boost problem
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Evolving Member
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Joined: Sep 2006
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From: San Antonio/Houston, Texas
boost problem
Ive searched the threads and havnt found an exact answer
A couple of weeks ago i installed a FORGE MBC on my 03 evo VIII and set it at 21psi with no problems holding at 19 or 20 then just last night i did a few runs with some buddies and i was only spiking at 18 or 19 dropping to 16 at redline. It was pretty cold last night could weather effect my boost this much even with my MBC? and i checked all the lines everything seems to be hooked up right should i just crank the MBC all the way down then try to set it at 21 again?
Any info would be much appreciated thanks.
A couple of weeks ago i installed a FORGE MBC on my 03 evo VIII and set it at 21psi with no problems holding at 19 or 20 then just last night i did a few runs with some buddies and i was only spiking at 18 or 19 dropping to 16 at redline. It was pretty cold last night could weather effect my boost this much even with my MBC? and i checked all the lines everything seems to be hooked up right should i just crank the MBC all the way down then try to set it at 21 again?
Any info would be much appreciated thanks.
Cold weather actually will raise boost higher. I think what's happening is that the spring is breaking in and that's what's causing you to lose a few pounds of boost. Just turn it up a few cranks back to desired boost and keep an eye on it.
Springs don't "break in" then suddenly start showing less boost.
YOu may have contracted a boost leak. It is not normal for boost to randomly drop unless the weather gets hotter. It should go up as the weather gets cooler, so since yours is opposite, it suggests a mechanical problem. Start by taking the UNOS apart, ensuring the spring is seated on the nipple, clear the small bleed hole of any debris, and use some synthetic grease on the ball (not much). Put it back together and start from minimum setting and re-set the boost to 21psi. If there are still issues, then do a proper boost leak test.
YOu may have contracted a boost leak. It is not normal for boost to randomly drop unless the weather gets hotter. It should go up as the weather gets cooler, so since yours is opposite, it suggests a mechanical problem. Start by taking the UNOS apart, ensuring the spring is seated on the nipple, clear the small bleed hole of any debris, and use some synthetic grease on the ball (not much). Put it back together and start from minimum setting and re-set the boost to 21psi. If there are still issues, then do a proper boost leak test.