It can sometimes be tricky to identify and differentiate between the Nissan SR20 engines if you are not familiar with them. With these simple visual clues I’ve put together, you’re sure not to mix them up again.
|Chassis Code||Year||Engine Code||Turbo||ECU Pinout||Valve Cover||Rear Slant||Front Hump||# of Gears|
Every Nissan engine has the engine code stamped into the block. It’s located on the front of the engine to the right of the exhaust manifold, right next to where the engine and transmission bolt together, followed by the engine serial number. I’ve circled it in the photos below.
Another really simple way to tell the difference is to see if it’s turbocharged. For those of your who don’t know what a turbocharger looks like, here is a photo one on a SR20 engine (circled in red). Not only that, but stock SR20 turbochargers are made by Garrett, and will be stamped into the turbo (2nd photo).
ECU (Computer) Pinouts
Your engine most likely came with an ECU (computer). It has a specific number of pins.
Take the S13 ECU for example. If you lay it flat (horizontal) it has 16/14/16/18 (pictured below)
Valve Cover Color
Every engine has a valve cover. It sits on top of the engine covering the valves. Simple enough. On the Nissan SR20 engines they are two colors, red or black.
Rear Slant & Front Hump
Nothing complicated here. This is simply the shape of the valve cover. Some have a rear slant and some a front hump. And some have neither.
The front of the engine is the direction facing the timing chain and fan belt. And the rear is facing the transmission.
And lastly, one of the easiest ways to tell if you have an S15 SR20, is by the number of gears in the transmission. You can easily check by manually shifting the gears on the transmission. But be aware, some engine sellers might stick a S14 transmission to a S15 engine. So make sure you are using all the clues to identify the engine.
Identifying the Nissan SR20 engine is pretty easy once you know what to look for. Hopefully these clues will help you avoid any confusion in the future.
If you’d like to share any of your experiences or leave a comment, post them below in the comment section.