Can you use a S2 ecu on a S1 motor?

[240z4u]

I think you can. Help me out? Thanks guys!

Evan
Modified by 240z4u at 7:37 PM 2/16/2009

[Coolwhip]

The S1 ECU can work on both series 1 and 2 motors. However the S2 ECU is limited to the S2 motors.

[240z4u]

Thanks Ricky!

[lilskyline240]

Thanks Ricky!

at least we found the answer to the question me and u were talkin bout lol

[Carl H]

iirc its actually the other way around...the s2 ecu will run an s1 engine but for whatever reason the s1 wont run the s2.its been a while tho.

[Coolwhip]

I buddy here is running an S1 ECU I sold him on his S2 motor... Runs like the champ.

Haven't had the oppertunity to try a S2 ECU on a S1 motor personally however, I've seen cases that it was a no go for the S2 ECU on S1 Motor.

There was a thread that had inside shots of both ECU's and this discussion went on before. Wonder if I can dig it up.

[Coolwhip]

Find it!zerothread?id=287704

[Nissan2367]

The ecu you had Evan was a s2 wasnt it? It ran my car and it has a s1 in it...

[Coolwhip]

The ecu you had Evan was a s2 wasnt it? It ran my car and it has a s1 in it...

interesting, please do confirm

[eh?]

So it's been a year with no definite answer? lol.The one way interchange doesn't make sense.

[Coolwhip]

Well I have a Series 2 ECU (G8) in stock, if anyone with a Stock Series 1 RB25 is willing to try out the ECU on their car, let me know, I'll foot the shipping to get this cleared up.

eh? is right, this should be a vice versa type thing.

[240z4u]

Ricky, I know an Series 2 ecu will run an Series 1 motor. The one I have did it. The guy who I sold my spare ecu to said that he had an S2 ecu on an S1 and after a while It cooked the ecu.

Evan
Modified by 240z4u at 8:49 AM 2/17/2009

[matafied]

iirc its actually the other way around...the s2 ecu will run an s1 engine but for whatever reason the s1 wont run the s2.its been a while tho.

this has been true in every rb25 that i have ran into, lets just say i have had some ecu woes lol

[Coolwhip]

hm, strange. As actual user experience has varied with the whole mix-n-match ecu and motor.

Evan, I guess the frying of ECU is varying as well, as the S2 motor I'm aware of running a S1 ECU has been running with it fine for over a year+ now, don't know if the issues lay in the way the harness was converted or what?

[240z4u]

hm, strange. As actual user experience has varied with the whole mix-n-match ecu and motor.

Evan, I guess the frying of ECU is varying as well, as the S2 motor I'm aware of running a S1 ECU has been running with it fine for over a year+ now, don't know if the issues lay in the way the harness was converted or what?

Ricky, this dude was running a S2 ecu on an S1 motor. Ill clarify my post.

Series 1 series 2
Modified by 240z4u at 8:49 AM 2/17/2009

[Coolwhip]

opps, I guess I was reading too much back and forth with the posts and perhaps had messed it up.

(btw, could we as a board start replacing the use of S1 and S2 with Series1 and Series2? As the 2 digit identifier is unsearchable via NICO search function)

[lilskyline240]

didnt u use that s2 ecu i bored from u on keiths series 1?

[Carl H]

in theroy a series one ecu should work on a series 2 engine and vice versa...however there have been reports that it does not work.all sensor signals are the same only difference is integrated ignitors on the coils but even then the triggers are the same.

[240z4u]

^yes^

[Coolwhip]

+1, I agree Carl

Yet if anyone wants to be a guinie pig to try this out speak up :P

On a side note, aftermarket units get around this feat with one box, iirc the PowerFC has only one R33 RB25 unit listed, eh?

[eh?]

+1, I agree Carl

Yet if anyone wants to be a guinie pig to try this out speak up :P

On a side note, aftermarket units get around this feat with one box, iirc the PowerFC has only one R33 RB25 unit listed, eh?

Yes just one box, same with aem.However the aem had a different ignitor dwell time for R33 RB25 and R34 RB26. Knowing the R34 RB26 coils are the same as R33 RB25 s2 coils, I brought it up to the aem engineers and I believe they updated the calibrations to reflect that in the R33 coil setup. So one has to wonder if the S1 and S2 coils indeed require different dwell times and the stock ecus are programed with different dwell times. Would it make a difference, I doubt it.

[matafied]

in theroy a series one ecu should work on a series 2 engine and vice versa...however there have been reports that it does not work.all sensor signals are the same only difference is integrated ignitors on the coils but even then the triggers are the same.

i have got a series 1 ecu to work on a series 2 motor but only after grand national coil conversion with igniter

[Coolwhip]

i have got a series 1 ecu to work on a series 2 motor but only after grand national coil conversion with igniter

As in, "only after" the coil conversion or "this was after" the coil conversion?Had it ran with the S2 coils?

I think we're traveling further down the rabbit hole

But more actual insight like that is what we need!!! I'm liking this thread!

[Carl H]

i would think that even if the coil dwell time was different it still would atleast fire, but perhaps not be optimal...right?

[eh?]

i would think that even if the coil dwell time was different it still would atleast fire, but perhaps not be optimal...right?

Maybe not optimal and the off chance of buring up the coils or IC's in the ecu. What also complicates the matter is there are 15 MT&AT ECU P/N's for the R33 rb25.

[240z4u]

Fact; I have run a Series 1 motor with an S2 ecu.

However, its hard telling the long term effects. I think the reason this guy said it cooked his S2 ecu was because he basically stacked ignitors. Now, the ignitors on the series 2 are built into the ecu. So ignitor firing ignitor instead of directly to a coil. I am willing to bet there is some sort of impedance mismatch that eventually kills the ignitor in the series 2 ecu.

If the impedance is too low, it should be as simple as adding 6 resistors inline with the coil wires to raise it to a reasonable level.

Evan

[eh?]

No ignitors in the ECU but IC's that control dwell and whatever. I'm not sure of the whole story but he could have fried those.

[Carl H]

or he tried to run a set of series 1 coils with a series 2 ecu...without an ignitor.that would fry drivers with the quickness.

[matafied]

As in, "only after" the coil conversion or "this was after" the coil conversion?Had it ran with the S2 coils?

I think we're traveling further down the rabbit hole

But more actual insight like that is what we need!!! I'm liking this thread!

only worked after the conversion

or he tried to run a set of series 1 coils with a series 2 ecu...without an ignitor.that would fry drivers with the quickness.

oh and ive done this also carl this is what one looks like after that happens

yea i always thought this was cut and dry but i guess not

[240z4u]

or he tried to run a set of series 1 coils with a series 2 ecu...without an ignitor.that would fry drivers with the quickness.

Carl, he was using an ignitor.