How can i lower my boost?
OK, now with my new Shore Motorsports intake my car is making 17.2 lbs of boost(woulda been higher but i noticed it and took my foot off). As you can see in my sig i run a stock 99 motor with an MSM turbo. Any immediate suggestions to keep the boost from going that high? I've heard anything over 12 is dangerous with this bottom. Gonna have Tim elongate the wastegate arm to help but was looking for something quicker. I know the easiest way is to not keep my foot in it but I have a heavy foot.
for reference the car was making 12.0psi before the intake. i have plenty of fuel, max duty cycle was 73% air intake temp max was 76 F |
Boost controller?
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you can only go as low as the wastegate will allow. taking some preload out of the arm will help, that's about all you can do.
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I really don't see how just an intake would make you start boost creeping that bad all the sudden.
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just checked to see if the "Vacuum" line(sees boost only so should i call it a boost line?) to the wastegate actuator had blown off.
it didn't so that means 1 of 2 things. 1. the actuator diaphragm is shot 2. the system is now so efficient that the small size of the wastegate on the MSM turbo is so restrictive that the system is still building boost while the wastegate is open. |
Are you sure the wastegate arm isn't somehow getting pinned open? Intakes do not cause 5psi jumps.
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#2 is possible, but you would have see that happen after you installed the exhaust most likely.
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i gotta figure out a way to apply some air pressure to it to see if it's responding.
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Take a bycicle pump and cut off one end then stick it on the WG nipple. with a boost gauge teed in not the pressure at witch the WG moves and then if you notice any problems go from there. If the WG moves fine and has full motion then a simple reverse helper spring can do the trick just fine. Also the boost is not the problem with the NB bottom end it is the tune if the tune is good then the motor will hold together. GL bud
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I assume you weren't at redline to be at only 73%DC at 17.2psi on the 460cc injectors?
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Originally Posted by magnamx-5
(Post 168161)
Take a bycicle pump and cut off one end then stick it on the WG nipple. with a boost gauge teed in not the pressure at witch the WG moves and then if you notice any problems go from there. If the WG moves fine and has full motion then a simple reverse helper spring can do the trick just fine. Also the boost is not the problem with the NB bottom end it is the tune if the tune is good then the motor will hold together. GL bud
Originally Posted by Atlanta93LE
(Post 168212)
I assume you weren't at redline to be at only 73%DC at 17.2psi on the 460cc injectors?
actually that max DC was at 15.0psi and 5666rpm. at 17.2psi my DC was 65% and 4874rpm |
ok. did some testing.
so to response to Savington & neogenesis2004: intake design changes can make a 5psi jump in boost pressure if the original was too restrictive, the exhaust is unrestrictive enough, and the wastegate is too restrictive. |
Some further testing.
So as not to JUMP to any conclusions about the new intake being responsible for the 5 lb increase in my boost pressure I removed it and reinstalled the stock MSM intake. Results: I stand by my earlier statements. IOW, Boost max=12psi. |
Sell it and go garrett like I told you in the beginning :p
-Attempt to enlarge/smooth the internal WG passage. -build a MSM replacement manifold with an external WG (probably around $350 in parts) -find a welder (BEGI maybe?) who is willing to weld a external WG flange and/or pipe to the MSM manifold The following will restrict that killer spool you now have: -you reinstall the MSM intake (I threw out the MSM exhaust a few weeks ago) -I can weld a 1" restrictor plate into that new intake. -Perhaps that muffler/restrictor gizmo you were considering to quiet your exhaust may restrict it enough to bring down boost |
Originally Posted by Savington
(Post 168134)
Are you sure the wastegate arm isn't somehow getting pinned open? Intakes do not cause 5psi jumps.
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Originally Posted by TurboTim
(Post 168555)
I call my line of intake and exhaust components "absurdflow". TM and copyrighted.
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Originally Posted by neogenesis2004
(Post 168136)
#2 is possible, but you would have see that happen after you installed the exhaust most likely.
That on that particular MSM, clamping the WG fully open produced around 10 psi. That was with FM's intake kit, stock intercooler & plumbing, and my 3" turboback/divorced DP. With the WG rod lengthened to removed basically all of the preload, it makes 11psi. |
with the stock msm exhaust and stock intake it was making 10psi
with the 3" exhaust and stock intake it was making 12psi and getting there a hell of a lot quicker now with the new intake and the 3" exhaust i'm hitting 17+ and again spool is reduced. |
so why are you complaining ;)
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Too close to BOOM, maybe:eek:
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