I'm still running a stock setup except turbo back exhaust into twns,stock turbo and stock psi...Any mod suggestions ?
what can you turn the boost up to without damaging the car ?

 

What year/model? This information should always be posted in any technical thread.

I'm going to guess S5 TII from the limited info I see in your profile. I would not suggest turning the boost up at all over stock, if you have no fuel or fuel control modifications. Besides, you will hit fuel cut at 8.6 psi (stock S5 boost is 7.5 psi). For modification information, browse the 2nd gen section for information on what other people use to run more boost on the stock turbo. Upgraded fuel pumps, larger injectors and something like a chipped ECU or an SAFC w/ FCD are the common routes.

 

Add Megasquirt and you can remove your boost limit and with a good tune you can run more power on stock boost.

 

On that exhaust system alone you will already be hitting 8-9 psi because of the boost creep. So just leave it alone until you get more fuel and something to control that fuel.

Rteck chipped ECU
Larger secondaries
FD or Cosmo fuel pump
Boost controller

This is a very basic setup and at 10psi can net you 200+ rwhp

Always remember what good is a fast car if it isn't reliable? So make sure you take care of basic reliability mods before you start working on performance mods.