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Discussion Starter #1
I have had exhaust leak problem at the gasket at the exhaust manifold. After the problem was fixed, (which required the manifold and turbo removed) I took my car from the garage and drove home. I accelerate the car and checked the boost guage, 14-15psi max and stable. Acceleration seem slow a bit but everything seem normal.

When I got home and open the hood I found that APC hoses were miss conected.
The C was connected to wastegate actuator. The W was hanging freely. The R was correctly plug to intake before turbo. (The connector on the turbo where C should connect was left openned).

By what I describe above, there was no pressure from the turbo to feed to APC. I think APC must have turbo pressure (normally from C hose) so it can control the wastegate actuator.

I was confused. Anyway, I reconnected the APC hoses to their correct connection and went out for checking. No different. The car run normal(same as when I drove out of the garage). Max boost still 14-15psi.

I came home, openned the hood again. This time I disconnected the W hose from the wastgate acutuator which mean no presure to the wastegate at all. Went out again and accelerate hard and ... normal
. Just like before, the boost pressure still rise smoothly to max at 14-15psi without any fluctuation.
I accelerated hard again and checking the boost guage, 15psi max and stable at 4000rpm and the rev. still goes up since I was still WOT.

Can anyone explain if this is normal. I think something is wrong but I don't know what it is.


There are things I should mention here.
- I lost boost spike for sometime. Previously the boost peek and drop slightly ~2psi. Now the boost just rise smoothly to max(14-15psi) and stable until drop again when rev. goes above 5000rpm.
- My car is 9000cs 2.0lpt autobox with maptune stage3. I have top end power, but low end is not good at all. The real power only come at high rev. and high speed, 3500+ rpm/140-150kmh up.
- I hear hissss noise everytime boost goes up but can't find any leak. I doubt if the noise come from the intake air suck in by the turbo.
- I've just changed new APC and new bypass valve. Both are saab standard.
- The wastegate actuator is Forgemotorsport. It is still quite new. I use it for 2months. Basic boost is set at 0.49bar.
- My turbo was leaking oil recently so I had it fixed and upgraded to the larger size compressor prop. (exhaust prop. size remain same.)



Thanks in advance for any comment.
 

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Discussion Starter #2
I suspect two things.
1. The wastgate actuator spring too weak, thus, the exhaust pressure can push the wastegate open.
2. The turbo upgrade false and 15psi is maximum.

I will try changing the stiffer spring in the wastegate actuator to see if the boost pressure goes up more than 15psi.
 

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hi pomlpt, did you perform an adaptation run, i would connect your hoses as they should be, then do your adaptation run 3 to 4 times. hope this helps you.
 

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hi pomlpt i no u are running stage 3 but 1bar boost ive got 97 aero auto jt60 cat back jr filter i run a 0.45 base and 0.7 ish bar on a run what wos u running b4 stage 3
 

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Originally posted by lizard:
[qb]hi pomlpt i no u are running stage 3 but 1bar boost ive got 97 aero auto jt60 cat back jr filter i run a 0.45 base and 0.7 ish bar on a run     what wos u running b4 stage 3 [/qb][/b]
Translating (I think....)

Hi Pomlpt,

I know that you are running a Stage 3 conversion with 1 bar boost.

I have a 1997 Saab CS Aero Auto with a JT60 catalytic converter back 3" exhaust system combined with a JR Air intake filter.

My vehicle is running with 0.45 Bar base boost pressure with only a peak boost pressure of 0.7 bar when running hard.

What maximum and base boost pressures were you running on your vehicle before you installed the Stage 3 conversion.

Hope I got that close.
 

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Discussion Starter #8
hi peter, I guess the adaptation run is completed since I run WOT in 3rd and 4th gear up to 120-130mph many times.

Lizard, I used to run higher boost,1.1bar, when I was at maptun stage1. That was before I upgrade my turbo and the wastegate actuator. After the change, maximum boost drop to 1.0bar. I switched to maptun stage3 and boost pattern is identical to stage1(but more
)

Anyway something is wrong and I can't figure out yet.
 

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Discussion Starter #9
I think you got it right Scaero

My basic boost was 0.45bar when I was at stage1. Max boost was 1.1bar.

I once set the basic boost up to 0.8bar and max. boost hit 1.4bar.
 

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Discussion Starter #11
The problem was found. It was that hisss noise I kept hearing. The L-shape rubber hose that connect intercooler and intake pipe was broken. There was 3inches crack at the bottom. Had it changed already. I have just driven from the garage back to my office. Boost spike is back. Short acceleration show boost pressure approaching 19-20psi



 
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