[eriklit]

I have had my car fitted with a maptun stage 1.

First at high revs/high gear the power was fluctuating quite a bit. Between 1 and 1,4 bar.

This was adressed to a faulty wastegate actuator.
Yesterday we put a stronger actuator in (for 0.6 bar). This caused a new problem. The car is now building up to much pressure which makes it end up in an occasional fuel cut. This is especially the case coming out of very low revs and WOT.

I am using 98 octane fuel and this is what we already changed:
- soleniod valve and hoses
- wastegate actuator (now an uprated model for 0,6 bar)
- map sensor and hose
- maptun software (tried 1 other computer, both give in another car steady 1,1 bar pressure)
- dumpvalve
- di-cassette

I'm out idea's .....anybody else got a clue

 

[Julian]

Sounds like base boost is too high. Replace the actuator with a new standard one and set base boost to Saab spec. or perhaps 0.5 bar higher.

 

[eriklit]

I was thinking that direction too.
Would there be any other options

 

[saabman]

You could try to lengthen the actuator rod a bit and see if this helps?

 

[billj]

With the actuator disconnected, does the wastegate arm move freely? It should be able to fall open under its own weight. A sticky wastegate could cause this problem and the original one.

 

[eriklit]

The rod is as long as can be without the wastegate being open to start with.

The wastegast does freefall open if not attached to the rod.

So everyone thinks it's too high baseboost? Because according to maptun it can be 0.8 bar.

 

[pomlpt]

I have the same problem now. Boost pressure come too fast and the actuator fail. My actuator spring is rated 5-10psi. Current basic boost is 0.5bar. I have already ordered stiffer spring, 9-15psi. But it has not arrived yet. I will try winding up the actuator to 0.6bar to make the spring compress a bit more.

My current setting
9000cs 2.0 lpt autobox
Maptun stage3
Forge wastegate actuator with 5-10psi spring
Modified turbor with larger size prop. on the compressor

 

[mark e]

Originally posted by eriklit:
[qb]So everyone thinks it's too high baseboost? Because according to maptun it can be 0.8 bar. [/qb][/b]

When I have spoken to Maptun about my custom Stage 5 software, they have said 0.5 bar is the maximum that should be used.

 

[peter messenger]

cant you adjust your new actuator? when i fitted my uprated actuator, i needed almost no pre-tension.

 

[pomlpt]

I guess it might depend on individual tuning. Anyway, according from their website, maptun uprate actuator for later stage tuning start from 0.6bar

-----------
Quote from maptun website (9000 2.3t stage4)

Actuator

Adjustable pressurebox in aluminum with 80 mm diameter. Supplied with stick, screws and spring in stainless steel. The membrane of the pressurebox is manufactured by Kevlar to assure long lasting. There are different springs for different different boost settings between 0,6 and 3,0 bar.

 

[zeke]

I could be wrong on this, but I believe that the uprated actuator that Maptun carries can have it's spring set for what the peak boost requires - surely, Maptun wouldn't change the base boost settings from what Saab designed (Johnny did work for Saab, afterall) and a base boost of 3 bar is absurd. Some may even feel that a peak boost of 3 bar is absurd

For a daily driver, I find 1.65 bar is more than sufficient to satisfy my own

 

[zeke]

Oh, I forgot to say that I would do what Julian suggested, however I would use the actuator you got from Maptun - it looks like a very well built unit. With a calibrated gauge, adjust the rod so that you get a base boost that's at Saab spec' (.45 bar?). If the base boost is set too high, the T5 ECU will do a negative adaptation which won't allow peak boost to be reached. There's only two other things I've experienced that result in vascillating boost - improperly gapped plugs or a bad BPC solenoid. But I have a feeling that this is a base boost issue.

 

[pomlpt]

I will set my base boost to standard as soon as I get the new stiffer spring. Johnny did give instuction to set the base boost to standard the last time I set it to 0.8bar with my previous HKS actuator. He explained that the trionic will not be able to cut boost if engine knock is detected.