FWD vs RWD: Adders, Subtractors, and Weight, Oh my...!

[lateapex911]

Why FWD?
While the actual act of driving the car thru the front wheels might, or might not, be entirely responsible for the cars deficits in lap times vis a vis equivalent RWD cars, we use it because it's a consistent and easy to identify trait. In other words, IF the real reason these cars are slower is the weight distribution, well fine. But the ITAC doesn't have that info. But the fact that FWD cars consistently have bad weight distribution helps the ITAC to adjust the process in a fair and transparent manner.

Do other cars that have crappy weight distribution get the dick sandwich? Yup. Oh well. But we need to use obvious "triggers", and the FWD spec is easy.

It's not perfect, and will never be, but it's better than classing two cars with equal specs other than driveline layouts at the same weight.

I think we just need to find appropriate "bogeys" for each class.

[Jeremy Billiel]

Why FWD?
While the actual act of driving the car thru the front wheels might, or might not, be entirely responsible for the cars deficits in lap times vis a vis equivalent RWD cars, we use it because it's a consistent and easy to identify trait. In other words, IF the real reason these cars are slower is the weight distribution, well fine. But the ITAC doesn't have that info. But the fact that FWD cars consistently have bad weight distribution helps the ITAC to adjust the process in a fair and transparent manner.

Do other cars that have crappy weight distribution get the dick sandwich? Yup. Oh well. But we need to use obvious "triggers", and the FWD spec is easy.

It's not perfect, and will never be, but it's better than classing two cars with equal specs other than driveline layouts at the same weight.

I think we just need to find appropriate "bogeys" for each class.

I am with you Jake. So how do we go about creating these boguys? This is the challenge. We can model it out on LapSim, we can speak to it, I believe we ALL know the problem. Do we bump up the ITS and ITR deductions by 50 lbs each?

[ekim952522000]

I am with you Jake. So how do we go about creating these boguys? This is the challenge. We can model it out on LapSim, we can speak to it, I believe we ALL know the problem. Do we bump up the ITS and ITR deductions by 50 lbs each?

The only real stance i have on it right now is that I believe whatever deduction ITS get's ITR should get slightly more.

EDIT: But on second thought as I said earlier I don't think any of the ITR cars can get any lighter so it may not matter. It's also such a new class maybe it would be better to see how things shake out first.

<----------The more we talk about this stuff the more I realize how hard being on the ITAC would be. I can see how someone could just end up wanting to say no to everything but even that has it's problems..........

[Andy Bettencourt]

The only real stance i have on it right now is that I believe whatever deduction ITS get's ITR should get slightly more.

I agree. 100/150?

125/175?

150/200?

This is the problem...we have identified the issue and we are at 100/100. 100/150?

[Jeremy Billiel]

I agree. 100/150?

125/175?

150/200?

This is the problem...we have identified the issue and we are at 100/100. 100/150?

I would think 150/200 would be about right looking at the lapsim data.

[Greg Amy]

...we have identified the issue and we are at 100/100.

200/250, but this is coming from someone who still believes in the Tooth Fairy...

[Eagle7]

[quote=JeffYoung;281605]That is where I am headed.

Stock hp * 1.25 in almost every case with a torque adder, and that is IT. Nothing else. quote]
I know this is the wrong thread, but I'd be interested to know what the distribution is of the HP multiplier used for cars that have been through the process. This seems like a hugely subjective part of "the process". I hope Kirk et. al. can make some progress in objectifying it.

[Andy Bettencourt]

I would think 150/200 would be about right looking at the lapsim data.

Good. You guys are right at -150. :eek:

[Ron Earp]

200/250, but this is coming from someone who still believes in the Tooth Fairy...

So an ITS Acura Integra that weighs 2430 and 2590, depending on which model it is, would receive a 200 lb deduction off the current weight?

These cars put down the same rear wheel hp, or more, as any other S car. They have great brakes and a great suspension and in well-built trim, at least down here at VIR, they turn laptimes that are similar to the fastest ITS guys in strong fields.

I know we can't use on track performance to adjust the rules and that sort of thing, but dang, this would turn an already great car into a heck of a car to have in ITS.

I don't know how that would shake out in ITR. I doubt the Celica can acheive a 250lb break with out a remote control driver. I think the current weight is 22XX lbs.

I think I must have something screwed up. Don't the weights already reflect a 100lb deduction for FWD? So in essence the proposed deductions is X - 100lbs?

[Andy Bettencourt]

So an ITS Acura Integra that weighs 2430 and 2590, depending on which model it is, would receive a 200 lb deduction off the current weight?

No Ron. It would change the FWD dedcution from 100 to 200lbs in Greg's scenario. Here is the GSR in a -150lb scenario for ITS.

170*1.25=212.5*12.9=2741.25

2741.25 -150lbs for FWD, -50lbs for lack of torque and +50lbs for double wishbone = 2590!

[ekim952522000]

I agree. 100/150?

125/175?

150/200?

This is the problem...we have identified the issue and we are at 100/100. 100/150?

Something I would like the ITAC to consider is removing the -50lbs that FWD cars recieve for having struts. It is the only suspension modifier used in the ITR and seems out of place.

