? how to stop boost spike

[pwhite]

I have my boost set at 16 psi and when i first punch it my boost jumps ot 20 and then settles down to 16. this seems to happen mostly on downshifts. thanks.

 

[Fred 86 GN]

Do some port work on the wastegate hole in the exhaust housing of your turbo. Open it up some, being careful to leave at least 0.06" around the hole for the puck to still seal up against. Most improvement can be made by grinding the inside edge of the hole for a more gradual blend into the volute.

Checking all your vacuum lines around the turbo and boost solenoid for cracks/leaks would be a good idea too.

 

[UNGN]

Whose chip? Opening the wastegate hole probably won't change this. It sounds like a "quick spool" code in the chip and the solenoid is allowing the overboost. If it doesn't close until the boost reachs 20 psi, it will still overboost.

 

[pwhite]

Its a street chip from precision to go with my 42.5 injectors. I also cant get my o2s on my scanmaster to go below 850s at wot. I have adj the fp way down and still cant get them to drop.

 

[UNGN]

Usually when someone has 42# injectors, they also have a big turbo, etc. Chip burners don't think you are going to be running a stock car with 42# injectors, so they put in things to help spool the big turbo and make the chip fat to compensate for the additional airflow. You may want to try another chip, to see if things improve.

 

[pwhite]

Thanks....... I needed new injectors and didnt want to buy them twice so i went big . Planing on a turbo within the next 2-3 months. I was told the chip would be for my app. stock turbo and all. Any suggestions on a new chip?thanks again

 

[ross87t]

Sounds like what my "quick-spool" Thrasher did.
I didn't like it, so I swapped it out.

Your best bet would be to call your chip maker back, and describe your problem to them. They'd probably reburn it for you for little or no fee.

Ross