I've seen a lot recently about high octane fuels (super / optimax / etc).

 

When I had my Z I had it set up on a rolling road and chose to do this on normal unleaded fuel. Using filter / exhaust / decat / 1 bar boost / custom mapping, this gave 432 bhp at the flywheel (based on wheel bhp plus transmission loss on the over-run). Those of you on an SE chip probably have something based on mine.

 

I suspect that a higher quality fuel might have given me 10 or 20 bhp - so what ?

 

My point is that you can get pretty good bhp on normal unleaded. After the tuning, I always ran on super whenever I could to give me a safety margin. This saw me good on a 2 hour stint at 150 mph+ down to Le Mans 2 years ago.

 

There's a lot of people posting that their car runs like shite on normal unleaded. My advice is to get it sorted so it will run on normal unleaded and then run it on super. My car was 100% unreliable - if you're getting det because of 95 octane when 97 octane is OK then you are running WAY too close to the limit.

 

Just offered as food for thought ...

 

Dave

I just adjusted the timing on my '90 NA, and the car has developed slightly more power than before, but it is delivering a barely noticeable popping sound when it gets very hot, even with high octane fuel. I've heard this before, but not so much of it Is this detonation, and should I back off a bit on the timing? Will adding more octane booster reduce this?

 

Also, since cleaning the throttle bodies and intake manifolds, the idle has increased to 2100 rpm. Even fully adjusting the idle nuts (both idle and cruise control) has left the idle at 2 grand. Is there another way to bring this down?

 

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--Maxx

Timing. If you're running over 15deg then bring it back down to 15.

 

After cleaning the throttle boddies disconnect the ecu overnight (neg battery terminal) to clear the settings.

I was told that they run like shite coz they're all Jap imports and used to running on Jap fuel. Is this true ! Mine certainly has problems with high boost pressures on standard but no problems with Optimax.