RB FAQ

[GSXRJJordan]

Originally Posted by ProjNightshade

I saw earlier in the thread that the S1 MAF is the same as J30, but what if you have an S2 RB? what us maf can I use?

I've been discussing this same thing with a few people - a lot of people say a S1 ECU will run a S2 engine, but no one seems to mention whether they're using a S1 MAF or S2 MAF. The diameters are the same, and they're rumored to read the same, so it's possible they have compatible internals and just different plug.

I'm interested in anyone who's done some actual testing here!

[Flaco S14]

anybody have the wiring diagram on how to install a Q45 maff on a S1 rb25?

[GSXRJJordan]

You'll need some type of correction (SAFC, ROM tune, etc), but here's the wiring diagram I found that covers most Nissan MAFS - credit goes to whoever made it.

[eh?]

S2 maf is the same as the 4th gen maxima.

[Flaco S14]

Originally Posted by GSXRJJordan

You'll need some type of correction (SAFC, ROM tune, etc), but here's the wiring diagram I found that covers most Nissan MAFS - credit goes to whoever made it.

that should work ill put it on tonight, thanks for the quick response.

[Sileighty_85]

Originally Posted by GSXRJJordan

I've been discussing this same thing with a few people - a lot of people say a S1 ECU will run a S2 engine, but no one seems to mention whether they're using a S1 MAF or S2 MAF. The diameters are the same, and they're rumored to read the same, so it's possible they have compatible internals and just different plug.

I'm interested in anyone who's done some actual testing here!

I might be doing some testing soon,

I have a S1 RB25

Other RB's im seeing are using Green Tagged J60 MAFS when the MAFS I was sent is a Pink Tagged E61. When i ran the number it came up as an "01 INFINITY Q45 AIR FLOW METER
98-99-00-01 MAXIMA-I30" I can Find Nothing else on this MAFS. It would seem
that it might be an RB Series 2 MAFS but the Series 2 are E60's

havent really gotten a confirmation it it will work though....

[ProjNightshade]

I know this is alot of text, but please bear with me and read through it. This is why i asked about the maf.

On Sunday morning 11/1 (a pretty cold morning, about 35-40) I started my car and it idled ok, but would not rev over 2000-2250 rpm before it started acting like it was bouncing off the rev limiter. It would idle for a while but would eventually die. I unhooked the battery for about 10 minutes, but that did nothing to help the situation. It cranks right up and idles every time.

The shop engine manual I have for the R33 shows that the MAF is a 5 pin plug, but mine is only a 3 pin. So I couldn't really test the MAF to see if it still worked. I did manage to test the coolant temp sensor (red 2 prong) that goes to the ECU but I saw no resistance and no continuity. Unplugging that sensor and letting the car run resulted in a crappier idle and it seemed like the car would die after I stopped revving the motor.

I have no idea what this is, but I feel like it might be a faulty coolant temp sensor and the ECU is stuck in safe mode. But obviously I really have no idea.

Do any of you guys have any ideas? Everything worked awesome until I had issues with my boost controller and unhooked it to mail it back. The boost controller was taken out earlier on Saturday. I don't know if a small vacuum leak from one of the hoses associated with that would cause this much issue or not. Please advise.

Thanks for reading guys.

[eh?]

Originally Posted by ProjNightshade

I know this is alot of text, but please bear with me and read through it. This is why i asked about the maf.

On Sunday morning 11/1 (a pretty cold morning, about 35-40) I started my car and it idled ok, but would not rev over 2000-2250 rpm before it started acting like it was bouncing off the rev limiter. It would idle for a while but would eventually die. I unhooked the battery for about 10 minutes, but that did nothing to help the situation. It cranks right up and idles every time.

The shop engine manual I have for the R33 shows that the MAF is a 5 pin plug, but mine is only a 3 pin. So I couldn't really test the MAF to see if it still worked. I did manage to test the coolant temp sensor (red 2 prong) that goes to the ECU but I saw no resistance and no continuity. Unplugging that sensor and letting the car run resulted in a crappier idle and it seemed like the car would die after I stopped revving the motor.

I have no idea what this is, but I feel like it might be a faulty coolant temp sensor and the ECU is stuck in safe mode. But obviously I really have no idea.

Do any of you guys have any ideas? Everything worked awesome until I had issues with my boost controller and unhooked it to mail it back. The boost controller was taken out earlier on Saturday. I don't know if a small vacuum leak from one of the hoses associated with that would cause this much issue or not. Please advise.

Thanks for reading guys.

You have a S2 maf and a maf/maf circuit problem. Double check your wiring. Use the diagram posted above for reference.

[GSXRJJordan]

Originally Posted by eh?

You have a S2 maf and a maf/maf circuit problem. Double check your wiring. Use the diagram posted above for reference.