So in reality if we were talking about about some common FWD cars in ITR recieving a 150lb deduction instead of a 100lb the weights would look like this

Celica 2380 = same since it would not be getting the strut dedcuction
Type R 2535 = 2485
Prelude 93-96 = 2570 = 2520
Prelude(97-01) 2640 = 2590
RSX-S 2665 = same since it would not be getting the strut dedcuction
Legend 3135 = 3085

Which I think is very close to achievable for the cars with a 180lb driver.

[Ron Earp]

No Ron. It would change the FWD dedcution from 100 to 200lbs in Greg's scenario. Here is the GSR in a -150lb scenario for ITS.

170*1.25=212.5*12.9=2741.25

2741.25 -150lbs for FWD, -50lbs for lack of torque and +50lbs for double wishbone = 2590!

Well, that is why I asked and put that last line in my post - I had to have had something screwed up!!!!

[Greg Amy]

Good. You guys are right at -150. :eek:

Proving that I was right when I suggested the 200.

Again.

[Andy Bettencourt]

Proving that I was right when I suggested the 200.

Again.

Based on what? That is the point Greg...what are you using for evidence that your car is 50lbs 'heavy'? How much is too much? 201lbs? 250lbs? 300lbs? The LapSim seems to support about 150 as Jeremy states, so when do we go too far?

[ekim952522000]

Based on what? That is the point Greg...what are you using for evidence that your car is 50lbs 'heavy'? How much is too much? 201lbs? 250lbs? 300lbs? The LapSim seems to support about 150 as Jeremy states, so when do we go too far?

Maybe it's not the 150 FWD subtractor that's wrong maybe it's the 50lb add for double wishbone suspension?

[Knestis]

Apropos of nothing (I LOVE THAT), I think the suspension adder is less meaningful by a long shot, than the FWD subtractor. Yeah - I'd love it if the Golf didn't push like it does but I think it can be worked out, and it's a smaller-magnitude thing than driveline configuration.

K

[Tristan Smith]

so when it rains, do the front wheel cars have to add weight? Cause everyone knows the FWD cars have an advantage in the rain. So I propose that when ever there is a wet track, all FWD cars not only have to add the weight that you propose that they take off, but that RWD cars either get a weight break, or some lead has to be thrown in the FWD cars.

[Andy Bettencourt]

Sweet, I'll take my 50lbs back thanks!

Seriously, I am having 3 off-line conversations on this right now. 2 that think 200lbs is CRAZY given equal suspension and equal power and one that seems to be going by 'feel'. I just want to know why 200lbs is 'more right' than 150lbs.

[ekim952522000]

No Ron. It would change the FWD dedcution from 100 to 200lbs in Greg's scenario. Here is the GSR in a -150lb scenario for ITS.

170*1.25=212.5*12.9=2741.25

2741.25 -150lbs for FWD, -50lbs for lack of torque and +50lbs for double wishbone = 2590!

Andy do all of the FWD cars in ITS get the 150lb weight break right now? I think they might....I always thought it was 100......

Prelude Si
160*1.25*12.9=2580 + 50 DW - 150 FWD = 2580 current weight is 2555?

[tnord]

this whole thing is a big heaping pile of poo from where i sit. this is a new approach to the same old agenda....."my car needs less weight."

it was maybe only a couple months ago certain people were campaigning that we should give the same % weight break to the ITS/ITR cars that we do for the ITA listings, it was argued that the ITA weight break was good and to use that as the bogey. that seemed like a somewhat reasonable request rather than the adders we have now. so i actually ran the numbers. my post from another thread talking about the power gains from Honda motors;

the last time this came up, it was said that the FWD "adder/subtractor" was correct for ITA, but for ITS and ITR it wasn't enough. so i actually took some time to see just what would happen, if we used the same % weight break for ITS/R as we do for ITA FWD cars.

i took 18 popular ITA cars, and came up with an average % weight break of 2.08. going through the list of FWD cars in ITS/R, % weight breaks for FWD ranged from a low of 1.58% for the Mitsubishi 3000GT, and a high of 2.06 for the Celica GTS. applying the 2.08% to all of these cars didn't change much, with 16lbs more coming off the the aforementioned Mitsu. the cars everyone likes to complain about flowed through as follows;

Integra GSR; -5lbs
Civic Si; -2lbs
Prelude VTEC; -11lbs
GTi VR6; -7lbs
Acura RSX-S; -6lbs
Celica GTS; -1lb

well since that didn't result in what the flag waivers wanted, here we are again....but this time they want a subjective weight break, and are trying to back into "data" to support it. FWD is already accounted for, and i know you claim it's the biggest issue outside of horsepower, but fuck me how much granularity do we need here?

if we really want to get that specific, then the convienently overlooked comment by someone a few pages back about how FWD cars suffer less drivetrain losses than RWD cars should be evaluated. after all, power is even more important than a FWD layout. lets give all FWD cars a 28% multiplier rather than 25.

i'm not buying this "for the good of the category" campaign BS at all. this is all about personal agendas and egos.