Ouch...

Definitely do a boost leak test, then compression test... Also 20psi? Thats nothing.... id crank it up to like 25... however going to 8k isnt gonna make your power higher

 

Up the boost, at least 25PSI. Power is low should be 350+ with cams.

 

Yeah, you will need more boost if you want to surpass 300. 25 will get you a lot. With pretty much same mods (3" turbo back exhaust, AEM intake with cone filter, mystery cams that might be 272 of some sort, and a crappy tune by previous owner) I was around the 350 mark.

 

Can I pull 25psi from my evo 8 2005 stock turbo? Does 25psi in my stock engine will be safe?

 

You are barely above stock boost, and I have seen people run 30+ lbs on a stock motor. If there are no problems 23-25 on the VIII turbo and stock motor all day...

 

it's fine with safe tuning not just pushing it to 25 psi.

 

i was going through this last month my car only made like absolutely no power on the mustang dyno. Turned out it needed a head rebuild, its now making close to 300 on a conservative tune. Id say rule out the stupid thing first, boost leak, compression test, other than that it may be something more critical.

 

Does a turbo from evo 9 10.5 help me to get more HP? cause I have good parts and I only made 279whp.

 

your boost needs to raised up of course, you can run 93 octane to squeeze more power out of it, your afrs should be at a certain point to burn better depending on how much power you want to make.

do you have just the injen intake or do you have the full injen setup? if its just the intake then there is most of your problem the the stock licp will hold back alot of power.

 

where did you get it tuned?

 

you should do a boost leak test before getting tune make sure everuthing is tight and zip tied