3rd gear boost creep, external wastegate

[DougsfastZ]

I'm running a stock turbo with a 3" downpipe and an external wastegate. I have the MAF Pro setup (with their boost solenoid) and set the boost to 20 psi. 1st and 2nd gear, the car holds a solid 20 psi, but as soon as it shifts into third (and I lock the converter) boost creeps right up to 23-24 psi. Then it will begin to come back down to 20 psi by the top of third. I ported and radiused the wastegate hole in the turbine housing thinking that would help, and it didn't, same creep. Vaccum lines are new.

Any ideas?

Thanks,

Doug D

 

[GNVYUS 1]

1st, this is the oddest combo I have seen on here, a wastegate with the stock turbo??

I am assuming the gate is off the turbo instead of the headers so open the wastegate hole a ton since it doesn't matter how large it is vs the puck and see if that helps any. I know you said you did it but if there is a specific tube coming from that hole to the wastegate then you can open it up a ton and it won't matter with spool up down low.