Agreed, you def have a S2 MAF, and that doesn't sound like a vacuum or CTS issue. It's interesting that you couldn't measure resistance across the CTS, the FSM states where it's supposed to be (I don't remember the range off the top of my head). Sounds like a MAF problem.

[ProjNightshade]

Originally Posted by eh?

You have a S2 maf and a maf/maf circuit problem. Double check your wiring. Use the diagram posted above for reference.

I know I have a S2 MAF and I know it was wired correctly b/c it ran for 3 months with no issue at all.

I thought it was also very weird I couldn't get resistance or continuity from the CTS. Losing continuity leads me to believe that maybe the element in there failed.

I need to know how to test the 3 pin MAF and if there is something else that failed that would cause these issues. My wiriing was professionally done by Syko, and like I said, ran like a champ from first crank from the time the motor was in the car until november 1st.

How do I test the 3 pin MAF since obviously it's different than the procedure for the 5 pin?

[ProjNightshade]

Originally Posted by ProjNightshade

I know I have a S2 MAF and I know it was wired correctly b/c it ran for 3 months with no issue at all.

I thought it was also very weird I couldn't get resistance or continuity from the CTS. Losing continuity leads me to believe that maybe the element in there failed.

I need to know how to test the 3 pin MAF and if there is something else that failed that would cause these issues. My wiriing was professionally done by Syko, and like I said, ran like a champ from first crank from the time the motor was in the car until november 1st.

How do I test the 3 pin MAF since obviously it's different than the procedure for the 5 pin?

So I went back tonight armed with the diagram of what wire does what, and I got voltage with no air passing and with air passing that was damn close to manual spec.

I also retested the CTS and determined that my leads on the multimeter were making poor contact. So that came back at a reasonable resistance since its cooler than 20 deg Celsius in my garage here in TN.

Since both of those work, anyone else got any thoughts about why my ECU seems to be in failsafe?

[Rittmeister]

Just curious.

Yes, I know it wouldn't make much power, so let's get that out of the way first. However, you'd be getting the smoothness of an I6 engine, none of the overheating worries of a turbo motor, and holy crap they're cheap. Like $900 for the engine and tranny. This is for an R33 RB25DE engine/tranny, with VCT. According to the intarweb this motor is good for about 200hp at the crank.

With header, intake, cams, and some kind of tuning, I think it'd be possible to get near 200 hp at the wheels on a 2.5L RB. I have no idea the cost of parts like these, and it's conceivable that a header would have to be custom-made to fit LHD vehicles.

Don't know how hard/expensive it would be to find the harness and ECU and get it to work in the S-chassis, but it can't be too much different from the turbo Skyline engines. Mounts, driveshaft, wiring.

This is kind of just for discussion, for my own curiousity. Comments welcome.

[GSXRJJordan]

Originally Posted by Rittmeister

Just curious.

Yes, I know it wouldn't make much power, so let's get that out of the way first. However, you'd be getting the smoothness of an I6 engine, none of the overheating worries of a turbo motor, and holy crap they're cheap. Like $900 for the engine and tranny. This is for an R33 RB25DE engine/tranny, with VCT. According to the intarweb this motor is good for about 200hp at the crank.

With header, intake, cams, and some kind of tuning, I think it'd be possible to get near 200 hp at the wheels on a 2.5L RB. I have no idea the cost of parts like these, and it's conceivable that a header would have to be custom-made to fit LHD vehicles.

Don't know how hard/expensive it would be to find the harness and ECU and get it to work in the S-chassis, but it can't be too much different from the turbo Skyline engines. Mounts, driveshaft, wiring.

This is kind of just for discussion, for my own curiousity. Comments welcome.

Comment: All that work for nothing. What's so bad about having a turbo attached to the motor? It's not like RB's have turbo lag on anything smaller than a GT35, and overheating is an addressable problem.

As soon as you have that N/A RB25 installed with a custom header/intake/exhaust, you'll hate the fact that you didn't pay $1k more and get the DET.

[Rittmeister]

That wasn't my question. Your arguments are 100% right, but it really depends what end result you're looking for. This was more an "it's fun to think about" question - I tried to start a separate thread but it was moved here.

Not all of us are into big power. My car makes about 300whp on an SR/T28 right now, and that's more than I need for what I do with it. I suppose I could go to a KA but the idea of an NA straight-six really appeals to me for some reason.

[gearhead55]

I've thought about building an N/A RB also. Something like you see in Rocky Auto kpgc10s and 240Zs, ITB'd or carbed. I think it would be awesome to have something with high comp pistons and N/A specific cams but everything would have to be completely custom unless you import directly from Rocky Auto or something. I ended up deciding just to do forged pistons and i plan on going with a gt3076r, but built N/A is a cool idea...

[jspecusa]

Originally Posted by gearhead55

I've thought about building an N/A RB also. Something like you see in Rocky Auto kpgc10s and 240Zs, ITB'd or carbed. I think it would be awesome to have something with high comp pistons and N/A specific cams but everything would have to be completely custom unless you import directly from Rocky Auto or something. I ended up deciding just to do forged pistons and i plan on going with a gt3076r, but built N/A is a cool idea...

