Power:Weight in Mod Classes

[Loren]

Okay, we've pretty much decided to leave most of our classing alone for the coming season. Definitely leaving Stock classes where they are until the smoke clears from the latest SCCA stock class prep rule changes, and no major changes seem to be indicated in other classes.

Several people have brought up the issue of underpowered cars in our M2 class, however. And, I think it is a relevant issue that warrants further discussion. Our mod category preparation rules are different enough from the SCCA Street Prepared classifications that we use for a basis for classing, as well as from the SCCA Street Touring classifications, that we shouldn't expect every decision those guys have made (or every Frankenstein creation that someone decides to build) to apply directly to our system.

I would like to explore two options. (not mutually exclusive, we could potentially do both)

1. Allow any car that is COMPLETELY eligible for SCCA's STS class to run in our M3 class. This is generally low-powered sports cars with a specific wheel width limit (I think), and limited slip differentials are not allowed. These cars can't compete with our M2 class and should be a good fit for M3.

2. Allow any driver to petition to run their M2 car in M3 if the can demonstrate to us (us being Steve, myself and at least one other "expert" of our choosing) that their car has a power to weight ratio equivalent to more than 16 pounds per horsepower. I have NOT run every possible scenario to test the feasibility of this, but I feel that to come anywhere near to top of our M2 class, a car needs to have a good (or at least well-sorted) suspension and push no more than 16 pounds per hp. And I am reasonably certain (prove me wrong if I am) that no car that has 16lb/hp or more will be an overdog in M3.

Why consider any of this? Because FAST is a "run what you brung" club and a lot of people "bring" cars that don't fit the SCCA's Street Prepared mold of building a car to the "best of breed" standards. We want people to be able to come out in the car that they happen to have and not feel like they HAVE to do an engine swap to be competitive. Sure, some cars are hopeless, but in general, I like to think that just about any sports car or truly "sporty" car should be able to be reasonably competitive in mod with just bolt-on suspension, wheels and tires and some basic bolt-on intake/exhaust stuff... with a good driver, of course.

There's something that I never really expected happening in FAST over the past year or two. In spite of the fact that we're a small local club and building a car to meet OUR rules pretty much makes the car illegal or uncompetitive under ANY other ruleset (especially SCCA's), people are building their cars closer and closer to the limit of our rules... which very much stresses those rules and results in "spending wars" in pursuit of podium finishes. THAT is the one thing I don't want to see in FAST. I don't want people to HAVE to spend a ton of money to be competitive in anything other than our very top classes.

So, IF item #2 above is seen as a reasonable idea, we might even consider "upper limits" for power:weight in the mod classes. Rough ideas:
M3 = 14:1 max (no min)
M2 = 10:1 max (16:1 min?)
M1 = 8:1 max (12:1 min?)

Now, like many of our rules, these would be primarily "self-policing guideline" rules, as we have no way of knowing exactly what a car weighs or how much power it's making. BUT... for instance, if someone took a 2100 pound Miata and put an 345 hp LS1 in it... we could be certain that the power-to-weight would be in the vicinity of 6:1, which is way beyond the 8:1 max for M1. Likewise, something like an old 1800 pound VW Rabbit with a 200 hp VR6 swap would be about a 9:1, which is beyond the M2 limit. This kind of puts a cap on our "very open" engine swap and forced induction rules and prevents overdogs being built that make factory-powered cars obsolete. Our game is not intended to be won by the guy who says "watch me exploit these weak rules and build a car that is faster than anything else in this class", but by the guy who says "my car is no faster than the fastest cars in this class, but I'm going to win it because I know how to DRIVE".

Note that the numbers I used above are all just examples to explain the concept. They may or may not be close to "correct". If the concept is sound, we can do a little research and pin down the numbers.

Discuss.

[Jeremy]

This is such a pretty thread, I hate to ruin it, but...

Here is a list of cars that finished greater than 2 seconds away from first in M2 in the last 5 events. Don't they all have a case for moving down?
I just don't feel comfortable telling the 1.6 driver that "they are OK to move down a class", but all the people that finished beneath you, "you are in the right class, you just suck real bad."

I see both sides, I would just prefer to keep the rules simple (ie same) and tell the 1.6 drivers to suck it up and take their 10hp deficit as a challenge. Maybe we can force to the 1.8 and 2.0 drivers to run with their AC on to even the playing field.

