New BPV should not do this.

Mid_Life_Crisis

Member
Contributor
:
2007 MS3
Okay, I just had something happen that is absolutely not supposed to. I swapped out my BPV during lunch and went for a quick drive to check it out. I take a turn in second gear, get on the throttle coming out, and boost goes up to 15. My gauge is tapped into the line that runs between the manifold and the BPV vacuum reference port. So far as I know, that should give a pretty accurate reading. I had food for lunch, no drinking, no drugs, so it wasn't a hallucination. Any thoughts?
 
Last edited:
Was it a one time thing or is it consistently doing that? I wouldn't think a BPV could cause that. I'd think something with the wastegate maybe? Of course I might not know what I'm talking about.
 
Was it a one time thing or is it consistently doing that? I wouldn't think a BPV could cause that. I'd think something with the wastegate maybe? Of course I might not know what I'm talking about.

As I said, I went for a quick spin during lunch. I'll check it more carefully on the way home.
If the level of a person's intelligence is determined by how much they agree with you, then so far you are a genius, because we both think a BPV shouldn't do that. Problem with the wastegate theory is that I haven't fussed with that.
 
Considering boost is limited in 2nd and I've never seen mine go that high in that gear I'm suprised. Don't quite remember what it normally spikes to in that gear though.
 
you swapped from a stock to aftermaket right? consider this if your stocker was leaking and you swapped to a after market like forge,synapse,ect. it would seal and you could possibly see higher boost spikes.
 
you swapped from a stock to aftermaket right? consider this if your stocker was leaking and you swapped to a after market like forge,synapse,ect. it would seal and you could possibly see higher boost spikes.

Very true. I was surprised just how cheap the stock BPV seemed to be when I replaced mine.
 
Mine hits 15 on first and second gear...

Whats the problem...? (huh)

You must have done something to bypass/cheat the factory boost control.
I have not. The only mods I have are an MSCAI (in SRI configuration) and the BPV. The ecu limits boost in 1st and 2nd gear.
 
the highest ive seen in 1st was 8 psi... but i dont floor it... but it 2nd i always see 15-16 psi... what is the 'limit' for 1st and 2nd?
 
I'll double check mine and see what I hit in 1st and 2nd, all I have is cobb sri and a forge bpv. It oughta be close enough to your setup. I'll post it up later this evening.
 
Maybe the duty cycle limit for the solenoid is not great enough to limit boost in 2nd gear after changing to a valve that leaks less than the OEM.
 
Maybe the duty cycle limit for the solenoid is not great enough to limit boost in 2nd gear after changing to a valve that leaks less than the OEM.

A possibility. This is the ugly valve, Patty. I have the yellow spring in it.
Drivability on my short ride was excellent. I'll pm you with more after I get home, which means you probably won't get it until Monday, unless you check in over the weekend.
 
Okay, I just had something happen that is absolutely not supposed to. I swapped out my BPV during lunch and went for a quick drive to check it out. I take a turn in second gear, get on the throttle coming out, and boost goes up to 15. My gauge is tapped into the line that runs between the manifold and the BPV vacuum reference port. So far as I know, that should give a pretty accurate reading. I had food for lunch, no drinking, no drugs, so it wasn't a hallucination. Any thoughts?

Yes. It is not unusual to see 15+ PSI of boost in 2nd gear on a stock MS3.
 
Back