R33 Rb30 Conversion

[Steve]

4K drive in drive out 3L with forgies, shame they dont have a shop in adeliade.

[Ender]

Alright, I have read all the posts here, fantastic, this thread should live foreva...

Heres what I am planning...

I have seen numerous series 2 engines for sale for 600 or so, rebuilt with reciepts 20000km ago ..sort of thing...

Use the bottom end off this motor...do nothing to it, botl on a stocker rb25de head.....have yet to find which turbo will be best for me, but spend the cash and get a top notch gcg or similar...

Then...at my leisure...build a better bottom end, with better comp ratios as per recommendations on this thread, and swap it in later.

I figure the increase in power and drivability of the stocker option will keep me more than happy for some many months...

Now a couple more queries...do I need a different dump/front pipe because of the small increase in height of the rb30 block? I will prolly use my rb20exhaust manifold....

Thankyou for any input....

Russ

[lowlux]

i would rather buy a complete rb30engine ender and work with that and put all new parts in,as there fairly cheap also ive seen complete rb30's for $100 in need of rebuild,then get the complete motor ready to bolt in to your car,then when yourve got a spare week off work put the motor in,thats what im doing and it means i can still drive my car around untill the motor is fully complete,also i think u might need the front pipe modified because it might end up to close to the floorpan but thats easy stuff

[Ender]

Also could someone please attempt to clarify for me how much difference there would be between a CR of 8.3:1 and 9:1 in feel...I just want to know if it is a different engine with the higher or if it is just a good improvement in low down power etc...

Thanks, I know describing this is hard please give it a go you guys who know...

Russ

[DennisRB30]

By far the most common CR seen in turbo engines is 8.5:1, so I doubt 8.3 is going to be to low. RB20 SR20 RB26 all have 8.5:1, I would think of the slighty lower CR to be a bit of extra protection against detonation. The RB30ET has a CR of 7.8:1 now thats low, and it was deemed fine for a production engine.

[Ender]

I just see people reccomending 9:1, due to improvements in turbo technology...maybe 8.3:1 is better for an everyday car anyway??

Thanks,

[Ender]

Lowlux...my engine is already out thats my motivation to get going....not sure if I can build the engine myself?? never done it before, have a good idea but?? I would probably get someone else to actually hook all the electrics up and start it and tune it etc...I cant do that.

But yeah new stuff is cheap so prolly better off....

Thanks

[lowlux]

i dont think that 8.3 will be very laggy, but compared to 7.something that the turbo pistons give ya then thatll be laggy. Really ender i think doing the engine yourself will be alot cheaper and most of the ppl that are interested in doing this and have replied to this thread are probably doing it themselves, really u should buy a few good tools espicially a torque rench then buy a rb30 engine manual which I HAVE!!! with every bolt and nut in the complete rb30 engine and there torque settings everything which will make my life alot easyier

[S13 Silvia]

Originally posted by Steve

I read somewhere that factory RB26 pistons are forged, and are good for up to 550+bhp.

Is that correct?

[Sydneykid]

Hi GiJOr33, 320 rwkw is 500 bhp and that's at least 150 bhp short of when I'd start worrying about an RB25DET gearbox not handling the power. My understanding is that "Try09" uses an auto for launching and to overcome its narrow power band. Not because a manual box wouldn't handle the power. It always was an auto anyway, if I remember rightly, used to blow up the Jatco and/or the Trimatic, now has a Powerglide I think.

The 5 speeds in the Supras are nothing special, looking at them they are way weaker than an RB25DET box. More like an RB20DET box.

The Getrag 6 speed would be a bit better, but cost an arm and a leg last time I checked around. If you could find one. Then you would have to have a bell housing adaptor, starter motor adaptor , different flywheel, clutch, tailshaft and the gear lever looks to be in the wrong place for a Skyline. One very expensive prospect.

I reckon a close ratio/stronger gearset for the RB25DET box would be a better and cheaper solution. Munro had one for sale recently for a very reasonable price.

Hope that adds to the discussion.

[Sydneykid]

Hi guys, I have a standard RB26DETT piston in my hand right now and it ain't forged. It is what I call "low pressure cast', so it's better than "gravity cast", but only slightly. As for "being good for 550 bhp" that a bit more than I would give them. 500 bhp may well be OK, depending on the quality of the tuning and the boost used. 450 bhp is the number we use as a "safe" max.

Hope that clarifies that

[Steve]

So you rate them on a par with RB25 stock pistons? You say that they are good for 450 also? I shall try and chase down where I read that.

[GiJOr33]

Sydneykid... i always like to here that things are stronger then i've been led to believe!

So if i pump 400rwkw off it should be able to do it all day assuming i don't always rip the gearbox through to 2nd gear and pop the clutch out which inturn induces a sharp power hit in the back wheels causing the ass end to swing all over the road untill i find 3rd gear?! :burnout: :uh-huh:

I'll be glad when the block is finished and i'm ready to bolt the head on... that means not long till it's in the car! I'd better go shopping for a set of 265 tyres for the back wheels then if i want any chance of traction!

[lowlux]

does any1 know what the rb30 pistons are made of and whether the non turbo and turbo pistons are made out of the same thing?

[Ender]

I need to know 2 more things,

I assume I need to have a new front or dump pipe made to cover the extra distance in height on the rb30 block....yes or no...

And what clutch will fit behind this engine and people have found reliable, which will fit my rb20 Gbox for a start, I assume it doesn't matter about the G/box though.

Thanks,

[Cubes]

The are both stock standard pistons lowlux.

Gijor33.. Are you running 17's?

If you go for a low profile even with 265's say good bye to any chance of traction. You need side wall flex for decent traction which means a trade off in the handling department slightly.

I'm going to find my self a set of 32 GTR Alloys and stick with the 16's..

[Cubes]

Originally posted by Steve

So you rate them on a par with RB25 stock pistons?  You say that they are good for 450 also?  I shall try and chase down where I read that.

If 4k is with forged pistons then I worked out the price if I do it my self to be fairly close..

You could always go for a cruise over there and drive in and drive it back running it in..

By the time you get back to Adelaide it will be ready for a little bit of stick.

[lowlux]

i think youll have to use the rb30 clutch as there about 10mm bigger in diameter, also u MIGHT! have to get a new front pipe

[Steve]

Thats not a bad idea, got to do something with the holidays. It would be tough on the way home, all those open roads and an engine that isnt run in.

[GiJOr33]

Ender:

I LOVE my OS Giken Twin Plate... i'll definantly be keeping it for a while. Depends what sort of power you are chasing. I think also the style of the friction plate makes a difference. Little pucks means there is more pressure on a smaller surface, which means that it's much more bitey and has less slippage. A bigger surface area will mean that you can slip it a bit and it's smoother on take off. Having 2 plates like in the OS Giken or Daiken (or any other twin plate) means that you have more surface for contact so it grips better... and the bigger pucks means it's a little more user friendly.

Depends how much you want to spen... You should be able to find Twin Plate clutches for around $900-$1500 for a second hand one in good condition. And as i've said before... i highly recommend the OS Giken Twin Plate

Joel:

I'm running 18's at the moment. I'm also looking for a set of 16's, one pair for the strip and one pair for drifting

Cheers,

Andrew