I've was running 10psi all summer long and had no issues with spiking or not reaching full boost....... but now I can't hit 10 psi.

Yesterday I hit 15 psi when my car was ice cold and now when it warms up, it will only hit 7-8.

Any ideas on what the problem could be? I have not changed anything. I checked all vaccum connections and everything apperas to be connected.

I'm using a profec B, tial 35mm, inline pro manifold, and a leak in the downpipe

 

The leak probablly doesn't help anything first off. I think a lot of people seem to spike when it gets very cold out. I do to sometimes. I run 9PSI and sometimes it'll spike to 12 and so i have to let off the gas and try again another day. Why? I have no idea. I have been looking around and it sems that no one really knows. As an Engineer I'd say that since the Wastegate is very cold to the touch even after driving the spring inside is probablly cold as well giving it greater strength and not opening the valve until more boost is delivered.

YOu may be getting the spike becuase of cold weather but after the car warms up it's the profec B that is not letting it go past 7-8lbs. I bet if you reset the fuzzy logic (once it's warm) it might get you the results you want.


Does anyone know why cold weather does this to wastegates? Am I right?

 

I dont know how sophisticated the profec-B is, but when its colder the atmpospheric pressure is higher, and boost is pressure over ATM that is being put in your car, and if the profect B measures absolute pressure, that could be why.

get what i'm saying?

 

Thanks for the response, that makes sense about the wastegate spring being too stiff in the cold weather.
But I'm still unsure about it not hitting 10 psi. Sometimes it will, most of the time it won't.

How do I reset the fuzzy logic? THX

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">The leak probablly doesn't help anything first off. I think a lot of people seem to spike when it gets very cold out. I do to sometimes. I run 9PSI and sometimes it'll spike to 12 and so i have to let off the gas and try again another day. Why? I have no idea. I have been looking around and it sems that no one really knows. As an Engineer I'd say that since the Wastegate is very cold to the touch even after driving the spring inside is probablly cold as well giving it greater strength and not opening the valve until more boost is delivered.

YOu may be getting the spike becuase of cold weather but after the car warms up it's the profec B that is not letting it go past 7-8lbs. I bet if you reset the fuzzy logic (once it's warm) it might get you the results you want.


Does anyone know why cold weather does this to wastegates? Am I right? </TD></TR></TABLE>

 

may be a dumb ? but have you checked your oil level? if you have very low oil pressure the turbo won't boost nearly as well... I know from experience stupid stock ringlands...

 

i would have to say that the charicteristics of oil change in different temperature and so the turbo which depends on the oil flow will have significant effect on it. also true for gas. and when u buy a 91, 92 octane gas, its never actually 91, 92 but is of the average. so when u pump a 91 today , u might be getting the low end of 91 and two weeks ago, u may have gotten the high end of 91. i learned this in my physics class. my teacher made it sound more educated but i tried.

 

I don't see how the oil would have an effect on boost except maybe slow or speed up the spool time.

When boost controller senses 10 psi it should send the signal to the waste gate to open and that is not happening.

There must be a leak somewhere or the profec B is malfunctioning.

Any word yet on how to reset the fuzzy logic?

THX guys

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by s1ngle &raquo;</TD></TR><TR><TD CLASS="quote">I dont know how sophisticated the profec-B is, but when its colder the atmpospheric pressure is higher, and boost is pressure over ATM that is being put in your car, and if the profect B measures absolute pressure, that could be why.

get what i'm saying?</TD></TR></TABLE>

Actually after going back over and reading this again, it does make sense if that is the way the profec b is set up.

But the car does not feel as fast.....I think the profec b or the vaccum lines are the culprit

 

an e-boost controller works by releasing the valve right before the set boost level...sometimes it overshoots that guess and sometimes it undershoots that guess. That's the why the first couple times you use it the e-boost controller isn't very good. the more you drive it the more it knows how to release the valve at the exact point. I don't know how to reset it, but read your manual and it may tell you. If you get full boost sometimes I say it's more of a vaccum or boost leak somewhere in the system