Nissan did made limited amount of N/A RB26, so I'm sure you can order the stock N/A piston from Nissan.
but less money, I would build a RB25DE neo with ITB instead due to VVL and RB25DE neo cost less then 1k.
good luck,

sam

[eh?]

Originally Posted by jspecusa

Nissan did made limited amount of N/A RB26, so I'm sure you can order the stock N/A piston from Nissan.
but less money, I would build a RB25DE neo with ITB instead due to VVL and RB25DE neo cost less then 1k.
good luck,

sam

No VVL on any RB ever.
An AL block'd RB with a VVL head would have been awesome.

[jspecusa]

RB25DET vs. RB25DE NEO - HybridZ

[eh?]

Originally Posted by jspecusa

RB25DET vs. RB25DE NEO - HybridZ

Sorry man but this is a neo head


Virtually the same as the DET head but one can tell the DE intake ports are smaller.

[deep in silvia]

Could any one please put a list together of all the parts a person would need to add power steering to there s13 if they have a RB25det swap?

ALSO

Could any one please put a list together of all the parts a person would need to add A/C to there s13 if they have a RB25det swap?

Thanks

[Silviaracer1988]

ok so im trying to research doing a rb25det swap in a s14. now all i see over this thread use syko, so with that said thats what im going to use. but at the bottom of the conversion page it says "
This conversion kit is designed and sold for off road use only!

Like the SR20DET, the RB25DET and RB26DETT engines are not legal for use on any pollution controlled vehicle!!"


so i live in pittsburgh, pa and we have emissions. now this has been answered before i bet, but what would i need to make it legal for that? please dont make fun or ask me to search further or anything. just looking for help. thank you

[GSXRJJordan]

Originally Posted by deep in silvia

Could any one please put a list together of all the parts a person would need to add power steering to there s13 if they have a RB25det swap?

ALSO

Could any one please put a list together of all the parts a person would need to add A/C to there s13 if they have a RB25det swap?

Thanks

Sure, although these are pretty straight forward.

RB25DET's usually (almost always) come with a power steering pump. You need the AN fitting adapter for the rack and the pump (I don't have my notes with sizes at this computer), an AN line connecting the two ($80 or so for all of this from Hung @ Baker Precision, he knows the sizes), so that takes care of the high pressure side. Then you need an AN fitting for the low pressure side of the rack, and run a -6AN line up to the cooler or reservoir if you're not running a PS cooler. From the reservoir to the pump is -10AN (5/8") low pressure, you can use AN line or heater hose.

A/C is slightly more complicated, and relies on you having a working A/C system in the S13 (since the Skyline stuff never comes over). Get a RB25 A/C compressor (most motorsets come with them since all R33's it seems had A/C) and have an A/C shop make you some lines to go to the factory S13 ports. Shouldn't be very expensive if your S13 A/C is workable.

[ThatGuy]

Originally Posted by Silviaracer1988

ok so im trying to research doing a rb25det swap in a s14. now all i see over this thread use syko, so with that said thats what im going to use. but at the bottom of the conversion page it says "
This conversion kit is designed and sold for off road use only!

Like the SR20DET, the RB25DET and RB26DETT engines are not legal for use on any pollution controlled vehicle!!"


so i live in pittsburgh, pa and we have emissions. now this has been answered before i bet, but what would i need to make it legal for that? please dont make fun or ask me to search further or anything. just looking for help. thank you

You can not make it legal, federally.

The engines were never offered in the United States, they are not legal. End of story.

Good luck.

[Silviaracer1988]

damnit. gonna have to stick with the ka til i move south carolina

[Silviaracer1988]

forgot, thanks for the quick answer

[Silviaracer1988]

oh wait you live in NC. whats the deal with cars there. my girl and i are talking about moving to charolette or close to that area for her work. and i want to know what i can do with my 240. cause i want to do a rb25 swap but i dont want to do something that will prevent me from having a dd.

[ThatGuy]

FEDERALLY illegal. That means nationwide. Meaning they are not legal in ANY state.

I do not run an illegal engine, nor do I plan to. NC has different emissions laws for different areas. With my car being OBDI, I wouldn't have to worry about emissions checks in most areas, not even visuals.

Then again, I am also Military, so my car doesn't even require an inspection in my area.

[BIGGJERRYC]

RB motors dont even fit in 240sx's.... i dont know where you all got your information....

[PacificDrift_Nick]

Originally Posted by BIGGJERRYC

RB motors dont even fit in 240sx's.... i dont know where you all got your information....

why dont go crawl back under the rock that you came from and STFU!

[foreverdark]

Originally Posted by BIGGJERRYC

RB motors dont even fit in 240sx's.... i dont know where you all got your information....

Really dude!!!! Really???