So now that i have passed etest, time to move onto fixing some of the annoing issues with the car.

Fresh engine and turbo rebuild, exhaust is not plugged up. Air filter just replaced.

I loose boost with rpm. When i'm on it, i will see a gradual climb to 8psi by 5000 rpm, but after that it drops off to about 3psi by redine.

Anyone having a similar problem?

thanks,
brandon
88 TII, stock turbo, rtek 1.5, 2.5" exhaUST, emissions removal.

 

Shouldn't peel off that much boost. Of course, it sounds like its only running stock levels so it doesn't sound **too** far out of whack.

How many cats did you say were on there again? Any restriction (good cat or not) is going to hurt boost. And with the fact that it takes you until 5K to make 8psi on the stock turbo - it sure sounds like its restricted.

 

True dat....

Possibility that your turbo isn't as efficient as it was when it was new. Send it to BNR.

 

It was designed to drop off some high end boost in case you had to use low octane fuel.

Your twin scroll door may not be working. I'd check that first.

To get more high end you may want to give up some low end and remove the twin scroll door & clean up the flow path through the exhaust manifold.

 

Your exhaust is too small.


-Ted

 

Exhaust too small? Really? I am going to add a boost controller and see what happens if i bump it up to 10 psi.

There are two magnaflow cats...

and dont worry, i am running the rtek 1.5 now so 10psi on the stock turbo should be safe with 94 oct, right?

thanks,
brandon

Ok and it is an S5 turbo, with ported wastegate (both ports have been opened a little.