R33 Rb30 Conversion

[bubba]

I don't have torque printouts but I have power sheets of RB20 and RB30 running same turbo and boost. Made the same power bit a shitload sooner

[xsv_32]

What an awesome thread! I thought that 10 page pdf was impressive but damn!

Im building an rb30/25 and have got the block almost ready to put into my 32 coupe. The parts used in the block are as folows:

-Rb30e block

-Factory crank (re balanced)

-Wiseco forged pistons (40thou oversized)

-Forged eagle rods

-N1 oil pump

-ACL race bearings (big ends and mains)

-ARP bolts

The block was honed bored decked and acid dipped and now is back in my possession.

Ive bolted up the mounts, sump, water pump and flywheel and it is about to go into the car. BUT only recently ive heard i should restrict the oil flow to the head using TOMEI gallery restrictors so the blocks oil isnt pumped all to the head.

Is this a necessary and recommended mod?

My next querie is will I need to replace the factory rb25de valve springs to cope with big boost? With the block ready to make mumbo i dont want the head to restrict me too much!

Any tips would be awesome

Cheers xsv 32

[Adriano]

Yes, you will need the restrictors, and upgraded valve springs. Hope you fitted a crank collar.

[xsv_32]

umm no i didnt fit one. i didnt plan to rev it too hard but i guess i should have. What springs can i use and what diameter should i restrict the oil to ?

[dano4127]

afaik just order tomei springs to suit RB20DET heads

[SirRacer]

ring performancesprings in queensland. he did mine and is a great bloke to deal with

allen waye is his name

[xsv_32]

Um thanks but im from christchurch new zealand lol. Anyone know how to tell the difference between a r32 and r32 rb25de head??

[R34GTFOUR]

Um thanks but im from christchurch new zealand lol. Anyone know how to tell the difference between a r32 and r32 rb25de head??

the r32 doesnt have vct and has smaller ports afaik, the springs should be the same as any rb25 non neo (aftermarket wise)

Edited May 8, 2008 by R34GTFOUR

[Spoolup]

R32 RB25DE non VCT has different springs to R33 RB25 VCT - they are same as RB20 or RB26, equal length on both the ex and in so you can not use R33 ones.

the r32 doesnt have vct and has smaller ports afaik, the springs should be the same as any rb25 non neo (aftermarket wise)

[R34GTFOUR]

well there you go, learn something new each day

[xsv_32]

Awesome. Im pretty sure its a r32 25de head which is perfect bar the weak springs...

Was just masking up the block to paint and discovered that the engine builder had already put oil gallery restricters in for free! SCORE.

Any suggestions on the best gasket to use? The block and head have only been surfaced and not skimmed so what thickness should i aim for to get around 8.5:1 - 9:1 compression.? Also the pistons are oversized about 1mm...

[Alf]

Rb30's came with oil restricters as standard. 2 x 1.8mm.

For a twin cam oil pump its best to block one feed and use a smaller restricter in the other.

[Adriano]

Ive got a set of rb26 springs for sale if you are interested

[xsv_32]

If they fit?... How much NZD?

[xsv_32]

Apparently the gtr springs wont fit? Only rb20det ones or something like that. Anyone have an answer to what springs will and wont work in a 32 25de head?

[Dahtone Racing]

ive got GTR springs in my R32 RB25DE head

[GTRgeoff]

Straight fit or did you use some aftermarket/GTR items to fit?

[The Ant]

Based apon my thread named "Which RB engine combo?"

I'm looking at building a performance RB motor out of the bits and engines that I already own.

Here is the list;

RB30 engine (non turbo) complete

RB25DET complete (worn rings)

RB26DET rods and pistons (only)

Do I start with my RB25DET engine and work it or the RB30 and work it and say put the RB25DET head on it? Surely I dont have to use the RB25DET head on the RB30 to get 300plus rwkw? I know the RB26DET rods and pistons fit into the RB25DET but do they also fit into the RB30 crank and block as they are all the same bore size? Im not wanting to spend to much money but prepared to spend some money of course for extra performance bits. I'm wanting to get as much hp as possible and still use pump fuel and have boost under 20 psi.

Any other suggestions?

The engine will be going into a 1970 fibreglass car (total weight 750kg) that has no loom for these motors so I may consider a carburrettor version of the above or obtain the appropriate loom/computer.

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My latest thoughts

Ok...why cant I just use a standard rb30 head (maybe port the head a little) on my rb30 block? What benefit am I really going to get putting my rb25 vvt turbo head on to the rb30 block with all the head ache and modifications needed to do so?

Surely the rb30 head with some work done to it can do the job as well or better? The rb25 vvt turbo head is probably worth $700-800 at then I still have to change 2 cams in it costing probably $1500 plus in total. I only have to buy 1 cam for the rb30 head?

So...the rb26 turbo pistons fit on to the rb30 rods and can then be used into the rb30 block. What compression ratio will this give me using the rb30 head?

Edited May 11, 2008 by The Ant

[Cubes]

Surely I dont have to use the RB25DET head on the RB30 to get 300plus rwkw?

The idea of the 3ltr is it spools a larger turbo quicker and makes more power 'under' the 300rwkw curve.

An rb20det can make 300rwkw but it will be as laggy as hell and have bugger all mid range.

I know the RB26DET rods and pistons fit into the RB25DET

The rods fit but the pistons will NOT unless you also run with the rb26dett crank.

The rb26 gains its additional 100cc by using a slightly longer stroke and pistons with a reduced pin height. Drop 'just' the rb26 rods and rb26 pistons in to an rb25det and the comp ratio will suck not to mention the piston sitting down the bore. So definitely not a wise move.

but do they also fit into the RB30 crank and block as they are all the same bore size?

No the rb30 has a longer stroke and rod length. So no.

Ok...why cant I just use a standard rb30 head (maybe port the head a little) on my rb30 block? What benefit am I really going to get putting my rb25 vvt turbo head on to the rb30 block with all the head ache and modifications needed to do so?

Surely the rb30 head with some work done to it can do the job as well or better? The rb25 vvt turbo head is probably worth $700-800 at then I still have to change 2 cams in it costing probably $1500 plus in total. I only have to buy 1 cam for the rb30 head?

You can but the rb30/25 will ALWAYS make the power easier and be much more fuel effient and friendly to drive.

Start working the sohc head with big cams to get near the stock flow level of the rb25det and fuel economy/driveability suffers.

[Rolls]

Lots of people have made very powerful RB30ETs but a det sounds nicer, makes more power and is all round a better motor. As for carby you'd have to get something custom and would cost a lot of money.