A/F during spool up

[yokotabrat]

All this talk of tuning in some of the other threads, I thought I'd throw this one out there. Has anyone tested different A/F ratios during spoolup and noticed a decrease or increase? I had read something a while ago that indicated leaner mixtures might aid in decreasing the amount of time to spool a given turbo. Spool up isn't too much of a concern with the 16g, but I'm more interested in the theory rather than applying it at this moment.

[DSMtuned]

My theory is that the hotter (leaner) the mixture is during spool-up, the faster the turbine will spin due to the hotter exhaust temperatures.

I'll tell you how I came to this theory. I have two WI nozzles. One is set to spray at about 6psi and the other is set to 16psi. (The first stage was set so low because the stock IC would heat soak when under constant boost going up to the mountains. I need to raise it to 11psi or so, since the stock SMIC has since been replaced with a giant FMIC). Anyway, with the first stage of WI on at 6psi, my 16g turbo spools noticebly slower than with it off. I think the methanol/water mix cools the combustion down enough to where there is not good exhaust heat to spin the turbo.

I would assume that having a rich fuel mixture would have the same affect on exhaust temperatures and therefore slow spool.

-Craig

[renovatio]

I would have to agree with dsmtuned. The hotter (leaner) the exhaust gas is the faster spool up you will get. The only problem is that you are all so increaseing your combustion temp. and increasing the risk of putting a hole in you piston. Also this added heat in the combustion chamber can aid in pre-ingtion, and we all know thats bad. The correct a/f ratio is your safest bet as rich conditions aid in lowering combution temps.

[97TurboTalon]

I'd agree with you guys, that hotter exhaust helps. Increasing the compression and making sure the waste gate isn't blowing open can also help spool. Boost leaks can effect the spool. Erron mentioned that his electric boost controller made big difference in how fast the turbo would spool.