Nissan 240SX Performance Modification/Engine Swaps/SR20DET
The SR20DET is the most commonly swapped engine into the 240SX Chassis. The Availibility of the engine and the relative ease of the swap make this a popular choice for 240SX owners who want more power.
Specs and Versions 
SR = Block
20 = 2.0L Displacement
D = Dohc E = Electronic Fuel Injection
T = Turbocharger
SR20DET Red Top
2.0L DOHC Turbo
Turbo Type: T25
Compressor A/R: 0.80
Injector Size: 370cc
Bore x Stroke: 86.0mm x 86.0mm
Power (HP): 280@ 6,000 rpm
Torque (TQ): 240@ 4000 rpm
Compression Ratio: 8.5:1
Speed Limiter:180 Kmh -112 mph
Stock Boost: 7 psi
ECU: 62 (redtop) OR E5 (blacktop). 63 (automatic) will also work.
MAFS: 89-90 240sx mafs works. MAF is a 52F00 for SR20DET. the 40F00 from the 89/90 240SX works, but resolution is off a bit. Not the same power/drive ability potential as factory SR MAFS
Rev Limit: 7500rpm (no need to really go over 7000)
The SR20DET is available in several different stock forms ranges in power from between 205HP and 250HP.
S13 "Redtop" - Came from S13 Silvias and 180sx 1990-94 (Garrett T25 turbo). Easily identifiable by bright red valve cover. Equipped with 370cc injectors and a side mount intercooler. Uses 'Skinny' O2 sensor. With raised boost to the s13 Redtop motor can push 250hp safely with no modifications. Maximum Safe boost on the stock turbo is 13psi-15psi. The Engine Should produce 230-250rwhp on safe boost. With a larger turbo (e.g. GT2971r), bigger MAF (e.g. Z32 N62) and upgraded fuel delivery (e.g. 255lph pump, 740cc injectors) 375-430 can be had on stock internals (yes, It's actually true).
S13 "Blacktop" - Came from 180sx's 1994-1998 (Garrett T25 turbo). Most of the same physical construction as S13 "Redtop", with black valve cover and additional cooling fins on the front. Uses slightly different engine management configuration (higher bit fuel map) and uses a different 'Fat' O2 sensor. The pistons are made from a denser aluminum for higher strength. the port design on the heads are more open to allow more air flow. Maximum Safe boost on the stock turbo is 13psi-15psi. The Engine should produce 230-250rwhp on safe boost. With a larger turbo (e.g. GT2871r), bigger MAF (e.g. Z32 N62) and upgraded fuel delivery (e.g. 255lph pump, 740cc injectors) 375-430 can be had on stock internals (yes, It's actually true).
S14 - 94-98 Silvias (also refered to as a notch top by some to avoid confusion with the S14 and S13 "blacktop") - Variable Timing Control aka VTC was introduced. Equipped with 370cc injectors and sidemount intercooler. Intake manifold is significantly different from S13 SR20DET, and valve cover is black with a large lump on the forward portion. Maximum Safe boost on the stock turbo is 13psi-15psi. The stock engine should produce 250-260 RWHP at safe boost using stock turbo. Upgrading turbo, fuel and rest of need parts will yield 300-375.
S15 - 2000+ Silvias. (Garrett Ball Bearing GT28R turbo and 6 speed transmission) Equipped with 480cc injectors and larger sidemount intercooler. Valve cover is black with a large lump on the forward portion. The easiest way to tell if you have an S15 motor and not an S14 is the ECU plug. Also the A/C compressor part number. other than that, the S15's front cooling fins on head surface appear to have been sanded off. The stock engine should produce 250-260 RWHP at safe boost using stock turbo. Upgrading turbo, fuel and rest of need parts will yield 300-375.
Oil(with filter change): 3 1/4 qt (3.7 L)
Cooling System (including resevoir): 5 1/2 qt (6.2 L)
Manual Transmission: *GL-4* 4 1/4 pt (2.4 L)
Differential carrier gear oil: *GL-5* 3 1/8 pt (1.8 L)
Automatic Transmission: 7 qt (7.9 L)
Power steering 3/4 qt (0.9 L) ATF recommended
Swap Guide 
Required Items 
If you are swapping into a chassis that had the KA24E, and want to retain power steering, DOHC power steering resevoir and lines are needed. Keep the KADE power steering pump as they are interchangable if you have the SR20det pulley and bracket.
An aftermarket electric fuel pump(z32 or sr20 stock pump).
A twin cam 91' and above cluster for s13 models due to Rpm reading not working with a pre 91' cluster (how to tell the 2 apart?... pre 91'reads 115mph post 91' reads 110mph.
If you are swapping from auto-manual, you will need the manual driveshaft or a custom one piece.
- Drive shaft lengths differ with ABS(shorter) and Non ABS(longer), earlier base models may require separating drive shafts and using half auto/manual to fit.
Custom wiring is required as well. You can either splice the KA harness with the SR (which can get hectic at times) or purchase a pre-made harness from a provider or specialist such as Wiring Specialties or run a standalone such as a Painless harness.
Step by Step 
-Relieve fuel pressure. Do this by removing the fuel pump fuse in the engine bay, start the car, let it die, crank the motor over a few more times. -Drain all engine and transmission fluids. Be sure to drain the coolant from the block if you don't want coolant all over your work area. - Disconnect battery. - Remove anything in the way, items like intake piping, fan shroud, and radiator. - Disconnect exhaust.
-Disconnect all harness connections and then plug everything back in the other engine.
