MBC at minimum setting, boost way too high

[BrianV]

With my MBC at the minimum setting (basically the screw completely removed) I still spike 10.5 then stay at 10 until going down closer to redline.

With the cold weather I feel this will still bring me too close to the cut.

I really want to run like 9-9.5 max.

Interesting notes are,
My car stock was putting out 8LBS and my autometer guage reads 1 PSI when the engine is off.

I hit cut off once, last night at around 11.5-12 PSI (around 45-55 degrees outside).

Anyone else seeing similar conditions (minimum MBC setting = 10.5)?

 

[BremertonMSP]

If you are reading more boost with the MBC installed, there is an obstruction in the flow somewhere. With the valve fully open, you should read stock boost. Did you try the blow through method?

When I took my MBC off my Mustang and put it on my MSP, I had it fully open and hit over 15psi. Turns out, something had decided to make a home in it. I finally dislodged it by blowing through it in both directions. After I cleared it out, I was able to run stock boost levels with the valve fully open. I then closed it to the point where I could run 10psi.

 

[BrianV]

Yeah I did the blow thing when I first installed it.

I'm wondering if there's a kink in one of those hoses or something.

I hit 12PSI peak in second gear coming back to work from lunch.

I may try removing it and seeing if my stock PSI has changed any.

From what I read, the MBC even full open isn't stock boost, the unit itself provides a restriction.

 

[505zoom]

If your gauge is reading 1psi with the car off, then it is inaccurate. That is why you're seeing 8psi at stock level. An MBC will always increase boost a little, it's a restriction in the line even when it's fully opened.

You should try bremmerton's suggestion of blowing through it though. Just take it off and blow through it, then adjust the screw and blow again. You should be able to get a nice flow through the MBC at the lowest setting, and not hardly at all with it cranked up.

 

[ARunto]

you got a f'ed gauge probably

 

[BrianV]

Yeah what's real weird is my readings haven't changed much by adjusting the guage. I had it at the blow point (where I could just start blowing air through), now I'm all the way removed. The boost really hasn't changed much, maybe there is a restriction somewhere.

 

[mikeeeee]

i get that s*** tooo but worst. I have it set to the minimun boost setting and the b**** keeps hitting fuel cut. I've tried to blow in it and s*** it still hits boost cut. supposedly they say to get a FCD and it'll be all good. But what do i know

 

[BremertonMSP]

Yeah what's real weird is my readings haven't changed much by adjusting the guage. I had it at the blow point (where I could just start blowing air through), now I'm all the way removed. The boost really hasn't changed much, maybe there is a restriction somewhere.

So if you adjust it while you blow through it, can you make it harder and easier to blow through? If so, the side that you are blowing into on the valve is the side that you are plugging the line that runs from the manifold to the valve. And the other end is the end that is being plugged into the waistgate correct?

 

[ARunto]

also you want to have the hose lengt as short as possible...mine on MBS is only like 2" long. The longer the hose the higher the spike at intial WOT. Mine used to spike 3psi more but since cutting it i get about 1.0-1.5psi spike.

-Alan

 

[Aaron]

just by installing the mbc will cause some restricition therefore upping the boost just by putting the mbc in. I believe this was stated for Mr Joe P himself.

 

[BrianV]

Yeah, but the restriction alone shouldn't be 4PSI.

I have it installed correctly per the instructions and pictures from Joe (not backwards). My hose isn't excessively long (and I'm using the old wastegate hose, so it's as short as it can be). I could trim 2-3 inches off of the Tee'd hose.

mikeee I know FCD will help, but that's not the point.

 

[jersey_emt]

With the JoeP, the lowest boost I can get is 9psi in 3rd gear, and 9.5-10 in higher gears. My gauage reads 7psi stock.

 

[BremertonMSP]

just by installing the mbc will cause some restricition therefore upping the boost just by putting the mbc in. I believe this was stated for Mr Joe P himself.

I don't run a JoeP MBC. I have one made by Ric Gillis, bought it years ago for my Mustang.

http://www.boostvalve.com

 

[BrianV]

I reinstalled the unit, there was no block-up in the MBC. I did clip about two inches off of the bpv's side hose.

Also, I noticed a slight kink in the hose that connects to the wastegate. I twisted the hose while putting it on the MBC the first time and it made a slight kink right next to the wastegate.

When i reinstalled I made sure there were no kinks.

I then went for a test drive (MBC in wide open position) and it peaks 10-10.25 for a millisecond and then goes to about 9.5.

That is about a 2PSI up from stock. I guess the restriction of the MBC alone is worth about 2PSI.

Now before I was peaking like 12.5 (as tested right before I did the reinstall). I can definitely tell the difference between before and after, but I feel safer at 10. Without the fuel cut I really can't do any more then 11, and I haven't driven in a sub 45 degree condition yet.

We'll see if 10 max works out, if not the MBC will come off for the winter or I'll do the FCD.

One more note, the boost max seems a lot more reliable since the reinstall (removing the kink). Before it seemed to peak anywhere from 11-13 PSI, now it's right on about 10.25.

I get my new boost guage tomorrow (my current boost guage reads 1PSI when off). We'll see if it affects my reading for max boost, I may only be hitting 9 max. Right now I JUST BARELY lose traction after 4500 RPM in first, BARELY. Before I fixed the kink it was much worse.

Thanks for the advice guys.

PS - all testing today done at 57 degrees, fuel cut didn't happen even at 12.5 PSI. Yesterday was about 43 degrees and it happened at about 11.5, just an FYI.

 

[BrianV]

Got my new guage in, reads 0 PSI when engine is off.

I didn't change anything else and now my PSI reading (with MBC fully open) is right at or slightly above 8PSI. This is starting to sound more realistic.

Thanks for the help.

If your guage doesn't read 0 with the engine off THEN GET IT REPLACED.

 

[Emode]

im assuming your gauge doesnt show vac?

 

[BrianV]

My new one does, my old one did not.

I had the Automete 0-35 before, now I got the Autometer -30/+20 one.