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A R34 GTR V-Spec II Nur is powered by the Nissan N1 RB26DETT

Identified by the number 24U marked on the block, where as the standard blocks are marked 05U.

Cylinder walls are thicker

Water cooling channels are enhanced to increase flow.

N1 Block

N1 Oil Pump

N1 Water Pump

N1 Pistons - 1.2 mm (0.047 in) top rings and were balanced before assembly but otherwise very close to standard.

N1 Turbochargers (Ball Bearing Steel internals)

Connecting rods are stronger and balanced.

Standard crankshaft is balanced to a higher level.

Cam Shafts are further balanced.

Higher flow exhaust manifolds.

rb26nur1024.jpg

I have my doubts that the 24U block really has thicker cylinder walls. From what i've seen they appear to be dimensionally identical to the 05U block.

They seem to have a similar cylinder wall thickness to the 05U block with an upper OD of the cylinder wall around 93-94mm near the top of the block. When boring to 92mm for sleeving, the 24U breaks through into the coolant galleries in a few places around the height of the large welsh plugs.

I recall reading somewhere that the casting metal used has a higher nickel content, making the material stronger. The porosity doesnt seem to be any better. I hope to have some pictures of a bored 24U block pre-sleeving inside a week or two, so I'll post them up when I get them.

Ta, If the water channels are bigger, it would stand to reason that strengthening of iron with nickel is a logical way to go; otherwise the walls would in fact be weaker. Thicker walls? I wasn't aware of that either - nor the nickel factor.

With the coolant gallery changes, it probably means just larger holes exist behind the top row of small welsh plugs. I haven't pulled the plugs on a 24U block to confirm this, but it makes sense as its the only area you can improve coolant flow into the block.

The top row of welsh plugs on the right side of the block is the main coolant gallery. Behind these small welsh plugs holes are drilled through the outer crank case, to the inner chamber in the block where the cylinders are. Coolant flows through the drilled holes and direct to the top area of the cylinders, where most of the heat is transferred to the block from combustion.

Because the coolant flows in around the cylinders and then up into the head through standardised size coolant galleries (which match all head gaskets), the holes on the top of the block are no different to an 05U block.

I have my doubts that the 24U block really has thicker cylinder walls. From what i've seen they appear to be dimensionally identical to the 05U block.

They seem to have a similar cylinder wall thickness to the 05U block with an upper OD of the cylinder wall around 93-94mm near the top of the block. When boring to 92mm for sleeving, the 24U breaks through into the coolant galleries in a few places around the height of the large welsh plugs.

I recall reading somewhere that the casting metal used has a higher nickel content, making the material stronger. The porosity doesnt seem to be any better. I hope to have some pictures of a bored 24U block pre-sleeving inside a week or two, so I'll post them up when I get them.

Ta, If the water channels are bigger, it would stand to reason that strengthening of iron with nickel is a logical way to go; otherwise the walls would in fact be weaker. Thicker walls? I wasn't aware of that either - nor the nickel factor.

I think I should have said re-enforced block rather then thicker walls...

wow.... thanks for all the info guys...

http://www.tomeipowered-usa.com/japan/nissan/jdmnissan.htm

:D

So is there a dramatic increase in power and response of an N1 engine over a standard 34 RB26? (factory tune)

I think the power output was not huge.

But due to the N1 Turbos it ran 1 Bar of boost, so power would be up a tad.

And being ball bearing turbos along with a further refined RB26, it all added up to better response.

not sure on factory tune, but after adding some straight forward mods I've gotten some amazing gains!

This!

i think the beauty of the N1 engine is more in its reliability factor cos the standard RB26 is already pretty impressive... thus u shd be able to push the nur more with its stock parts.. (stock parts being N1 items like steel bb turbos as compared to ceramic trust bearings ones :worship: ) so is that even a fair comparison? LOL :D

that said...vspecIInur .. are the ecu settings any different than the normal V spec II ?

The two 24U N1 Blocks in the current issue (#161) of PI Mag.

1) VS2 Nur

On high boost + N1 turbs + Motec M800 ECU + JUN Cams + Nismo Plenum + Bosch 044 + Sard 700cc + Sard Fuel Reg + Splitfire + Nismo Dumps + Nismo Ti Weldina Twin 90mm

Matthew-21.gif

On med boost > 323 wKw thanks to Unigroup Engineering where Yavuz needed to attend to lambda sensors and change tune

2) VS N1

On med boost + N1 turbs + PFC D-Jetro ECU + Nismo Plenum + Bosch 044 + Sard 700cc + Mine's Dumps + Mine's Front + Fujitsubo Ti 80mm

Terry-290.jpg

Both were also in Performance Garage mag #11

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