Circle Track Racing awesomeness.
 

I need to know what would be the best RX7 to use as a circle track racer. 1st or 2nd gen? It will be a full blown racecar. Almost a full framed racecar. Has to be stock ports, 2 rotor, non turbo. I am looking for the best handling.

It is a 3/8 oval track.

Dirt or Asphalt?

If you have to use the stock unibody and suspension layout, I vote for an FB. There is way too much information available for a solid rear axle car in circle track racing to ignore. The IRS in the later cars would be too hard to work with - too fragile for that environment especially if you are talking about dirt. Also there is the cost consideration and FB's seem to be the cheapest cars to buy.

So where do you get to run a rotary in circle track racing? What would you be racing against?

In KC the rules for 4cyl cars (pony stocks) specifically rule out Rotary powered cars. Frankly they are rigthly scared of what a rotary could do in their environment given the right competition.

It is asphalt. I already have 2 SA's i could use. But i want a GSL-SE because they already got the 13b and LSD. I am VERY familiar with oval track cars because i use to race a quarter midget (mini sprint car) for 6 years. They are a full suspension oval track car so i will just set up the RX7 similar.

The class is called a Mini Stock. It is similar to a Hobby stock or pony stock. The people at my track have no clue what the potential of a rotary engined car is. They will prolly end up banning my car. HAHAHAHA. But other cars in the class include: Prelude's, Civic's, Rabbit's, Shiracco's, Corrado's, one 240sx and one RX7. Those are the only RWD cars in the whole class. I will be the third one. :)

Hey that should be cool. A GSL will get you an LSD too just not the 13B Oh and the 84-85 GSL also has the bigger axles - just with the 4x110mm pattern.

One thing I would stay away from are the GSL-SE's front brakes. In road racing we have found that the hub/rotor assy is prone to failure without warning. They cannot handle the high side loads generated by sticky tires. I have seen the aftermath of several failures and it was not pretty at all. I'm guessing that would make the Hub/rotor on the RF suspect in a circle track car We have not seen the same issues with the 12A hub/rotor combination, by the way.

Good luck with your project and keep the board posted on your progress. Pictures would be cool.

What kind of tires are you allowed to run in that class? Is there a web site for the track? Is the rule set listed online?

Ok. I didnt know that. Thanks for the info. I will kist get a GSL then. haha.

We have a spec tire. Idk what it is.

Here is the rules for the class...
http://www.evergreenspeedway.net/art...icle_384.shtml

Okay - I looked over the rules. Pretty interesting.

From the way the rules are structured I think the FOX body Mustang with a SOHC 2300 4cly will be the car to beat because they can port the head. Plus they are cheap to race.

For an RX7 I think the sound requirements are going to be a challenge. In a rotary noise equals flow so you have to be careful about how you knock the sound down. I have seen and heard 13B RX7's from California that are both quiet and fast. The car was built by Mazdtrix - maybe they could give you some ideas

As far as setup -

I would run 84-85 spindles with 12A front brakes - the spindles are stronger and the outer wheel bearing is bigger. The 12A brake is big enough for what you are doing as long as you use racing brake pads like Hawk Blues.

The suspension rules are fuzy so it is hard to say what they allow and what they don't They don't seem to disallow hiems and or alternate control arms so I would look into that. I run a 3rd link on my road race car and in the higher classes they are running true four link rear suspensions. We call then "traction bars." Maybe you can too?? Good struts and shocks will be important.

For the engine I would run a 13B with a Holley 500 2V carb on a Racing Beat 4V manifold. There are adapters out there to make this work. Use side hung floats on the carb instead of the center hung floats. The center hung floats swing the wrong way when you mount a Holley on a rotary.

There doesn't appear to be any rules regarding the year 13B you can use so running a later 13B with higher compression rotors would do the trick.

Spend money on a good header, free flowing exhaust, and a good carb.

Keep us posted

Thanks for the info man!


There is one foxbody and it is SLOW!

There is a 2nd gen Rx out there and it wins all the time.

I might be going to the dark side (drifting) instead. haha. But i will keep everyone posted on whatever i end up doing.

Oval racing is where the Tri-link, Panhard was born... in road racing it's a comprimise because it works better one direction than the other -- guess which direction? Unless you plan on going ridiculous with the setup, you can't argue with the simplicity of the trilink/panhard setup, and Jim Susko sells 'em for a reasonable price.

Getting enough camber in the front will be your only real issue. We semi-converted an SA based SCCA ITA car for oval, I had to make a new Left Front camber plate out of steel, and cut out most of the shock tower, and we were only able to get +1 degree of camber on the LF. Much better than the -1 we started testing with, but it needed more. IIRC the RF was somewhere between 3-4 and was "OK" with Road Race Hoosiers, but we were told by our local suspension oval guru we'd need more with their radial (or, shit, was it bias?) tire.

These cars are fun on the oval, at least in practice. I don't have one ready to go that I want to beat and bang around there, but I thought about putting a Miata engine in one to go run in a 4cyl class called Texas ProSedans, but it wouldn't be worth it since the chassis isn't allowed in the first place. Somebody long before us showed up to some Texas tracks with a rotary, so that isn't even an option except in exhibition.

The track we ran on was a 3/8 mile D-shaped oval with lots of banking here in Central Texas called Thunderhill Raceway, not to be confused with the road course in NorCal.

2nd Gen wins all the time
 

First of you clearly have never watched a race at Evergreen! I am crew cheif on the 64 car RX7... as much as I would like to say that we win all the time that isn't true. The 240sx wins all the time... we are front runners.

However towards the end of the year we had made great strides with a STOCK 86 motor with 100+ miles on it... (thousand).

You can only modify external components... no internal or porting etc. All we have is a header and a cold air intake and some backhills modifications but nothing crazy. Mostly eliminating smog etc.

We are capable of winning races when we get a 91+ motor... that is freshend.

BTW NO, and I mean NO... solid axle car does that great at Evergreen. The 240 is an indy Rear End, and so is the RX's. There is only one RX-7 that runs currently... but the first one to the track years ago will be back next year and there is talk of others building several RX's after seeing what can happen with these cars.

I am thinking about building a gen 1.. and I am wondering if the solid axle setup is better than most, compared to a pinto or mustang rear end. If I get the same results as a Mustang I will be very dissapointed. I have thought a ton about doing a full indy swap off of a miata or or second gen RX7? I can't find good info on that though.

Since we are allowed to basically to tube a car it would be easier to make the swap..