Nissan 240sx - SR20 RB25DET Engine Swap

It's a natural progression for most 240 owners-pick up a used chassis, beat the hell out of the KA (unless it craps out on you first), swap in a SR20DET because hey, we could all use more power, and proceed to spend frivolous amounts of money on bolt-ons to make that SR scream. When all is said and done, we'd guesstimate roughly 300 to 350hp would be satisfying, but by that point your car becomes fairly unstreetable as well. Your last alternative forces you to buy a beater Honda and let the Nissan sit in the garage, only to be driven on weekends because quite frankly, it's too damn scary to drive it like it's a normal car. We suggest another alternative for you 240 enthusiasts (and no, this doesn't require you placing any rainbow stickers on the back bumper)-how does RB power sound to you?

Gary Narusawa, along with Marco Vargas at SR20Store, recently kicked things off righteously for his own company, Syko Performance, with the release of a bolt-on swap kit that will allow all S13 and S14 owners to swap in the coveted RB25DET (or RB26DETT for those willing to go the extra mile). The kit's designed for easy RB25 installation mainly because an RB26 does require more modification to fit properly, but both will fit. The kit includes all the mounts and accessories you'll need to make it fit like it came from the factory. Once all is said and done, the jump in power is enough to make you think twice about why you even went SR in the first place (I know I did). As of press time, Syko Performance is only selling a DIY kit for the RB25DET, and during the next few months their RB26DETT package will only be available as a fully installed service by a qualified shop like SR20Store due to the complexities of this swap. Keep in mind, however, that just like the SR20DET swap, an RB25/RB26 engine conversion is not smog-legal and should be used for off-road use only, unless you like paying huge smog fines. Follow along as Gary and Marco give the SR20Store's S13 an engine conversion worthy of the gods.

1. First things first-pull whatever motor's sitting in your engine bay. KA, SR, CA-get it out and refer to a manual if there are any pressing issues. Chances are that if you are removing a SR like Marco, you know a thing or two about engine swaps, so this should be fairly easy, although time consuming.

1. First things first-pull whatever motor's sitting in your engine bay. KA, SR, CA-get it
2. Once the engine has been removed, be prepared to start unbolting the engine brackets, crossmember and sway bar (if equipped). Syko's RB swap kit is designed to work only with the factory Skyline R33 GTS-T engine crossmember and metal engine brackets, so if you're thinking about ghetto-fabbing this thing together, then this kit isn't for you.

2. Once the engine has been removed, be prepared to start unbolting the engine brackets, c
3. If you're planning for the RB26 swap, Gary suggests a modified RB26 oil pan since he's seen a few engines go broke with the RB25 pan in place, not to mention an RB25 pan is missing a few key bolts towards the backside of the transmission that should not be left unmanned, especially when dealing with an engine conversion of this caliber. The RB26 oil pan needs to be modified to clear the front sway bar and have its side cut and welded to eliminate AWD.

3. If you're planning for the RB26 swap, Gary suggests a modified RB26 oil pan since he's

4. Upon test-fitting the Syko RB26 downpipe, you'll see clearly that the oil return on the rear turbo must be modified to clear.

4. Upon test-fitting the Syko RB26 downpipe, you'll see clearly that the oil return on the
5. Gary goes the distance for S13/S14 tuners by providing you with a new downpipe (RB26 shown), engine mounts, sway bar spacers and transmission adapter brackets that allow you to mount the transmission to the crossmember perfectly.

5. Gary goes the distance for S13/S14 tuners by providing you with a new downpipe (RB26 sh
6. The RB26 has to use an RB25 front crank pulley to allow for more clearance from the radiator as well as proper alignment with the power steering pump since an RB26 crank does not line up with the RB25 power steering pump. Switching to the RB25 power steering pump is recommended to eliminate the HICAS pump on the R32 RB26DETT engine.

6. The RB26 has to use an RB25 front crank pulley to allow for more clearance from the rad

7. Bolt the oil pan to the engine but apply gasket sealant beforehand. Refer to your manual for the proper torque specs.

7. Bolt the oil pan to the engine but apply gasket sealant beforehand. Refer to your manua
8. Unless you have a forklift at home, we'd recommend a cherry picker to move the engine around. The RB is obviously a much bigger engine to try and squeeze in, so it's probably better to go in from down under.

8. Unless you have a forklift at home, we'd recommend a cherry picker to move the engine a
9. Some last minute ideas you may want to think about while the engine's out: change the rear main seal, water pump, timing belt and front main seal. Also, you must use a clutch that's strong enough to hold the power, even if it's a stock RB.

9. Some last minute ideas you may want to think about while the engine's out: change the r

10. Custom heater hoses will have to be used since neither the factory SR or RB hoses will work. You can find these at a local auto parts store.