89 Ford Mustang
91 Mazda Miata
92 Mazda Mx-3
91 Mazda Miata

89 Ford Mustang
91 Mazda Miata
92 Mazda Mx-3
91 Mazda Miata
04 Subaru wrx

95 Mazda Miata
06 Mazda MX-5 Miata
06 Mazda Miata
94 Mazda Miata
93 Mazda Miata
91 Mazda Miata
12 BMW M3
13 Ford Boss 302
90 Ford Mustang
90 Ford Mustang

13 Ford Focus ST
93 Mazda Miata
13 Subaru BRZ
90 Miata
02 Mazda Miata
90 Ford Mustang
92 Mazda Mx-3
72 Chevrolet Chevelle
90 Ford Mustang
70 Buick Skylark

92 Nissan 240sx
97 Chevrolet Camaro
91 Mazda Miata
02 Mazda Miata

[Loren]

Now, take out all of the cars on that list that are either not eligible for M2 or not known to be anywhere near prepared enough for the class and not driven by a driver who is known to be able to drive the car consistently to at least 9/10. What does that leave you with?

And that "10 hp deficit" is a lot more than that. The 1.8 Miatas have more than a 10 hp deficit, but they MIGHT be able to overcome it due to their light weight and good suspension. A lot of other cars (not just 1.6 Miatas) have much more of a deficit than that.

Current M2 top dogs:
1987 Mustang est. 240 hp 2800 pounds = 11.7:1
Turbo 240SX conservative est. 220 hp 2700 pounds = 12.3:1
2006+ MX-5 est. 180 hp 2500 pounds = 13.9:1
1994-97 1.8 Miata est. 140 hp 2200 pounds = 15.7:1

Now, I think 3 of our club's best drivers are in the Mustang, 240 and MX-5 (that's me, Jeremy and Drew, even though Jeremy and I are driving in M0 this season)... and it's a toss-up as to which car will finish first at any given event... but they're almost always within about half a second or so. What about those 1.8 Miatas? Arguably, maybe not quite as good drivers... but I think Steve, Greg and Kurtis are pretty damned good. And they're usually within about a second of the top... so maaaybe it's driver skill that's keeping the 1.8 Miata from winning M2. But, even when Drew drives Steve's Miata, he's still over a second back.

I think this readily demonstrates that power-to-weight is a factor and it's unlikely that anyone with LESS power (to weight) than those 1.8 Miatas can compete in that class.

And Miatas are just the easiest example to produce because we have lots of them and I happen to be very familiar with them. Got a 1995 Mustang V6? 3000 pounds and maybe 160 hp = 18.8:1. An obvious candidate for M3. I'm sure there are tons of other "underdog" cars that would be a much better fit for M3 than they are for M2. Acceleration IS part of the equation for success in M2, though. Please drop the "Miatas against the world" angle. That's not what this is about. Any CSP or ESP car that is typically competitive in SCCA with a particular engine, but HAS an engine option that is readily available and has nowhere near the same output is a potential benefactor here.

[AScoda]

1987 Mustang est. 240 hp 2800 pounds = 11.7:1

No Mustang ever weighed less than 3K.
I weighed mine once. It is just over 3200lbs empty. The 240hp is about right, which puts me at 13.3 lbs/HP.
I think Steve's car had a bit more in it the event I drove it. Probably wouldn't have caught Charles, but on a different course, who knows.
I don't know if that stuff is helpful or if it just muddied the water.

[Jamie]

...we have no way of knowing exactly what a car weighs or how much power it's making.

Therein lies the problem. As with the camber rule in the stock classes, unless someone brings in actual measurements or credible calculations, this camouflages guessing with what sounds like measurement and analysis. It's not even good back-of-the envelope math.

I like to think that just about any sports car or truly "sporty" car should be able to be reasonably competitive in mod with just bolt-on suspension, wheels and tires and some basic bolt-on intake/exhaust stuff... with a good driver, of course.

There's where you've identified the problem. Don't want to bruise any egos, but we haven't had a really good driver in one of those low-powered, open-diff cars lately, so we don't have any decent comparisons. A hazard of being a fairly "young" club, with a large contingent of casual and inexperienced drivers. Looking at a few months of results, shifting the cars you're talking about from M2 to M3 won't really change much in terms of class position until the drivers get better -- they'll just form the back half of M3. Owners willing, maybe have some of our hotshoes co-drive cars (or configurations) they're familiar with for a few events and see what shakes out. I'm betting on a significant change in performance potential.

Thinking a bit further out of the box, we may be pinning our mod classes to the wrong SCCA classes. You pointed out that real SP cars aren't much like our Mod cars -- R-comp tires, different (and more) restrictions on modifications. Maybe we look at pinning the Mod classes to Street Modified, which while not identical, is far closer as a ruleset. Or run Mod off a points system, a la NASA. Or ? Nearly anything is better than rules based on best guess by an arbitrary panel.

