Overboost issue Solved?

[snow3d]

What's up yall? I have some info to share with you guys.

I have been tracking down an overboost problem for the past few days. I've searched the forums and I've done some testing.

My car has the stock turbo (brand new) and O2 housing. 2.5" down pipe, 2.5" test pipe, a bullet muffler, and then it's 3" after that and it ends in one of those huge cans. (It came with the car and I hate it!)

Here is what I have done and what I have determined:
1) Vacuum leak test - OK
2) Boost leak test - OK
3) Smoke tested the exhaust and intake systems - OK
4) Pressure tested wastegate - OK
5) Bypassed BCS and MBC - Overboost

The exhaust system is too freakin big, is all I can surmise. Am I correct?

I don't want to port the wastegate, or put a dump on the O2 housing. Since I hate the exhaust anyhow, I figure I will just change that.

The question is how much restriction do I have to add to stop the overboost?
Could I just hack it at the down pipe and run a normal 2.5" system with a muffler and a cat?
Or two mufflers and no cat?

 

[knochgoon24]

You can try porting the wastegate passage. Also make sure the wastegate flapper can open all the way. You may have to remove some material to get it to open far enough.