When it comes to N/A performance, most people immediately think of the Honda brand. Even though Honda motors are coveted for their all motor revving ability, there are other motors that do well in tuned naturally aspirated trim, especially for street California pump gas applications. One such motor is the Nissan SR20DE, its big 2000cc displacement is an excellent choice for building a low buck highly streetable motor that can motivate 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 will 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, for an entire weekend. This is far more rigorous and hard on the motor than drag racing or a street racers pull though the gears.
The SR20DE engine has been Nissan’s workhorse performance 4 cylinder for more than the last 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 1998-2001 Infiniti G20. The 2000-2002 B15 Sentra SE was the last application of the SR20DE in North America.
The SR was built tough to take lots of punishment. With a square 86mm x 86mm bore and stoke with a rod length of 136.25mm, the SR liked to rev more than its more pedestrian longer stoke siblings like the KA24. 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 shotpeened steel unit with plenty of journal overlap. The blocks main caps are tied rigidly together with a stout girdle. The rods are forged and shotpeened 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 are a tough hypereutectic material and have strong detonation resistant ring lands. It is not unheard of that a totally stock bottom end SR20DE can withstand over 400 turbocharged whp reliably. All North American versions of the SR20DE have a 9.5:1 compression ratio and a combustion chamber volume of 46.1 cc. The SR20DE also has quite a bit of aftermarket support, as it was a very popular engine for racing and street modification in Japan.