I remember reading on EvoM about it is not good to up the psi of boost until you install an aftermarket exhaust. I have the exhaust and I also have the test pipe. Do I need a downpipe before I try to boost 21.5 psi's??

 

if it is a stupid question can i still get a reply

 

I've had a mbc since day 1 before any other mod. Just remember they all work together.
Depending on what octane you can get and your fuel system (pump) you can turn up the boost up a little. Before getting it tuned properly I wouldnt go up that high. Maybe 20 max.

 

also, putting a full TBE on with no form of boost control will increase your spike and hold psi quite a bit. probrably more than your stock ecu will like, may lean out or hit fuel cut. it's a good idea to have some sort of boost control prior to a TBE.

 

A downpipe will help you reach your intended psi target quicker. Get an mbc to keep boost from dropping at higher rpm, rather than raising psi (at first). 20 psi is no problem. Prolonged 21.5 is pushing it (depending on who you ask) for stock headbolts. Get arp headstuds, a tune and think about a fuelpump, and you will enjoy the improvement.

 

thank, those are the awnsers I was looking for

 

Actually, 21.5psi is nowhere near the point where you need to worry about the stock headbolts. Don't worry about studs until doing cams, and that's only because you're opening the head anyway.

Get the DP and MBC together, otherwise the DP will probably cause boost spikes in cold weather that induce fuel cut quite often.