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Houmack
07-12-2007, 11:42 AM
So this is strange, and it might just be cause I have something not set correctly...

Engine:
SR20DET - built bottom end
Garrett T3/T04E 50 trim w/ .63 A/R Stage 3 wheel
Peak Boost Turbo manifold/DP
38mm Tial WG
Freddy IM
regrind cams to 264 Step 2 (or so I've been told)
72# MSD injectors
Microtech LT10s EMS
2.5" hot pipe to and 2.75" cold pipe
Manual Boost Controller

Issue...
I have my boost set to ~16 psi... But it doesn't build 16 till about 6500 rpm!!! I think that's a bit too high, don't you think? My 60 trim last year had full boost (24psi) by around 5100.

My timing is based on Scotts calculations on the "best of" section (-2* in boost for now)

Could this be an issue with my Boost controller? I set it to close, and it built 20psi by 5000 and of course, running pump i had to back off right away...

My boost source for the Boost controller is not on my compressor, instead, a nipple off the hot pipe about 3-4" away from the compressor... this shouldn't be a problem right?


Thanks in advance!

Wedge
07-12-2007, 01:23 PM
I'd take the MBC off and go from there. What spring is in your wastegate?

My boost source for the boost controller is that close and I never had a problem, but then I again, I am still using the stock turbo.

janders211
07-12-2007, 01:48 PM
If you turn the boost way up, and it builds boost quicker = crappy MBC.
Easy to test...if you do it CAREFULLY. pull hose to WG, block off source...drive very slowly to 5th gear(i.e. no boost) ~2000RPM, stomp on it and watch your boost gauge, and let off as soon as you hit...say 10psi (for pretends say 4000 RPM) reconnect MBC, run from 2000 to 10 psi (if it say hits 10psi @ 4500(i.e. later than w/ MBC disconnected that means your MBC is leaking 'signal').

BTW..do this wrong, don't let off early and you can put holes in large metal objects

Houmack
07-13-2007, 10:27 AM
thanks guys. Problem was indeed the MBC. Changed it and it boosts to 16-17 by 4300. That's where i like to be :)