RB25 240SX Swap and OBD

[Zeifer]

So I'm searching for a '98 240SX, and planning on dumping an RB25 in it. Obviously that raises some problems with OBD and all that.

I've run a few searches on this forum and found little to nothing that would help me figure this out.

I live in upstate New York and I was wondering how to get an RB25 swapped 240 through inspection, since the mechanics I know that inspect cars will just plug in the OBD tester and pass/fail based on what it says. I know that the RB motors don't have OBD equipment. Is it possible with OBD-II, or do I need get a '95 240SX for OBD-I?

What do I need to do to pass it with OBD-II (if possible) or OBD-I short of moving to a new state? I was under the impression that as long as there are no CELs I'd be golden. But I don't think that's true. I looked at New York's smog testing and I don't have as strict standards as I would if I lived in NYC, but I still think I'm screwed.

(My only problem with the '95 is I don't know if the S15 front-end conversion [which is part of the grand-plan] will work on it. I assume it will, provided Nissan just swapped out parts when going to Kouki and kept the bolts and everything the same.)

Any (legal lol) help would be appreciated.

[Zeifer]

Update: Thanks to the great article from NICOClub's own Greg Childs and Matthew Moody (http://www.nicoclub.com/archives/the-fa ... tes-1.html), I've stumbled across JK Technologies who can get the OBD system hooked up and ready to pass all tests.

It'll probably cost a good chunk of change though. I think it'd be worth it. An RB25 swap is far down the road anyways.

[Carl H]

no skylines were equipped with obd2 compliant ecus...
that document outlines the mechanical modifications required for conversion to us spec.

[Zeifer]

no skylines were equipped with obd2 compliant ecus...
that document outlines the mechanical modifications required for conversion to us spec.

I'm aware of the lack of OBD-II on the RB motors. However since R33's were imported via Motorex and the biggest concern there seemed to be the crash testing, is there a way I can get a waiver or something that will allow the engine swap to pass NYS inspection? That'd obviously be cheaper than JK's OBD convert.

[Carl H]

nope. in theory if it dint come in a us car its 'illegal'.
find a 95 or find a dirty inspector.

[Zeifer]

nope. in theory if it dint come in a us car its 'illegal'.
find a 95 or find a dirty inspector.

I was told by a mechanic that as long as all the sensors and emissions equipment is in place it should work. However, I was under the impression that you had to swap the ECU with one compatible with the RB motor. Can you clarify on this issue? And what are the differences that allow OBD-I to allow that engine but not OBD-II?

Also, since car manufacturers release cars a year early (selling the "all-new 2012 BlahBlah in late 2011"), wouldn't a '96 240SX manufactured before Jan 1, 1996 (according to EPA laws) have OBD-I?

I've tried searching the issue but it seems that instead of answers I get threads of people trying to prove the other wrong and one-upping each other.

And will the '95 accept the S15 front-end conversion? I'm almost certain it will considering it's still an S14.

[Carl H]

It might pass visual inspection but it def wont pass the actual scan without a functioning obd2 port.
you would have to find an obd2 compliant ecu to run the motor, only one that might do it without a major headache would be the 96 z32 na ecu, but it would have to be retuned and you'd have to add in all the emissions equipment that came on the z for it to pass.

even if a car was built in a different year than the car was sold as (ex: my chassis is an early 94, but is a 95 MY) the inspection is still based off of model year...not actual build date.
even the 95 chassis had an obd2 capable ecu (altho not 100% in compliance).

as far as the s15 front end...wont matter.
glass is glass and the chassis didnt change, just the fenders/hood/rad support.
slap on a 97-98 rad support and roll with it.

[Zeifer]

Alright, so '95 it is. Thank you for all the help Carl. Glad I didn't up and buy the first '98 I saw now.

What do I need to do for OBD-I?

[TimTurboZ]

Research more about you want to do and in the meantime find someone to do an illegal smog, considering there is no smog equipment on the motor. In theory if you run a cat and it's running excellent an RB could pass a smog test thru the exhaust IDK New York smog laws but based on the population I assume it's just as terrible as California.

I'm sure if you googled s14 with s15 front or s14.5 you could have found a thread on numerous sites showing a person's step by step process of converting their front end.

Car being OBD 1 or 2 just effects what wires need to go where to make the RB run. The vast majority of S14's are 95's but I'm sure plenty of people with OBD2 equipped cars have illegal smogs done.

[Zeifer]

Research more about you want to do and in the meantime find someone to do an illegal smog, considering there is no smog equipment on the motor. In theory if you run a cat and it's running excellent an RB could pass a smog test thru the exhaust IDK New York smog laws but based on the population I assume it's just as terrible as California.

I'm sure if you googled s14 with s15 front or s14.5 you could have found a thread on numerous sites showing a person's step by step process of converting their front end.

Car being OBD 1 or 2 just effects what wires need to go where to make the RB run. The vast majority of S14's are 95's but I'm sure plenty of people with OBD2 equipped cars have illegal smogs done.

This is why I get confused lol. Someone says I need an OBD-I car and someone else says OBD-II will work.

The smog laws are more lenient in New York than California, and even more so because I'm upstate. A smog check isn't a problem (I know a guy who won't even do the smog check), but running the computer through an OBD-II (if the car is OBD-II) check is absolutely required in New York to get an inspection sticker.

From the quote highlighted in bold, these questions are raised:

Do I need a different ECU to run an RB motor? If no, I'm guessing I will need to have it tuned to accept said RB.

If I need a different ECU, am I better off getting an OBD-I car? Or will I need to swap the ECU there too?

And why does OBD-I/II matter if the inspection tester is plugged in if all the sensors are hooked up and I'm running a catalytic converter? Does it just not communicate correctly with the motor because it's swapped? Or will it be perfectly fine no matter what?

As you can see, my concern is only the OBD test, not the smog testing and safety inspection.

[Carl H]

just get a 95 chassis if you're worried about it, plain and simple.
obd2 or obd1 has nothing to do with wiring, they wire up the same just obd2 chassis has more wires which arnt used when the swap is done.
if you're in BFE ny then chances are your inspection is lenient.

the short of it is if you buy a post 96 car REGARDLESS of make or model it will have to be obd2 complaint to pass state inspection.

[Zeifer]

Alright, thanks. Will I still need to swap the ECU, or just tune it? (I come from an old school carbureted background lol.)

[Carl H]

just drop it in stock...no need to tune off the bat.

[Zeifer]

just drop it in stock...no need to tune off the bat.

True, but the goal is ~400hp at the wheels. And I'd like to get it all done instead of taking the motor out again. Besides, who knows what kind of problems a used motor could have. I want to take a different approach and get it as efficiently as possible and increase engine durability at the same time. Because let's face it, I'm gonna wanna beat the hell out of this thing when I'm not babying it, and I'm definitely planning to get some serious drift practicing in.

Thanks for the feedback and help man. I really appreciate it.

[OutToWinPAHC]

hey ODB2
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