Low end boost prob

[Snikty]

My guy is having some probs with the boost since the new exhaust and it sounds like it might be the bpcv but wanted to check it with you guys first. I'll just cut and paste his query as he speaks better mechanic talk than I do :blush:

The Problem I am having: Now with the new free flow exhaust and fuel system sorted I am having problems with the vehicle over boosting at low rpm when on the supercharger. In the higher rpm when only on the turbo its fine(boost is higher than std). I have sourced a vac/boost diagram and checked over all the plumbing and its okay. The vehicle has 3 boost controller solenoids and we need some info on how we can control the boost at low to mid rpm. There might be a fix with setting up a restrictor in one of the vac/boost lines.

Cheers, guys.

 

[Baz]

My guy is having some probs with the boost since the new exhaust and it sounds like it might be the bpcv but wanted to check it with you guys first. I'll just cut and paste his query as he speaks better mechanic talk than I do :blush:

The Problem I am having: Now with the new free flow exhaust and fuel system sorted I am having problems with the vehicle over boosting at low rpm when on the supercharger. In the higher rpm when only on the turbo its fine(boost is higher than std). I have sourced a vac/boost diagram and checked over all the plumbing and its okay. The vehicle has 3 boost controller solenoids and we need some info on how we can control the boost at low to mid rpm. There might be a fix with setting up a restrictor in one of the vac/boost lines.

Cheers, guys.

Could be one of two things and is simple to fix if it is one of these problems,I'll be on later I'll explain it, I'm recovering from the trackday:laugh: I'm so tired

 

[Snikty]

Thanks Baz. Sleep well!

 

[Baz]

Check pipes on solinoid 14956w(or beside point 1)that they are the correct way around,If your not sure switch them see does this cure the problem,if not switch them back.
Also there should be a restrictor in the yellow vac line coming off the bpcv at point 5?

And tell your mechanic the exhaust is not the problem in any way shape or form

 

[Snikty]

Awesome thanks man. That is pretty close to what I was thinking but don't trust my own judgement on such things

I've passed on what you said and dropped in my spare bpcv so I'm hoping he can get it sorted out soon...he is pretty cluey so should have it all figured out soon enough. Thanks again, man.

So in regards to recent discussion about boost on the sc. Puting a boost controller on the yellow line would allow you to manually alter the sc boost?? If so what point would be the best place for it? Or have I misinterpretted again??

 

[Baz]

Awesome thanks man. That is pretty close to what I was thinking but don't trust my own judgement on such things

I've passed on what you said and dropped in my spare bpcv so I'm hoping he can get it sorted out soon...he is pretty cluey so should have it all figured out soon enough. Thanks again, man.

So in regards to recent discussion about boost on the sc. Puting a boost controller on the yellow line would allow you to manually alter the sc boost?? If so what point would be the best place for it? Or have I misinterpretted again??

Thats right, on the yellow line near the bpcv is where mine is

 

[Snikty]

One more thing, what size should the restrictor at point 5 be? That appears to be the issue...

 

[Baz]

One more thing, what size should the restrictor at point 5 be? That appears to be the issue...

You should find one on the same pipe on your spare engine(Y)

 

[Snikty]

Would anyone have any other ideas on what could be causing this?? We've played around with it, tried an adjustable valve restrictor so we can play around etc and still having only grief with it... tried swapping over bypass cv and a bunch of solenoids have been replaced, it's still over boosting heaps in s/c range. Suggestions?

 

[Baz]

Would anyone have any other ideas on what could be causing this?? We've played around with it, tried an adjustable valve restrictor so we can play around etc and still having only grief with it... tried swapping over bypass cv and a bunch of solenoids have been replaced, it's still over boosting heaps in s/c range. Suggestions?

If its over boosting it you vac lines ,two are mixed somewhere along the line

 

[Snikty]

Ok cheers, man. I'm going out there to go through all the vacuum lines this arvo. He said that he had sourced a vac diagram that was in a different format to the one you use and had made adjustments based on that. Are you aware of another vac diagram floating around that may be incorrect and if so where would the mistake on it be?? Also, where would suggest as a good starting point when checking the lines?? Around the bpcv and the yellow line?? cheers!

 

[smidge]

hey mate, keep it simple if you can

its most likely a backwards hose, mine did this during testing when i was first trying to get everything sorted out

check ALL of them, you can even plumb things direclty (not through the metal lines) kinda point to point so you can visually see that everything is where its meant to be

the biggest thing causing problems for me was the line going to the turbo crossover Y pipe thingo and back to the intake were backwards

the other issue was the solenoid next to the vac reservoir was wrong also

 

[Snikty]

Cheers smidge, I'll double check the piping around that join is right too.