i turboed my na ba too, about 2 yrs ago now or more (jan 2011)..
i made 246rwkw with my 2.5 exhaust on 9 psi... who ever is tuning your car is a gay C***... if your car has a problem that bad it only makes 190 kw or whatever on 8 - 10 psi and the tuner cant figure out why, dump him.... If he cant fix it, he should be able to AT LEAST tell u why its making s**t figures.

definitely chuck a walbro 255L fuel pump in, the fact your tuner guy didnt mention this to you is ridiculous, a good fuel system is key to making power, the crappy n/a pump would s**t itself trying to supply 4bar xrturbo reg instead of n/a 2.7bar and hi flow injectors, my injectors are 42lb bosch greens, 4bar xrturbo fuel reg and 255L walbro pump, i run it a bit rich for peace of mind.

A standard xr turbo runs about 190 - 200 rwkw stock at about 6psi, with only a fuel system upgrade, like mentioned above (minus the reg cuz its already an xr turbo) you can safely up the boost to 10, tune the fuel system and go straight to the 250rwkw mark.

if your still having problems let me know what you have done to your car and i can help....trust me ive done it all with mine (and im never doing it again lol) atm im running twin 2.5 exhaust 3 in cat and dump making 268 at 10 psi, if i pump the tap up to 12 - 14 psi i get about 280 - 290, but that was just one or two runs on the dyno with that boost and down the quater... 10 psi i ran 13.2 and 14psi i ran 12.9, BUT my motor started pinging toward the end of the run and i backed off, so could have been a better time i dunno...

I would be running an intercooler. Why aren't you running one?

Get rid of that tuner, and give prostreet automotive a call. Their in frankston. If you talk to paul in their he will help you.
Trust me his making 560rwkw out of a holden 202 engine in a fc. The three of him in there know what there doing

I'm thinking there's a few things wrong with this. As has been pointed out below;














^^^ this would alert me to the fact that the phaser on the cam bank may be faulty. Also, that if the tuner hasn't butchered the fuel map (with the standard pump dribbling fuel in past stupidly large injectors) that the o2 sensor is probably shot. Get a new one. Re the fuel system, an XR6t can achieve ~260kw at the wheels without any major rework of components (new exhaust & intake with a good pump & tune) but will definitely need a tune. I'd like to know what makes your tuner confident that the standard pump in an NA motor like this is good for boost.

old thread but just saw it...
standard fuel pump and 4bar fuel pressure is still enough to make at least 200rwkw, the fuel pump wont last as long but it will do it.

considering you can get an EA, put 7psi through it with no cooler and if you wanted just run a rising rate reg and retard the timing on the dizzy and still make more power than you are, something is wrong.

your tuner should never hand a car back and just say its got problems but don't know why.
as has been said above, 2.5" exhaust is enough to make over 200rwkw, thats not the problem.