ITB - what a bunch of crap

[Andy Bettencourt]

Send me the details>>>>

[CRallo]

continuing the hijack:

possible additional factor(s): does a fwd car tend to have less driveline power loss than a RWD car. Additional friction caused by a larger/longer/heavier would cause this... and a fwd car typically would have less driveline mass also, which would of course have less inertia and therefore provide better accel/decel...

The power numbers are important because flywheel hp numbers are used in the process, while it's wheel hp that actually makes the cars accel. This can be estimated, the effect of the inertial differnces would be harder to quantify...

the other big issue, in my eyes, is that a fast ITR/S fwd car may be able to be fast but can't keep the pace over the length of a full race... this however may be a factor of setup and driving style and how would this be corrected anyways??

[lateapex911]

It would be a good excersize to try and tie some math to the theory. ITA to ITS goes from 50 to 100lbs. ITR need 150lbs? Geez that's a lot...but like you point out, we are talking about cars with pw/weights in the low 11's.

Well, as long as we're doing some blue sky thinking, why not take that 100 pounds assigned to the middle of the bell curve car, back out the percentage, then do the same in ITR, but with a different percentage to equate to 150? That way the light FWD cars get less, heavier ones more.

[Greg Amy]

I think we wait a bit and see how the FWD R cars do before any changes are made.

...sesz the boys that don't race front-wheel-drive cars...

...why not take that 100 pounds assigned to the middle of the bell curve car...

So, effectively, make it a percentage of classified weight instead of a fixed number? That would address it better, though I think you'd want a "weighted formula" to also take into account power.

Alternatively, if you choose to base it on one factor, do it as a percentage of power instead of weight. Power has more of an effect on FWD front tire longevity and corner exit speed than weight alone. Ain't sayin' weight DOESN'T, just not as much as power.

The real limiting factor for lap times in FWD is "can you put that power down through the course of the race?"

[JoshS]

So, effectively, make it a percentage of classified weight instead of a fixed number? That would address it better, though I think you'd want a "weighted formula" to also take into account power.

Alternatively, if you choose to base it on one factor, do it as a percentage of power instead of weight. Power has more of an effect on FWD front tire longevity and corner exit speed than weight alone. Ain't sayin' weight DOESN'T, just not as much as power.

The real limiting factor for lap times in FWD is "can you put that power down through the course of the race?"

Man, you guys like to get complicated.

Let me remind you that all cars in a given class have roughly equivalent power-to-weight ratios. So an adder based on power vs. an adder based on weight is likely to result in basically the same answer for all cars in the same class.

So can't we just use a fixed number and make life simpler? Oh wait ... we already do!

[Greg Amy]

So an adder based on power vs. an adder based on weight is likely to result in basically the same answer for all cars in the same class.

Good point. So, since weight is based on power, ignore weight and adjust the subtractor on power. Same ole.

So can't we just use a fixed number and make life simpler? Oh wait ... we already do!

No, that doesn't follow your point above. If we were to base it on either weight or power, than the numerical subtractor must vary based on that.

A fixed number only works if there's a fixed amount of power or weight for all cars in the class. What you're actually suggesting in this last case is to base the subtractor on the chosen power-to-weight ratio, which is class-specific, not vehicle-specific and thus would not change. Circular logic...

What would be interesting is to know the "baseline" ITB car and its power level, then vary the current-50# subtractor as a function of its power...

[JoshS]

No, that doesn't follow your point above. If we were to base it on either weight or power, than the numerical subtractor must vary based on that.

Good point (back at'cha). But how much do we expect the current 50lbs (or 100lbs) to vary? Because it seems like it would be well within our normal margin of error based on the assumptions in the process ... in which case I still conclude, simplicity is good.

[Greg Amy]

...it seems like it would be well within our normal margin of error based on the assumptions in the process ... in which case I still conclude, simplicity is good.

Could very well be! It would be an interesting arithmetical exercise for someone with all the data...maybe someone that also owns an ITA Miata...hmm....wonder who that could be....

[Andy Bettencourt]

Could very well be! It would be an interesting arithmetical exercise for someone with all the data...maybe someone that also owns an ITA Miata...hmm....wonder who that could be....

Naw...that dude is ghey.

[Ed Funk]

Naw...that dude is ghey.

:eek:...yeah, and???

[RSTPerformance]

ITB is so diverse, it would be cool to build something for sure...for me, it has to be RWD so the 924 and the MR2 would be the most viable. Wishing there was a Mazda-based choice! We would have a driver in there fo-sho!

Hey Ray-Ray, why don't you try ITA?

I want a chance to win and my girlfriend says that I cant drive a "ghey" car...

