out 2370. (So the car is 130 pounds heavy as listed) But, there is discussion that one of the subjective adders needs to be applied, at 50 pounds. Split decision, but the weight is added. Now it's 2420. THAT new weight is within 80 of it's spec weight, so it stays put.
Car B is out there, same situation. There's no request to run the process, but if there was, it would turn out to be light, by oh, say 95 pounds. No change! net net on that is that the cars compete, and the delta is almost two hundred pounds, and that's not considering the adder debate. In nearly half the ITACs eyes, it's even further off. That's a significant nut to haul around in ITC, B and even A and S.
I think that things like adders that are subjective are fine, and truly needed, but that we need to be very careful to apply them consistently. And I'd like to see the line in the sand drawn closer to center to minimize the delta...yea, maybe that's making the dart board smaller, and I know we're not as smart as we'd like to be, but, if we aim for a tighter target, our misses won't be so great.
But. The issue at play in my mind is the adders, and the consistent application of them.
Lets say there's a car spec'ed at 2500. We run the process on it, (Let's say it never was carefully scrutinized in the GR), and the process spits out 2370. (So the car is 130 pounds heavy as listed) But, there is discussion that one of the subjective adders needs to be applied, at 50 pounds. Split decision, but the weight is added. Now it's 2420. THAT new weight is within 80 of it's spec weight, so it stays put.
Car B is out there, same situation. There's no request to run the process, but if there was, it would turn out to be light, by oh, say 95 pounds. No change! net net on that is that the cars compete, and the delta is almost two hundred pounds, and that's not considering the adder debate. In nearly half the ITACs eyes, it's even further off. That's a significant nut to haul around in ITC, B and even A and S.
I think that things like adders that are subjective are fine, and truly needed, but that we need to be very careful to apply them consistently. And I'd like to see the line in the sand drawn closer to center to minimize the delta...yea, maybe that's making the dart board smaller, and I know we're not as smart as we'd like to be, but, if we aim for a tighter target, our misses won't be so great.
I understand what's going on, and what defined a "miss" in the past. i just don't want there to be expectation of extensive "adders" due to gear ratio, slope of power curve between specifc RPM ranges, # of piston caliper adders, CG, and so on and so forth.
the "adders" on the end of the formula are sufficient, if you want to refine them to a % weight break for things like FWD that's fine, but i think tacking on add'l factors to the end of the formula in the name of accuracy is a mistake.
the "adders" on the end of the formula are sufficient, if you want to refine them to a % weight break for things like FWD that's fine, but i think tacking on add'l factors to the end of the formula in the name of accuracy is a mistake.
seckerich
New member
The lack of building of very popular cars classed in ITR is directly due to the formula. As the power goes up the % off gets much greater. In ITR every HP you are off is 14 pounds. Doesn't take much of a goof to kill a car. In todays economy nobody is stupid enough to build a car and hope you will fix it in it's third year. Some of those cars need to be looked at again.
1 X 1.25 X 11.25 = 14.06
1 X 1.25 X 11.25 = 14.06
JoshS
New member
In your opinion, other than the RX-8, what very popular car isn't getting built due to its spec weight?
Why yes, yes they are. If they weren't, a Renault Drapeau Blanc with a 1488CC engine would get the same weight as a Volkswagen KlasseüberHund with an entirely different 1488CC engine. The adjustment comes when we consider that the Renault produces 18HP and automatically pits when in the proximity of a German car and the VW will generate 92HP.
We've adjusted the weights for competition reasons. The difference between the IT and prod philosophy is that we do it a-priori and they do it ex-post ad infinitum. Another difference is that IT does it 3 Musketeer-style (all for one and one for all) and prod does it High Noon-style (one man, all alone).
Yes and that's the point. For competition, we adjust the weights, in-advance, based on a subset of their characteristics. We then stick with those weights as if they came down from Mt Sinai, unless its a really good car that does more than what the process thought it would, and then we do it ex-post.
It works, for the most part, except for outliers and, usually, outliers aren't that numerous. The question is what to do about those outliers? Either the process needs to adjust for the factors that make them outliers with an across the board adjustment for those factors or we do nothing and we don't see those cars.
I think that's what people are suggesting... adding new parameters that would be applied to all cars in another realignment.
Here are a few numbers to show that transmission ratios are more important than torque, based on actual dyno plots.
An unrestricted E36 325i is 32 hp below max after shifting from 3rd to 4th. The same car is 22 hp below max after shifting from 4th to 5th.
The Rx-8 is 10 hp below max for both shifts 4th-5th, and 5th-6th.
Don't get me wrong, I don't want transmission ratios included in the formula, I just don't want the single torque value there either. Limited adders I can live with. The only way to accurately account for torque is with real dyno plots for each car, and that will never happen. I'll guarantee that very few of us are as altruistic as Jeff. I won't be providing any dyno plots unless it is absolutely necessary to support some critical argument. For that same reason, I don't fully trust any other dyno data supplied by others.
So since some car hasn't been built it must be an underdog? I might believe that in a decade. As far as I know, only about 1/3 of the cars that are ITR eligible have been on the track so far, and few of those were new builds.