10. Custom heater hoses will have to be used since neither the factory SR or RB hoses will
11. Bolt the clutch plate and flywheel on; make sure you use the right bolt length for an aftermarket flywheel, especially if you're using a twin or triple disc setup.

11. Bolt the clutch plate and flywheel on; make sure you use the right bolt length for an
12. With the help of a friend, attach the transmission to the long block, then bolt the starter back on and install the lower harness, alternator and oil pressure sending unit. Attach the Syko transmission brackets by using only the rear bolt first, and screwing it in downward. The other bolts will go from the bottom up once the engine's in.

12. With the help of a friend, attach the transmission to the long block, then bolt the st

13. Bolt the engine mounts on top of the RB crossmember. Make sure each mount is installed accordingly to the left or right side (sides are indicated on mounts).

13. Bolt the engine mounts on top of the RB crossmember. Make sure each mount is installed
14. Raise the car and prepare to guide the engine assembly into the engine bay as you lower it back down. Double check for proper clearance between the downpipe and steering shaft as well as the space between the bell housing and transmission tunnel.

14. Raise the car and prepare to guide the engine assembly into the engine bay as you lowe
15. Complete the transmission crossmember bracket installation by inserting the front bolts that go into the chassis. If finding a R33 transmission crossmember proves too difficult, you can use one from an automatic USDM 240SX.

15. Complete the transmission crossmember bracket installation by inserting the front bolt

16. Once the engine's bolted into place, you'll notice that the sway bar bracket arms will be uneven. The longer side must sit in the step of the spacer properly, and the sway bar bracket must be rotated 180 degrees (flipped front to rear). At this time, it's also wise to replace the bushings with stiffer Nismo bushings (shown) by removing the rack and pinion.

16. Once the engine's bolted into place, you'll notice that the sway bar bracket arms will
17. For RB25 swappers, Syko's downpipe is designed to replace the stock turbo exhaust elbow (O2 housing) and downpipe, and comes with two twelve-point 10mm ARP bolts, which should be installed in the two center holes of the turbo flange (refer to instructions). The smaller bolt heads will make it easier for you to work a wrench between the bolt and the side of the downpipe. Install the provided driveshaft and catalytic converter or test pipe (not included). RB26 owners can simply install the new downpipe onto the factory exhaust elbows.

17. For RB25 swappers, Syko's downpipe is designed to replace the stock turbo exhaust elbo
18. Since your car's now a combination of Skyline and 240SX, you need to make a few modifications to the power steering pressure hose/line by removing the lower hose bracket and looping the line into place. The other line/hose then becomes your return line. Since this line loops around the crossmember on the '91-and-up KA24DE and you're no longer using the original crossmember, it's time to improvise. Attach a 3/8-inch hose to the metal line coming off the rack and pinion unit, which is then connected to the power steering reservoir. You should also place a small cooler inline on this hose by using either an aftermarket power steering or automatic transmission cooler, or by making a loop out of 3/8-inch metal line. For '89-90 240s, use '91-94 power steering lines.

18. Since your car's now a combination of Skyline and 240SX, you need to make a few modifi

19. You should be using the RB clutch slave cylinder since the mounting holes are in different positions.

19. You should be using the RB clutch slave cylinder since the mounting holes are in diffe
20. Attach your upper intercooler piping and aftermarket air filters.
21. Plug in the lower harness, reattach the ground wire to the passenger side firewall and connect the throttle cable.

21. Plug in the lower harness, reattach the ground wire to the passenger side firewall and

22. The RB26 will require a resistor pack for the injectors because it utilizes low impedance injectors. This was configured by wiring the factory GT-R resistor pack in line on the positive wires leading to the injectors. The power was tapped from the S13 fuse box.

22. The RB26 will require a resistor pack for the injectors because it utilizes low impeda
23. A factory KA (SR won't fit) radiator can be re-used but even slim aftermarket fans will have to be retrofitted to clear the front crank pulley. S13 owners should source a thicker S14 radiator, if possible. Install the battery, refill all necessary fluids (engine oil, tranny, radiator fluid and the like) and don't forget to plug in your RB ECU! Double check all hose clamps (turbo, intercooler and air intake) and cross those fingers! Fire it up when ready!

23. A factory KA (SR won't fit) radiator can be re-used but even slim aftermarket fans wil
24. See? Marco's a happy guy thanks to Gary.

With a stock RB operating solely on RWD alone, Marco put down 306.72hp with 246lb-ft on SR Motorcars' Dynojet. Raising the boost and adding simple bolt-ons should yield close to 400hp. We went for a test ride (look out for a full feature and evaluation shortly) and all we can say is "WOW!" If you're even remotely considering the SR swap, we say save your cash for the RB conversion instead. The torque is incredible and a stock RB will far surpass the thousands of dollars that would make an SR fast.

With a stock RB operating solely on RWD alone, Marco put down 306.72hp with 246lb-ft on SR