Car just came back from dealer. No leaks in system. ECU "updated" Now i can routinely hit 16 in sport mode.

 

Uh, shouldn't you see 18 lbs in overboost?
One thing I wonder about, how does the dealer test the system for boost? Man, it is almost impossible to see max boost at legal speeds on the road. Does he take the car out and hammer it?

 

1.2 bar = 17.4 psi so 16 is reasonable with 17.4 max. You can get max boost in 3rd or 4th without getting too dangerous.

 

As you all know, the gauge in my 997.1 TT with SC only read 14 psi and like others stated, my service advisor also didn't want me to bring in the car as he was confident early 997.1 TT came with 14 psi.

Even Porsche was clueless as to why it would read 14 and told the tech that though Porsche doesn't keep these types of records but probably the early 997.1 TT's did come with a different boost gauges.

Told SA, I wanted that in writing especially for a re-sale purpose.

Few hours later I was told they were able to re-code the system and that it's all fixed

Just for clarification, Porsche did replace my DME last year for cold Idle issue so quite possible they forgot to recode the DME.

 

Excellent information in this post. Thanks to the OP...also thanks to Evolution Motorsports for their input.

 

Repost from another thread regarding the boost meter in our 997.1 Turbo.

This is "normal" in my car, a 2008 997.1 with GIAC tune. Because I keep original ECU (2 ECU's, one is untouched original I keep in a safe box :-), the one in the car is a duplicate original, then has GIAC tune loaded onto it) and because the GIAC tune could be used to load the stock program, I could still measure the stock behavior. Incidentally, behavior of boost pressure reading and the scale has not changed with the GIAC tune.

How I measure without breaking speed limit: Empty, safe, straight freeway, 5th gear, let car coast at 50 mph, should be around 2000 rpm or so. Now let go of gas pedal completely, then after 1 second smash it to the floor. By 68 mph, around 3000 rpm or so, my car consistently hit max psi. All the following is from the stock program, not GIAC (which behaves identically anyway, except that it would hit max boost sooner at around 64 mph, completely within legal speed limit, just have to put up with all the cacophony inside the car ).

What I see numerically:
Normal: 15 psi (not 14, but 15). I believe this is because 1 bar is 14.504 psi, rounded up to 15 psi.
Sport: 17 psi (never 18, only 17). I believe this is because 1.2 bar is 17.4 psi, rounded down to 17.
Ah... German engineering's precision and logic, even in rounding.

What I see with the bar graph: The scale is psi-9-18 regardless of mode.
Normal: Does not go all the way to the right of the scale
Sport: Goes all the way to the right of the scale, at the 18 mark.

What I see with Durametric in Stock Mode, the actual measured boost:
Sport Normal 2020-910 = 1.110 bar = 16.1 psi at 3248 rpm
Sport Stock 2250-910 = 1.340 bar = 19.4 psi at 3471 rpm,

What I see with Durametric and GIAC (you could see boost hitting higher and earlier)
Normal GIAC 2350-910 = 1.440 bar = 20.9 psi at 3423 rpm
Sport GIAC 2550-910 = 1.640 bar = 23.8 psi at 3343 rpm

Unless there is an explanation for why, and I know this is requested, not real boost, it actually would bother me a little bit if my car doesn't hit 15/17 on the numerical scale. The next step I would do would probably be to get a Durametric cable to measure just for peace of mind. Hope this helps on this very confusing topic.