So...I'm thinking about building up my dad's old 1st-gen RX-7 that I bought back and have in storage, and am trying to figure out how far to go with it. It's a GSL, which means it has a rear limited slip and discs on all wheels (vented, I think). It has a 12a engine (as opposed to a GSL-SE with a 13b). It doesn't run, although I haven't investigated at all to see what's wrong with it. I know the engine has pretty low mileage since a factory new replacement, although it has been sitting for years so it might be screwed regardless, and 12a parts are very, very tough to come by.

The intent would be to track it a few times per year, autocross it once or twice a year, and drive it around locally for fun a few times per month.

Option #1 would be to go totally nuts...swap in a ported to hell and back Renesis or 13b, stitch weld and brace the chassis, add stiff coilovers, aftermarket brakes, maybe even lexan windows, etc...not eligible for any particular class in any form of competition, but just a fun lightweight track day machine.

...but what I think I'd really like to do is Option #2, which is to find an autocross class where it would be fairly competitive. I'm not sure what that would be, though. I'm pretty sure that it would get annihilated in E-Stock by Mazdaspeed Miatas and supercharged MR2s!

It could run in Street Touring Roadster (STR), but it would be bringing a spork to a gunfight against S2000s, E36 M3s/M-Coupes/M-Roadsters, S2000s, 987 Boxster S, etc. Maybe it a lot of rotary engine porting is allowed in that class, it could even things out a little? An S2000 or 00-05 or whatever Boxster S would be a handful of an opponent even with double the stock power in the RX-7, though.

Street Touring Sport (STS) might be ok. It has Honda CRXs and a bunch of other slow stuff. Sounds pretty boring and pretty tightly limited. I'm not sure I'd even want to bother.

C-Street Prepared has CRX, E30 M3 (unlikely to encounter one, of course), NA/NB/NC Miatas, FR-S & BRZ, all 1st gen MR2s (included supercharged), plus MR-Spyder, as well as non-turbo FC RX7s. My gut feeling is that even with mods, this class would be an major uphill climb. In fact, I think it's basically the Miata Show.

Then there's F-Prepared, which might also be OK...you can go nuts, all the way to peripherally ported 13b or Renesis swaps. There are all sorts of handicapping measures and allowances, based on weight, displacement, suspension configuration, etc. However, this might require getting so deep into it that (a) it costs way more than what I'd envisioned for this, and (b) permanently (?) ruins the cars for anything than dedicated track/autocross use, which is not what I want. I'd just buy a racecar if that's what I wanted.

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Other things:

Porting: Intake and exhaust ports and manifold openings may be matched pro- vided no change is made more than one inch from the port/manifold interface. Material may be removed to facilitate port matching, but no material may be added.

That's allowed in Street Prepared, but that wouldn't allow significant rotary porting, right? Maybe if I could bridgeport, or maaaaybe aggressively street-port, I'd be competitive there, haha.


Updating/Backdating:

Equipment and/or specifications may be exchanged between different years and models of a vehicle if:
1. The item is standard on the year/model from which it was taken, and
2. The years/models are listed on the same line of Appendix A, Street Prepared Classes.

Does that to allow me to swap a 13b into my RX-7 GSL, since the GSL-SE model (of the same year, even) is 13b-engined?




and then Option #3 is fuck it, leave it in storage...another project for another day, maybe when it's in more suitable SCCA classification. There are regional classifications for Improved Touring that spec a Renesis swap, since 12a are hardly available nowadays. If that ever went national, for example, it would make the car eligible for Street Prepared in autocross.

[Edited on April 16, 2019 at 10:35 PM. Reason : ]

4/16/2019 10:34:35 PM

I say to hell with worrying about autocross class you'd fit in and be competitive with. Perform modifications to make it fun and fast on the track.

4/17/2019 9:38:44 AM

1. See if you can actually get it running
2. enter it in STS and see if you even place top 10
3. WHEN the engine implodes, swap literally anything else in it and/or sale it
4. .......
5. PROFIT!!!!!

4/17/2019 11:13:23 AM

any form of racing outside spec racing is largely a wallet race. i'd make the car fun and get a more useable version of your 7. every form of racing I've done, outside spec flat track, I was racing the clock and racing folks in a given corner way more than I was racing for outright placement. if you get good enough, you'll get more serious and get the best platform for a given class, but until then just have fun and get better.

4/17/2019 8:10:55 PM

well if i just went nuts and built it to be fast, class allowances be damned, it would be a more usable version of my 7. It would be about the same power, prob 1000 lbs heavier, with less sophisticated suspension (but in the words of Colin Chapman, "any suspension will work if you don't let it", or something to that effect).

Even if I went with aftermarket seats and harnesses, it would certainly be more comfortable than the Kirkey buckets I had in the 7, which also pinched the harnesses against your neck. Even if it's a loud-as-shit rotary, at least the exhaust won't exit 3' from your left ear. It would have a place to put your left foot rather than jammed into a tiny pedal area. It would be enclosed, and have mirrors. It would have power assisted brakes.

4/17/2019 11:53:43 PM

^^ So...not always a wallet race!

I did my first autocross in the FR-S yesterday, running in STX (Street Touring Extreme). It's a decently well-prepped car in that limited class, but certainly not all-out. It would benefit from coilovers, 1" wider wheels + 30mm wider tires, harder bushings, and if I really wanted to go crazy, maybe lighter seats, battery, etc).

At any rate, out of 38 drivers, I was the 4th fastest in PAX and I think maybe the 6th or so fastest in raw time. Decent, but no big deal. The real story is that my best run was almost a full second faster than my next fastest run, and would have made me the 2nd fastest even in raw time (and maybe a contender for top honors on PAX)...except that I hit a cone.

Were it not for that cone, I would only be 2nd by about .2 seconds behind a guy who is a perennial national contender in DSP (someone told me he won nationals once, and finishes on the podium every year). This was his 5th auto-x of 2020...and my first in 5 years.

I thought I was gonna get my dick kicked in, at least on raw time. That little FR-S did great, though, and if I decided to make a few more tweaks, it would probably be a serious contender. I don't think any of those remaining STX mods would negatively impact the car on track days, other than maybe the 9" wide wheels and 265-series tires.

[Edited on February 23, 2020 at 2:09 PM. Reason : that DSP car (330ci) is all-out for its class. Almost a racecar. Mine could be a DD.]

2/23/2020 2:07:52 PM