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Stock turbo boost pressure?


19 Nov 2010
I have a 2004 non x50 turbo, on the obc display it never gets above 0.7 bar is this right?
.6 - .7 bar on a normal 996TT.
.8 - .9 bar on an X50.
These are steady state numbers, you may occasionaly see higher spikes.
+1 I never see more than 0.7 bar - mind you, I average around 27 mpg!
Always good to have a boost pressure test done from time to time on these cars.
Mine will very occasionally show 0.8 in the higher gears.
Conditions must be ideal though cool ambient and decent fuel.
Before the remap I would occasionally see 0.8 but now 1.0 bar every time...! :thumb:
My non x50 shows 0.6 to 0.7. Have seen 0.8 once or twice
Jamesyg said:
My non x50 shows 0.6 to 0.7. Have seen 0.8 once or twice

T8 said:
Jamesyg said:
My non x50 shows 0.6 to 0.7. Have seen 0.8 once or twice


IIRC, the 996 Turbo's (non-S) max system pressure was 0.8 bar, and it would have been mapped to achieve that boost only under wide-open-throttle and full-engine-load conditions. You'll rarely see those conditions for more than seconds driving on British roads. (If you value your driving licence, that is). :)
Hopefully Ken at Nine Excellence will post a reply to this - he is the guru with turbo boost pressure and re-maps.

Calling commissioner Gordon - please turn on the bat light tonight in the night sky.
Ken may tell you that what you see on the boost guage on the dash is not necessarily what you are getting. Ours had his pressure test and then some fettling - it was like a different car!
I didn't want to dash hopes and expectations! I had a PM exchange with Ken a while back on this topic and know that what you see on the OBD is not necessarily what you are getting in the real system. But lets not complicate it.

But agree with the after result when Ken had tinkered with it - he really seems to know what he is doing with turbos, boost pressures and remaps for Porsche.

If you are reading this Ken, please chip in (excuse the pun)!
K16 based (normal) tends to be in he range of solid 0.7 but you can see 0.8
K24 based (x50/s/gt2) tends to be in the range of solid 0.8 but you can see 0.9

Spikes of boost should be ignored - e.g. See 1 bar if you smash it in 2nd for example.

Simple method is 4 gear ( 3rd tip ) at 2000 rpm foot flat down.

Boost gauge is always a little higher reading than actual boost.

Boost is derived from ( mainly ) the load table. If the target load is achieve, that is when the boost peaks. If due to a number of factors e.g. Ambient temps etc it does not need so much boost to reach the target load, it won't get you more. This is why you can see for example 0.6 during cooler weather but 0.8 in warmer times.

Boost leak checking is something that should be done on a regular basis.


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