R32 Rb25 Engine Rebuild

[sic200]

hi guys,

a mate of mine has got a r32 gts-t with an n/a r32 rb25 in it.. that has been det'd in japan, apexi turbo, gtr intercooler, tomei reytec, etc. anyway, number 1 and 3 cylinders are goneski. questions we/i have is:

what pistons doest the non vct r32 rb25 use? same as r33 rb25?

what headgasket do you use? same as r33 rb25?

from what i can tell, the head is an rb20 unit, has rb20 intake plenum, etc, but block has rb25 stamped into it.

i told him to try and source a rb25 turbo block because of oil squirters etc, considering he's gonna be thrashing the crap out of it on the track.

his build will be consisting of something like forged pistons/rods, metal headgasket, and reco'd /balanced assembly, std everything else, cams, etc blah.

thanks for any help.

[skylinekid]

dont be a cheap bastard and just got buy an r33 turbo motor... simple

[sic200]

dont be a cheap bastard and just got buy an r33 turbo motor... simple

eerr, yeh, no problem money bags, clearly stated we are rebuilding the engine with forged internals, so why the f**k would i go and buy a stock turbo motor? if your answer is to fix shit with 2nd hand rubbish then go ahead, i'd just like to know what pistons and headgasket will suit the engine.

[infamous_t]

lol you just bagged him out for the same advice you gave your mate... classic.

I don't know what kind of power your/hes aiming for, but I reckon if your gonna spend the money on a 'full' rebuild, maybe go a 25/30 hybrid... considering RB30E block can be had for around $100 and the r32 25de head will bolt on, its not such a silly idea.

[sic200]

lol you just bagged him out for the same advice you gave your mate... classic.

I don't know what kind of power your/hes aiming for, but I reckon if your gonna spend the money on a 'full' rebuild, maybe go a 25/30 hybrid... considering RB30E block can be had for around $100 and the r32 25de head will bolt on, its not such a silly idea.

wtf? i told him to get a turbo block, not a whole engine... thought about the 30 combo, but he doesn't like the idea... pparently a "bogan" motor... each to there own, personally i'd be building a 30. but then again, not to sure i'd like the idea of a vl engine in my car so anyone actually know about these engines? if we get a 25det block, will the 25 non vct head bolt on? and can we just use normal 25 forgies?

[nizmo_freek]

wtf? i told him to get a turbo block, not a whole engine... thought about the 30 combo, but he doesn't like the idea... pparently a "bogan" motor... each to there own, personally i'd be building a 30. but then again, not to sure i'd like the idea of a vl engine in my car so anyone actually know about these engines? if we get a 25det block, will the 25 non vct head bolt on? and can we just use normal 25 forgies?

RB30 a "bogan motor''? your mate has issues!

And you do know the rb30 in vl's were buit by nissan and not holden? so technically you will still be using a nissan motor!!

[Roy]

RB30s are lazy low reving truck motors for people that love their Winnie Blues up the sleeve of their medium Bonds shirt

With regards to the rebuild. I would beinclined to go DET block. There are plenty around with so many woners going RB30, they have the squirters and are a more known quantity. But the RB30s dont use oil squirters and they dont have a problem so perhaps they are not that critical so wouldnt be spending too much money on another block. Especially oif the car already has an RB25 engine number on its rego papers, you dont really want to be inviting the registry bodies to be inspecting the car with a engine swap and a engine number check for rego

[BHDave]

I believe Sydneykid has added squirters to some of his 30DET engines though so it'll be achievable in the 25DE block. Failing that, ceramic coating on the pistions is another alternative.

Other than that, build it like you would any other 25DET. I'd be guessing on the head gasket compatibility between different rb25's though. It may be worth having a read through the rb30 section and finding out what gasket the guys running 25DE heads use.

[sic200]

RB30s are lazy low reving truck motors for people that love their Winnie Blues up the sleeve of their medium Bonds shirt

With regards to the rebuild. I would beinclined to go DET block. There are plenty around with so many woners going RB30, they have the squirters and are a more known quantity. But the RB30s dont use oil squirters and they dont have a problem so perhaps they are not that critical so wouldnt be spending too much money on another block. Especially oif the car already has an RB25 engine number on its rego papers, you dont really want to be inviting the registry bodies to be inspecting the car with a engine swap and a engine number check for rego

i agree, rb30's are lazy, nothing like a high revving rb.. your advice is very appreciated, we'll certainly look into a det block, had no idea the 30's dont use oil squirters, so maybe its not that critical? but i guess while its apart, why not.

[blind_elk]

wtf? i told him to get a turbo block, not a whole engine..

If you are going to buy the block, then you might as well get the whole engine.

Anyway, the RB25DE and RB25DET will have different pistons, because of the different C/R.

If the current engine is a RB25, then the head will be a RB25 - there's no way (well, very little way) a RB20 head will work on a RB25 block, due mainly to the massive difference in bore diameter.

