Rb25 Block Q's

[FelixTRX]

Hey all,

I've been told that the 4WD Stags have a different RB25DET block compared to the R33 Skyline's.

Is there any truth to this?

The reason I'm asking is because I'm having nasty thoughts about a RB30DET swap. Getting the labour for free, just paying for parts but I'm told the RB30 block won't bolt up to the Stag's 4WD sump and gearbox (auto).

Cheers, Greg.

[mitchy_]

25 block is the same, you'll just probably need a custom sump for the RB30.

how did you manage to score free labour? theres a fair bit involved, and the parts for a 30det build arent cheap either if you are going to do it properly.

[unique1]

The rb25 block in the stagea is not the same as the r33 gtst ones at all, the stagea ones have the 4wd sump bolt holes and the 2wd holes, but the gtst ones only have the 2wd sump holes. If u are going rb30 bottom end in the stagea u will need the adaptor plate that they use for rb30s into gtr's (the stagea sump is a gtr sump) and they are about $500 and require a fair bit of machine work to fit from what ive been told.

Edited September 23, 2007 by unique1

[Duncan]

hmm but the only difference between stagea and gtst rb25 block is the bolt holes for the sump, and they don't matter since they both have the holes for a rwd.

Any rb30 block going into a 4wd needs the adapter plate so that has nothing to do with the rb25 block either?

Not sure how well the standard auto would work with an rb30 block.....don't know if it will handle the extra torque well.

[FelixTRX]

Was only planning a blueprinted RB30E bottom end and keeping the boost capped at 10psi, so nothing drastic.

Mate is doing the labour (with me helping and learning) because he just wants to see a RB30DET in the bus and kill some HSV's!

Have seen these adaptor plates on Ebay, but surely it's as simple as getting a RB25DET and RB26DETT sump gaskets, overlaying them, then getting a 10mm steel adaptor cut to suit. I'm a boilermaker with access to everything so that can be done at a fair price.

Are there any online shops that sell the adaptors so I know exactly what I'm looking at?

Cheers, Greg.

[unique1]

the rb26 bolt holes are studs and bolts which are heaps bigger and stronger (about m12-14 roughly) than the rb30 m8 bolts, they support the sump and front driveshafts remember and i wouldnt trust m8 bolts holding that heavy diff/sump setup personally. The adaptors join the sump adaptor to the girdle bolts and tie it into the block to strengthen it all up, and i think they tap bigger threads to use larger bolts but not 100% sure on that.

for the power u would make on 10psi i wouldnt even bother with the rb30 idea its simply not worth it when u factor in all the custom work and hassles involved, buts that upto you

Edited September 23, 2007 by unique1

[FelixTRX]

I'm learning more and more that this isn't going to be as simple as I thought it might have been!

Might can the RB30DET, or put it in my 31!

Anybody ever bothered measuring up for a RWD conversion with a VQ45???

I know they fit in a 31 so logic would say it would fit in a Stag!

[Stinky Rooster]

....for the power u would make on 10psi i wouldnt even bother with the rb30 idea its simply not worth it when u factor in all the custom work and hassles involved, buts that upto you

I always thought that the whole point of the RB30DET was the fact that it made a crapload more torque than the 25 & 26?

Thus, doesn't it make sense that you would not need as much boost unless you were one of these meatheads that want to drive around in a 600hp soccer mums car?

[FelixTRX]

Agreed, the whole point of the RB30DET is torque, which in a Stagea, is really what you need!

[unique1]

Yes the rb30 will make more torque but is it worth the hassle/cost to do when u wont have that much of a gain in performance, and im not sure the auto box would like the added torque at all, but as i said its just my opinion. Its the 4wd side of things that make it harder, in a 2wd car its simple.

Convert the stagea to 2wd and use a rb25 sump and gtst 5 speed box and u will have no issues with a 30 bottom end and lose some weight as the tranfer case and front sump/diff/axles are bloody heavy buggers

Edited September 25, 2007 by unique1

[FelixTRX]

Yeah, going RWD would be fun but my wife loves the ability to have AWD when needed. After the Subaru Liberty, she's stuck on the 4 paw grip!

Would the R33 auto box work in the Stag?

[HR31DRFT]

Hey thought i'd say somethin...

I'm am currently building a 30/26...

My block is coppin some $$$ love.

Grub screwed, crank collar, tomei pump.

Reset all the bearings and re-line bored.

Forged this forged that

7ltr sump etc so much more :-(

I started this build and found its not cheap !!!!!!

But still moving forward knocking off bits off the list.

I'm lookin at around 20g for completion with the race ported 26 head, autronic etc.

But will be killer in my 31 will bang some pics up or create my own build thread.

Sorry no jacking intended bud, just a insite of my build n costs.

[captinsane]

tyeah - i was thinking about this also - but have decided to leave it until i have a house and 5 yeasr in which to slowly the 30 blcok to perfection...