I have just installed a s5 jspec turbo into my dead supercharged / N/A( It is a long story but a water hose blew and i fried the engine, the s/c didnt) and am having a weird problem. I have a TurboXs boost controler and a 2.5" apexi down pipe , with no cats, 2.5 all the way back. I have the boost controler set at 10psi.

here is the problem.

The car hits 10psi by 3200rpm and holds 10psi rock solid till about 5700 rpm. Then it progressivly drops to 6psi by 7000 rpm.

why is it doing this, The car runs very strong, and has an even 105psi compression test on all rotor faces

I need a s5 boost sensor still if anybody has one, i use paypal

give me any ideas please. thanks zac

 

Because it is a stock turbo.

It does that. Loses efficency at high rpms.

James

 

Talk to Nik.. he was having problems similar to yours,well alot worse..

something with the stock inlet pipe to the turbo colapsing at 5500 RPM

Frank

 

Same thing happens to my setup with the s5 turbo. I we are just maxing out the turbo. Time for a hybrid....

 

that is what i mildly suspected , but thanks for confirming it.