Power:Weight in Mod Classes

[Loren]

That's half of the equation, Doug. To get true power:weight, we'd also need a dyno.

And if we were fully basing our classing on that, it would probably be the thing to do. All I suggested was that we could use a loose approximation of power:weight as a sort of "filter" to help with extreme cases. Between a couple minutes of internet research and looking at a car, I think most of us could estimate the weight of a car within 50 pounds or so, and HP within 10%.

Back to the M2 example: If our estimate of a car (and it would be estimated as favorably to the car owner's side as possible) puts it at better than 10 lbs/hp or worse than 16 lbs/hp... it's probably extremely unlikely that car would be able to compete in M2. I don't think you need scales or a dyno to come to that "broad level" conclusion.

Example: 2007 Mazdaspeed 6
Factory Weight: 3600#
Factory HP: 274

Estimate "class legal" weight reduction at no more than 100 pounds for 3500 total.
Estimate 10% power increase (conservative for a turbo car)... more if there are obvious boost enhancers.

Estimated weight: 3500
Estimated power: 301
Lbs/hp: 11.6

Way below the 16lbs/hp low power threshold, and well above the suggested 10lbs/hp threshold... and would be all the way up to 350 hp.

The "limits" I'm suggesting are so far out that only extremes in either direction should hit them.

[rab]

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.

As a driver of one of those venerable slugs. I did a check, I run right at the mean std of our autocross times.
Is it the car or is it the driver? I don't know but I can tell you that Loren drove my car and while he was faster than me, he would have only beat one more individual than I would have. Still putting the car on the low point of M2.
Am I still a bad driver? Possibly, but if I can drive next week, we shall see when I co drive Matt's Mazda Speed Miata. I for one vote to do this change. Some of us don't have the budget to make a killer Miata.

[Jeremy]

In the last 3 events. You have actually been finishing better in M2.

7 out of 11 in M2 Top 63%
5 out of 5 in M3 Top 100%

9 out of 12 in M2 Top 75%
6 out of 9 in M3 Top 66%

8 out of 12 in M2 Top 66%
5 out 6 in M3 Top 83%

M2 average - Top 68%
M3 average - Top 83%

So... if that's what you want, then I support you 100%.

[Loren]

If you want to use Rick as an example, subtract 2.5-3 seconds from his time. As I recall, that's what I did when I drove his car and is probably a better indicator of what his car is capable of. Will he still fare better in M2 than M3?

[Jeremy]

Where did you get your numbers?

From Mazda brochures...
http://www.miata.net/faq/

2474/170 2006 Miata 14.5
2299/140 99 Miata 16.4
2293/128 1994 Miata 17.9
2116/116 1991 miata 18.2

Maybe you need to boot the NC out of M2, that's the cheater car.
Saying the 1991 is classed wrong but the 1994 isn't?

[Loren]

Where did you get your numbers?

From Mazda brochures...
http://www.miata.net/faq/

2474/170 2006 Miata 14.5
2299/140 99 Miata 16.4
2293/128 1994 Miata 17.9
2116/116 1991 miata 18.2

Maybe you need to boot the NC out of M2, that's the cheater car.

I'm going to bet that you can find lost of cars in M2 that have far greater power than the NC.

Saying the 1991 is classed wrong but the 1994 isn't?

I know Miatas. (not so much NC's) Factory specs are one thing, and are a good basis... but we need to consider reality. M2 cars are permitted some weight reduction, and some bolt-on power-adders like headers, exhaust and ECU tuning to make the most of it.

But, I know that in "M2 trim", any NA Miata can get down to 2100 pounds pretty easily. (it may require ditching AC and other options to get there, but it can be done) So, I tend to use that for the weight of an NA. NB's are slightly heavier, but can still get down to 2200ish.

For M2 purposes, the only difference between the 94 and the 91 is hp. In M2 trim (assuming no exotic internal engine building), actual power is about 120-125 for the 1.6 (<100 hp to the wheels, 26 hp drivetrain loss), and 140-145 for the 1.8 (~115-120 to the wheels, same drivetrain loss).

