R33 Rb30 Conversion

[Cubes]

I bought the R32 RB25DE head so that I can use the Rb20det loom, injectors, sensors etc. From the outside the R32 RB25DE looks exactly the same as the RB20.

My aim is to try and keep it looking as stock as possible.

With a R33 RB25 inlet manifold and plenum hanging off the side it will be obvious its not the plain ol RB20.

I am using the RB20 plenum bolted up to the RB25 inlet manifold (slightly bigger ports compared to the RB20 inlet manifold) as is Darren.

The initial run in with no boost will be fine with the stock RB20DET ECU.

AFR's should be pretty much spot on.

If I were to start running boost then it will richen up which I'd prefer not to happen.

If you want to keep things simple if you have an R32 use the head from the R32's if you have an R33 use the head from an R33.

That way there is no fiddling with looms sensors & injectors etc.

I do believe the R33 RB25DET head is slightly better than the R32 head but only by a bee's dick.

This is due to a slightly different port design and obviously the VCT.

Valve sizes etc are all the same.

So whats your plans Andrew? R32 GTST?

[Cubes]

I am going to be using the RB20DET injectors, after that the turbo, injectors etc all gets bolted on.

[Bl4cK32]

I am using the RB20 plenum bolted up to the RB25 inlet manifold (slightly bigger ports compared to the RB20 inlet manifold) as is Darren.

 

Yer, basically u use the loom u got in your car. If you got an r33 use the rb25det head with vvt to keep using the same loom. The r32 doesn't have it, so use the r32 RB25de non vvt head. Sound simple?

If you want the most basic explanation, all you are doing is swapping the block for the rb30 complete block. Then some fiddling with the vvt (r33) to feed it some oil (i dunno cos i dont have vvt ) . All sensors, plugs, everything bolts to the rb30 bottom end.

The computer uses the afm to keep mixtures correct, so you dont need a aftermarket computer to start it, or a remap of the std computer. Joel is starting his himself on the std ecu, injectors, turbo.....everything that was in the r32 before he removed the rb20. Dont tune it past the limits of the parts and you should be right.

[predator]

Thanks for the headsup guys.. all helps.

Well I picked up an rb25det head pretty much complete today. Missing a few things (such as the loom - hence why I as asking), but have time to track them down.

Looks like I have to go the RB25det(vvt) route as thats pretty much what I have. Not a drama I guess as there are plenty of r33 out there to scavenge parts off. So guess its really going to be an RB25det conversion and then some.

Total cost so far : $500 for head + free block. Fairly cheap so far.. but its after now that its going to get expensive Bought an rb30e complete that had come out for an RB20det conversion.. sold a few bits off it like the gearbox for a few bucks. So in the end basically ended up being free. 1989 block w/ 200,000km on the clock so should be fairly fresh.

Probably won't be until next year that I really get stuck into it. Kind of missing something vital like a car to put it into :Oops:

[Bl4cK32]

1989 block w/ 200,000km on the clock so should be fairly fresh.

I think mine had near 400,000 kms on it when i got it out of a vl. Still had the hatch marks in the cylinders and the std (origional) size pistons. In perfect condition. Had it all crack tested before work was done

[GTR-Ben]

The bonnet definately won't close with the RB30 in a R32.

 

I'm redrilling the holes on the engine mounts that bolt to the block, then welding up & grinding flat the old holes. All it needs is around 8-10mm.

The problem appears to be with the front of the plenum fouling the bonnet.

 

Luckly its not on the torque side.

Is this with the RB25 head and the manifold going over the top of the head that hits the bonnet, or with a GTR style intake manifold. Thought it did fit in an R32 with a GTR style intake??

I'm guessing you mean RB25 when you say the front of the plenum hits the bonnet.

Probably going to be stronger to make a spacer plate than to drill holes in the alloy engine mounts blocks..

[Cubes]

I know of one bloke who has redrilled the engine mounts 8mm lower and there hasn't been any problems, YET.

In an accident I am unsure if it would weaken the engine mounts to the point of allowing them to break.

But yer.. Ben it is the RB25/20 plenum that I am talking about. The GTR style will clear easy. Even in a S13 and a GTR style plenum I can't see it hitting. RB25 plenum, no chance.

[predator]

the rb25de plenum is slightly flatter from what I remember.. think the rb25det plenum would be even worse..

if you're going the whole hog (which i guess you are if you're going rb30det) I am sure you'd want to go for a front facing plenum anyhow.

[Cubes]

Not sure about the 33's but the R32 RB25DE and RB20DET plenums are the same.