[Jeremy]

Power:Weight is great for drag racing. But I think weight plays more of a role in autocross than power does.

Sweet, my V6 Mustang is now faster than an s2000!!!
So I went from M2 to M3, and now I am in M1!!!

3632/444 mustang boss 8.2
3433/348 Genesis Coupe 9.9
1984/190 Lotus Elise 10.4
3351/300 STi 11.2
3501/305 mustang v6 11.5
2809/240 s2000 11.704
2900/220 SRT-4 13.2
3069/225 87 Mustang 13.64
2441/170 2006 Miata 14.3
2299/140 99 Miata 16.4
2182/116 1991 miata 18.8

[Greg]

In the past 7 events (that I've checked), I've been averaging top 10 finish. In terms of H.P powah levels.. I would say my car is the fastest lowest H.P car in the club

My car has 181K miles on a unopened 1.8 motor.
The only motor upgrades I have is a Jackson racing catback and a eBay cone filter taped onto my stock MAF intake.
I'd be lucky to get away with 125hp.
The car probably wights more than 2250 Lbs.
Torsen.

"I" cant really get faster than this.. however, 1.6 cars with similar mods technically shouldent be much slower either?

Moral of the story is Jeremy and Drew are a bunch of no good stinking cheaters, and should be banned from FAST...

[eborn986]

Alright, I know I'm pretty new here, but here are my thoughts - take 'em or leave 'em...

First - I think Power to weight is A factor, but not THE factor for changing classes. The best thing that I have seen come up that eludes to this is Jamie's suggestion of a point based system like NASA.

I'm consistently a couple of seconds behind the lead pack in M2 in a car that is somewhere between 9:1 and 10:1 power to weight. Additionally, I consistently finish within less than a second of Richard in a 91 Miata which I believe is a 1.6 car? All of that being said - moving me to M1 for Power to weight wouldn't change that a lot - I would still be placing at the back of the pack and down by a few seconds.

Additionally - as Jamie and Jeremy pointed out, classing by power to weight on the fly is likely to become quite the slippery slope. Somebody could "mask" their ratio to drop a class (or stay in class) by considering wheel hp instead of crank hp and a loaded weight (i.e. spare tire in the trunk, driver and passenger in the car, whatever crap you have in your car day to day) instead of emptied out as it would be on the track.

I know M0 is a voluntary class and I think that's a nice thing to have, but maybe to make things more competitive across the board there should be some drivers stepping up and moving into M0 if they really are just dominating the class... And I'm not saying this is happening in the classes in question, just pointing out that we can keep discussing ways to change the classes and there will always be reasons to do it and reasons not to.

Without making specific classes for each little time group that seems to form within our current classing there is always going to be some sort of gap to fill in the class - especially with all of us new guys coming in and the learning curve associated with that. We don't need to fill that with more/new classes - we need to keep filling that by setting up the newer/younger drivers with good instructors to get them around the track faster.


TL;DR: Keep the classes the same - focus on driver modification


FWIW, I am happy to come out and run in any class and also happy to have any of the "hotshoes" run some laps in my car and see what they can do in it.

[Jeremy]

Here are the results from GA in March.
http://scca.cdn.racersites.com/prod/ass ... esults.pdf

Look at all the classes Darrin Disimo could have won or trophied in his "outclassed" car.
That doesn't count though because...

[Loren]

Okay, good to see some healthy discussion here and especially from some new faces.

I'm about ready to drop the whole "power limits" thing... maybe. Part of me still thinks that even if it's a lot of "guesswork", if we put a limit way out there and a car still OBVIOUSLY exceeds it (in either direction, high or low), that a change in class is warranted. Just to keep the "Frankenstein potential" or our loose ruleset somewhat limited. But, that's sort of a tangent to the main issue here.

Nobody has said anything about option #1 in the first post. STS cars to M3? BTW, STS is a very small group of cars:
BMW Z3 (4-cyl)
Honda CRX & del Sol
Mazda Miata (90-97) (non-Torsen differential)
Mazda RX-7 (non-turbo)
Pontiac Fiero (4-cyl)
Toyota MR2 (non-turbo or SC)

STS limits wheel width to 7.5" and tire width to 225, doesn't allow internal engine mods, doesn't allow limited slip (other than factory viscous) otherwise is very similar to our mod class rules.

Let's reign things in a little bit:

NOT looking to change the world this season. The possibility of going to a points system, or of using SCCA's Street Touring category as a basis for classing are both reasonable ideas... but we are NOT going to pursue anything like that for THIS season. For this season, the ONLY thing we MAY consider is a minor change or two to address the issue of underpowered cars being uncompetitive (due to SCCA's SP classing structure expecting them to swap in a larger engine).

