Alright guys all of you have been very helpful for me so far with my questions about these cars, and I have learned alot in the last 2 months I have been on this forum.
So here is the last qustion for you.
Why is it that on these Evo's does the boost taper off? All the turbo cars I am around spike a certain boost and hold it. My GTi holds 30 psi from 4500 rpm to 6500 rpm.
I am yet to come across someone on this forum explaining why these car have to do this. Basic mods and everyone talks about not going over 22 psi and by redline the boost is at 19. Why not hold 22 psi to redline. What is it that stops you guys from holding 22 psi to redline.

 

We could hold boost at 22psi but we need a upgraded Wastegate actuator, and a BOV that will hold that much boost.

As for y it s best for the boost to taper by redline, i will let someone more knowlegable respond to that. From what i know the turbo is more efficient that way.

 

It naturally tapers, because it can't push enough air to maintain that psi at high rpm. There is a point at which there is more air going through the engine than the turbo can keep up with at a given psi. You can't force the turbo to NOT taper - you can only lessen it. If you somehow manage to make it stay flat all the way to 7000-7500rpm, it will just end up blowing hot air.

 

I knew you would post on this Why can't you force it not to tapper. What if you leave the accuator, plugged in and run the boost controller straight to the wastegate. We did it on my buddys Audi TT. We put a diode in the harness going to the pressure senser in the intercooler and his car has been running really good. He has the k04 and its alot smaller than the 16g.
So basically if the turbo is upgraded and bypass valve your good to go?
Will the 20g fix this problem? I know the 35r will.

 

Again, this is not a problem, so there's nothing to fix. It's just only efficient to a certain psi at certain rpms. We are already running a ton of boost, so there's not much room for raising it at high rpm. The fact that it tapers allows us to run really high boost in the low and mid rpm ranges without blowing hot air up top.