Posted to Renntech but didn't get anything, so I thought I'd register and try here.

A 1.0 bar wastegate actuator has recently become available for the 996TT. It's being sold as an upgrade for cars that have already been chipped - but I've been thinking... The stock ECM measures boost and controls the wastegate actuator through a solenoid. Both the spring in the actuator and the solenoid via ECM and MAF open at 0.7bar. The idea is there may be slightly improved response if both the ECM and wastegate are set to match at 1.0bar. This seems especially the case if there are some leaks in the solenoid or vacuum lines, since what does the actuator's setting matter when it's the solenoid actually running the show.

The ECM uses 1.4 bar as an emergency boost cut, I would guess this is because you're hitting 100% duty cycle on the fuel injectors at the stock fuel pressure. The fact the limit is so high suggests the factory ECM, unchipped, can run over 0.7bar maybe even up to ~1.3bar.

Has anyone ever tried to change out just the wategate actuator for the 1.0 bar unit rather than chipping the ECM? The part difference is about $1000, excluding the cost of a more complex installation.

 

forget about it... you will get codes .. the fuel cut off is at .84 bar up on top on a OEM flash...

 

1 bar WGs just became available for the 996TT "recently" ?

 

WG actuators. so yeah sure, AFAIK... Jan 2010.

https://www.6speedonline.com/forums/...r-upgrade.html

 

To the best of my knowledge, AMS makes great stuff. That said, 1 bar WGs are fairly ubiquitous in 996TT tuning. Other vendors (besides AMS, who just somewhat recently got into the Porsche aftermarket) have offered them for years and years.

 

Hey,I dont think thats a good idea Because the fuel and timing have to go along for that boost...IMO...

 

Tony@epl - I had no idea there was also a MAP on the car, or that the factory boost cut was so low. But thanks for replying I'm glad to hear from someone that's really tried what I was suggesting. Looks like it's time for an ECM tuning!