Series II Motor vs Series I

[DezertEagle]

Hi all

I've purchased an 'RB25DET' through my mechanic and when it cam in he informed me it was a 'Series II RB25DET'

He said they would produce more more power then a Series I

I was just wandering how much more? And what differences does it have over a series I motor to make it better?

Thank you in advance.

[Duncan]

there is no difference between the series I and series II motors.

There are some differences outside the motors:

Different coil packs and ignitors

Different ECU from 95 onwards

Different Turbo in series 2, spools up more quickly.

Are you sure about ur mechanic?

[predator]

Just the stock ECU is a little more intelligent.. it also has direct fire ignition coils rather than an ignitor pack. I don't think actually makes it any better though(??) just the coils are more expensive per piece. By the time you throw out the stock ECU and turbo it matters little.

Otherwise as far as I know, a s2 WILL NOT make any more power... as the basic engine block, pistons, cams, rod are exactly the same. The later s2 turbos are meant to be different exhaust wheel but again that doesn't make much difference in terms of power or anything like that.

Its an interesting one though. Maybe somebody out there can be more specific...

Also likely that a series1 RB25DET is more likely to be older and worn compared to a newer rb25det. Newer engines generally make better power just because of the km and age.

P.S. and SNAP with Duncan

[DezertEagle]

Duncan, it's John from UAS, my car is there at the moment and the engine went in today. I trust he has good judgement with these things.

So it's possible I have a better turbo too now aye, very interesting

[Duncan]

lol pred

Well John knows his stuff so he must have been talking about one of those differences. Did you ask him about the specific thing which makes it better? I reckon the one thing that would make a real difference is the younger engine, prolly lower klm, so prolly better compression, so prolly more power...

There's some disagreement about whether the SII turbo is "better", its got a plastic wheel instead of steel and some people think that means it will last less time with extra boost.

[DezertEagle]

I'm calling him tomorrow morning to discuss my clutch options, I'm getting a slightly better then factory one as he says my factory one won't last very long anymore hehehe

Will ask him about the differences and keep this thread updated!

[Pandaemonaeon]

The Series 2 also has Variable Valve Timing.

[dojobi]

The series 1 has VVT too. Both R33 s1 and 2 have stepped VVT, whereas the R34 has continuously variable VVT. Maybe that's what you were thinking of, Pan?