Greddy Oil Pan - Worthwhile upgrade. Baffled interior and extra port for temp sensor is very nice.
Greddy Oil Catch Can - Nothing Special, just a catch can!
Greddy Pulley Set - Lightweight aluminum, blue in color. Easy install.
Greddy VSPL Intercooler Kit - Must modify or remove front bumper support.
Koyo Aluminum Radiator - Consider this upgrade when doing the swap.
HKS SSQV - Universal application, extremely loud when not recirculated (depending in insert), pull type so it wont leak under vac.It is not recommended to run an open BOV, without the aid of some type of fuel controller. Some people have had success from tightening down the BOV (resulting in the BOV not opening within cruising RPM range), but in general it causes the car to run rich due to the air that has been metered is being dumped to the atmosphere. Since the ECU thinks the engine will be receiving that mass of air, the amount of fuel is still injected into the engine even though that mass of air is missing which in thus causes it to run rich temporarily. (not really necessary as this costs extra money, those on a budget should consider putting the MAF sensor after the BOV i.e. in between the BOV and the block itself, its probably a better idea anyways).
Nismo Thermostat - Another part to help with keeping the engine temps down. This is not necessary for most SR owners that do not track their cars for the Nismo unit opens at a lower temp than the OEM one.
Greddy Airnix Air Filter - Foam cone style with 2 different layers of foam. The inner is denser than the outer for better filtration. Good product. (Non-oiled filter recommended for MAF-operated cars)
Samco Silicone Radiator Hoses - More reliable than standard hoses because silicone can stand up to temperatures better than the standard rubber hoses.
Flex-a-Lite Dual 12" Fans - Extremely nice fans. I have them hooked up with a painless wiring kit which turns them on at 190 and off at 170 and it takes them less than a minute to do that. Very impressive and fits perfectly on the S13 SR20 Koyo radiator. Or a set of Altima Electric Fans, from the '93-'97 Nissan Altima, these fans have a higher CFM rating than Flex-a-Lite and are cheaper to boot. You can pick a good set with shroud for $40-$60. They wire up just as easy and the shroud allows for more air flow. E-fans are a common upgrade. The stock clutch fan is prone to slippage, and robs power (up to 20hp), E-fans are a much better choice. (FAL's often burn up if not wired with an independent relay for each fan. do not wire the fans both through one relay - Taylor Durdan)
Power Enterprise V-belts - the best belts that I've ever used. They hold up strong
OEM USDM Replacement Parts 
Some parts Courtsey of Kazuo - Zilvia.net
Oil filter (S13 SR20DET)- 91-94 Sentra SE-R Part number: 15208-53J0A
Oil filter (S14 SR20DET)- 95 Sentra SE-R/200SX Part Number: 15208-65F0A
Fuel Filter - 1990-1996 300ZX TT
Upper injector o-ring - 7/95 and newer 300ZX TT (small/upper)...
Lower injector o-ring - 7/95 and newer 300ZX TT (big/lower)
o2 sensor (S13 SR20DET REDTOP)- '87 300ZX Turbo AKA Skinny Type.(requires splicing of harnesses. 300zx is 3 wire square plug, SR is 3 wire linear plug. Stock redtop 02 sensor was never produced in US market)
o2 Sensor (S14 SR20DET BLACKTOP)- 95 300ZX TT
Exhaust Manifold Gasket (Red Top)- 91-94 Sentra SE-R
4 Hole Turbo Manifold gasket / 5 Hole Turbo Extension Gasket - 91-96 300ZX TT (Z32)
Fuel Injectors - 91-96 Z32 300ZX TT (purple plugs; 370cc)
MAF - 89-90 240SX
Timing Chain Kit - 91 B13 Sentra SE-R
Belts (PS, AC, alt) - Gates K050370 Alt., K040345 PS & most AC (Dayco belts - 5050370 ALT, 5040345 PS)
Spark Plugs - 91 Sentra SE-R (USE ONLY NGK Iridium/Platinum BKR6E or BKR7E gapped to .028 (upgraded turbo) - .032 (Stock turbo)
Water Pump - JDM ONLY!
Head Gasket - JDM ONLY! (can be ordered from GReddy)
IACV Gasket - JDM ONLY!
Engine Coolant Temp. Sensor - '91-94 B13 Sentra SE-R and KADE Temp Sensor
Throttle Position Sensor - '91-'94 B13 Sentra SE-R
Water Temperature Sensor - Sentra (equal to year of you motor)
Front and rear main seal(Red Top) - 93 sentra SER
Stock sr clutch disk - 89 Nissan Maxima
Nissan Part Numbers 
Oil filter for S13: 15208-53J0A
Connecting Rod Bearing: 12111-1N500
Crankshaft Bearing: 12207-60J00
Front main seal: 13510-53J00
Rear Main seal: 12279-0M300
Piston Ring set: 12033-53J10
Exhaust Manifold Gasket (S13): 14036-53J10
Exhaust Manifold Stud: 14065-75F00
Intake Manifold Gasket (S14): 14035-5U000
Intake Manifold Gasket (S13): 14035-53J00
Oil Strainer Gasket: 15053-1E400
Intake Valve: 13201-1E711
Exhaust Valve (Not found at Nissan): 13202-53J01
Tensionner Gasket: 13079-2J200
Intake Valve Seal: 13207-84A00
Exhaust Valve Seal: 13207-53F00
Intake/Exhaust Valve Seats: 13205-53J00
Valve cover gasket (S13): 13270-52F00
Spark Plug Well Gasket: 13271-52F00