my car is boosting 8psi with 450cc and safc, it works fine from 1st gear to 3rd gear throughout the rpm band, but for some reason in 4th gear around 5k rpm, it doesnt accelerate, but boost is present, also the a/f reads rich. im thinking of only 1 possibility : stock fuel pump. i have 255 walbro pump im about to install, but i was also wondering what else could be the problem. thanks

 

since you said you havent installed you new fuel pump. I say you go ahead and install it, and let us know what happens. Might as well try it since you'll be installing the fuel pump sooner or later

 

how much boost are you boosting?

 

slipping clutch?

 

my bet is that you retarded your timing entirely too much and aren't making any power-- that'll really show up in 4th gear.

How much did you retard it?

 

4 degrees

 

im now also noticing i am getting cel during boost under 4th gear...grrrr