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Boost pressure

C

Cooper81

New member
Joined
Dec 23, 2015
Location
Germany
I'm new here so first a very small introduction.

I'm from Germany and I have a '96 940 LPT.
Plan is to tune it step for step, no exact hp goals, just for the fun off it.

What I've done so far.
Stage 0 tune up
Full flow 3" exhaust
Air box mod
Chassisbrace
Front anti sway bar off a 960

And here's where I'm at at the moment.
I've installed a wideband gauge and tru boost controller, both from AEM.
When I'm sure everything works as it should I'm going to raise the turbo pressure.
The wideband seams to be working as it should but the tru boost controller doesn't.
When I'm on full throttle to redline the pressure raises on the gauge to a max off 0,8 bar.
My turbo config is standard, so to my understanding it should do about 0,35 bar.

Can anyone say what their pressuregauge puts out with a standard turbo config?

Gr. Patrick
 
Hi

Around 0.3 bar is stock boost on a B230LPT
B200LPT might be a little higher ?
0,8 bar is higher than any stock B230 turbo except those with turbo+ kit installed.
(some actually had it factory/dealer installed)

YS
Jaybee
 
Its not fast enough to have the turbo kit.
Can anyone give my the vacuum at idle?
I'd like to compare with mine to see if the gauge is off.

Gr.
 
Gr??e und herzlich wilkommen!

If you're running 0,8 bar, then it sounds like someone put in a new wastegate for you. My turbo runs around 18 hg at idle.
 
I replaced the boost gauge with another and it's stays the same.
So it's safe to say that the gauge isn't the problem.

The boost pressure rises linear from app. 0,35 bar @ 3000 rpm to 0,8 bar @ 6000 rpm.
To my onderstanding this shouldn't be linear and with a stronger wastegate spring it would reach 0,8 bar before the redline.

Therefore I concluded that my wastegate doesn't fully open.
Does anyone have another idea what it might be?

Gr. Patrick
 
I have the solenoid bypassed to first be sure everthing engine related works fine.
So now I know I have a turbo problem :-(
Maybe a good time to upgrade it to a bigger one :cool:
 
Cooper81 said:
I have the solenoid bypassed to first be sure everthing engine related works fine.
So know I know I have a turbo problem :-(
Maybe a good time to upgrade it to a bigger one.
Click to expand...

I dont understand. You are building pressure way late in the RPM range, that means your wastegate is bleeding off exhaust gas (opening) too early, or you have a massive boost leak.

What wastegate are you using?
 
Car is with stock turbo and wastegate as far as I know.
To me it looks like the wastegate opens just a bit or is stuck open just a bit.
 
Cooper81 said:
Car is with stock turbo and wastegate as far as I know.
To me it looks like the wastegate opens just a bit or is stuck open just a bit.
Click to expand...

fix that. tighten it to where you have to pull on the actuator to slide it over the mounts. Or hook the waste gate line up to an air compressor an fill it to .3 bar and adjust the rod so the waste gate is just barely open.
 
I've been reading the forum and saw that a freeflow 3" exhaust can cause this problem, is this correct?
If so how can I correct this on the stock turbo?
 
Cooper81 said:
I've been reading the forum and saw that a freeflow 3" exhaust can cause this problem, is this correct?
If so how can I correct this on the stock turbo?
Click to expand...

3" exhaust from the turbo back won't cause issues like that. Your waste gate is not tight enough. tighten the waste gate rod.
 
my turbo on my b200ft boost up up to 1.0 bar only with mbc, open air intake, and a vikingchip.
with out thechip u run in to boost cuts
 
Next wednesday I'm planning to take the turbo out of the car an check it.

This should make thgins clearer. ☺
 
A little later than planned but last weekend I took the turbo out of the car and checked it.
The turbo itself is in good shape, bearing could be better.
I checked the function of the wastegate and it does what it should, at +/- 0,35 bar the wastegate is fully open at 0 bar it is closed.

While I was at it, I replaced all of the vaccuum hoses by better quality ones. This makes a lot of difference, the others ones were probably acting like balloons. Idling is better and response is faster,

But all in all the issue remains, booste pressure still climbs to 0,8 bar at redline.
I'm beginning to think that it might be that the wastegate can't handle enough flow in combination with my 3" full flow exhaust.

Any suggestions?

Gr. Patrick
 
That's definitely it. The 13c wastegate is tiny. The puck is large enough, but look underneath it. The hole is almost only half the size. Stock boost is what, 6-7psi? I have a 'stock boost' 13c on my +t with a 2.5" straight pipe. On colder days I'll see 10-11psi. Port the wastegate if you want to maintain stock boost pressures.

FWIW, I got a 15g and the wastegate hole was MUCH larger. Never had a boost spike issue with it.
 
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