But, SCCA may be right... the 1.8 NA Miata (94-97) could be considered nearly equivalent to the 1.6 as long as the 1.8 doesn't have a Torsen. Especially if you consider that the 1.6 chassis is lighter from the factory due to having less factory bracing. (that can be easily removed from a 1.8... though most people don't)

It may very well be that simply adopting the suggested "STS-legal cars to M3" rule would take care of things... for Miatas. And for the affected Hondas. Won't do anything for any of the rest of the underdogs in M2, though. It's a big class and half of the entries don't have the slightest chance of seeing a top 5 finish no matter how well they drive.

[Jeremy]

So the 1.8 responds better to mods?
Because the factory difference of 12 HP became 15-20 in your M2 scenario.

Also the 1.8 entire drivetrain is going to weigh more, engine and diff at least.
So a 1.8 could never be as light as a 1.6.

My point is that a 1.6 has just as much of a chance against an NC as a 1.8 does and that chance is slim to none.
So if you are going to move the 1.6 I think the 1.8 NA has just as much of a reason to go also.

This would be the case if the M classes were based on stock classes, because all NA's are in the same stock class.

Which I think is the real solution, but I know you want to hold off on that.
I say do it, and then redo it again in a year or two. Big deal.

You can tell Greg is frustrated in M2, as he should be, NA's have no business messing with NC's.

[Jeremy]

Get rid of M0

S1 M1 - SS AS BS - Corvettes, S2000's
S2 M2 - CS - NB, NC, 370, BRZ
S3 M3 - FS - Mustangs
S4 M4 - DS ES - NA Miata, Subaru, BMW
S5 M5 - GS HS - Civic, VW, 240

I might throw GS into S4 and just let HS have the 5 classes. That would solve the turbo 240 "problem". Cause then we would bump up into Drew instead of with the NA miatas.

[Jeremy]

or add some rule like altering factory boost pressure is a 1 class bump, adding forced induction or swapping turbos is a 2 class bump.

Engine swap rule stays the same.

[rab]

This is making my head hurt. You guys argue it out and tell me where to run next year. That is of course if I can get my Miata fixed.

[Loren]

So the 1.8 responds better to mods?
Because the factory difference of 12 HP became 15-20 in your M2 scenario.

Do your own research. I have. For many, many years. I've been driving NA Miatas since 2001.

But, it's like this: Stock 1.6 on the dyno is about 90 hp (Remember that 26 hp drivetrain loss? That's where it comes from... and it's accepted as universal for NA Miatas.) Stock 1.8 (NA) is about 100-105 (they're not all the same, minor tuning differences between OBD1 & OBDII). Add 10% to each of those for common bolt-on mods and then add the 26 hp drivetrain loss back in. You get 124 for the 1.6 and 141 for the 1.8. So, yes... the 12 hp difference in stock power does become about 17.

And, those modded dyno numbers are pie-in-the-sky for a 1.6 (120 to the wheels is pretty significant for a 1.6), and not all that conservative for a 1.8.

Also the 1.8 entire drivetrain is going to weigh more, engine and diff at least.
So a 1.8 could never be as light as a 1.6.

Remember, M2, the 1.6 will likely be running a 1.8 Torsen. No weight advantage there. OR, if a 1.8 was going for lightweight, they'd be free to run a lighter 1.6 diff... until it breaks. (they break easily under 1.6 power) The rest of the drivetrain is identical, only difference would be an extra inch or so of crankshaft. Maybe a pound?

My point is that a 1.6 has just as much of a chance against an NC as a 1.8 does and that chance is slim to none.
So if you are going to move the 1.6 I think the 1.8 NA has just as much of a reason to go also.

I would almost agree with that, but I'm not 100% sure. But, I don't want to create overdogs in M3. If we had a restriction of no-LSD, or especially a wheel/tire size limit, then they might not be such a threat to M3. But, with our current Mod rules, I think a blanket "move all 94-97 Miatas to M3" statement would just kill M3 (at least with the well-prepared and well-driven Miatas)

The question is, would that be a bad thing? (I always try to be as hesitant as I can be when it comes to being prejudiced toward Miatas, even if it doesn't seem like I do.) As someone recently pointed out, this club was born of a Miata club. And Miatas are extremely popular and cheap sportscars that are GREAT for autocrossing... thus lots of them show up at autocrosses. Our last big event had 91 competing entries. 19 of them were Miatas! That's over 20% of our entries. Maybe that warrants consideration? I'm not talking Porsche-club level "a class for every model" or anything... but something that's as popular as a Miata SHOULD be able to be competitive in an autocross classing scheme.

