Homebrew Stage III Experts needed for help: I have been fighting overboosting issues
03-19-2008, 03:29 PM
#1
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Homebrew Stage III Experts needed for help: I have been fighting overboosting issues
with my N75 valve in parallel with my MBC. MBC only it holds the requested boost like a champ. Today I ran the N75 back in parallel with the MBC and it started overboosting to 25 psi plus at WOT in all gears. If I ease into it there is a sound with 3 whistles of sort then it will hold to redline. It does this in all gears never fails.
Now it gets interesting, I unplugged the electrical plug from the N75 and it feels great. (The hoses are all still hooked up in parallel???) It seems like it has part throttle and is much smoother than MBC only. How can this be, shouldn't my car be in limp moce or something? I don't have a clue what is going on but I think I will leave it as is and run some logs~
Ideas???
FYI I have relaced the N75 valve x 3 and the MBC. Also I have an IBE Chipswitch running the GIAC XR file on racegas. The symptoms are the same on the X file.
Now it gets interesting, I unplugged the electrical plug from the N75 and it feels great. (The hoses are all still hooked up in parallel???) It seems like it has part throttle and is much smoother than MBC only. How can this be, shouldn't my car be in limp moce or something? I don't have a clue what is going on but I think I will leave it as is and run some logs~
Ideas???
FYI I have relaced the N75 valve x 3 and the MBC. Also I have an IBE Chipswitch running the GIAC XR file on racegas. The symptoms are the same on the X file.
03-19-2008, 03:47 PM
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^2nd. I would say a torn wastegate line perhaps. If the MBC is working properly, then...
the problem is between the MBC and the wastegate, either a torn line or a stuck wastegate perhaps.
03-19-2008, 03:48 PM
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or some interaction between the MBC and the N75 causing it to lose wg pressure
i've seen odd things before in my parallel set up too, i haven't really thoought about it, but maybe there is a way for pressure to escape via the n75 such taht the mbc can't crack the wg.
03-19-2008, 03:51 PM
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You could have a bad N75. I've seen it before...esp if you've taken it out...
try replacing it. But first, I'd double-check to make sure that you are, in fact, properly parallel in your tubing. Check for leaks in the tubing too. Lots of spaghetti in there when running parallel.
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03-19-2008, 03:53 PM
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yes, remove the line from the N75 connect it to an air compressor and listen to it
you should be able to hear the wg opening. If you have a good seal on the line the WG will remaing open for while even when the pressure is off and just sealing the hose.
03-19-2008, 04:12 PM
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I put 8ish psi to the WG line and could hear the WG actuators opening, not sure what you mean that
they should stay open for a while or how I will be able to determine this?