Hello, I am new to this forum and don't know a whole lot about about rx7s or rotaries. I plan on getting more into autocross this summer and was wondering if a first generation rx7 would be a good autocross platform and project. Our courses our generally smaller and you don't get going too fast. Would a 12a with bolt ons be competitive or should I look for a gsl-se? Rotaries don't exactly have the reputation of being very reliable so would it be better to buy a freshly rebuilt one if I plan to run it often? Suspension wise I imagine there are many options, correct? What is the widest tire I can run with the stock body? How many of you guys autocross your fb's regularly and have any of you built your cars for just that reason?

Thanks a lot!

 

I don't personally autocross, but I'd say look for a GSL-SE. Last time I checked, all NA RX-7s run in the same class, and of these the GSL-SE has the best power-to-weight ratio by a fair margin. On the other hand, FCs do have better suspension in many ways, and have rack-and-pinion steering.

As far as reliability, NA rotaries are ridiculously reliable, especially in a racing context. Turbo rotaries are the ones with the bad reputation, mainly due to the FD and people who don't know how to tune them.

 

I have a 12A with over 170k without a rebuild and i drive it fairly hard. These engines are just as reliable as long as you maintain them. That being said, carbed 12A's have a good aftermarket that easily can make you faster than a GSLSE and they are much easier to come by.

Suspension options arent the greatest but these cars are set up well from the factory so not much is needed. Racing Beat has great products for autocross but some say they aren't stiff enough. Sway bars and strut bars as well.

Tires, I'd say no more than 205's if you plan on getting somewhat lowered.

Where in Oregon are you at? you should check out the NW section here

 

I'm in the Bend area. I'll check out the northwest section for sure. Possibly a stupid question but is the 12a any more reliable than the 13b? Thanks for the responses guys.

 

Depends really. I'd say they are even but 12A's arent usually turbo'd so they last longer that way but 13B's make more power...Its a toss up. I love how raw my 12A sounds. The GSLSE's are so much smoother. The non GSLSE's are lighter but make less power, but there are cheap and free mods that make it faster. I have less than $2k in my car with full suspension, engine mods, full exhaust, and wheels and tires.

 

I run my 83 in CSP every chance I get. There are other cars that are a little more competetive outta the box, but they tend to cost more to get into.
As for tires, I have 205/50-15's on 15x7 +15 wheels. The car sits very low (old ST springs) and there is minimal rubbing on the rear, after I removed 1.25" off the rear bumpstops. Any larger tires will usually require more agressive measures to allow for clearance.
I have fun giving heartburn to the guys with $1200-1500 worth of race tires and wheels on their Miata, with my car. Total investment in my car ~$1200. I may not always win the day, but I took the season championship for last year, and am undefeated for this year. Makes me feel good knowing my $500 car was a solid investment........

 

What are the free mods that you are talking about? Does it involve taking off the emissions equipment? Are there any coilovers available for the fbs or is it just spring and shock combos? Thanks

 

Rock on Rogue! Miatas quake in fear when they see my fb roll in on her street tires...

Yes, there are many options available for suspension upgrades on these babies.
Check out www.re-speed.com Great people to deal with and they've got everything you'll need to put together an autocrosser.

For tires, I run Sumitomo 215/50/13 on the stock rims without any fitment issues.

Reliable? Hehe, check out the link in my signature line for my race videos. All of those races were run with an untouched (never rebuilt) 12a with over 200,000 miles on it. I would drive it 200 miles to race for three days, then drive it home again. Once you understand them, you can't help but to love them...

 

Thanks a lot. It looks like I may have to give the rx7 a shot!

 

great cars for autocross, dont worry about modifing it, just get it running, and go enjoy it, once you have money for tires pick up some sumitomo htr 200's. then when you get a chance, shocks/springs. talk to billy from re-speed, he'll help you select whats best for you car, hes got great products that are competitively priced.

as far as power is concerned, its not so important but if you really want to upgrade the power, you can get a new exauhst, start with RB or sdj($$$) header, and free flow the rest. and like a sterling/holley/weber carb. sterling will be the cheapest/easiest to get going.

depending on how you feel about your car and its presentation, there are some things you can do to help you for free, like yesterday i completely gutted my interior, there are also many things you can get rid of under the hood(search for rats nest) that will save weight a free up power. you can also do mechanical secondaries, and if your super cheap, you can cut the stock springs, if this is done in moderation, it will boost the spring rate a small ammount and give you a lower center of gravity.

most importantly, enjoy your car! but you want to make sure its up to the task before you jump out there. do a 60k tune up, and check your tie-rods, and ball joints. just this weekend, i saw an rx7(fc) lose a tire because the shock mount was so rusted it snapped, then broke the ball joint. just make sure the car is in good over all shape, and your not going to break a brake line or anything like that.

if you have any more questions, dont hesitate!

rock that 12a for life!!! we whoop on 13b's. from gsl-se's and s5 na's. **** we beat up on lotus elise'!!

 

What class do you want to be in? perfect_circle's advice will put you straight into modified class, which is expensive to be competitive in.

 

i run csp, i dont know what your talking about with a modified class, and as far as competitive, i place 2nd most often, only behind kentetsu. unless your refering to the stripped interior, i just did that to remove the tar, im going to be putting carpet back in.

 

I meant to say "prepared", you didn't say that you were putting the interior back in.

 

i realized that, because i wasnt really in a hurry to put it back together until you reminded me, that i wouldnt be in the same class. lol, my bad.

