complete RB20det ----> s13/s14 FAQ

[NotDave]

-A31 Cefiro RB20det vs. R32 Skyline RB20det

info here

-RB times aka how fast is it?

RB times here

-Does the RB20 bolt in?answer here

-mounts (if any or adjustments to stock mounts)

you can use stock r32 mounts and crossmember or you can use aftermarket mounts. aftermarket mounts will help sit the motor slightly lower than stock mounts but you can get away with stock mounts and save yourself $350.

info on mounts here and here

-wiring (for 89-90 s13, 91-94 s13, 95-98 s14 and the differences in wiring them if any)

RB20 into an S14 here

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RB20 wiring basics:

hook up the lower KA harness, then:

You need to get constant and switched power, fuel pump ground ECU ground. Then swap the oil sending unit and knock sensors from the RB lower to the KA lower and hook them in to the guages and ECU respectively. Using the KA lower you should be fine on starter signal, speedo and reverse lights....

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Info: RB20 into an 89 S13

Soooo, here is my dilema: what do I need to do to get power to the engine harness? I am running the KA lower harness to the starter (constant power), running the KA lower harness to the alternator (switched power), and both of these to the battery (effectively using the lower KA to run the engine power).

Now, what do I need to power on the RB ECU? I am pretty clear on the fuel pump (pink wire on the small RB connector by the ECU), but thats it. I have the rb motor harness on the motor, and running into the firewall.

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Ok, you don't need the 8 wire plug because you're using the KA lower harness, Start with the 6 plug harness, cut the plug off, you only need 3 wires from this,

start with the white/purple on the RB harness, run it to the white wire coming off the ignition 30 amp fuse from the fuse box, pull the box apart, make sure you find the right white wire from the fuse, then splice the white/purple wire into that white wire.

Next the 2nd Rb wire on the 6 plug, black/red, find the KA gray oval plug, near where your battery was, cut the old KA plug off, leave avout 6 inches, and connect the rb wire to the black/red ka wire

Next the 3rd rb wire, white/black, connect it to the white wire on the same KA plug.

Last, the brown ka plug next to the gray oval KA plug, run a wire from the black/pink wire on the plug and splice the wire into the black/pink wire at the ecu.

This will get your RB20 started, it worked on our 90 model today with the earlier Rb20. That should be it man, if you need any help you can call us at the shop, 678 770 4516.

If anyone thanks we're missing something feel free to correct us.

Eric

*note- the wiring colors on 89-90 sohc and 91-94 dohc are the same, the only difference is that they are in different locations. so the guide above should work for 91-94 dohc s13s also.-----------

-speedo/tach issues and how to resolve them

the rb20 has a cable driven speedo.you will need to take the cable out of the clip and run it throught into the cabin some how.i ran mine near the accelearator pedal right under the heater core box.*edit* if you use the rb cluster you will have to run the speedo cable.sorry bout that.

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Or you can just swap speed sensors with one from a manual ka24de transmission and it should work with the stock cluster.

Nick

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-downpipe issues, O2 housing, and other piping issues

doing a RB20det swap into a 95 240sx. The exhaust downpipe is hitting the steering linkage and seems to be keeping the motor from sitting right. Anyone else run into this problem? Anyone know where to get a custom downpipe or have any good info?

That's not your downpipe, that is your O2 HOUSING. Big difference.

I took a grinder to my O2 housing and shaved it down until it had adequate clearance. Depending on where the steering shaft bolt hole is, you could do this to the knuckle on the steering shaft as well and probably save yourself the hassle of making sure you don't grind straight through the pipe and give yourself an exhaust leak (ask me how I know )

I have an S13 though, the clearance problem on your S14 might be worse.

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Ok, so yeah, that's the O2 sensor housing aka dump pipe. The downpipe goes from the O2 sensor housing down to the 1st resonator (looks like a catalytic converter) on your S14. There are no custom pipe you can buy to fix this, at least not yet. However, you can make the custom fix yourself. If your clearance problem is not that bad, you can just shave a bit of the O2 sensor housing as Project240 suggested. If you end up shaving off more than 1/8", then you'll want to take the pipe to a welding shop to get notched. They can notch the pipe, fit in a piece of half-cut pipe, maybe 1/2" or 3/4" diameter, and braze-weld it to the pipe.

I just got the brazewelding done to my pipe. I had clearance when the car was parked, but when turning hard right it rubbed the exhaust.

Of course the best solution is to get a good welding shop to make up a custom 3" pipe that goes from the turbo to the cat-back.

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or....

FOR THE DUMP PIPE ROTATE THE RACK FORWARD UNTIL THE LOCK BOLT ON THE STEERING INPUT YOKE HITS THE NOTCH ON THE SHAFT, THIS WILL GIVE YOU ALL KINDS OF ROOM BETWEEN THE DUMP PIPE AND STEERING YOKE.

