Rapidly Flucuating boost

[alex1090]

I am all out of ideas with this one. So here it is guys........


Having a problem with rapidly flucuating boost. For example, If the boost is set to around 35, the boost will actually flucuate up and down 4 -5 pounds, sometimes more. In a 3rd gear pull from lets say 4k to redline, from the second it builds 35 psi it will flucuate 40-50 times in a matter of around 4 seconds. I have tried to fix the problem by putting another spring in the WG, it now has the big green and small green. And also switch boost controllers, I now have the new Buschur inline. None of these fixed the problem. No boost leaks, car pulls good considering its probably varying about 60 hp 40 times in a pull which is sligthly noticable. A/F's are fine, I have no more theorys left.

Thanks for the help guys

Forgot to mention one thing, Has anyone had a problem with a Tial BOV leaking? I have never had a problem with one, but anything is possible.

 

[brryder]

Where are you gettting the boost source from?

 

[aero_sallee]

Sounds like severe compressor surge to me.

 

[Defiant]

If the boost is set to around 35, the boost will actually flucuate up and down 4 -5 pounds, sometimes more.

Don't panic. At that level, it won't be "flucuating"[sic] for long. It'll steady-out at zero.

 

[Kevin Jewer]

This sounds like a classic case of too little WG spring pressure. 35 psi I'd be running the stiffest springs available (~21 psi). The two greens are around 17 psi. There are other potential causes, but this is it 99% of the time in my experience.

 

[alex1090]

Don't panic. At that level, it won't be "flucuating"[sic] for long. It'll steady-out at zero.

???????????




I had the same thought. I just ordered the 2 heaviest springs for it. The big and small blue springs. Dave (Buschur) thinks its not a wastegate problem for some reason. He did something to my calibration and told me to try it. Hes 99% sure hes right, the catch is he wont tell me what he did to the calibration until I tell him it fixed the car. , but whatever, help is help.

 

[Black_Bullet]

???????????




I had the same thought. I just ordered the 2 heaviest springs for it. The big and small blue springs. Dave (Buschur) thinks its not a wastegate problem for some reason. He did something to my calibration and told me to try it. Hes 99% sure hes right, the catch is he wont tell me what he did to the calibration until I tell him it fixed the car. , but whatever, help is help.

Im sure Defiant was just picking on you from your spelling of the word fluctuating.

I agree with Kevin ( 95GSXracer.)

Set your boost lower, to like 20-25 psi and see if it is still going all over the place.
If its not then I would try some stiffer springs...

The general rule of thumb is to have the WG spring at least half of the desired boost pressure for accurate boost control.

 

[Defiant]

No, Defiant was suggesting that 35psi boost without serious engine mods is going to blow it up in a very short time.

 

[Black_Bullet]

No, Defiant was suggesting that 35psi boost without serious engine mods is going to blow it up in a very short time.

Defiant... Or the Riddler.... Lets take a vote

 

[T9S1i]

No, Defiant was suggesting that 35psi boost without serious engine mods is going to blow it up in a very short time.

haha, especially if it fluctuates up 5psi to 40lbs!!!!!

 

[alex1090]

Between the WG springs and whatever Dave did I got it figured out. I emailed him to ask what he did but he hasent responded yet. It holds rock solid now.

 

[Defiant]

For what little time it will.

Seeya in the Exploded Engine Forum.