RB FAQ

[d0pe240]

Im looking to buy an clutch for my rb25, how do I know if I have an rb25 or rb20 tranny? Or are the clutches the same for these two trannys?

[Sileighty_85]

Originally Posted by d0pe240

Im looking to buy an clutch for my rb25, how do I know if I have an rb25 or rb20 tranny? Or are the clutches the same for these two trannys?

If your tranny looks like this you got a RB25 Transmission,


the NA 300ZX uses the same clutch

[d0pe240]

does the rb20 use the same clutch as the na 300zx and rb25? thanks for your help!

[GSXRJJordan]

Originally Posted by d0pe240

does the rb20 use the same clutch as the na 300zx and rb25? thanks for your help!

The internet says they're interchangeable, except for the Neo motors which use a push-type (rather than pull-type).

[godzilla_753]

Originally Posted by s14owner95

Of course, I forgot to mention that JWT also suggested my engine might be from a C35 laurel..

Also, I spoke to the guys at NIStune and they told me that if the ecu/connector is Gray then it is made by Hitachi (it also says Hitachi on the ECU's) and the blue is a JECS style (normal information I'm sure) but they were telling me that if you get an R34/C34/C35 engine like mine, but it's a non-NEO version, you can get an NEO Version ECU and use a NIStune on that, since they don't support the non-NEO version ECU.

I also made some progress on the wiring harness pics. The two gray and 1 white connector that are attached to a group of grounds and go to the engine bay are for the ABS system, so I removed that part. The blue connector goes to the "Turbo Pressure sensor" and the three wire gray connector goes to the "heated Oxygen Sensor" (I'm dumb for this one, since I pluged it in one.

But that one last big black connector, it's 8 pins. I traced all the wires, and it goes to various places:

Line Pressure Solenoid (A/T Only)
Line Pressure Dropping Resistor (A/T Only)
Control Unit Power Supply (Counter-Electromotive Current)
Control Unit Power Supply
The purple connector on the IACV
Air Conditioner

Do you guys know if these are input signals to the ECU? I obviously don't have the other end of that connector, and I can't seem to find the diagram in the FSM. (I should really just make a thread of my failure)

I didnt read through everything you posted but I do have a running NEO swap. Mine came out of a C34 Stagea RS4. I had similiar problems with identifying my ECU and such. Ill tell you right now, skylinesaustralia is gonna be your best bet. I found threads on there for all ECU serials and thats how I ID'd my own. PM me i guess if you need more help, or get in touch through email which is easier for me [email protected] Ill try to help you as best I can. I did all the wiring myself on my swap and learned alot. Its not as hard as you think it is, I would def pull off the engine wiring schematic off of the FSM and start from there. Ive been meaning to put up a how to on the wiring but Ive just been super busy with school.

[SoCalDrifter]

1. what is the best turbo manifold for a rb20(i know that you can use rb25 turbo manifolds also) top mount or bottom doesnt matter to me but im using a rb25 turbo on my rb20..

2. also my rb has this weird problem when i try to do a full u-turn to the left the engine bogs and i cant really turn that fast when its fully locked anyone have any ideas what that is?

thanks for the help

[eklips3]

Originally Posted by SoCalDrifter

1. what is the best turbo manifold for a rb20(i know that you can use rb25 turbo manifolds also) top mount or bottom doesnt matter to me but im using a rb25 turbo on my rb20..

2. also my rb has this weird problem when i try to do a full u-turn to the left the engine bogs and i cant really turn that fast when its fully locked anyone have any ideas what that is?

thanks for the help

1. stock manifold works fine, rb20 and rb25 exhaust manifolds are the same. aftermarket manifolds are a little expensive for just running a rb25 turbo.
as for top mount manifolds, Full race .. but be ready to dish out a couple thousand dollars but you wont run a rb25 turbo as a top mount .. atleast i hope you wont.

2. i have the same problem , when i turn the wheel when im stopped at idle the revs drop a bit , but it dosnt necessarily bog. i guess the power steering pump takes alot out of the motor.

[SoCalDrifter]

Originally Posted by eklips3

1. stock manifold works fine, rb20 and rb25 exhaust manifolds are the same. aftermarket manifolds are a little expensive for just running a rb25 turbo.
as for top mount manifolds, Full race .. but be ready to dish out a couple thousand dollars but you wont run a rb25 turbo as a top mount .. atleast i hope you wont.

