Absoulutely correct---no castor. I'm friends with an owner and professional dirt biker/four wheeler idiot and he turned me on to the full synthetic Yamaha pre mix. He alsao castor well eventually give you problems. I run premix on the track only and only add 5 oz's per tank(almost a 1/3oz per gal) I know that is light but it does make a differance even at that low concentration. I only use maybe 1/2 quart oil for a track day Apprx 175miles. I get good gas milage on the street and have 30thou on the car.
I suggest pre mix for everyone that does anytype of high performance driving. Autocross, dragging or track
olddragger

 

Mine turned out to be a fried cat. We think the direct root cause is adding 2 cycle oil to the gas. That helps protect the engine more, but kills the cat whether you use castor or synthetic oil.

Through this experience I've learned a bunch and loss of power can be so many things… fuel, air, and spark.

We are harder and wear things out quicker racing, but maybe some of our experience will help those on the street too…

Fuel…

No external fuel filters, it is all built into the fuel pump below the rear driver side seat. I haven't heard of an RX8 with fuel problems yet, but lack of fuel flow (filter or bad pump) would cause the symptoms of power loss under load.

Air…

As others have mentioned, make sure your air paths are clear.

Spark…

Coils go bad, white marks around outside of coils indicate spark being lost.

Plug wires can go bad.

We are changing spark plugs every 3rd race weekend.

Good luck with your problems.

 

As for plug wires, Jim Langer at Racing Beat said his Ultra wires are good for 50K of rotary use.

 

Old school Castor is very slippery, and OK, short term, in a racing motor.

The old 12A engines differed significantly, peri-port exhausts obviously, but more importantly - they used a thermal reactor system and NO cat. Nothing to plug up, no fine mesh to foul.

S