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Simply, the block on a Nissan RB30 is not up to the quality standards that the RB26 was designed. You take a 2.6l specificly that was designed for high performance then you add a full counter billet crank, forged rods, a perfect cylinder wall, all designed and ballanced to work perfectly with each other. plus the square 86*86 bore stroke. How can you compare that to a engine that was designed to run in a sedan/truck/tractor, with probably a red line of not more then 6000 rpm. even if you match money spent and put in all the same parts installed you are still stuck with the less then ideal bore*stroke ratio and the weaker base engine.


I dont think that you can even compare the two
 

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SteveN said:
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.

Oh, I think you could get the RB30(E) engine to run the same revs as an OSG, but that sort of defeats the object, as it would end up costing what an OSG does, and for car resale, you would get more back selling a genuine OSG engined GTR.

Personally I think stretched displacement RB's are overated for all out power. Sure there is no disputing that an OSG (or RB30E for that matter) makes for a superior road car experience, but for what they (OSG) were designed for, i.e. on the drag strip, certainly in the UK, they haven't lived up to the expectations.
Perhaps although capable of revving to silly revs, the OSG is just not as eager to do so, as the old faithful short stroke RB26 is.
Maybe something has to be said for burn duration on Turbo engines, and residual cylinder pressures.

Who knows, maybe Keith will set the record straight.

It is nice to know that there are a vast choice of configurations for the Skyline, probably more than any other car? Better than just having to argue over single v twins:p
 

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oh it all comes down to this.......now are we all paying attention!!!!!!!!!! what ever can be done to the rb26, to make it the all impressive osgiken " RB30 " kit,,,,,, can be done to the REAL RB30........ but hey it doesnt need a big bimetalic strip bolted to the top of it to make it 3L............ so yes the REAL RB30 can be made to rev as high as a osgiken " RB26/SPACER kit" and have made a 1000hp with the standard crank.................
 

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backnblack said:
oh it all comes down to this.......now are we all paying attention!!!!!!!!!! what ever can be done to the rb26, to make it the all impressive osgiken " RB30 " kit,,,,,, can be done to the REAL RB30........ but hey it doesnt need a big bimetalic strip bolted to the top of it to make it 3L............ so yes the REAL RB30 can be made to rev as high as a osgiken " RB26/SPACER kit" and have made a 1000hp with the standard crank.................
Care to post a link to a Holden RB30 making 1000bhp on a std crank then?
 

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what im saying,,,, YOU LISTENING?????? the money that can be spent on the 26 to make the osgiken kit,,,,, can be be spent on the real rb30, but hey you dont need the bimetalic strip on the top!!!!!!!!!! LIKE IT OR NOT!!!!!!!!
 

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Cokey- You all might rather spend all your money on cars, but personally im young and straight so I find fit birds and going out far more enjoyable than skylines and showing off to middleaged men about the flashy parts on my 15 year old Nissan.

Toby Broom- Why does that have any relevance? You can spec the compression on any lump to whatever the hell you like. The Aussies and Nz lot run less compression to UK Skyline folk as they not stupid and actually want to run big boost on pump fuel, unlike here.

Nisfan- I dont get it, you go on about Nissan RB30s not being able to rev, so when I explained that you could easily get them to rev just as well you say building a revver isnt what they about!

Personally the reason for a Nissan RB30 is CLEAR for me...

Mine is a road car.
I dont want to have nothing worthwhile below 5.5k like many big power RB26s.
I dont want to need to rev to 9k for useable power.
But want to be ok to rev to 7500 all day long.
I want big power and huge torque.
At least 700bhp and 700lbft, but probably more power and maybe torque too.
I havent got tons of money.
I dont want to re-torque my crank pulley every morning for fear of it flying off and smashing everything, causing me a big bill and nearly writing my car off.

Nissan RB30 on standard crank does all what I want it to.

If I wanted 1000bhp+ and 3litres I maybe would go for the OSG, or a linered Nissan block, or who knows, never looked into it as it dont interest me.

Surely if chasing all-out power then capacity is irrelivant anyhow, and youd be just as well off sticking with 2.6 and using nitrous to help the spool if its an issue.
 

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backnblack said:
what im saying,,,, YOU LISTENING?????? the money that can be spent on the 26 to make the osgiken kit,,,,, can be be spent on the real rb30, but hey you dont need the bimetalic strip on the top!!!!!!!!!! LIKE IT OR NOT!!!!!!!!
You Aussies and your tractor technology RB30 and hype crack me up!:p
 

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NISFAN said:
Oh, Personally I think stretched displacement RB's are overated for all out power. Sure there is no disputing that an OSG (or RB30E for that matter) makes for a superior road car experience, but for what they (OSG) were designed for, i.e. on the drag strip, certainly in the UK, they haven't lived up to the expectations.
Perhaps although capable of revving to silly revs, the OSG is just not as eager to do so, as the old faithful short stroke RB26 is.
Maybe something has to be said for burn duration on Turbo engines, and residual cylinder pressures.

Who knows, maybe Keith will set the record straight.
I was not going to post on this thread but after reading the above i feel
that i have to say something.

NISFAN

I can tell you that the OS Giken engine is not overrated for all out power
on my last 2.7 engine I run with the rev limit set at 9K.I now have a extra 300c
plus loads more torque and I can still rev it to 9K.:)

We wanted big power but did not want to have to rev the engine to 11K
to get it,because that is when failures happen and then the engine needs to be
refreshed more often to try and keep it all together.

The decision was made that I would go for the 3L OS Giken engine and it is
simply awesome it makes the old 2.7 feel very slow.

The engine is running 2.5 / 2.7 bar boost.
1600cc inj running at about 70% with 6.5 bar fuel pressure.
We think that it is now making a good 1150+ bhp.

4000 revs still running -2 vacuum
5000 revs 0.3 bar boost.
6000 revs 2.7 bar boost:clap: :clap: :clap: :clap:

Keith
 

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backnblack said:
yer and keiths cars running 1200!!!!!!! PROOF???????? :blahblah: :blahblah:
With the boost,fuel and revs we are running plus looking at the logged runs
we think that the new 3L is making a true 1150+ bhp
not like most of the bullshit figures that get quoted all over the world.

I guess the black dyno will let us know soon enough

Keith
 

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Keith,

There are a number of OSG engines in the UK, bought when OSG's were significantly more expensive than they are now.
In addition they have a lot of supporting mods to get the best out of them, yet even as impressive the figures they give out in competition are, to most they fall far short for the amount of money invested.
As I said, maybe your all out spec will put that to right, but I am only commenting on proven figures thus far.
Perhaps longevity is what OSG's are all about, I don't know, but they do seem to be reliable.

SteveN,
I am truely baffled by your build, you say you only want 700hp, but have fitted a 900+ Turbo????? Perhaps you've changed your goals, but to answer your question, why would you spend OSG money on an RB30E just so it could safely rev higher? Surely buying a OSG crate engine is far easier? Upto you, as I said, nice to have the choice, and hope you get what you wanted.

Steve are you blacknblack? or is it Todd? Don't you hate it when someone snipes anonymously? Come on mods tell us who this mysterious person is. lol.
 

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NISFAN said:
.

Steve are you blacknblack? or is it Todd? Don't you hate it when someone snipes anonymously? Come on mods tell us who this mysterious person is. lol.
:wavey: hello
 
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