How to deal with class G?

[Solar]

Correct me if I'm wrong, but to determine which class I'd be in I would divide my vehicle weight by the HP ? Then add or subtract any modifiers??

My Civic Si

Curb Weight (lbs.): 2744
Horsepower @ rpm (SAE net): 160 @ 6500

2744 ÷ 160 = 17.1

17.1 + 2 = 19.1 Class "C"

[Loren]

Correct.

[Anonymous]

I think if you are going to use a formula it needs to be weighted to put more importance on curb weight.

IE the pax system says these cars are almost equal and it would be a drivers race and mostly course dependent...

96.9
FS
Mustang
Infiniti G35
Camaro z28

96.5
ES
Miata (1st Gen)
MR2 (2nd Gen)
Porsche 944

Yet, your example puts a Mustang Cobra at 9 (class A), and a 1991 Miata at 18 (class C). I would like to see these 2 go head to head. However, I have no interest in watching a Mustang get spanked by s2000's every month.

Maybe Steve can write us a weighted formula? I forget how to do math.

Something like ((Weight X Weight)/HP)/1000. LOL

[WAFlowers]

A Cadillac CTS-V has a better power to weight ratio than a Lotus Elise, so it should be faster, right?

My ex senior partner owns a CTS-V. The way I've seen him drive it (he once raced a Porsche) I believe the Caddie could be faster. :shock:

[impalanut]

Just watch Kenny beat most people with his 4200 lb Impala. Beat everyone but Danny Shields at one event with a basically stock 95 Impala SS and dot R tires.

[Dave-ROR]

Just watch Kenny beat most people with his 4200 lb Impala. Beat everyone but Danny Shields at one event with a basically stock 95 Impala SS and dot R tires.

Yeah but ask Kenny about his award for the Fastest Impala to get beat by The Isuzu Truck. Sure, we were both on street tires, but I only had 93bhp

[Loren]

Okay, here's a formula that puts the Cobra in with the Miata, like Jeremy suggested. (I'm not sure I agree with doing it... I think in the right hands, the Cobra should be WAY faster than a stock Miata, especially a 1.6)

This formula takes into account Power, Weight and Tire Width (drive wheel tire):
WEIGHT/(POWER/TIRE) = CLASSING FACTOR

For a 1.8 Miata, that's:
2300/(130/205) = 3637

For a 1.6 Miata:
2200/(110/195) = 3900

For a heavy V8 car (guessing at Cobra numbers):
3600/(300/305) = 3660

For my Yaris:
2400/(106/195) = 4451

For an Elise (guessing at specs again):
1900/(150/195) = 2470

For a Z06 Corvette:
3200/(505/325) = 2059

Some statistical genius like Steve will need to look at this closer to see if it will REALLY work. But the trend seems to indicate that cars with greater potential are clearly identified by this method. Looks like you could make the break points something like <3000, 3000-4000 and 4000+

Somebody play with it. See if it can work.

[Native]

I'd love to play with the numbers, but I have absolutely no time to mess with it, and don't expect to any time soon. Besides, it's up to the committee that will eventually form.

And I'm a little confused now - are we revamping class G, or talking about completely restructuring our classing system? Cobras, Impalas and CTS's aren't in G...

[Loren]

Given our formula-based classing system, unless you want to make exceptions or a special formula for cars under 3 liters... perhaps a whole new formula is best?

[TracAction]

I like the formula idea but if you use stock power to weight ratios then you should not punish factory turbos on cars because that is their factory specs. MSM and the mazdaspeed3 and yes my 1.8T german car are factory cars and to then place an additional penalty because I have factory equiptment would not be right. NOW if i had an aftermarket or non factory turbo then yes add a modification to the formula.

example formula

everyone starts at stock with the stock formula being (W/1000)H= stock preformance factor (just an example)

race tires=T where T= 200
Fuel mods = F where F = 100
suspension mods = S where S= 100
light weight mods =L= 100
(optional ultra competative mod) =R= 200

Or optional novice =0 clubman class = 100 and pro class = 200

could even add things like deducts for 4door cars and stuff (you get the idea)

So my car would be

(3131/1000)180+100+100 = 663.58

and a stock 2000 s2k would be
(2809/1000)240 = 674.16

stock 2000 miata
2332/1000)140 = 326.48

stock 2007 mazdaspeed3 is 829.239


so if you do the breaks at say
1000+ class A
801-1000 class B
601-800 class C
401-600 class D
100-400 class E

[TracAction]

I'd love to play with the numbers, but I have absolutely no time to mess with it, and don't expect to any time soon. Besides, it's up to the committee that will eventually form.

And I'm a little confused now - are we revamping class G, or talking about completely restructuring our classing system? Cobras, Impalas and CTS's aren't in G...

yea sorry I guess my method is a total revamp so I duno if it would apply here

[Loren]

We're focusing on stock classing right now. Using factory stated HP rather than displacement, the 1.5 turbo factor is a moot point, we won't be using it.

I'm not sure anyone has expressed any problem with the modified or race tire class structure. I would assume that we'd leave those classes as they are for now.

[WAFlowers]

For a heavy V8 car (guessing at Cobra numbers):
3600/(300/305) = 3660

Actually for an '04 SVT Cobra it should be:
3665/(390/275) = 2584 (sources edmunds.com and tirerack.com)

That puts it between an Elise and an S2000 I think and I'm not sure that that is the right place for it. Crap, now I've just got to dig up those numbers to satisfy myself (if no one else) as to how the Elise calculates.

