R33 Rb30 Conversion

[Cubes]

I don't think the issue with clearance is where the strut brace is but towards the front of the motor where the bonnet slopes down.

Will be interesting to see how much clearance the Nismo strut brace has on a std rb20det.

Can I measure it Darren?

[Bl4cK32]

it actually rubs the bonnet liner with the old rb20 in there....

[Cubes]

So the Nismo strut brace uses every little bit of room available then.

What I want to measure though is the clearance between the strut brace and the plenum.. oh sorry collector

[Guilt-Toy]

i can barely fit my finger inbetween the nizmo strut brace and top of the throttle body mount. so its going up 30ml.. its gona be higher then the strut brace??

I really want to keep the strut brace as it makes a huge difference for handling

[Cubes]

Remember the drivers side of the motor can be quite snug as it isn't the torque side and won't lift. The torque side (passenger side) will obviously lift.

Replace the engine mounts or even get a set of more solid engine mounts (nismo) to prevent the motor from twisting on acceleration.

I think Nismo only make the torque side.

My old 250 cortina used to break engine mounts constantly, upon acceleration it would lift the back end of the bonnet.

[w1ngzer0]

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.

ok Ben, which is my name to kinda ironic. Anyway mckenny said their RB25 mounts for the S13 will work with the RB30 and clear fine

[Roy]

Question for the ppl running the RB25DE/RB20DET inlet plenums on their RB30s, with your GT30/35 turbos (what 500-750hp depending on which individual) are you concerned about running those sorts of turbos chasing those sorts of outputs with the RB20 plenum/throttle body?

[Cubes]

When I consulted Mark Tilbrook with regards to this matter he said the RB25DE inletmanifold and RB20/25 plenum will handle up to around 600hp with no problems. Over that and you will want to start looking at the plenum.

The inlet manifold for the RB25DE is fine. (i.e SK's Rb30 which runs a std inlet manifold with a subzero plenum)

The RB25DE inlet manifold does have larger ports than the RB20DE/T.

If we are talking about uneven air distrubution at these power levels... I have no idea.

[Roy]

When I consulted Mark Tilbrook with regards to this matter he said the RB25DE inletmanifold and RB20/25 plenum will handle up to around 600hp with no problems. Over that and you will want to start looking at the plenum.

 

The inlet manifold for the RB25DE is fine. (i.e SK's Rb30 which runs a std inlet manifold with a subzero plenum)

 

The RB25DE inlet manifold does have larger ports than the RB20DE/T.

 

If we are talking about uneven air distrubution at these power levels... I have no idea.

...mmm food for thought... the Sub Zero plenum with its big dirty aftermarket throttle body is a fair bit different to the RB25DE setup , or so i would have thought...will keep my options open and see what parts come across cheaply

[Bl4cK32]

I was going to go the tried and tested Greddy Front facing plenum, with a q45 throttle body....its just coming up with the cash that stops me

[Cubes]

I've only seen the Greedy plenum available for the R33 & RB26 head?!?

It never lists the R32 RB20/25.

[Roy]

Careful Bl4cK32 , check that the Greddy plenums fit on the RB25DE head, as its my understanding they dont.

Someone hurry up and get their cars going...by the time i go solid lifters and buy a new plenum then an RB26 head makes fiscal sense, like that fiscal just watched Business Sunday!

[Skyrine-Dave]

hey guys, i will be using the greddy plenum on my rb30 with rb25det head. I will be using the stock rb25det throttle body as thats what i have at the moment. I also have a GT35 so i'll be able to tell you what thats like once it is up and running

[Sciby]

My god this thread is huge now.

Well, I'm back on the road again and starting to regret selling the 30det I picked up... and this thread is too huge to do an indepth search right now, so a quick question... is the modification of the oil gallery for a 25det head to mate up with a 30 block that difficult?

It may be somewhat hard to find decent 25de heads and there seem to be more variety in go-fast bits for the det head.

[Bl4cK32]

Careful Bl4cK32 , check that the Greddy plenums fit on the RB25DE head, as its my understanding they dont.

 

I always have my back up plan....RIPS front facing plenum kit made with the rb25de runners i believe....ala sub zero...but a better design i believe due to the way it tapers to the back....like the greddy one

[Sydneykid]

My god this thread is huge now.

Well, I'm back on the road again and starting to regret selling the 30det I picked up... and this thread is too huge to do an indepth search right now, so a quick question... is the modification of the oil gallery for a 25det head to mate up with a 30 block that difficult?  

It may be somewhat hard to find decent 25de heads and there seem to be more variety in go-fast bits for the det head.

Hi Sciby, I plumb the oil supply from the main oil gallery that runs down the LHS of the block, just drill a hole, tap it, whack a fitting in it and away you go.

But (there is always a BUT) I have yet to find one "go faster" bit for an RB25DET that doesn't fit an RB25DE. What did you have in mind that is unique to RB25DET's?

[Bl4cK32]

so has anyone compared (measured, or dropped a gasket to just check) what the inlet porting differences are from an r32 rb25de head to the r33 rb25det head??

[Sciby]

SK, you've changed your pictures! Oh well, at least Stageas are somewhat pretty.

The reason for the interest in the 25det head is that there's simply just more of them, theorhetically driving the cost down... or prepping and setting up the block and just swapping the head (albeit, with any changes needed).

Imho, I don't think there'd be a world of difference between the 25de and the det heads?

Sydneykid, the external line that you've outlined, that solves the different gallery mouth shapes? Would you do anything to allow for that? apart from cutting away at the gasket to fit both, I can't see a huge problem, but the reason I asked the forum is because I'm not a mechanic.

I may have $3k very shortly, to throw at the car, so I'm exploring the RB30 path again...

[predator]

How much are people getting their RB25DE heads for?

I ended up with a DET head, simply because it was cheaper and easier to get access to.. $500 although it does need a couple of things which I will have to track down. There was another one forsale on here recently for similar pricing.

By the time I track everything down will be around $800 all up I think.

I have seen at times DET bottom ends (not blown) for under the $1k mark. It actually seems cheaper to buy the head and the bottom end separatelt, bolt them together and save the $3000 or even more it costs to get a RB25DET complete. Crazy..

[Sciby]

predator: Yeah, some people do it in expensive strange ways.

If I decide to do the 3L thing again (just been looking at http://www.shemboy.com - it stills the hoon inside for a while)... I think I'll get a 3L block all set and prepped, then spend two weeks taking the head off, transferring all subsystem stuff to the 3L and getting the head ready... the only thing I'd be worried about sorting out myself is the path for the larger timing belt.