2. i have the same problem , when i turn the wheel when im stopped at idle the revs drop a bit , but it dosnt necessarily bog. i guess the power steering pump takes alot out of the motor.

thanks im not really looking to keep the rb25 turbo just looking to see what i can do when it comes time and for #2 i dont really know what it is it only does it when it turns left not right and ya it does that to when i full lock left i can hear the rpms drop as if someone turned the AC on in a KA and if it was the power steering pump wouldnt it do the same to the other side? Anyone have any ideas what we should look for

[SoCalDrifter]

anyone have any kind of idea?

[lrb99]

can anyone send me a link for a RB20det FSM manual thanks

[GSXRJJordan]

Originally Posted by lrb99

can anyone send me a link for a RB20det FSM manual thanks

http://www.nicoclub.com/FSM/rb/R32_A...ine_Manual.pdf

[omgRWDgoodness!]

I was going to start a new thread for all this but instead I'll just post it in here. I have a few questions regarding my RB25 into S14 wiring and some other misc things. Here goes:

I was looking at my RB's upper engine harness and compared it to the pics of Sileighty_85's finished one in his Project RB thread and noticed that his did not have some of the connectors that mine does. In this first picture, I have an extra of what I call the "mini-F3" (circled in white) plug along with the usual relay, F3 and of course the ECU. What is this plug and is it necessary or can I just cut it off and tape it up?


Next, I need help identifying these plugs and whether or not they are necessary. Circled in white are the main culprits in question, the one in yellow is already plugged in to something so I'm guessing it's necessary and just wanted to know what it is for reference. Notice the completely (and cleanly) cut section of harness near the black box.


Here is a better shot of the black box piece and the cut section. The black box says "Jideco Japan" on it and when you shake it, you can hear something rattling around inside.


This is the last one wiring-wise. White plug protruding just above the rubber firewall grommet. "Mini F3" makes another appearance. Yes, my F3 plug looks like a mess because I am still in the process of re-pinning it. Does anyone know if it is possible to buy the little pins on the end of the wires separately? I'd really rather finish it cleanly by re-pinning rather than cutting & soldering just a few wires, especially with the (albeit rather minor) difference in gauge of the wires. Most are already re-pinned with the exception of about 6-7.


This is the stock wastegate actuator on my stock turbo. Obviously the nipple has been clipped and the line isn't there. I read and was told that it should go to another nipple on both the cold and hot pipes, which one is it? There is also another nipple with some cut line still on it just to the left of that. What about that? I will eventually be buying the RB25 HKS adjustable actuator (or the S14/15 SR one if it's compatible, anyone know?) but for now just going to hose clamp a small line onto there to make it work.


Lastly, here is the back of my intake manifold. I believe the large taped-off line goes into the vacuum line along the firewall, but I'm not 100% on that. How about the tiny line just to the right of it? I honestly haven't a clue where that should go.



Thanks in advance to all who contribute.

[zerodameaon]

Originally Posted by omgRWDgoodness!

where that should go.



Thanks in advance to all who contribute.

That line thats taped up goes to the brake booster iirc.

[SoCalDrifter]

anyone know what could be wrong with my rb i just put a new exausht on it and now it smokes when i start to slow down alittle bit at first i thought it was just burning the new exausht but now its still there any idea what it could be? the smoke is white and its only when im coming to a stop

[Sileighty_85]

This might help a little




No Idea on that Little F3 Looking plug must have been some special option on that R33

[omgRWDgoodness!]

Okay, so far Mini-F3 can be taped off to the side and is not used. The amp itself is not needed, only the plug which looks like should fit into my stock amp. I seem to be missing the wiper motor plug, which is probably what those two little cut wires to the extreme right of that picture near the amp are that I also forgot to mention (green and black wire).

Any idea what the rest of that cut section after the wiper amp could be? Should I be concerned or do I not need any of it? The white plug right after the firewall grommet is not present in your harness either, so that can also be taped off and not used I presume.

