I was wondering if the kouki black tops (the ones with the J4 ecu) come with a t-28 or t-25?? The reason i ask is because my friend has a blacktop with the j4 ecu in his s13 and it pulls alot harder than some other s13 that ive ridden in with red tops in them. They have the same bolt ons downpipe, front mount, intake etc. No boost controller, no fuel tune nothing. Maybe its just my imagination but, I really think his pulls harder than the others with red tops in them.

Thanx

 

there are many factors as to why his car could be faster such as fuel delivery, condition of turbo, leaks, tires, drive train upgrades etc.

s13 black to comes with t25

s14 t28

s15 bb T28

 

s13 red/black t25

s14 t28bb

s15 t28bb (better than the s14)

 

s14 turbo is a ball bearing T28

 

sooory bro didn't notice i forgot my first set of BBs