How many bars of boost should my 2002 996 TT get?

[KSchoknecht]

Six months ago I bought a 2002 996TT with 33,000 miles. It didn't seem to have the performance I expected (I traded up from a '99 C4). The check engine light came on, and codes P0234 (boost pressure curve upper limit exceeded), P0492 and P0491 (secondary air banks) were generated at my shop's computer. A broken vacuum hose at the intercooler induction switch was found and repaired.

The car still didn't seem to have as much boost as I expected - I could get .4 or .5 bars, but that was all. I took the car in again, had the secondary air pumps cleaned, and replaced the diverter valves with Fabspeed units (one of the diverter valves had failed). I also installed a Fabspeed maxflo exhaust system from the catalytic converters out, and maxflo intake kit. I'm now getting .9 bars and much better acceleration.

Is .9 bars what I should expect? I'm thinking about adding an upgraded ECU, then stop fiddling with it.

Thanks for anyone's help.

[porscheralph]

I am assuming you do not have the x-50 power kit on your car. Given the mods you have made and without an ECU flash I think you are about right for boost at this point. With a flash you might see 1.0 - 1.1 max and you should consider changing the plugs to match your more aggressive set up. I would be careful about going for a higher boost without changing injectors etc. Others with more knowledge will add to this comment. Good luck.

[wross996TT]

assuming you have the K16 turbos, you SHOUL be getting .7-.8 max sustained boost. This is the boost when WOT in third or fourth gear....not spikes. If you are actually getting .9, you have been flashed (perhaps not well, but that is better than normal). If you do get a flash, K16 limits for power is about 1.0. Best to know what other mods you have (e.g., exhaust).

[Boxxy]

assuming you have the K16 turbos, you SHOUL be getting .7-.8 max sustained boost. This is the boost when WOT in third or fourth gear....not spikes. If you are actually getting .9, you have been flashed (perhaps not well, but that is better than normal). If you do get a flash, K16 limits for power is about 1.0. Best to know what other mods you have (e.g., exhaust).

At what RPM will you see Max sustained boost in 3rd gear what at wide open throttle? I have a stock 02, non-X50. Saw 0.9 bar briefly in second, but was going too fast in third (vs speed limit) to keep my foot in it.

[yvesatlanta]

Correct. This car is already flashed.

With my stock K16s I saw max 0.7 Bar

Now, after an FVD flash, hybrid turbos and DVs, I see 1.3 Bar as of 3rd gear.

One way or another you are still losing power. Take off all 4 boost hoses and re-attach. Make sure the clips 'click' in.

Also wouldn't hurt if you cleaned your MAF.