Another thing I didn't mention was while re-pinning my F3 plug, one of the wires that must be moved is in terminal #4 and should be solid red in color (wire is for "ignition relay power") was absent from my plug. Where it should have been was just an empty terminal. Is it possible that this wire may be another color or in another terminal? Or perhaps somehow got cut/lost from my plug? Although I find the latter unlikely since all 22 of the other wires which must be re-pinned were there, seated in their correct terminals. An interesting thing to note is I did find a solid red wire after unlooming a little bit of the cut section of the harness, but it looked much too big of gauge to have originated from the F3. After close inspection, I did not find any solid red wires originating from the ECU plug either.



And of course there's still the issue of the actuator and small intake manifold lines What exactly is the purpose of the "test point", out of curiosity?

[omgRWDgoodness!]

I've been trying to find a pinout for a Stagea motor, figuring perhaps that being the reason why I have the extra mini-F3 plug and the missing red ignition relay power wire, and apparently they're hard as hell to find. Anyway, I took this off the R33 FSM in the hopes that someone can understand it better than me and give clues on what I should look for.



Also thinking that since my wiper motor plug is missing I can cut off my KA's and solder it onto the RB's, even though the KA's looks to have 2 extra wires besides a green and a black one.

Still haven't the foggiest on the cut section of wire, which is also confusing me seeing as Sileighty_85's wiper amp and wiper motor plug are junctioned off separately from the harness as opposed to leading off the cut section on my own.

I've been digesting this ECU pinout in the hopes of finding the whereabouts of that damned ignition relay power wire (to no avail of course):

[eklips3]

Whats a safe boost level for a Rb20 with a to4e turbo ? turbo specs are .63ar exhaust side and .50ar compressor side.

boost is at 15psi , stock injectors.

im worried about the duty cycle on the injectors using the stock tune on the ecu.

[millsaps]

i have searched and searched and need to know asap. does a ka24de starter work with an rb20det? mine died yesterday after i bought my car and need to have the car ready by monday.

[eklips3]

Originally Posted by millsaps

i have searched and searched and need to know asap. does a ka24de starter work with an rb20det? mine died yesterday after i bought my car and need to have the car ready by monday.

^^^ does not work

[TOVI]

Hey guys, im installing tomei Type A valve springs on my rb25det. Just wondering if you can still use the stock cams when you use the valve springs or do i need to upgrade the cams?

Also when installing the valve springs do i need to shim the valve springs? thanks

[Pandapants]

Question about differences between rb25 and rb20 fuel rails:

I have an rb20, and it has what looks like an rb25 fuel rail. It has some kind of regulator by the #6 fuel injector, what exactly is it? The line it's connected to is a positive pressure line, same air the iacv and air regulator units receive.

Pictures for reverences:

rb25 rail



rb20 rail

[R.I.P.S NZ]

Hi,

I havn't been on here for ages but thought I'd say Hi.

[R.I.P.S NZ]

Just trying to sort out how to add some pictures to show you..........

[josephin510]

[QUOTE=R.I.P.S NZ;4202639]Hi,

I havn't been on here for ages but thought I'd say Hi.[/QUOTE

Originally Posted by R.I.P.S NZ

Just trying to sort out how to add some pictures to show you..........

I need a Rb30.. Sponsor yes?

[redline racer510]

NOpe ,no sponsors for you.
BTW let me borrow that spare rb25 block you have.

[twinspool]

Originally Posted by SoCalDrifter

anyone have any kind of idea?

Should make your own manifold, would be cheaper.

[eklips3]

Originally Posted by Pandapants

Question about differences between rb25 and rb20 fuel rails:

I have an rb20, and it has what looks like an rb25 fuel rail. It has some kind of regulator by the #6 fuel injector, what exactly is it? The line it's connected to is a positive pressure line, same air the iacv and air regulator units receive.

Pictures for reverences:

rb25 rail



rb20 rail

there is no way it can be a rb25 rail because rb25 uses side feed injectors and rb20 uses top feed. you cant use a rb25 rail on a rb20.
rb20 fuel rails on the other hand there are two types, one with the fuel dampener and one without. all the dampener does is it makes the fuel flow in the fuel rail more consistent.

[Pandapants]

Originally Posted by eklips3

there is no way it can be a rb25 rail because rb25 uses side feed injectors and rb20 uses top feed.

God I cant believe I forgot about that.

[P-Funk alot]

is there a a/c compressor that will fit on the rb25. does anyone know if there is a detailed harness write up on series 1 rb into s13 i have one that works but it looks like shit and im almost 100 percent sure that there is alot of shit missing