Main reason I went the RB30 is it was going to cost the same to build up a RB25. If not slightly more for the RB25 as the RB25DE blocks are a little more expensive than the $100 RB30 blocks.

[Bl4cK32]

Can we clear something right now?

PLENUM = WHOLE INTAKE MANIFOLD

COLLECTOR = TOP HALF OF INTAKE MANIFOLD

RUNNERS = LOWER HALF OF INTAKE MANIFOLD

Right, now saying that....

the RB25DE and the RB20DET "COLLECTORS" are the same. The Rb25DE and RB20DET "RUNNERS" are the same port size going from the collector to runners, but the ports that go form the lower runners to the head are DIFFERENT SIZES. The AAC valve is different on the RB20DET as well, hence why you use the RB20DET top half to keep all wiring std, and the RB25DE lower half to keep ports similar size (when using the rb25de head in a r32)

The only difference with the RB25DE lower runners, and the RB20DET runners, is the STD. turbo coolant line that runs around the back of the head. Normally (in a RB20DET) the line separates into two lines. One joins to the coolant lines under the runners, the other joins into the actual lower half of the runners. The RB25DE does not have the connection in the lower runners to plug the second line back into. This gets blocked off. The other line that returns under the plenum, requires a longer piece of coolant hose to connect back to where its supposed to go because of the extra height of the new motor.

Yes a aftermarket intake manifold, ie front facing plenum, will clear the bonnet. Saying that, looking at the motor in the car now, I'd prefer to have the motor dropped down to give it the clearance for any twist the motor may have.

[Cubes]

Your almost right Darren.

The meaning of Plenum is an enclosed space that has a higher pressure than that of outside. So technically speaking both the collector and inlet manifold are the plenum, ONLY WHEN they are under boost.

So that being said techinically we cannot call a collector or inlet manifold a plenum EVER AGAIN! as they often come under vacuum

Its either that or when under vacuum we call it a collector then when under boost a plenum.

The top half is the collector or what is known in the engine manual as the 'Collector Assembly or Intake Manifold Collector'

The part that bolts on to the head is the Intake manifold.

The general consensus is that the plenum is an area where the inlet manifold runners meet.

[Bl4cK32]

Well for this conversion, (to simplify things for others:)) Id thought id clarify it when we say use this top half, or this bottom half But yes....smarty pants goin the right old wasy for a slappin, arn't ya :slap:

[GTR-Ben]

Yeah Joel.. I don't think it's going to fit into my S13 even with a GTR manifold. Considering people have to cut the bonnet parts out to fit a stock GTR motor in. 30mm higher, no chance.

I am going to lower the engine as much as I can. Looks like my turbo will hit also.

[w1ngzer0]

thats not something i want to hear....

There are people over here that drop RB25's and they don't have to cut out the bonnet....McKinney Motorsports over here makes RB25 mounts for S13's. and yes it makes the engine lower

[GTR-Ben]

Yeah they make those funny engine mounts that lower the engine quite a bit.

That's why I am going to make a plate to do it.

[meggala]

ben I'm amazed you didnt remember sketchys silvia wioth the rb30e in it the whole rocker cover stuck out of the bonnet he had to make a scoop for it.

you will have to lower it a fair way

cheers

[GTR-Ben]

No never saw that... show me pics

Great.. well I will lower it as much as I can and then make a custom bonnet.

[Guilt-Toy]

I am worried that my Nizmo strut brace is not going to fit anymore after the rb30det is installed, so we are going to have to drop the engine. anyone here know how to do this or has done it and has pics or what not ???

[Bl4cK32]

If you can wait a week or two, mine is getting the engine mounts re drilled. This should be enough so i can refit my Nismo strut brace

Hey where is SK in all this?? What do you do to make the motors fit Gary???

[Sydneykid]

If you can wait a week or two, mine is getting the engine mounts re drilled. This should be enough so i can refit my Nismo strut brace

 

Hey where is SK in all this?? What do you do to make the motors fit Gary???

I'm here :wavey:. The "old" R32 GTR with the RB30 in it had no problems, plenty of clearance. The R33 GTST had a Sub Zero inlet plenum on top of the standard inlet manifold, so it had no problems either. The current R32 GTST has plenty of room as it also has a GTR plenum on its RB31DET. I have seen 2 other R33 GTSTs with the standard inlet plenum, it looked like the guys removed a bit of the underbonnet insulation. I couldn't see any dents in their bonnets. :confused:

But I can't speak from personal experience, so I keep quiet when I don't know for sure:cheers: