R33 Rb30 Conversion

[Cubes]

A 3ltr really wouldn't make that much difference to hit the 11's as with a 2.5ltr you have the power to hit the 11's just not the traction.

Even cracking in to the 12's is a lot harder that you think.

[Zdenko]

then y is everyone wanting to go 3 L??

[Sydneykid]

Hi Zdenko, you asked "then y is everyone wanting to go 3 L??"

If you are into drags and want to do 8's, 9's or low 10's then 3 litres is the go. If you want high 10's, 11's or 12's then RB25 will do it.

If you have a clapped out RB20DET and want to upgrade, why go RB25DET, when for the same cost you can go RB30E/RB25DE hybrid. Ditto if you have a stuffed bottom end on a RB25DET, cheaper to go RB30E bottom end than fix the RB25DET bottom end.

Both RB25DET bottom end and RB30E bottom end will handle 450 bhp, so you might as well have the faster spool up, better throttle response and more off boost torque from 20% more capacity.

Cost versus bhp, the RB30 is hard to beat. But if you have a perfectly good RB25DET, I wouldn't bother unless I wanted to get over 500 bhp and was prepared to spend $20K on the car to use it.

Hope that clarifies.

[GiJOr33]

i'm doing the conversion, but the problem i'm faced with at the end is that i'll have this bullet proof motor capable of something like 800hp, but will have to tune it only for 500hp as i don't want to be replacing the gearbox all the time and i can't afford an aftermarket gearbox!

[Zdenko]

arnt our gear boxs good for 400rkw??

[GiJOr33]

i heard 550hp at the engine is what they'll handle... but a couple of people have also said that there are 650hp skylines on stock boxes.

[MetBlue_GTST]

This is an awesome thread and i have been following it closely coz i'm plannig on going the RB30 conversion near the end of the year...

I know for a fact that the Rb26 gearbox can handle 650HP at the rear wheels, but if abused the 3rd gear will strip itself... as for the 25 box, i know they are strong, but not sure how much power they will handle... Does anyone know if the Rb26 box can go onto the 30 block???

[rev210]

same as the RB26 box internal wise.

[GiJOr33]

what are they good for? reliably... no point saying they can hack 700hp if only one car has done it. What power rating (at the engine) do they start breaking?

[25t]

Hey guys

how do you do the qoute thing?

I said a wee while back

the series 1 na blocks are stronger/thicker castings,the only fitting not in the series 1 casting is the turbo water return line,which isnt a really big problem,

i was wrong,the water line is there ,the fitting that is missing

is an oil drain from the head into the sump ,will plum it into the turbo drain line

cheers

[Cubes]

25t just above the post reply button their is a quote button that will quote the person..

Oil drain from the head into the sump? Sounds strange. Any pics?

[Skyrine-Dave]

i think what you mean is missing is the oi return line from the Turbo!.

this line gets plumbed into the sump i think?... i think you can get your sump "spiked" to allow for an oil return line to be plumbed in

do all the R31 skyline blocks have the oil return ?

[25t]

hi all

no i mean that the head has oil return/drain line that is plummed into the block just above the sump level,

Dave the turbo drain point is on the block / i plan to plum the head drain into this point as well

will take a pic to explain my rambling.

[DennisRB30]

Cool thread guys. What about the legalities of the big block? Its an older engine and that could cause probs right.

What mods have to be done to the R33 to get in to fit in if any, engine mounts ect? Is there plenty of bonnet clearance?

[JNR24]

same clearance as RB25,

RB30 Block bolts down to original RB25 engine mounts.

[DennisRB30]

I thought the RB30 was taller by a few CM?

Joel, you can take a boost controller off. Its *slightly* harder to change the bottom end

[Cubes]

The RB30 block is around 3cm's taller. You wouldn't even notice it.

Everything looks the same. Providing you use a RB25DE Non-vct head.

If you applied for the modification to be approved i don't think you would have to many problems. Even though this is 'wrong' if you were to have RB30 block stamped with a RB20 or RB25 engine number it would most probably go un-noticed providing the rest of the car looks relatively stock.. I.e no high mount turbo's.

[Sydneykid]

Hi guys, a couple of questions popped in since I last read through this thread.

Having looked at the internals of RB25DET gearboxes and RB26DETT gearboxes I can confidently say that they are physically identical save for the transfer case and associated parts. It is pretty much well recognised that GTR boxes will take 650 bhp and that is with the extra traction of 4wd. So there is sound logic in saying that a RB25DET box, being 2wd, will handle at least the same power if not more.

I'm about to put my money where my mouth is, the new RB31DET (RB30E/RB26DETT) will fully test the capacity of the RB25DET gearbox. It has a twin plate clutch, 2 way LSD, will be running on "R" type tyres and the suspension has plenty of grip. If it survives a few races I can definitely then vouch for the above.

All of the RB30 blocks (both N/A and turbo) that I have seen, have blanked off holes for turbo water feed and water return and turbo oil feed and oil return. It is simply a matter of drilling and tapping the holes for the fittings in the block. Don't let that put you off, it's a piece of cake.

If I had an RB25DE on one engine stand side by side with an RB30E on another engine stand, I reckon in one day I could have a 450 bhp capable RB30DET ready to go in the car. It is basically a bolt and unbolt exercise.

When you buy a new block from Nissan to replace a broken one, it does not have an engine number stamped into it. This is so you can stamp it with your original (broken) engine number.

Conversely, when you put a long stroke crank in your engine or bore it out, you don't have to tell the rego guys. It's got the same engine number, that's all they care about. Think about it? What are they going to do? Tell you to pull the head off the engine so they can measure the bore and stroke to see if you are over the limit. And if they are wrong, they will have to pay for a rebuild. Ain't gunna happen.

Emissions is the only way they are gunna do anything about it. A well tuned high performance engine, running unleaded fuel and a cat will have no problems passing that.

Hope that adds to the discussion.

[matlowth]

You're right...

I was running 124mph which is good for 10's (With traction), and the best run I managed was 12.3... Most of the others were 12.7.

No traction till 3rd gear (which is what most of you with this power will get) will hamper any chance of getting a really quick time on street tyres.

Cheers,

matt

Originally posted by -Joel-

A 3ltr really wouldn't make that much difference to hit the 11's as with a 2.5ltr you have the power to hit the 11's just not the traction.

Even cracking in to the 12's is a lot harder that you think.

[matlowth]

Sydneykid - some food for thought - while the gearbox is physically identical, but you're forgetting that the tailshaft and driveshafts are a lot smaller than that of a gtr... I'd be more inclined to say that one of my driveshafts would go before the gearbox...

In any case, I'm sticking to single plate clutches just in case!

Cheers,

matt

Originally posted by Sydneykid

Hi guys, a couple of questions popped in since I last read through this thread.

Having looked at the internals of RB25DET gearboxes and RB26DETT gearboxes I can confidently say that they are physically identical save for the transfer case and associated parts.  It is pretty much well recognised that GTR boxes will take 650 bhp and that is with the extra traction of 4wd.  So there is sound logic in saying that a RB25DET box, being 2wd, will handle at least the same power if not more.