Here's the situation.

1986 RX7 GX race car, NA 13B converted to Weber 45DCOE side draft carb, very aggressive Bridgeporting, Race engine with 285 hp. It was built on the dyno, and worked fine on it, but only ran 1/2 lap in the car before the previous owner blew the clutch, then parked the car for 10 years until we bought it (he drove it around the yard a bit, and winterized it, drained the fuel and the carb, etc).

Engine has turbo rotors and carbon apex seals. Runs on leaded 101 octane race fuel (VP Racing M105L) with 80:1 Amsoil premix oil (the OMP has been removed due to a previous leak causing an engine to fail).

Here's the jetting in the carb (this may matter later in this post)

mains: 210
air: 170
Emulsion tubes: F16
accel pump jets: 65
Idle jets: 65f9
Venturis: 45 (I think)

Here are the symptoms:

In neutral, the car will rev right through to 8,000rpm. When driving on the track, it will rev to 8,000rpm in 2nd gear, but in third gear, when it reaches 6,000-6,500rpm, it sounds like a rev limiter (but there is none on the car), it stumbles and cuts out and goes crazy until you let off and let the rpm come down. In 4th gear, it's even worse, only gets to 5,000-5,500rpm.

Also, in second gear, it will only go that high on gradual throttle, if you step on it really quickly, it won't get up that high.

If you sort of slow down and stop, the spark plugs are pitch black. Also, it was fouling the plug in the front chamber so badly, it was dropping rotor #1 at a couple times. If you go flat out on the track and shut down the engine as soon as it starts to act up and check the plugs, they have a slight white cast on them, and the bowl in the carb is almost empty. Also, it may be unrelated, but the racing beat intake manifold piece is getting so cold when you're at idle and playing with the throttle that it gets condensation and you could chill drinks on it, but the carb isn't cold, it's luke warm.

So here is what we've done already:

-new ignition coils
-new plugs
-new ignitors
-better ground on distributor
-cleaned pick up in distributor
-new cap/rotor button
-new plug wires
-played with timing a little bit, but it didn't help, so we put it back to where it was

-new Holley Blue fuel pump, 110 gph volume)
-new Holley fuel regulator, set at 3.5psi of pressure
-new 3/8" fuel hose from the pump to the carb
-new fuel filter (clear, we can see fuel inside it)
-Took carb apart and cleaned everything up, set floats to spec, checked all jets and needle seat, etc.


Here are some other jet combinations we tried on the weekend to no avail:

Main: 185
Air: 170
Emul tube: F16
Accel pump jet: 50

Main: 210
Air: 185
Emul tube: F16
Accel pump jet: 65

Does anyone have any ideas for this? Do you think it's a jetting issue or something else?