For an Elise (guessing at specs again):
1900/(150/195) = 2470

Actually:
1984(189/225) = 2361

Hmmm ...

For my '03 S2000 (and earlier):
2809/(240/225) = 2633

An '04 S2000 (and later):
2835/(240/245) = 2894

And, for fun, '05 Subaru WRX STi:
3300/(300/225) = 2475

I can't figure out if I like the way this formula works or not. And I sure couldn't figure out where I'd want to divide it if I did like it!

[WAFlowers]

For my '03 S2000 (and earlier):
2809/(240/225) = 2633

An '04 S2000 (and later):
2835/(240/245) = 2894

Quoting my own message is definitely bad form, but something about what I posted just didn't look right.

Ignoring other drivers, I've driven both an '03 and '04 S2000. The '04 is faster because the '03 doesn't have enough rubber (with stock wheels) to lay the power down, IMO. OK, there are other reasons too, but ...

By the proposed formula the lower number is faster, and that says that my '03 is faster than an '04. I disagree. Based on that I'd say the formula doesn't work for this case and may not for other cases.

And now I'll go to bed and ponder in my sleep.

[Loren]

I can't figure out if I like the way this formula works or not. And I sure couldn't figure out where I'd want to divide it if I did like it!

So far, it's the only formula I've seen anyone present that's SIMPLE and seems to get fairly close. Way better than the current <3 liters classing that puts an Elise competing against a Yugo.

To really analyze it, we'd need to do the math on all cars that we regularly see compete, plus a few other examples of common cars, and a few examples of potential "overdog" cars to see where they fit. That will help us decide where the breakpoints should be.

The interesting thing about this classing method is that a person who's car is near the limit (upper or lower) of their class could change their class by fitting a different width tire. I like that. It adds an element of strategy.

[Loren]

By the proposed formula the lower number is faster, and that says that my '03 is faster than an '04. I disagree. Based on that I'd say the formula doesn't work for this case and may not for other cases.

And now I'll go to bed and ponder in my sleep.

Bill, wheel and tire width is not something that we limit in our stock class. So, you could put the 04 wheels and tires on an 03... where would that put you? Hmmm?

No classing system is going to be perfect. I don't think we're looking for perfrect, we're just looking for "better".

[Dave-ROR]

Technically the OEM S-02's on a 2000-2003 S2000 are very very wide, right between a 235 and 245, despite the 225 rating. As we know, not all tires of XXX width are the same width... doesn't break the formula, but the 2.0L cars aren't that undertired, the suspension changes make up most of the difference.

[WAFlowers]

Dave, you're right; I'd forgotten that the OE S-02 is wider than stated. This is what happens when I crunch numbers late at night after taking Benedryl! I am running 245 rears in fact.

BTW, I agree that there is more going on than the tire width (i.e. suspension changes). For my own purposes do you know of someplace I can get a definitive definition of those changes?

Loren, the formula isn't bad. It takes into account the most comment metric (power to weight) and also says "bigger, heavier tires will slow you down". At least, I think that is what it is saying. Strong advantage is that it is simple using readily available (or guessable) numbers. And in truth it said the AP1 and AP2 S2000 are close to each other, which they are. So grossly the formula works even in that case. It doesn't take into account the other differences between those models (and no simple formula could) which tips the scales one way or the other.

I was just wondering if it worked in all cases and was trying to give someone a starting point for a detailed analysis that needs to be done (as you suggest) before it could be adopted.

And, yes, someday I will have '04 wheels (or similar) on my '03 wearing Falken Azenis. If it wasn't for buying the B&B (deal is done now) I'd have them already, but I'm not made of $$$.

[Loren]

and also says "bigger, heavier tires will slow you down". At least, I think that is what it is saying.

I hadn't thought of that... but yes, the lower powered cars that are on the verge of bumping up a class would penalize themselves by fitting a wider tire.

The real intent that I was going for with tire width was that if the car is high-powered, it is penalized more if it actually has the treadwidth to make use of the power. It's a very rudimentary way of separating the high powered "luxury sports sedans" from the true sports cars.

[Anonymous]

everyone starts at stock with the stock formula being (W/1000)H= stock preformance factor (just an example)

race tires=T where T= 200
Fuel mods = F where F = 100
suspension mods = S where S= 100
light weight mods =L= 100
(optional ultra competative mod) =R= 200

LOL at ultra competitive mod. I guess you just bumped me up a class.

Seriously though, I don't understand how you guys think formulas are an easy way to class cars. Let's say I am a noob that shows up to an event in a 1991 Camaro V8. Who is going to help me class my car that morning, and how long is it going to take? How many people are going to need help the morning of the event with car classing?

I think it's kind of a waste of time to try and write formulas when Rick Ruth has already done all the work for us with the PAX index.

Is the PAX index perfect? No.

Can we make a formula that is more fair than PAX? I doubt it, considering PAX is based on real results.

Sure PAX is based on cars with R-comp tires. is that going to make such a huge difference for our needs with FAST? Doubt it.

Also, you should consider the fact that some people such as myself already know off the top of my head what cars go in which SCCA class. There is no one here who knows the weight and HP of every car.