Rb30/25 In R33 Conversion Questions.

[bluegts]

G'Day.

I have searched, and I am aware of the 400+ page thread, but I still can't seem to find my answers and Im not gonna sit here and read 400 pages because the thread search button is a stuborn peice of shit.

Right, If I go ahead, I won't run VCT so please dont tell me to tap lines, I don't have VCT now and notice no difference. I want to leave the rb30 bottom stock. Balanced and whateva, but standard parts with new rings and bearings. I'm try to build another motor on the cheapest budget using as much of what I have. Im not chasing huge power, but will enjoy the low down torque and hopefully stronger motor than the rb25.

So just a few questions for rb25/30 setups for those that can answer them

With the instrument cluster, were there any issues with the revs or speedo after the conversion?

Did you keep the air con?

And what gearbox did you use? Can the rb25 gearbox be used?

I currently have an RB25det head and stock RB30 turbo botton end. If they are just bolted up, will the compression be ok? What headgasket?

And I assume an rb25 type of ecu is capable of running it?

Thanks Jack

[Simon-S14]

With the instrument cluster, were there any issues with the revs or speedo after the conversion? Makes no difference what the bottom end is, you'll still be running the same wiring loom and the tach will be the same

Did you keep the air con? - easy to do, bolt the AC bracket onto ther block (with some mods)

And what gearbox did you use? Can the rb25 gearbox be used? yes, easy, same rb25 clutch and flywheel aslo

I currently have an RB25det head and stock RB30 turbo botton end. If they are just bolted up, will the compression be ok? What headgasket?

And I assume an rb25 type of ecu is capable of running it? stock HG will be fine, comp should be around 9:1, give or take, you will need a chipped ecu or aftermarket ecu to make it run properly...

Thanks Jack

[Bliksem]

You dont need to mod the a/c bracket only the power steering braket.

Also the stock ecu will make it run.... but to make the most of it, an aftermarket one will be the best option.

[bluegts]

Thanks a lot. I was waiting for the flaming ahhaa. You've just restored faith with my idea.

Yeah I have a mappable rb20 ecu atm, which I can get re-mapped for $200 by Jeff.

My turbo fell apart on me, 10-11 pounds I've stripped most of the gear off my motor already, found all sorts of shit in the intercooler piping and plenum. I don't even want to compression test my motor, it'll make me cry lol. I was so happy achieving my 200kw, and it lasted two weeks....

I have a fair idea why the turbo's crapped out relating to a car accident a while back, i've been sus about the turbo since then.

So my rb25 gearbox and my month old aftermarket clutch will bolt straight up to the rb30 bellhousing? Killer if it does.

I was going to give all this a go at home, I've got crane and hoist access and an rb30et so why not I guess, I can't afford to rebuilt the rb25det and I don't wanna waste money rebuilding it to standard specs. May as well give the rb30/25 a shot and see where I end up. Hopefully no more explosions and disco shows hahaha.

Cheers, Jack

[Simon-S14]

the box has the bellhousing not the motor, and the RB bolt pattern is the same all across the board so u can bolt that box up no worries.

yeah Jeff remap FTW, i run a RB20 ecu on my 25 and its been awesome... and im thinking bout building a 30/25 soon myself!!

[Bliksem]

Yep, exactly the same bellhousing pattern

ps. not trying to rain on your parade but all of this information really was in the RB30DET thread and the cubes RB30DET pdf file. I did 90% of my conversion just based on a couple of reads over the pdf file so I suggest you get that!

Edited January 24, 2008 by MintR33

[Hootchy]

the CR will be really low with the turbo pistons you want NA ones

[bluegts]

yeah ditto until yesterday arvo... It left me with a strong smooth pull until redline, and didn't even have the VCT, as you'd know. lol.

Well with doing pretty much all work with this at home, what kind of budget would you suggest for bits an pieced along the way of the conversion? Excluding ecu tune, turbo, and all exhaust sides of things. Just to get the hybrid bolted up and in the car with powersteering and aircon??

Thanks again, Jack.

It's not all bad with this I guess... I mean its an excuse for me to get a new turbo as thats all I was missing before, and I'll learn a great deal about the RB's and front half of my car in doing so, even if it does take weeks/months longer than paying a workshop. My neighbour has just qualified as a mechanic at hamilton holden and he is always keen for things like this. He's nearly finished building a forged RB30 VL himself, got an average sized snail hanging on it.

[bluegts]

the CR will be really low with the turbo pistons you want NA ones

Dam really? Simon seemed to think it would be around 9.1. Well I wouldn't mind cleaning the block up a bit, so maybe it's worth brand new pistons and get it honed to suit and everything balanced etc.

Where abouts is this .pdf file? Sounds like it would help a lot. I didn't say it wasn't covered in the conversion thread, I just couldn't find what I wanted using the thread search over that many posts...... sorry lolz.

Jack

[Simon-S14]

it will be low if you use an RB30ET bottom end, however if you use an RB30E it willbe fine

[bluegts]

Hmm that sucks because its a rb30et I have! Can I use rb25 pistons or something? Or different pistons?

Cheers

[TiTAN]

30et pistons will give a ~7:1 comp ratio, Put some new 30e pistons in when you rebuild it they will give a better 8.3:1.

The RB30DET pdf file can be found in "Cubes" sig.

[MBS206]

If you just bolt from one to the other, excluding a tune, turbo manifolds, you're just looking at gaskets, so probably around $1000 to have a safe amount.

But then remember, you also have the issue of needing new injectors, if you get a new turbo, will it be internal or external gated?

Manifold cost?

Tune?

I've spent around $7000 on mine so far, and I haven't yet even started it (It hasn't even got the exhaust on yet! Although, it's currently being built...)

But mine was $3000 for motor, about $1200 on fuel system, $1200 on exhaust, $1000 on mani + turbo, and then theres random shit I've forgotten also! Like the $700 waste gate... etc etc... And it still isn't even startable!!!

[R31Nismoid]

Hmm that sucks because its a rb30et I have! Can I use rb25 pistons or something? Or different pistons?

Cheers

This is quickly turning into a "im too lazy to read the sticky" thread.

I know this has been covered in the RB30 thread about 10 times.

Go read it.

Your questions you couldnt find in the thread have been answered, much more and im going to lock it inline with all the other 25/30 threads as we've been over this stuff time and time again.

Thanks.

[Guilt-Toy]

make sure you use ACL race series bearings.

ARP 2000 rod bolts.

RB30e pistons.