An unrestricted E36 325i is 32 hp below max after shifting from 3rd to 4th. The same car is 22 hp below max after shifting from 4th to 5th.
The Rx-8 is 10 hp below max for both shifts 4th-5th, and 5th-6th.
Don't get me wrong, I don't want transmission ratios included in the formula, I just don't want the single torque value there either. Limited adders I can live with. The only way to accurately account for torque is with real dyno plots for each car, and that will never happen. I'll guarantee that very few of us are as altruistic as Jeff. I won't be providing any dyno plots unless it is absolutely necessary to support some critical argument. For that same reason, I don't fully trust any other dyno data supplied by others.
So since some car hasn't been built it must be an underdog? I might believe that in a decade. As far as I know, only about 1/3 of the cars that are ITR eligible have been on the track so far, and few of those were new builds.
seckerich
New member
300Z
Type R
S2000 (except 1)
Only cars I see in the class that are sweetheart weights are the E36 and Porsche. I am on the outside looking in now Josh because it is now very clear the majority of the ITAC will keep the status quo. Too many ITR BMW guys on the ITAC to be objective. You can tilt the smoke and mirrors all you want but it is spec BMW for years to come if it lives at all. Kirk will go down with his "process" and that is fine. At least he is consistent to a fault. Others will block any and all attempts to get it right because they like it how it is.
Prove me wrong and I will be the first to say "I was wrong" but not holding my breath. Grafton will continue his same BS he did when he tried to convince us all the E36 was classed properly and we see how that ended up. I guess I am just jaded after the goat screwing you guys gave the RX8 because of BS numbers. You will continue to ignore the fact it can not make even the rear wheel power of the E36 and way less torque and you somehow think you got the weight right. All the gears in the world don't make that right. Try to carry equal momentum in corners with that weight difference. Same for the S2000. Your process is broken in ITR and you know it. Now lets see what you do about it. Not personal guys, just the way I see it unfolding until now.
Pissed off but still
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JoshS
New member
First, understand please that there were *zero* BMW drivers on the ITAC when the weights of all of the original ITR cars were assigned. None. I personally didn't even know about ITR until after it was practically a done deal. In fact, one of the reasons I was told I'd be a good fit for the committee was because it would be good to have some BMW representation and knowledge because the BMW drivers in IT, in general, felt persecuted. Now you are saying that the BMW drivers have all of the control of the ITAC. I think the rest of the ITAC would agree that we (all both of us) don't. And we don't outnumber the Mazda drivers, BTW. And I'm an ex-Mazda driver. Mazda was so good to me that I actually feel guilty not driving one, I almost feel like I'm playing for the other team. But none of that has anything to do with the way weights get assigned, there's no personal bias.
Second of all, I personally know of at least two built S2000s, one 300ZX, and one Type R. Compared to other cars listed in the class, that's AT LEAST average, if not more than average.
You know as well as I do that the reason that there are so many more E36s running right now is because there were plenty of IT-legal cars already in the SCCA community at the launch of the class. That can't be said for any of the cars you listed. It's unrealistic to expect anything that wasn't already listed in IT to match that.
I never said we got the weight right for ultimate competitiveness. All I said was that we got the weight right with respect to the process. I'm relatively new (newer than you) to this process business, and I personally think there's a lot of room for improvement. But unfortunately, it's not possible to change the process without doing another huge reassignment of all of the weights of everything listed ... everything ... and that's too disruptive to do at this point.
Just in case it's not clear, the reason I say that is that because if you change the process mid-stream, then cars that were classed pre-change will not look like cars that were classed post-change, and that sort of inconsistency is worse (yes, in my opinion) than getting some outliers wrong.
In the meantime, we simply have to stick with the process we have. If some cars don't fit the existing process very well, they will just have to wait until the process can be changed.
I personally think that we should change the process to account for torque better. It'll help low-torque high-revvers, and it'll make it easier for us to include low-revving high-torquers like the pony cars as well. But as I said, we can't just change the process mid-stream without another great realignment, and I don't think the community has the intestinal fortitude to put up with that right now, not when most people feel things are better than ever.
Pissed off but still
Good thing you said that, because the tone sure doesn't come off that way!
With respect, Steve - it just didn't go down the way you want to believe. The fact that it didn't turn out the way you want is not evidence of shenanigans.
And you and I agree completely on the process. The ONLY place where we differ is the factor applied to the RX8 engine (and/or the veracity of the stock power quoted by Mazda, which is really different routes to the same destination).
I've agreed that since this car is a "class of one," that it is necessary to use a different power multiplier. Most of us participated in lengthy conversations trying to discern what the most correct multiplier would be. Many of us were willing to accept "real world data" and work BACKWARD to define that multiplier. I was - and remain - very leery of using that kind of data in that way, particularly if it comes without attribution, not for dissemination, and not triangulated from multiple independent sources that say the same thing.
I'm on record as suggesting that if we can define some "standards of quality" for the "real-world data" submitted, we might well be able to use them to influence factors applied to physical attributes - not individual cars unless their attributes are unique. To this point however, there's only limited agreement on the ITAC that there's any need to shift off of current practice: About that much we absolutely DO agree.
