Boost connections

Ultimatedsm · 05-03-2006, 08:08 AM

Hey how are you guys doing? Ever since my MBC took a crap on me, I have been running the J-pipe nipple boost source directly to the wastegate nipple.

Now I will be running this for a while but I noticed in the early rpm's around 4000-4500 RPM I get 10 psi but when I am closer to 6000 RPM I hit 15 -17 psi depending on the gear. Should I put a "T" inbetween those two sources and hook up my BS soleniod to it? Please let me know and only the people with experience in this please reply. Thank you.

daren_p · 05-03-2006, 08:13 AM

No I wouldn't hook the bcs back up. What you are seeing is probably boost creep, either that or a defective mbc but I doubt that.

Ultimatedsm · 05-03-2006, 08:40 AM

I got rid of the MBC, that setup is from the J-pipe nipple to the wastegate nipple (With a Vacuum hose of course). I was wondering putting a "T" in between those two connections and hooking the BCS back up will stablize my boost better.

Dream On · 05-03-2006, 08:47 AM

Might as well give it a try, but I doubt it. It sounds like creep to me too.

Ultimatedsm · 05-03-2006, 09:50 AM

Boost creep on a 14B? I even ported the exhaust side, but I didn't port the o2 housing or the exhaust manifold. I thought 16g's creeped?

daren_p · 05-03-2006, 10:35 AM

Quote:

Originally Posted by Ultimatedsm

I got rid of the MBC, that setup is from the J-pipe nipple to the wastegate nipple (With a Vacuum hose of course). I was wondering putting a "T" in between those two connections and hooking the BCS back up will stablize my boost better.

Sorry about that ,misread your first post, thought you still had the mbc hooked up. Either way it still sounds like boost creep but that seems like alot of creep for a 14b. This could be because you didnt port the O2 housing. I know when I had my evoIII hooked up directly, without the WG shimmed I would initially see about 8 psi on spool and about 12 or 13 by redline. I guess the best way to find out would to just hook it up and see.

zippyshoe · 05-03-2006, 10:42 AM

Quote:

Originally Posted by Ultimatedsm

I got rid of the MBC, that setup is from the J-pipe nipple to the wastegate nipple (With a Vacuum hose of course). I was wondering putting a "T" in between those two connections and hooking the BCS back up will stablize my boost better.

No, if you reconnect your BCS, your boost level will actually increase by a few psi. Since the BCS is basically a bleeder valve, when the valve opens, your wastegate actuator will see a few psi less and your resulting boost pressure will increase a few psi. If you are experiencing boost creep, your main options are: 1) Port your turbo's wastegate area and port your O2 housing, or 2) Modify your exhaust system to make it more restrictive (a far worse option).