Just put a full exhaust on my evo 8 now when I boost it wants to jerk when I build up boost so plz help guys thx

 

If "full exhaust" includes the cat and/or downpipe, you need a tune.

 

Really is that all it could be? And yes it's down pipe an test pipe

 

Yes, a much better-flowing exhaust can necessitate a tune. Can you log?

 

What u mean log?

 

Buy a tactrix cable, buy evoscan & log what your car is doing.

Also do you have boost gauge? & what psi are you hitting

 

To be blunt (which can, in the long run, save the listener a pile of money, even if it hurts your feelings for a minute), if you haven't heard of logging before, you're not ready to tackle this, yourself. Get on your regional sub-forum and get advice on a decent tuner near you. Don't push it until you have dealt with this Check for boost leaks in the mean-time, because it's not worth paying a tuner $X/hr to do this for you and they are going to ask if the car has been checked.

 

20psi holding at 15 though

 

So you have a gauge then, if your modded then you def need to get your car tuned. It's probably hitting fuel cut or boost cut if your not running atleast a better fuel pump