This would be the case if the M classes were based on stock classes, because all NA's are in the same stock class.

Which I think is the real solution, but I know you want to hold off on that.
I say do it, and then redo it again in a year or two. Big deal.

I get what you're saying. C Stock Miatas = NB & NC, E Stock Miatas = NA. My only hesitation when it comes to Mod is wiping out the "low powered sporty car" class (M3) with Miatas.

And then there's still the whole "what about other underpowered M2 cars" angle.

You can tell Greg is frustrated in M2, as he should be, NA's have no business messing with NC's.

You may be right.

We need more input. I mean, you and I like to argue these points just for the sake of argument (and maybe enlightenment), but if not enough people really care... why bother changing anything? So far, not a lot of people have had much to say about this whole thing. Which leads me to want to follow Steve's suggestion to "let it be". (and you'll note that he drives an NA Miata in M2)

[Loren]

Get rid of M0

S1 M1 - SS AS BS - Corvettes, S2000's
S2 M2 - CS - NB, NC, 370, BRZ
S3 M3 - FS - Mustangs
S4 M4 - DS ES - NA Miata, Subaru, BMW
S5 M5 - GS HS - Civic, VW, 240

I might throw GS into S4 and just let HS have the 5 classes. That would solve the turbo 240 "problem". Cause then we would bump up into Drew instead of with the NA miatas.

I like this, but I'm not sure we're ready for 5 mod classes. And how can you ditch M0? There WILL be people who show up with overly modded cars, and the way people think (even if it's not true) is that "the guy who's finishing in the top 3 consistently has taken a sawzall to his car to remove an extra 50 pounds... I must do the same to be competitive". Or... something like a well-prepared M1 car WITH added forced induction? There needs to be that upper-level "you have to spend lots of money and/or be very creative and/or be very talented, or just plain crazy to run here" class. And I don't think M1 should be that class.

In your example above... IF we decided to go with 5 mod classes... I'd keep M0 (even if it is lightly populated) and combine your M3/M4.

Not sure we need to discuss this much more right now. It's way too big of a shakeup to do right now. As I keep saying, we're not looking to change the world this season. We may make some small changes, but not big ones.

[Loren]

This is making my head hurt. You guys argue it out and tell me where to run next year. That is of course if I can get my Miata fixed.

You can't propose a change and then bail out of your own discussion. If you want it, you may have to fight for it. That's the way these things go.

If it's not worth putting forth a solid case for, then it's not worth us making a change for.

[Jeremy]

Get rid of M0

S1 M1 - SS AS BS - Corvettes, S2000's
S2 M2 - CS - NB, NC, 370, BRZ
S3 M3 - FS - Mustangs
S4 M4 - DS ES - NA Miata, Subaru, BMW
S5 M5 - GS HS - Civic, VW, 240

In your example above... IF we decided to go with 5 mod classes... I'd keep M0 (even if it is lightly populated) and combine your M3/M4.

Not sure we need to discuss this much more right now. It's way too big of a shakeup to do right now. As I keep saying, we're not looking to change the world this season. We may make some small changes, but not big ones.

Come on, discuss it, shake it up! It'll be fun. You don't even have to do much. Just delete the mod car lists and say refer to the stock lists. Done.

M0= boring. I win every event.
M1 = good
M2 = boring. It's Charles and Drew
M3 = boring. It's Dave and Greg

M0 = We haven't seen an M0 car all year. The only thing close was a Shelby Cobra and none on street tires have ever been faster than M2.
Plus if there is no M0 then I will have to race in M1, so everyone there can forget about winning any way, even if a swiss cheese car were to show up.
If one does show up, just boot them to R1. Like originally planned.
Combining M3/M4 = You are putting the 1.6 in with Drew. (ESP cars). Just leave it.
You mentioned the SCCA shake up. You might have to redo the stock lists anyway, might as well do the mod classes also.

[Loren]

Come on, discuss it, shake it up! It'll be fun. You don't even have to do much. Just delete the mod car lists and say refer to the stock lists. Done.

