i have a 89 civic si with a d16y8 turbo motor.....i have a chipped p28.....when i get to about 5500 give or take...the motor starts to break up and loose power...im running 10 pounds on RC400's....wut are all the possible causes of the breaking up....also v-tec is set around thier...could that be the problem...let me know thanks

 

Has it been tuned? I would think it something in your program like to much timing or not enough its hard to say. Was it working fine with the turbo and then just starting breaking up of did you just put the turbo in and its been doing it the whole time? And 400cc's are awfully small for 10psi. most guys run at least 550's . You might be able to get away with some 450's. It could also be getting too much fuel. If you are running on a 10psi basemap that is your problem probably too much fuel or too much timing. Get it tuned

 

Retarding the timing a bit is free and might help you out, i think that would be a good easy place to start.

 

the turbo was on the motor the whole time...i have a 3 chips from xenocron(Crome)...one has a decent amount of fuel...the next alittle less...and the last alittle less....all the chips i have make it breakup....im gonna check timing now....its actually RC440's