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i have a built b20vtec with a garrett gt40r turbo and i made 420hp and 300tq on 21 lbs on a mustang dyno today. i wanna know why the turbo stops making power after 7000. the turbo has a .95 t4 ar. and i am running skunk2 pro2 cams. with like 9.1 compression. i am aiming for 500hp. is this a common thing with this turbo. boost doesnt fall but power does. please please PLEASE HELP ASAP. THANKS

 

Whose doing the tuning?

 

You should be making 4xxwhp on 12-14lbs with that set-up. Id get that thing to Matt Shue asap, he will surely get 600+ out of the thing if the fueling is there.

 

Yeah power is really low for that psi. Hopefully its sleeved as well.

OP Whyd you decide to go with pro 2s instead of pro 1s? I made 524whp on 18psi and 630wp on 25psi on a 35r with ctrs so something is def wrong with your setup

 

I made 411 on a T4T67 at 15 lbs. I would think that with you setup you should make over 500, depending on the fuel system.

 

yea thanks guys for telling me u make good power but u have WAY different turbos and im really trying to find out if my turbo or cams are too big. maybe a smaller hotside or some thing. i went with pro 2 cause i got them at a nice deal brand new. but would trade for pro1 cams

 

what hotside and cams do u have thanks man

 

I think that we are all trying to say that you have something going on that needs to be looked at. I made 845 with a S372 at 24-28 lbs and OE Honda cams.

Like said let another tuner look at it.

 

Yeah, there has to be a bottleneck somewhere with that amount of power from a GT40R.

What's the full engine and exhaust setup?

 

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