Neo Vrs R33 Rb25 Piston And Rod Comparo With Pics.

[Simon-S14]

just awwwwwwsome when a BIG name company lies to you just to make a buck!

maybe they just dont actually know and assume it will work. either way poor form.

666DAN: wanna pull one apart for us

[KiwiRS4T]

My first Stagea was a late model Series 1 but had a Neo n/a engine - it was quite zippy. When I got my next Stagea another Series 1 but a turbo version (with the S2 R33 RB25DET) I was very disappointed how little more go it had than my n/a Neo version. It was only when I started spending some $$ on it that it started to get up and go.

Factory flywheel figures (just for comparison):

RB25DE 139.75kw

RB25DET 172.84

RB25DE (Neo) 147.10

RB25DET (neo) 205.94

So an R33 should be able to be converted to a Neo just by swapping the rods and pistons and the head and manifolds - although no doubt a six boost and FF plenum would do even more!

[Simon-S14]

i wanna get my hands on a NA neo motor and put a set of GTR ITb's on it and have exposed trumpets and run a 6 into 4 into 1 extractor set up... raise the limiter to 8500 and tune it on E85 with some timing cranked into it... now that would be awesome in a light car

[045HOW]

maybe they just dont actually know and assume it will work. either way poor form.

as a major performance workshop i dont see how they could think that, buit obviously there are idiots in all places.

my money is on them wanting my money.

but i wont name them and leave it at that.

[JonnoHR31]

so does anyone know what sort of compression one would get with a standard neo head on a standard 30e block. 33 25 head gives ~ 8.3:1 with ~62cc combustion chambers and according to the 30det guide neos have a 50-51cc combustion chamber. i know its not the correct way to figure it out but using that it looks like you'd get just over 10:1?

[045HOW]

i would also like to know what compression ratio i would get putting neo pistons into a series 2 RB25DET. can anybody calculate this?

[R32Abuser]

Here is a compression calculator I made in excel to check my compression on my RB30...

feel free to use.

You'll have to find out all the specs of the pistons, compression height etc etc yourself though. Im not making it that easy for you!

Cheers

P.S. Wouldn't hurt to double check all the calcs. Sydneykid seemed to think there was no problems with it though...

Static Compression Ratio Calculator.xlsx

Edited August 15, 2011 by R32Abuser

[Legionnaire]

Would be good to see what the 25DE is actually equipped with as well

Had both heads for direct comparo half a year back, so I may forget something, but basically it's like this:

Ports on DE neo head are smaller than on DET head

Valves are different

Rods are same as R33 DET rods. Pistons are different to any other RB motor I've seen, nothing special though.

I've also done chamber volume measurement on a DET Neo head, they were 62cc chambers in my case.

[dori34]

Would be good to see what the 25DE is actually equipped with as well

it uses the same conrods as R33 GTST, same thickness etc

the only photo i have on me atm, i have more on my home pc and will try get them tonight.

[The Mafia]

The RB25DE pistons just have a little more top on them to raise the compression further. I've got a RB25DE block and pistons here.

From what I have noticed - The NEOs use GTR rods. They have more meat at the base of the rod, so they are stronger.

[GTRsean]

The oil cooling channels in the neo25 piston crowns are the same as the 26 pistons' design!