True, it is easy. But, it affects a lot of people. Stability is good.

M0= boring. I win every event.

Selective memory? Bad at math? I have 6 class wins to your 4. Wear your 2nd place shirt proudly, my friend.

M0 = We haven't seen an M0 car all year. The only thing close was a Shelby Cobra and none on street tires have ever been faster than M2.
Plus if there is no M0 then I will have to race in M1, so everyone there can forget about winning any way, even if a swiss cheese car were to show up.
If one does show up, just boot them to R1. Like originally planned.

There have been a few, though admittedly not many, actual M0 cars. There were three cars that I specifically had in mind that I thought we'd see in this class regularly. One was my own Miata... I've hacked it up to where it's not M2 legal and I was considering doing a 1.8 swap on it and prepping it to compete there... but I just don't have the money or motivation to follow through with it right now. The other big one was Rob's monster Mustang, which he ultimately decided to put race tires on rather than street tires... and then sell. And the third was Joe's no-interior, lexan-windowed (but street-driven) BMW... he was a regular last season, not so much this season for whatever reason. But, there's also been at least one Mustang that I remember. And Kyle's drift-beast Miata. Looking at the points list, there have been 11 different competitors in M0. Perhaps 4 of them were there voluntarily for the competition.

I don't like the idea of telling someone on street tires (no matter how modded the car is) that they have to go compete against Scott and Howard in sub-1500 pound race cars on slicks.

Combining M3/M4 = You are putting the 1.6 in with Drew. (ESP cars). Just leave it.
You mentioned the SCCA shake up. You might have to redo the stock lists anyway, might as well do the mod classes also.

Good point. I didn't really look at things that closely.

We will have to reorganize things based on the SCCA stock class changes, but we don't have to do it now. We've produced our own car list, and we can leave it as static as we care to throughout the coming season. Then, after SCCA has had a year to see what changes need to be made and starts making them, THEN we can make the change... and make it once.

[Jeremy]

M0= boring. I win every event.

Selective memory? Bad at math? I have 6 class wins to your 4. Wear your 2nd place shirt proudly, my friend.

Oh, I meant next year when we don't have a car with the boost controller setup wrong, stealing about 100 HP. I believe the problem started some time around your first win.

[Loren]

Oh, I meant next year when we don't have a car with the boost controller setup wrong, stealing about 100 HP. I believe the problem started some time around your first win.

You're killin' me, man!

Seriously, it was a great year of competition for us. Rough for me at the beginning while we were getting John's car sorted out, a little better mid-season, but still anybody's guess as to which of us would win any particular event. I'm jumping ship and competing in S2 next season, though. What's the fun of being a car-whore if you don't drive different cars?

[rab]

This is making my head hurt. You guys argue it out and tell me where to run next year. That is of course if I can get my Miata fixed.

You can't propose a change and then bail out of your own discussion. If you want it, you may have to fight for it. That's the way these things go.

If it's not worth putting forth a solid case for, then it's not worth us making a change for.

I didn't propose a hp to weight ratio I agreed to it. The headache is real I can't focus on a lot of print yet.
I would hope most of the 1.6 Miata's would speak up. If you look at the numbers, reduce my time by 2.5 to 3 seconds. And that's the time you would get without a significant amount of modification but with a lot of driver improvement. It is somewhat depressing and disenchanting to realize that one could spend a significant amount of time and effort to improve ones driving skill only to bump up to the to 50% bracket. I have only seen one 1.6 that I would consider worthy to compete in M2. The guy brought it in on a trailer to the Martin class. (Ported polished, MS3, header, cams and a nice intake rolled fenders and 225 15 tires with very light rims). Do not also forget mid range torque numbers the 1.6. This car has very little low to mid range torque. Many of our courses have a few tight turns that kill the 1.6. The 1.8 does much better with the courses.

[Jamie]

Many of our courses have a few tight turns that kill the 1.6. The 1.8 does much better with the courses.

Rick -- what differential do you have on your car? If you're still running the open or viscous diff that originally came with the 1.6s, there's your answer in tight corners.

[Loren]

I didn't propose a hp to weight ratio I agreed to it.

No, but you proposed a problem that we're trying to either find a way to solve, or determine that it's not enough of a problem to bother with.

Thanks for the input.