did these engine come with different turbos? the sr20 comes with a t28 i believe. which one is better.
Only the s14/s15 sr20 came with a T28…s13 came with a T25, which is the same as a ca18 I believe.
A T28 is bigger, so therefore better 
Plus they have ball bearings.
both the ca18det and the red top sr20 had t25’s, but the ca18 one had a smaller housing.
The s13 black top kept the same t25 that the s13 red top had
than the s14 black top sr20 was introduced and it came with a non-ball bearing t28
than with the s15 black top sr20 and it had a t28 with ball bearing.
thanx guys. i was told that a ca18 im looking at has a ugraded sr20 turbo. hope its a t28. crossing my fingers.
there usually a t25G s13redtop/blacktop turbo
CA with a S14/15 T28 turbo is the best bang for your buck