Question about losing boost

[Bhamsan]

I went on the freeway last night and redlined my car in third gear to see how my car is holding boost. I'm not quite sure if I'm losing boost due to the MBC, or because my BOV is not tightened hard enough. It was running about 6psi or so until about 4500 rpm, then it dropped down to 5psi above that. I think it's my BOV, but I'm not sure. I don't want my car running below stock boost levels. Could it possible be because my gauge is not installed correctly? Any feedback will help on this one.

Thanks,
Brandon

[laracroft]

What is your MBC set at? If you run at those rmp, your boost will drop soon after you get to your set limit. Boost level usually does not hold for long. Tell us more about the conditions of the day, what kind of boost gauge do you have, do you FEEL the drop, etc.

[jurgs01]

Get a better boost controller than Joep's MBC if you want to hold boost better. What you are seeing is normal and has nothing to do with your BOV. If it was your BOV, you would never get to 6 psi. A BOV does not cause spikes.

[jurgs01]

Why are you running stock boost levels with an MBC anyway? Do you just turn it up at the track?

[laracroft]

My Speed occasionally drops boost. Not everytime I drive it, but it does happen. Your car may have had one of "moments". Turbo's are not always as predictable or reliable as superchargers. They are meant for short boost spurts and they can act that way on occasion. If this is a constant problem, it may be something you'd want to look into. One of my hoses had a leak and I lost boost. I replaced it and the problem seems to have subsided a bit.

My stock boost was 5-6 psi, after I got a few engine mods and an MBC, I turned it up to about 9-10 psi. Where is yours set at? You should not be getting 6 psi only if you have turned up your boost level. When did you install it and are you sure it's turned up?

[Bhamsan]

I was messing around with it, and was getting anywhere from 6-7psi. I had it turned up higher, but started hitting fuel cut at night when it cooled down significantly, which is why I turned it back down t stock levels.

So I'm guessing what I'm seing is normal and I should just turn it up higher if I want to hold boost at a higher psi at higher rpms.

[jersey_emt]

Boost falling off towards redline is common. Hardpipes and a downpipe gets rid of most of it...but it's still there

[Bhamsan]

OK, thanks for all the input guys. I guess I'll invest in an EBC, its next on my list of mods anyways.

[irr5302]

EBC and Down pipe cure this problem in my MSP

[DragonSpeed]

Hmm, i run 9 psi (10psi spikes) and hold it to redline.. what does ur vac read at idle? Only had fuel cut once, but i don't boost high too often..

[FSDET]

im hearing this weird noise when my boost is at about 4-6 psi depends on the gear , it goes vrrrrrrmmm.. sounds like a leak but i dont have any boost drop... my friend had it on his too after he installed hardpipes, but his was louder ..

[Brian MP5T]

I had a problem with my Manual Boost and replaced it for an electronic!! Yipee!!!

[turbo speedy]

my car doesnt hold boost but i think that it could be the inter cooler piping being cracked by the bpv

[Brian MP5T]

my car doesnt hold boost but i think that it could be the inter cooler piping being cracked by the bpv
You will have to go through your entire system and check it out piece by piece.

http://www.msprotege.com/members/Brian%20MP5T/Anim%20-%20(1).gif