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Discussion Starter · #1 · (Edited)
This is the place to share your knowledge, experiences and lastly views on either.
One is a bespoke piece of engineering built to exacting tolerances out of the best quality materials and as such Costs are relative.
The other is a single cam engine produced by nissan pre RB26 used in patrols later licensed to holden and also found in forklifts.

Hopefully this will keep other threads on either free of off topic sniping !

Your comments please. :flame: :flame: away.
Cokey
 

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There is no comparison, if you spend OSG RB30 money on a nissan RB30, the nissan RB30 would prevail. Any would wouldn't be forced to use a OSG clutch.
 

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Discussion Starter · #3 ·

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It was that thread that convinced me to have a go at my own RB30. They know loads more than we do cos its a domestic engine to them. UK poeple just this it's a pile of poo. I don't really know why. I guess it's just human nature.
 

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Discussion Starter · #5 ·
Its an involved process though, is it not ?
I just dont want the uninitiated thinking you can just buy one from an aussie scrapyard and take on **** and co.:)
cokey
 

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It would be easy on the RWD skyline, its the 4WD aspect thats a little tricky.

No, its wouldn't bolt straight in, but its not far away.
 

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I thought the RB30 was useful for getting more torque at lower revs than for out and out bhp.
I don't think R32 Combat is going for big bhp, though Hugh has got some nice figures and everyday driveability.
Am I wrong here?
 

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To me, the main thing that lets the RB30(RB30E)conversion down, is the rev limit.

Let me expand that, when you increase the power and torque of an engine, the standard gearing starts to limit the cars abilities (usually).
Many normal power conversions get round this to a degree because you normally increase the rev limit from standard. For example, you might extend the usable rev limit by another 1000rpm on a modified RB26. This gives you longer gears automatically, which works well, and makes better use of the additional power/Torque.
With the RB30 conversion the rev limit is actually lower than that of an RB26, therby shortening the in gear speeds - going to wrong way IMO.
Sure you could fit different final drive ratio's etc, but this all adds to the cost.

Obviously the OSG 3.0l does not suffer from this problem, as it has a very high RPM rating. Sort of best of both worlds, but it does come at a price.

The higher the bhp you want out of the engine, the more this problem will affect. So if you only wanted a stage 1 GTR but with loads of torque, you really can't beat the RB30E conversion. On a 1000bhp RB30E engine, you'd be bouncing off the limiter in 5th in no time at all.

Perhaps there is a counterbalanced crank out there that would help it, maybe an OSG one?
 

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So WHY has the OSG got a higher rev limit?

Surely if component strength was the same, itd be down to the rod ratio, ie piston speed.

And the Nissan/Holden engine has a BETTER one than the OSG engine.
OSG is 1.65:1, Nissan RB30 is 1.79:1.

OSG uses RB26 length rods (121.5mm) and the block is 18mm taller than a RB26 block, wheras the Nissan RB30 rods are 152.5mm and the block is 38mm taller.

So if you fitted a crank of the same quality to the Nissan/Holden engine (All ive seen producing big power still have the stock crank) surely there no reason its not safe to at LEAST the same rpm as the OSG engine...

I know the bearing surface area isnt as big, but surely thats not an issue for RPM, at least not as much as rod ratio, and even thats not as much as material quality.

So what am i missing here, or is there no reason a Nissan RB30 should safely rev less than an OSG RB30 if you bothered going for a steel crank?

Revving to about 8000 and occasionally higher will do me fine anyhow.
 

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Yes, the nissan RB30 has the optimum rod ratio.

If you were to replace the OEM RB30 crank/rods and pistons with despoke items and mod the block like OSG, then you would have a better result. Of that I'm sure.

Although the RB26 has a slightly stronger block, its easy to strengthen the RB30 block in a similar manner.

The question is, where do you draw the line??

There are some RB30's with massive power so that proves it can be done. Thats both the OSG RB30 and the Nissan RB30.
 

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121.5mm vs 86mm stroke do not make a ratio of 1.65 but of 1.413:1.
With 18mm longer it gives 188.5mm plus 18mm gives 206.5mm so 121.5mm rod is unrealistic as long as OSG runs 42mm compression height pistons that I don't think so.
I'm at the moment building an Rb26 to 3lt and I extented the block with 27mm which make a total lenght of 215.5mm an going to order a set of custom 142.5mm rods which will gives a ratio 1.66:1.
I don't know how it's going to rev but with a huge 88mm Turbo ,fullrace head ,100mm Tb and HKS 312 deg cams ect I'm sure I will 9000+ rpm.
 

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From what I read on the internet and talk to people, the OSG setup is dyno proven and also in Japan and is an excellent setup from my point of view I would buy with out hesitate.

The RB30E conversion for Skyline use seem like it was developed by back street garages in Australia for quick cheap torque increase. The RB30E block does not even have oil spray jets for cooling, the block is weak designed for 2 tone family cars and trucks, where the RB26 block which was designed for race and high power applications.

So either make choice for OSG RB30, HKS 2.8 setup or Apexi 2.9 conversion (if still available) Leave the RB30E for enthuastic testers and home brew mechanics who can do their own mechanics because the will be many reliability issues as we see R32 Combat having.
 

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I'll add some facts for you.

OS Giken RB30 con rods are 138.35mm centre to centre which gives a rod length to stroke ratio of 1.61

The aluminum spacer on top of the OS Giken RB30 is 24mm thick.


 

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So thats the rod ratio thing sorted, I was correct there.

Oil squirter issue is interesting, think I remember Mario on about this, didnt he say for a mega high revving engine it was technically a bad thing?

Either way, its not hard to get them machined in, i know people whos had it done on a variety of engines.

One thing is 101% for sure in this world, and ive found this out a lot over the last year or so, what people say publicly is often very different to the true thoughts/beliefs/info, as they are just trying to steer people certain ways for certain reasons, not in a money making way, but if someone with a lot of influence slags something off, nobody is likely to do/try it, barring maybe them ;)

Thatl do for me, its Friday night and im not even out yet.
 

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Discussion Starter · #18 ·
WELL That's worked so far....

Steve n if you spent half the time and cash you spent getting "crabs "
On your car ! you would be blazing us with numbers less embarrassing than hugh's :rolleyes:
wouldnt you ?
lay off the slappers and do it !

Mr combat,
whilst seeming to appreciate the concept of fine engineering , the soldered plumbing solution whilst functional as a jury rig has cost you some kudos soz for the spelling but my computer thinks I live in maliboo. :)

I have no axe to grind here... as
I blew the motor my car came with at knockhill !
I played with the boost controller the car came with.:bawling:
Having no concept of boost re fuel detonation etc.
Whupping the stock ferrari cost me £3500 for a replacement motor which lasted less than 600 miles from an r34 which upon inspection must of been a ram raider !:bawling:
After ingesting one of the inconell wheels this new wonder expired !:bawling: :bawling:
I decided to build my own new engine, to my spec.

I chose to go HKS 2.8.
Thanks Charlie , that crank pic was fatal !

Im not rich or gay,

well I have not turned to the Pink pound yet. dont want to offend any not sure sponsers. :blahblah:
But if nissan could have just slapped an rb 26 head on their already mass produced 3 litre single cam engine.........
Why invent the race bred RB 26 ??????
end of rant c
 
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