When it comes to N/A performance, most people immediately think Honda. While Honda motors are coveted for their all-motor revving ability, other motors also do well in tuned N/A trim, especially for street California pump gas applications. Once such motor is the Nissan SR20DE. Its big 2,000cc displacement is an excellent choice for building a low-buck highly streetable motor that can mimic like a B-series Honda engine for a much lower price. Our low-buck power goal will be at least 180 whp and 150 lb-ft of torque on 91-octane Cali pee water. Unlike many uber builds that end up as tech articles, we'll be looking at cost containment and total streetabilty as our end goals, keeping exotic parts to a minimum. Our engine will also be built with durability in mind. Now that track days are becoming so popular, it's not uncommon for built motors to be pounded around road courses all day. This is far more rigorous and hard on the motor, where drag racers or street racers pull through the gears.
The SR20DE engine has been Nissan's workhorse performance four-cylinder for more than a decade. Originally introduced in North America in the Infiniti P10 G20 and in Japan in the PS13 in 1990, the SR20 was designed as a performance motor from the beginning. Later, in 1991 the SR was dropped into the venerable B13 Sentra SE-R and NX2000. The SR20 was carried over to the B14 200SX SE-R in 1995 and the B14 Sentra SE in 1998 as well as the P11 '98-'01 Infiniti G20. The '00-'02 B15 Sentra SE was the last application of the SR20DE in North America.
The SR was built tough to take lots of punishment. With an 86mm bore and stroke with a rod length of 136.25mm, the SR liked to rev more than its more pedestrian longer stroke siblings. Its lightweight but tough closed-deck aluminum block was designed from the get-go to withstand the rigors of turbocharging in the PS13 Silvia-the much better JDM version of our 240SX. The crank is a beefy fully counterweighted forged and shot-peened steel unit with plenty of journal overlap. The blocks main caps are tied rigidly together with a stout girdle. The rods are forged and shot-peened with generous proportions around the big bolts and bushed floating pins. The cylinder head had finger follower valve actuation for aggressive valve movement control and to make room for high, generous flowing for the time split intake ports. Hydraulic lash adjustment at the pivot fulcrums kept maintenance low. Although the pistons are cast, they're a tough hypereutectic material and have strong detonation-resistant ring lands. It isn't unheard of for a totally stock bottom end SR20DE to produce over 400-turbocharged whp reliably. All North American versions of the SR20DE have a 9.5:1 compression ratio and a 46.1cc combustion chamber volume. The SR20DE also has quite a bit of aftermarket support, as it was a very popular engine for racing and street modification in Japan.
During its production run, the North American SR20DE underwent three different major changes.
'90-'93 The High Port
SR20DE's made during this period have a racing-type downdraft and straight-shot split-intake port, which is desired for all-out performance in a highly modified engine. The high port was rated at 140 hp. The curving under the intake manifold with the plenum and throttle bodies under the runner most readily identifies the engine. If you're building an all-out turbo or N/A engine, this variant is the most desired. Fortunately, this is also the most common SR20 out there. This engine is also plentiful and cheap from JDM used engine importers. This engine was redlined at 7,700 rpm from the factory.