Mbc all the way closed, car still hits 15psi on an ihi turbo
Ive looked and looked through all of the threads but havent come across any answers yet. Ok I have a d15b vtec with a ihi vj11 turbo, intercooled, 450's, dsm bov, yada yada.... I was running 2 1/2 dp through a cat, back to a stock muffler. With that set up and a mbc, i was running a steady 11 psi. I redid my whole exhaust 2 1/2 dp into a long resinator. thats it.
Now cant keep the boost down around 11 psi. It wants to climb. Now with the mbc fully closed shouldnt the turbo only spool to what the stock actuator is set at? its at 8 psi. Well it dosent. I let off the the gas at 16 psi. With the mbc closed. Wastegate must not be opening so that makes me think the mbc might be faulty. Or wastegate getting stuck shut? :S |
Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
No mbc all the way closed pretty much='s no WG :-X back the mbc off some or take it all the way off and just run a vac line to the WG if you only want 8psi and thats what your wg spring is.
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
the thing is I want more than 8 lbs. Ive tryed backing the mbc off a 1/2 turn at a time. maybe I should make smaller adjustments to the mbc
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
Originally Posted by 88dx
No mbc all the way closed pretty much='s no WG :-X back the mbc off some or take it all the way off and just run a vac line to the WG if you only want 8psi and thats what your wg spring is.
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
Originally Posted by Minor Threat
Isn't MBC all the way closed, not bleeding any air?
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
can also depend on the length of hose, remember that hose must fill up before the wastegate will see pressure.
and if it is a small turbo sometimes it spools up too fast and the wastegate cant catch it |
Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
"and if it is a small turbo sometimes it spools up too fast and the wastegate cant catch it" NCHATCH
Good point, I do have a damn small turbo that spools hella quick. I guess I can try shortning the lines again. I did that before and wierd things would happen. like boosting all the way to maybe 5500 and then boost would just quit. But Ill try again. nothin to loss. |
Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
I noticed you did not list the maker fo the MBC you are using. However, I had a Turbo XS MBC (the cheap one for $75.00) and the same thing happened to me. I had a Garrett turbo with A/R .60/.48. No matter the adjustment made with the screw or the lenght of the hose the boost would rise to 15 psi. It would hold the 15 psi until redline. I threw mine away and bought an adjustable internal wastegate. If you are using the same brand/model, good luck fixing the problem.
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
Run 16 psi :y Maybe I missed this but did you take your MBC off and see what it runs?
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
found the problem! bad mbc. The old one was a Norgren. I had never heard of it before , but it was the only one I had lying around at the time. A new mbc was made just to see if it was the problem, and sure enough it was. So now time to buy a good mbc. Any suggestions?
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
Why spend more money if you've now made something that works?
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
true
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
I have a $10 ebay MBC and its been fine for over a year now
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Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
Can you post a link ? to the 10$ MBC
Ok strange ---- happens when you play with the wg signal. This is one of the expeiments we tried a one way valve that would not allow air to pass untill it the presure was 10 PSI. In theory it should have worked. But car would hit strong boost gauge would show 15-20 PSI and car would stall. It wasnt untill we hooked up a Map sensor and a dataloger that we found that boost was spiking at 50 PSI for a fraction of a second and that would push all the fuel in the bowl out. Also like somebody said it depends on the brand of the MBC your runing. |
Re: Mbc all the way closed, car still hits 15psi on an ihi turbo
Originally Posted by nonvtec
I have a $10 ebay MBC and its been fine for over a year now
http://cgi.ebay.com/ebaymotors/Voodo...QQcmdZViewItem I run a different one, but this is just an idea. Go to eGay and search for MBC or Manual Boost Controller and you'll find them cheap. JP |
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