 

I would like to run in the csp class, full interior and such because I may still drive it on the street occasionally. What would be the best route reguarding a carb? Holley with an rb intake manifold? With a header, full exhaust, emissions equipment removed, electric fan, new carb and im how much power would I stand to make? Is Racing Beat the best option as far as power modifications go? I checked out Re-Speed, it looks like they have some really quality suspension parts. Do the gsl's and gsl-se's come stock equipped with lsds?
Thanks a lot, you guys have been very helpful

 

GSL and GSL-SE have LSD stock. The GSL has a tighter LSD, but both came with LSD and rear disc brakes.
I swapped a GSL rearend into my GS, as I was suffering from lots of wheelspin anytime I even breathed on throttle near anything that resembled a turn.
With the mods you listed, you're looking around 130HP or so. That's about the limit of a stockport 12A. Also about the limit of most street tires, on this light of a car.

 

as common as holleys are some people tend to have problems with them, ive read that they are difficult to tune, and starve during cornering. the sterling modded nikki will net similar performance, but bolt to the stock manifold, plus youve got help whenever you need it, sterling and carl are great tech gurus. as far as webers, ive tried two and had success with neither, in fact robert still has one of mine, and wont return. but thats neither here nor there. about 130-140 hp is the limit on a stock port unless you turbo or run nitrous, neither of which will help you in autocross.

 

A 12A with headers, freeflow exhaust and a Sterling or aftermarket 2 barrel carb will outrun a stock SE, even one with headers. Hp difference with those mods is close, advantage is the lower curb weight. LSD is a must.

Reliability is dependent on the owner's care and a maintinance. 12as have been known to exceed 300k before eninge failure and I've seen SEs with over 240k on the odo, still running strong.

Check my sig line for reference materials

 

Adding to trochoid's excellent advice: 83-85 12A's came with a very crappy "Beehive" oil cooler. Using the link in his sig as a guide, I replaced the beehive on my 83 with an FC front mount oil cooler. I strongly reccomend anyone considering autoxing an 83-85 12A car do the same.

 

Is that 130whp? How much less does the 12a equiped rx7s wheigh than the gsl-se rx7s? How difficult is it to swap in a lsd rear end? Where can I find the sterling carbs? I have read that the webers dont work well with stock ported engines. Is that true? I take it that an aftermarket intake manifold doesn't any or much power? Thanks

 

You have to remember that the 12A, in stock form, was rated at 101HP at the flywheel. This was largely due to the restrictive exhaust, and carb limitations. My car dynoed at ~96RWHP with stock intake/carb and stock exhaust manifold, but with a freeflow exhaust. Since that time, I have added an RB header. I haven't bothered to go back to the dyno, though.
Getting nearly the HP to ground, as the factory rated flywheel HP, makes for a rather fun ride.
The SE has ~200lbs in extra mass. Unfortunately, it's not located in a well balanced area. Most have power windows and rear wipers. Those motors add weight in the wrong areas. Of course, many GSL's also have these added options, but they are still lighter than the SE. This is why the S or GS is usually prefered, with the GSL rearend. Swapping the unit out is not hard, but you need all the correct parts before you begin.

 

I run my SA in F Prepard because of the gutted interior, and some other suspension mods. If your going to spend money on an autox car then spend it on the suspension , wheels(light as you ca get), and tires. if it doesn't handle then you won't be fast period.
I am running alot of stuff from GForce Engineering the parts are top shelf but the also cost Top shelf aswell. I also use Ground Control coil overs and Caber/caster plates. I have Advance Design stuts and shocks with Eibach springs.
the rear end is all spherical bushings replacing the rubber bushings.
I removed the Watts link and put in a adjustable Panhard rod and Trilink.
Wheels to use (light ) Panasports 13x7 with Hoosier Cantalevered slicks 20x9.5x13. or you can use (cheaper) Circle racing wheels. either way they will make them to your spec. brakes you can use the stock rotors I use Hawk hp plus pads for autox and track days they are also ok on the street as long as you don't mind squeeky brakes when there dirty. you don't need to "upgrade" to an se suspension to get the bigger brakes the gsl and other stock brake setup is good.

motor stock 12a with no emissions, Weber carb , Racing Beat race header with the steet prep. dual pipe exhaust. MSD direct fire ignition on the leading plugs only stock dizzy on trailing. remove the fan and added an electric fan.
replaced the rad with a Mazda Comp. aluminum rad. the set up that I am running right now dyno on a mustang dyno @ 125hp @5200 rpm and 114 lbs of torque.
the car is very fast and has been reliable for the past 8 years that I have been running it. I spent alot of money on my "$500" car to make it this way but I am the kind of person that will spend more the first time than spend a little over and over again on the same piece. good luck with your project.

 

The Sterling carb is a work of art, and I have no problem recommending them. The website is www.sterlingmetalworks.com

CSP is a great class to be in, because it allows you to do everything you would do anyways to improve the street performance. You get the best of both worlds that way.

And I will also agree with upgrading the suspension and tires before anything else. I never lost a race due to a lack of horsepower. Actually, the biggest improvment you can make is in learning how to drive. Pick up some good books, and check out the racing section of the form too. Good luck, and have fun...

 

Thanks a lot guys. very good advice and info!

 

No problem man! Any questions at all, feel free to hit me up. I love racing autocross, and anything I can do to help others get into it will gladly be done...