K
And you and I agree completely on the process. The ONLY place where we differ is the factor applied to the RX8 engine (and/or the veracity of the stock power quoted by Mazda, which is really different routes to the same destination).
I've agreed that since this car is a "class of one," that it is necessary to use a different power multiplier. Most of us participated in lengthy conversations trying to discern what the most correct multiplier would be. Many of us were willing to accept "real world data" and work BACKWARD to define that multiplier. I was - and remain - very leery of using that kind of data in that way, particularly if it comes without attribution, not for dissemination, and not triangulated from multiple independent sources that say the same thing.
I'm on record as suggesting that if we can define some "standards of quality" for the "real-world data" submitted, we might well be able to use them to influence factors applied to physical attributes - not individual cars unless their attributes are unique. To this point however, there's only limited agreement on the ITAC that there's any need to shift off of current practice: About that much we absolutely DO agree.
K
>> ...and you will get many more requests for this or that in order for them to be competitive.
I just don't know where you come up with this stuff sometimes, Travis. There's simply no provision in the category rules or practices to give anyone "this or that" to help them out. Yeah, people can ASK all they want but we'll continue to tell them "no" - no spec-line allowances, no creep, no additional allowances for modifications.
I appreciate your interest in keeping things simple but I don't think anyone here - least of all the ITAC members - are advocating for a regression analysis with dozens of factors.
K
I just don't know where you come up with this stuff sometimes, Travis. There's simply no provision in the category rules or practices to give anyone "this or that" to help them out. Yeah, people can ASK all they want but we'll continue to tell them "no" - no spec-line allowances, no creep, no additional allowances for modifications.
I appreciate your interest in keeping things simple but I don't think anyone here - least of all the ITAC members - are advocating for a regression analysis with dozens of factors.
K
Catch22
New member
I can easily see this discussion getting all crazy and headache causing, but to me Kirk has hit it on the head in the very first post.
If we don't have those things when cars are classed and weight speced, we might as well not even have a "process" at all.
In other words, if you use a process for some cars, but don't use it on others (because some *opinions* are that the process doesn't apply well to *that* car) you have exactly what we had before the ever was a "process" at all.
You have a group of people using politics and opinions to class and spec cars.
Not good. And not healthy for the class. Not at all.
Make a process, make it public, and do the best you can to fairly and openly apply it to ALL cars.
Anything else is just more "Secret Car Club" bullshit.
Scott, who says either you have a process or you don't. Having a process "sometimes" is just plain worthless and is the kind of thinking that got IT goobered up in the first place.
PS - Like Jeff noted on page 1, my biggest concern is members of the ITAC having an issue with this. Maybe I'm missing something, but thats pretty bothersome on the surface. And it explains why, as far as we've come in the past few years, on some cars the math just plain doesn't work. Seems like there are still some "politics as usual" at work. Not at all what I want to hear, and why I'm one of those folks currently not "bought in" to the process.
PS2 - Don't bitch on web boards. Make your feelings known to members of the ITAC and CRB either in writing (formally) or in person. Thats how this club works. Yeah, I've already done it.
If we don't have those things when cars are classed and weight speced, we might as well not even have a "process" at all.
In other words, if you use a process for some cars, but don't use it on others (because some *opinions* are that the process doesn't apply well to *that* car) you have exactly what we had before the ever was a "process" at all.
You have a group of people using politics and opinions to class and spec cars.
Not good. And not healthy for the class. Not at all.
Make a process, make it public, and do the best you can to fairly and openly apply it to ALL cars.
Anything else is just more "Secret Car Club" bullshit.
Scott, who says either you have a process or you don't. Having a process "sometimes" is just plain worthless and is the kind of thinking that got IT goobered up in the first place.
PS - Like Jeff noted on page 1, my biggest concern is members of the ITAC having an issue with this. Maybe I'm missing something, but thats pretty bothersome on the surface. And it explains why, as far as we've come in the past few years, on some cars the math just plain doesn't work. Seems like there are still some "politics as usual" at work. Not at all what I want to hear, and why I'm one of those folks currently not "bought in" to the process.
PS2 - Don't bitch on web boards. Make your feelings known to members of the ITAC and CRB either in writing (formally) or in person. Thats how this club works. Yeah, I've already done it.
are you going to be on the ITAC forever? Andy? Jake? didn't think so. how many times have we been over the sequence of events where if you allow something like bigger hubs from a civic on a CRX in the name of safety, that you will get washed down the hill with other similar requests in the name of "safety" which are really just thinly veiled requests at giving their car an advantage.
same thing if the process starts getting too granular. just watch people start asking for allowances to their car because of an upright windshield creating poor aero, or whatever else they can come up with.
and what was that you said earlier about volunteer organizations being poor at retaining knowledge? future ITAC boards won't necessarily have the same views as you guys. not to mention if/when it does go national, that just gives more tools for the CRB/BOD to screw with in the name of parity.
change the "adders" to a % rather than a set # and all is good in the hood.