[nizmonut]

RB30s are lazy low reving truck motors for people that love their Winnie Blues up the sleeve of their medium Bonds shirt

With regards to the rebuild. I would be inclined to go DET block. There are plenty around with so many woners going RB30, they have the squirters and are a more known quantity. But the RB30s dont use oil squirters and they dont have a problem so perhaps they are not that critical so wouldnt be spending too much money on another block. Especially oif the car already has an RB25 engine number on its rego papers, you dont really want to be inviting the registry bodies to be inspecting the car with a engine swap and a engine number check for rego

The last time i looked i didnt see any rb20's pulling 300kms an hour. or doing 4wd doughnuts

and i dont think any officer from the nation vehical registery center is going to crawl under your car to check what block your running....even the guy at the garage doing the 6 monthly saftey check wouldnt know what the f**k block was sitting under your twin cam head unless you tell him

as for your rb30e block i used one for my conversion, put it straight in at 300,000 plus kilometers,

pulled it out 120,000 kms later and still had hone marks down the bore...to replace an oil seal of all things

that same block now has a rb26det set up bolted to it and on thursday pulled 401 horse at all four wheels and 388 foot pounds of torque at all four wheels.

using a na rb30 block in a turbo set up isnt a problem, here's the proof

http://www.youtube.com/watch?v=C4pm7OvTqco

Edited May 11, 2008 by nizmonut

[sic200]

If you are going to buy the block, then you might as well get the whole engine.

Anyway, the RB25DE and RB25DET will have different pistons, because of the different C/R.

If the current engine is a RB25, then the head will be a RB25 - there's no way (well, very little way) a RB20 head will work on a RB25 block, due mainly to the massive difference in bore diameter.

come and show me how a rb25 inlet plenum will bolt onto the head, and i'll agree. its a 20 head, has a 20 plenum on it, only diff is the valley cover, has the rb25 one, that's how it came.. block is definately a rb25. is a whole engine as cheap as getting a block? hmmm, if you can supply one, he'll get one for sure. na rb30 seems the go if your on a tight budget, getting good power out of it....

[sic200]

The last time i looked i didnt see any rb20's pulling 300kms an hour. or doing 4wd doughnuts

and i dont think any officer from the nation vehical registery center is going to crawl under your car to check what block your running....even the guy at the garage doing the 6 monthly saftey check wouldnt know what the f**k block was sitting under your twin cam head unless you tell him

as for your rb30e block i used one for my conversion, put it straight in at 300,000 plus kilometers,

pulled it out 120,000 kms later and still had hone marks down the bore...to replace an oil seal of all things

that same block now has a rb26det set up bolted to it and on thursday pulled 401 horse at all four wheels and 388 foot pounds of torque at all four wheels.

using a na rb30 block in a turbo set up isnt a problem, here's the proof

http://www.youtube.com/watch?v=C4pm7OvTqco

what compression ratio are you running? seems to make plenty of power, doesn't sound like much torque but, what's a 2.5 / 2.6 make generally?

[nizmonut]

what compression ratio are you running? seems to make plenty of power, doesn't sound like much torque but, what's a 2.5 / 2.6 make generally?

it's compression ratio is 8.4 to 1 standard gtr is 8.5 to 1 25det is 9.5 to one,

everything is standard affair, ive used a multilayer steel head gasket from hks along with z32 afm and chip. this is pretty much the only aftermarket things on it engine wise.

yes it is low torque but it's only running 8 psi too. so theres plenty of room for improvement.

388 at the wheels, some dude on the uk forum worked it out at around 25% loss through the gtr drive train so at the fly close to 480. ft pound.

Edited May 11, 2008 by nizmonut

[sic200]

it's compression ratio is 8.4 to 1 standard gtr is 8.5 to 1 25det is 9.5 to one,

everything is standard affair, ive used a multilayer steel head gasket from hks along with z32 afm and chip. this is pretty much the only aftermarket things on it engine wise.

yes it is low torque but it's only running 8 psi too. so theres plenty of room for improvement.

388 at the wheels, some dude on the uk forum worked it out at around 25% loss through the gtr drive train so at the fly close to 480. ft pound.

holy shit, that's awesome for 8 psi.. what turbo/s you running to get that?

[Adriano]

come and show me how a rb25 inlet plenum will bolt onto the head, and i'll agree. its a 20 head, has a 20 plenum on it, only diff is the valley cover, has the rb25 one, that's how it came.. block is definately a rb25. is a whole engine as cheap as getting a block? hmmm, if you can supply one, he'll get one for sure. na rb30 seems the go if your on a tight budget, getting good power out of it....

Im pretty sure an r32 rb25 and r32 rb20 have very similar inlet manifolds, my guess would be that your mate has a complete r32 rb25de motor including the head.

Edited May 11, 2008 by Adriano

[BHDave]

They aren't similar, they are the same. Same cam covers too, just different coil cover.

[sic200]

a mate of mine has got a r32 gts-t with an n/a r32 rb25 in it..

my guess would be that your mate has a complete r32 rb25de motor including the head.

uhuh, i think i've established that! but thanks anyway!

[nizmonut]

holy shit, that's awesome for 8 psi.. what turbo/s you running to get that?

garrett 3582R highbrid ball bearing steel wheeled small exhaust large intake good for low down power, heaps of flow over the exhaust propeller sooner than a t4 etc

[Roy]

The last time i looked i didnt see any rb20's pulling 300kms an hour. or doing 4wd doughnuts

and i dont think any officer from the nation vehical registery center is going to crawl under your car to check what block your running....even the guy at the garage doing the 6 monthly saftey check wouldnt know what the f**k block was sitting under your twin cam head unless you tell him

When you get your car registered you bloody well should have matching numbers on your paperwork. Anyone driving around with a different engine number to that on their paperwork is playing a risky game in my eyes. Not sure what state you are in, but in Vic and NSW its part of a simple check that numbers match. And they only have to see the engine number being RB25**** etc to knwo what engine is in it A friend was caught out with an SR20 in his Pulsar as he was bit lazy getting his paperwork sorted. The fine was ridiculous. And that was for a simple engine exchange, not somone playing with the cc to weight regulations of engine conversions. Anyway, its something to consider, has insurance problems too

LOL, so RB30s are cool for circle work. Show me the 300km/h vid and i will be convinced