If the general consensus is that it's not a real issue, I'm okay with that. I'm merely going up to bat for the handful of people who have expressed concern. (and I'm tired of swinging for them, they need to get in on their own discussion)

[Jeremy]

I'm merely going up to bat for the handful of people who have expressed concern. (and I'm tired of swinging for them, they need to get in on their own discussion)

If M3 doesn't care, move them. The car to have for m2 will change from a turbo 240 to a turbo 1.6 miata.

What happens if a 1.6 puts a torsen in? They start from m2 again?

I think waiting and redoing the mod classes based on the stock classes is the best answer. I think that idea was dropped solely due to the 89-91 civic, as it starts in the lowest stock class and moves to m2 when modified. But I don't think it will be that big of a deal to leave it in the lower mod class.

[Loren]

I'm merely going up to bat for the handful of people who have expressed concern. (and I'm tired of swinging for them, they need to get in on their own discussion)

If M3 doesn't care, move them. The car to have for m2 will change from a turbo 240 to a turbo 1.6 miata.

Negative. The 90-97 Miata would ONLY eligible for M3 if it is completely STS-legal. Turbo negates that, so they start back at M2 and bump up to M1 for the turbo.

What happens if a 1.6 puts a torsen in? They start from m2 again?

Yes, same as above. Complete STS-compatibility, or back to the base classing.

I think waiting and redoing the mod classes based on the stock classes is the best answer. I think that idea was dropped solely due to the 89-91 civic, as it starts in the lowest stock class and moves to m2 when modified. But I don't think it will be that big of a deal to leave it in the lower mod class.

We will need to review this if not next year, the year after (when the smoke clears from the stock class shake-up). I still think a "stop gap" measure is worth looking at for now, though.

[Jamie]

Nobody has said anything about option #1 in the first post. STS cars to M3? BTW, STS is a very small group of cars....

Were we running a larger club, it might be worth discussion. But since NASA-X Florida and FAST emerged from the Sunriders Miata Club, how many of these cars have we seen show up more than once (if that)?

BMW Z3 (4-cyl)
Honda CRX & del Sol
Mazda Miata (90-97) (non-Torsen differential)
Mazda RX-7 (non-turbo)
Pontiac Fiero (4-cyl)
Toyota MR2 (non-turbo or SC)

So within FAST, we're really talking about a few Miatas.

...the handful of people who have expressed concern...need to get in on their own discussion

Yep. And prove it's the car.

[Jeremy]

Yep. And prove it's the car.

SCCA says it's the car. That's good enough for me.

Have you ever driven a 1.6?

[Loren]

Yep. And prove it's the car.

How does one go about proving that?

[Jeremy]

Yep. And prove it's the car.

How does one go about proving that?

https://en.wikipedia.org/wiki/Scientific_method

[Jamie]

Yep. And prove it's the car.

How does one go about proving that?

I already gave you that: plug some guys from the top of the time charts into these cars and see what changes. I'll even offer to run the test from the other end: put whoever's concerned into my car and see what effect that has. You'll have to wait until fall for that part, though.

SCCA says it's the car.

Not in 2014.

I have driven a 1.6. And if we were focused on reclassing the 1.6-liter Miata, based on results showing it's mis-classed in M2, fine. But this started with a sweeping change to the rules substituting guesswork for standards, based on an assumption that needs a little testing.

[Jeremy]

SCCA says it's the car.

Not in 2014.

What do you mean? I just meant SCCA created a class for the 1.6's and handicapped the 1.8's
I didn't see anything that indicated a change in 2014. If the 1.6 didn't suck than STS wouldn't exist.

[Jamie]

SCCA says it's the car.

Not in 2014.

What do you mean? I just meant SCCA created a class for the 1.6's and handicapped the 1.8's
I didn't see anything that indicated a change in 2014. If the 1.6 didn't suck than STS wouldn't exist.

Sorry...stock-class focus. All stock NBs and NAs are combined in E Street next year.

I don't know about any specific handicaps for 1.8 NAs in STS -- the dividing line there has always been the differential, with the assumption (going back to the original coupe origins of ST) that a viscous diff isn't that much better than an open one, especially after a few years of use. You can run an open-diff 1.8 NA in STS without a problem.

[twistedwankel]

So how much can a used old set of race car scales cost? Aren't they $2k new?

We could charge $10/car to weigh everyone's car and that should cover it?

They aren't all that big other than the 2x12's ramps to get on/off them.