Maxwedge

iTrader: (1)

RX7 owners take pride in the fact that our cars have always had near 50:50 weight distribution. My '85 came off the line with something like 50.3 : 49.7 balance. Fill the tank and add a 180' driver, and you're closer to 49:51.

So if you relocate the battery, remove A/C and heavy stock exhaust, get a fiberglass front clip, etc etc .... at what point does the balance go too-much to the rear? Is that even possible for our chassis?

I don't have a race car. But as I restore and upgrade my street car I wonder if moving too much weight will give any negative handling traits. Heck, a classic 911 is 39:61 so probably not. Just wanted to ask you guys with actual track experience.

WANKfactor

iTrader: (1)

Thats interesting. Im a bit foggy as it was probably 10years ago but i think mine was about 51 or 52 to 49 or 48.
thats with t2 engine and trans though.
probably a touch closer to parity now as the engine is 10mm further back and a heavier diff fitted since then.
I dont think there is a magic number per se.
You the driver will know what feels right.
I remeber nissan was making a big deal about the 350z being designed 1 or 2% front heavy when it came out, with the idea being that ot evens out better under acceleration but that was just marketing bullshit.

mustanghammer

iTrader: (3)

The short answer is no, you aren't screwing anything up.

A car's CG moves as the car moves. Forward under braking, rearward under acceleration and side to side in a corner. Compared to cars that have a higher weight percentage over the front wheels I find that an RX7 can be driven deeper into a corner and is more likely to rotate better through the middle of a corner. Corner exit traction in an RX7 has more to do with rear suspension design but with stock HP an RX7 has no real problem with traction. By the way Miatas are like this too. In short an RX7 has no vices and really doesn't require a driving strategy like a Mustang or Camaro.....slow in/fast out....because of it's inherit balance.

I'll never forget the first time I raced my RX7 at a driver's school in 2003. I couldn't believe how well it turned in. How deep I could go into a breaking zone. How well the brakes worked corner after corner. Prior to the RX7, I was autocrossing a fairly well developed Fox Mustang. It was faster and more powerful but it had none of the balance of my newly purchased RX7.

j9fd3s

iTrader: (3)

This one time we ran a spec E30, which is a BMW E30, and everyone has the same setup so its cheap, and competitive. Those things have ballast for an engine, so its like the mustang, 60/40 distribution.
we started with a back marker car, and eventually had it sorted and we finally had a weekend where it looked like we could podium.

minimum weight for the class at the time was 2750lbs, and our car was 2550lbs, so we added a bunch of ballast in the trunk.

car went a couple tenths faster, the weight distribution was less worse....