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Old 07-18-2010, 01:14 PM   #1
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Default Odd behavior when I adjusted boost

I raised my boost via the MBC in my car, but when I make boost above 17psi or so (hard to read this guage while I'm driving), the car seems to fuel cut or do something that would stumble the engine quite heavily. Any ideas what this is? Is there a fuel cut for boost in the hydra that I'm not finding or something?
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Old 07-18-2010, 01:20 PM   #2
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What's your target boost set at in the Hydra?
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Old 07-18-2010, 08:17 PM   #3
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Ah, set to 12 across the board. That'd do it I'm guessing
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Old 07-18-2010, 10:21 PM   #4
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Boost cut will do that to ya
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Old 07-18-2010, 10:37 PM   #5
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Woot new issue! I build boost fine, but it spikes to 15.5 or so, then drops to 12, then climbs to 14.7 and FINALLY settles down at 14.1psi. Not sure what could be causing it, but I did blow some oil through the system previously, maybe the BOV is leaking? Either that or the MBC.. I don't see this when I have i set to 12ish (it does do it, not as severely though) and its nonexistent at WGA default (8psi) without the MBC..
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Old 07-18-2010, 10:43 PM   #6
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Quote:
Originally Posted by Der_Idiot View Post
Woot new issue! I build boost fine, but it spikes to 15.5 or so, then drops to 12, then climbs to 14.7 and FINALLY settles down at 14.1psi. Not sure what could be causing it, but I did blow some oil through the system previously, maybe the BOV is leaking? Either that or the MBC.. I don't see this when I have i set to 12ish (it does do it, not as severely though) and its nonexistent at WGA default (8psi) without the MBC..
faulty mbc.
which one are you running?
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Old 07-18-2010, 11:31 PM   #7
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Stock one that FM sent me. It has a check valve of some sort on the WGA side that lets air out so the WGA can close again, but I blew in it a bit ago and it lets air both ways.. I'm assuming that's not what it should do? :(
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Old 07-19-2010, 12:14 AM   #8
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My duty cycle is roughly 80% at 14.1psi and 6k rpm, AFRs are around 11-11.5 (except when the boost spikes, it can be up to 12 then)... Wondering what I would see if I kept upping my boost? Currently using 550's, didn't think I'd hit my topend already :(
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Old 07-19-2010, 12:44 AM   #9
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try running a stiffer wastegate spring... you typically get a weird reaction when you try to double the pressure that the spring is supposed to open at.
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