Not to mention I think ITB has a lot more realistic competition week to week, although Beran is making it tough... We did have an oportunity to pick up a 2nd gen MR2 for ITA and thought real hard to build it together (Stephen and I) but we just didn't have the $$$ to build it right.

Raymond

[tnord]

....because i'm waiting for the wife to get home.

if you assume that the 50lb FWD weight break is ideal for ITA, and adjust ITS and ITR based on the % weight break given to ITA, well......nothing really happens.

i did this pretty quick, and it might be wrong.

[Knestis]

>> ...The key for the future will be to make correct classifications and add in some new blood that doesn't dominate quite as easily as the Golf III does.

Total BS.

If the car was magic, I'd have been in the top three at the 'festival. Beran and Aaron were up there because they had the right combination of car preparation, tuning, and talent. Bowie won the ARRC in a car that I couldn't get within 2.5 seconds of his qualifying time. He got there by grabbing by the scruff of the neck and wringing the shit out of it.

I daresay that if Vaughn put the time and energy he has into his 924 into an Audi, he'd be right up there.

K

[Greg Amy]

if you assume that the 50lb FWD weight break is ideal for ITA, and adjust ITS and ITR based on the % weight break given to ITA, well......nothing really happens.

Share the process on that exercise?

[shwah]

Valid points Kirk, but the car is light. Not over 100 light we are told, but light. I have seen the car win races against stiff competition and shatter lap records with stock bottom end - granted very well driven, but still. It's light, or other cars are heavy.

[RSTPerformance]

>> ...The key for the future will be to make correct classifications and add in some new blood that doesn't dominate quite as easily as the Golf III does.

Total BS.

I daresay that if Vaughn put the time and energy he has into his 924 into an Audi, he'd be right up there.

K

K-

First, I doubt Vaughn would be faster in the Audi, despite the age of our cars, they are very well developed. The 924 and the Audi are probably a toss up depending on the track. With that said, do I think the Audi or the 924 have a shot at winning on the "right track" against the Golf III, yup. I wont argue that.

However, with a good driver behind the wheel of a developed Golf III it is going to be tough to beat. It is a fast car that is well rounded and strong at most tracks. To me this is the dominant car for the class (Not a runaway that will always win, but will likely hold a lot of track records). I don't think you will find many that will argue against that. The Golf III is clearly not an oddball and is a good benchmark for where the top of the class should be maintained at a max.

Raymond

[tnord]

Share the process on that exercise?

i tried to upload the excel file so everyone can see the formulas behind the numbers, but the site won't let me.

basically i just grabbed a bunch of the popular FWD cars in ITA (ended up being 17 of them), added back 50lbs per car to get their base weights, then devided 850lbs (17 cars by 50lbs each) by the base weight to get a "FWD discount factor" for ITA, since that was thrown out as the ideal % break.

then i took a handful of the popular (and potentially popular) FWD cars in ITS/R, added back 50lbs to each of their min weights to get the base weight, the multiplied by 1-"ideal FWD discount factor" i calculated from the ITA numbers. compare that number to the current min weight, and that's your "delta" column on the far right. in the end it only resulted in a net change of about 10lbs at most.

i went through this not only because i had time on my hands waiting for lindsay to get home, but because i thought it was the proper method. i also thought it would yield a bigger weight reduction than it did.

i think in the end the FWD cars in the faster classes are already at lower weights because their power levels are lower, so the 50lb FWD weight break is still somewhat close to the ideal percentage based on ITA numbers.

my method or calculations certainly could be wrong, as i did it in about 10min. but on the face of it i think it's pretty good.

[gran racing]

K,
The car isn't magic but it most certainly is light and has some other nice advantages. No doubt about it. I had an interesting conversation at the IT Fest with a certain someone and we started talking about the Golf then my Prelude. He asked me what my car weighed and was surprised saying he thought it's kinda heavy. I replied that the Prelude isn't light for the class rather the Golf is light.

I will say that if a decent driver is put in other ITB cars then put in a Golf of similar prep, they'll be faster in the Golf. None of this means that a driver who does well with a Golf isn't talented. Oh, and yes I've certainly given thought to going out and getting a Golf myself but just doesn't work with my current racing budget.

[Andy Bettencourt]

Dave - what are the 'nice advantages' of the Golf? The only difference it has in its process weight is a -50lbs for a beam rear IIRC.

[924Guy]

LOL... I think you guys are forgetting that me and my car already have beaten Beran and his Golf... take another look at the IT-Fest results... Or just watch this, starting at about 7:55...
[ame]http://www.youtube.com/watch?v=c27uOudCuMo[/ame]


No, I don't think I could be as fast in an Audi. Certainly not faster...