Why is the 12a so heavy in STL??

[dickita15]

2. The Mazda 12A is permitted at 2600 lbs; porting is not permitted.

2. All cars shall use the installed engine’s stock air metering device (e.g., throttle body) and intake manifold, unless noted otherwise.

What am I missing

[Greg Amy]

What am I missing

Was that directed at me, Dick? I'm not sure what your question is...?

To summarize:

- The 12A-equipped RX-7 is allowed in STU in ITA trim (no porting) at 2280# (since the chassis was built through 1985).
- The 12A engine is allowed in STU with "street porting" at 2350#
- The 12A engine is allowed in STL with no porting at 2535# (changed Dec Fastrack).

If anyone thinks these should be lower, please do submit a request for the weight you think it should be to the CRB at http://www.crbscca.com.

GA

[dickita15]

Was that directed at me, Dick? I'm not sure what your question is...?

To summarize:

- The 12A-equipped RX-7 is allowed in STU in ITA trim (no porting) at 2280# (since the chassis was built through 1985).
- The 12A engine is allowed in STU with "street porting" at 2350#
- The 12A engine is allowed in STL with no porting at 2535# (changed Dec Fastrack).

If anyone thinks these should be lower, please do submit a request for the weight you think it should be to the CRB at http://www.crbscca.com.

GA

Not directed at you specifically Greg , although I applaud you taking the role of publicly furthering these discussions. The original posters question was why the 12a was so heavy in STL. In that class I have not found any allowances for porting of a carb change. As far as I know there are no allowances that would let the car make any more power that it does in ITA/IT7. Given that like the original poster I am not sure why the cars was speced in STL at 255 pounds more than the IT car. Hence my question, what am I missing.

[CRallo]

Not directed at you specifically Greg , although I applaud you taking the role of publicly furthering these discussions. The original posters question was why the 12a was so heavy in STL. In that class I have not found any allowances for porting of a carb change. As far as I know there are no allowances that would let the car make any more power that it does in ITA/IT7. Given that like the original poster I am not sure why the cars was speced in STL at 255 pounds more than the IT car. Hence my question, what am I missing.

+1

[AS-RACER]

Yea I was basically wondering why a 12a RX7 has to weigh way more then ITA trim if you run it in STL? I was looking at the 1.8 Integra GSR which is classified in ITS, it gets to lose more then 200 lbs in STL trim. I know you can put these engines into different cars (like the miata with the rotary or the crx with the GSR motor) but, it seems like the 12a is still way to heavy. That was basically my point. Unless I'm missing something?

What I would really like to do is run my ITS RX7 non ported 13B in STL or possibly build a 1st gen rx7 for STL but, if the 12a has to weigh 2600 then I'm just wondering what they would make the 13b run at? 3000 lbs. ?? I know this class is new and everything and not trying to bash the rules. Just trying to figure out what the thought process is on everything. Oh and I must have missed the weight change to 2535 lbs. but, it still seems a little high compared to other cars in the class.

[Matt93SE]

That's because they make a million horsepowers.

(sorry.. couldn't help it. I have nothing constructive to add to the thread.)

[Dano77]

You can say its 2535 all day,but its really 2600 once you add 2.5% for RWD. WOW a 320# weight reward cause I dont run a Honda. If I had a Honda I get to lose weight from my IT car.

Still Missing Something???? Ready, Fight

[lateapex911]

Yea I was basically wondering why a 12a RX7 has to weigh way more then ITA trim if you run it in STL? I was looking at the 1.8 Integra GSR which is classified in ITS, it gets to lose more then 200 lbs in STL trim. I know you can put these engines into different cars (like the miata with the rotary or the crx with the GSR motor) but, it seems like the 12a is still way to heavy. That was basically my point. Unless I'm missing something?

Yea, I figured they hated the sound of the rotary up there in the STL rulesmakers offices.
It made no sense otherwise! An ITS car making 185hp, LOSES 200 ponds, while an ITA car making 125 (SIXTY less!) GAINS 320!! That's a 500 pound swing! So the ALREADY faster ITS car goes even FASTER, while the Slower than ITA car goes even SLOWER. Hahaha....somebody clearly hates the rotaries!!

In other SCCA classes they allow "street porting", and have a tightly controlled easily available template that is used. Power output is well known. I'd suggest contacting members of that AdHoc (The STAC will have the CRB liasons on the call who can facilitate this).

On this board, Steve Eckridge is familiar with the template and expected outputs, IIRC.
Further, I'd suggest classifying both the 13B and the 12A, as the 12A parts are very difficult to get these days. The 13B at a reasonable weight is going to be the better draw. I think the ITS 13B would be a good candidate as is. No porting needed. The 12A though, would require porting as nearly any Mazda chassis would be impossible to make weight with, IF the weight was to be competitive.

[lateapex911]

This last post has made me think.

HOW does the STAC set weight? here's a case in point:
We know the Integra will weigh 180 lbs or so LESS than it would in ITS. Fine. So it should be faster than ITS. We know it's power. (And it gets to make some other changes, but lets ignore those for now).

Now, take a ITS 13B rotary. What do you make IT weigh? Well, the engines are very close in curves/hp/tq. The 13B (in ITS/ST trim) comes a leeetle short, but, for giggles, lets make it a wash. So, it would weigh the same as the integra, right? Plus 2.5% for RWD.

So, whats the Integra in STL, 2420? 2420 + 2.5% = 2480?
Now, if understand it, the assumption of the rules makers is that somebody will put that engine in the corporations best chassis. So, that be the Miata. So, a 2480 lb Miata? Now we're talking.
Somehow, I see the PTB saying, "Hold on, don't think so". (*, and **)
Fine, but how will extra weight be added?
I HOPE the STAC comes up with a repeatable, empirical, documentable and systematic way of doing it.
Otherwise, they are headed for trouble.
If there's POOMAs going in, they better be ready to defend, and fix them.

*Also, just as a reference point, there IS an ITS Miata and, in some pretty competent hands, it hasn't set the world on fire. It's classed at 2375, and makes 160 hp in race trim.
** I say that because I assume they will want to add weight because I have a hunch they are creating a FWD centric class. Now, I hope I'm wrong, or that the results we've seen thus far are merely random, with no actual intent. Because it's a cool ruleset, and i'd like to see it be as open as possible, give as many formats/manufacturers/cars an equal chance, and not aimed at any one demographic.