There always seems to be confusion as to what a “black top” SR20DET really is, and what makes it different from the “red top” SR20DET. Here are a few pointers so you can impress your friends with how much you know about Nissan motors.
First, how to tell the differences between s13 “red tops”, s13 “black tops” and s14/s15 “notch tops” visually:
S13 red tops:91-94
S13 black tops: Late 94-98
S14 notch tops: 95-98
S15 notch tops: 99-01
The changes/advantages of the s13 Blacktop:*
-Usually lower mileage
-Usually about $500 more expensive (because its newer)
-Minor ECU changes 96-98 (interchangeable with all s13 ECU’s)
-Minor wire harness changes
-Larger Oxygen Sensor (still narrow band, no performance gain)
There seems to be a misconception that S13 black tops have Variable Valve Timing and Garrett T28 Turbochargers, this is simply a confusion with the S14 notch top motor (also called black tops by some) and is not true.
If you know of any other differences between the S13 Red Top and S13 Black top, please post here and let your fellow 240sx fanatics know!