Boost dropping from 25 psi to 12 psi on the 2-3 shift... need to help!

[TurboDave]

bruce made some EXCELENT points! I might add (which you seem to already have discovered), with 114 in the tank, there's absolutely NO need for any alky. That should be more than enough octane to run you through, and the alky is throwing the state of tune and numbrs of.

I've often told folks, OK run alky if you must, BUT get the car running top notch without it FIRST. Throwing alky into a badly mistuned combo isn't going to do much but dig a deeper hole.

114 is good enough to get me down the track at 26# of boost and 29º of timing with no knock, so it's good stuff.

 

[Ormand]

EGT

Sounds like the alcohol is much of the problem, but I have one other question. Where is your EGT probe? I read that at one time the EGT was "sort where they needed to be", but there were no numbers with that. Seems to me that you get the engine running right, with no knock, on gas, and the EGT that matches that condition should be the "where they need to be" target. But then when you use alcohol, the combustion temp drops, and you will need to find a new, lower target. Because of variations in exhaust systems, engines, and probel locations, one car's target is NOT good for another car.