Exhaust help

[1984Rampage]

I need help determining if I should go full 3" exhaust on my car with the mitsu turbo. 3" isnt much more money and I plan on upgrading my turbo in a year or so but I hear that 3" on a mitsu will cause major boost creep. What are the fixes for boost creep besides porting the wastegate?
I heard that clamping a 2.5" reducer on the end might help?

Any suggestions are greatly appreciated

[detobias]

my opinion is 3" is overkill *unless* you plan two or more of the following

hybrid / larger turbo (S60 or larger, T3/T4, etc)
high boost >20 psi
extensive porting to head, intake & exhaust manis
Much better flowing IC
DOHC
3" swingvalve

otherwise IMO you are adding weight, cost, and complexity for very small if any gains

well it does sound nice too

with a Mitsu, to prevent boost creep, you would need to add restriction to the 3" (or 2.5" too) system in the form of a cat &/or muffler &/or other restriction ; I doubt a 2.5" reducer by itself would be enough

[1984Rampage]

K, Thanks detobias. Anyone think that 2.5" with just a strait-through muffler will still haveboost creep?

[aRTie]

I put a full 3 inch exhaust on my van with the stock turbo and I did get a lot of boost creep on my low boost setting. The low setting was the boost nipple from the turbo going directly to the wastegate. Stock exhaust showed about 5 psi, with the 3 inch exhaust it spooled to about 7psi and did the creep to about 10-11psi. Actually I did not mind a little extra boost or the bit of creep, the 5psi was a little too mild for my daily driving habits. On my high boost setting which was 17 psi through a grainger valve I did not see any boost creep. Of course I knew I was going to upgrade to a S60 turbo so when I did my exhaust there was never a question that I would be running 3inch. I hope that my experience will help with your decision.