-power steering

P/S is easy, just requires some bending of lines and castrating/plugging the power steering pump.

-air conditioning

info and theories on a/c here and here more a/c info here***working A/C in an S13***beware. its works but from what i can tell isn't safely put together...not until it incorporates the center console controls.

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DIAGRAMS AND MANUALS

meggala-The wiring diagram of the rb25det in English. -rb20-26 wiring diagram -explode view of r32 turbo setup.-photo's of how to remove the intake and injectors. RB25det.org-RB25 swap info

RB20 manual -RB20 manual

KA manuals and other helpful files

taken from http://www.rb20det.comRB20 ecu pinout

Ecu pinout: rb20det eccs control unit pin layout.1 Ign signal (power transistor) Cyl #1 2 Ign signal (power transistor) Cyl #5 3 Ign signal (power transistor) Cyl #3 5 engine. A/T control input signal (bt1) 6 Sub electrical fan relay (engine temp switch)7 Tacometeter speed signal9 AC relay (AC cut signal) 10 Ground (ign signal system)11 Ign signal (power transistor) Cyl #6 12 Ign signal (power transistor) Cyl #213 Ign signal (power transistor) Cyl #414 engine. a/t control input sigal (bt2) 15 engine. a/t control input sigal (bt3) 16 ECCS relay 18 fuel pump relay19 Power steering switch 20 Ground (ignition signal system) 21(RX) Receive (control unit data reception) 22 (TX) Transmit (data sent from control unit) 23 Detonation sensor 1 (cyl 1-3) 24 Detonation sensor 2 (cyl 4-6)26 Air flow meter ground 27 Air flow meter intake air quantity signal28 Engine temp sensor 29 Exhaust gas sensor30 Sensor ground (throttle sen, ENG temp)31 clock (synchronization signal) 32 Monitor and check lamp (red)38 Throttle opening output 41 Crank angle sensor (120degree signal) 42 Crank angle sensor (1 degree signal) 43 Ignition switch START signal 44 Neutral switch 45 Ignition switch (IGN) 46 AC switch47 (CHK) Check (diagnosis activation) 48 Throttle sensor power supply 49 Control unit power supply 50 Ground (control unit) 51 Crank angle sensor (120 degree signal) 52 Crank angle sensor (1 degree signal) 53 Vehicle speed sensor 54 Throttle valve switch (idle connection pt) 56 Throttle sensor output signal 57 Throttle valve switch power supply 58 Battery power supply 59 Control unit power supply 60 Ground (control unit) 101 Injector #1 103 Injector #3 104 Fuel pump terminal voltage control output105 Injector #2 107 Injector ground 108 Injector ground 109 Injector power supply 110 Injector #5 112 Injector #4 114 Injector #6 115 exhaust gas sensor heater ground 116 injector ground



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and thats it. this should answer most of your basic questions. all of this was found by using the search feature and i did you guys all a favor and combined it into a single FAQ. i did not include info on how much the clip is or where to buy the motor because it varies too much.

if you have something to add or correct post and ill edit this post.

Modified by NotDave at 6:46 PM 9/23/2004
Modified by NotDave at 6:48 PM 9/23/2004

[skillzilla]

awesome job, maybe you should link to other sites with info, like Magalla's site and others. I know there is a lot of info on parts and upgrades there.

[NotDave]

anybody with a working a/c?????

[BoostFab]

tony (frosted flakes)....his a/c is working...click here

[blk240sx]

Excellent thread for info. I'm picking my RB up this weekend !!!

[NotDave]

tony (frosted flakes)....his a/c is working...click here

awesome...thx for the link. i couldnt find that thread from searching for some reason. it has been added :ylsuper

[HybridOne]

this is an awersome thread....good job.

[NotDave]

bump diggity for any new info.

[NotDave]

i just remembered i did all this work to make this faq and my car is still bone stock

[Carl H]

Quote:the rb20 has a cable driven speedo.you will need to take the cable out of the clip and run it throught into the cabin some how.i ran mine near the accelearator pedal right under the heater core box.*edit* if you use the rb cluster you will have to run the speedo cable.sorry bout that.

hrmmmmm.that looks like something i wrote down at some time or another either on a post of one of the guides i did for the rb20 into s13 chassis.also on another note the rb25 speedo sensor reads in kph, so your stock speedo will be right just as long as you look at kph and not mph, if you can get a s14 canadian cluster or s14 cluster from europe or japan and get it recalibrated (mileage set to your car remember to convert it to km's from mi's) it will work too.same applies to the s13 as you will need a cluster from a 180sx/silvia to make the speedo read right.
Modified by Carl H at 4:36 AM 9/24/2004