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N-1 vs std oil pump

The Alchemist
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The Alchemist Collaborator

The Alchemist

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got my N-1 oil pump yesterday and took it apart to compare to my std R32 GTR oil pump...(2 screws worked loose as they do )

here are the differences for interest sake:

1: the relief spring

std has a twin spring system N-1 has a single...both measured identical spring rates at 3 different heights starting from the installed height.

Interestingly the N-1 relief plunger has a small oil hole drilling about 8mm down from the top edge, level with the relief oil passage in the pump housing. This would have a dampening effect on the way the relief valve works as the spring cavity would have a head of oil in it that would have to squeeze out the small oil drilling first.

Plunger size was the same and relief valve cavity was the same.

2: the oil pump gears are where the biggest difference lies.

The N-1 inner gear has 1 less lobe (11) vs the std which has 12...this allows the internal volume of the pump gears to increase using a redesigned shape on the outer gear/inner gear meeting surfaces. We didn't CC the difference as the N-1 was obviously much larger than the Std R32 gear.

3: The gear hardness and material...

a hardness test was performed using a proper hardness tester in the machine shop. The std gears were a 0.56 and the N-1 scored a 0.96 a marked difference!

Also the gears were made out of the same material!! Sintered steel.

The major reason , I believe , that the N-1 gears have been hardened is that in order to increase the pumping volume the outer gear wall thickness has been dramatically reduced thus hardening is required to keep the strength up.

4:Internal channels are all larger in the pump housing and redesigned to increase flow

5: the pump backing plate has a redesigned screw fixing arrangment with an extra screw on the N-1 ( 8 screws vs 7 in the std ) Also the backing plate is 0.5mm thicker ( 6.5mm on the N-1 vs 6mm on the std )

A note worth noting :D the backing plate screws were not lock tighted, needless to say that they where during reassembly!!!

Cheers Mike

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GTRgeoff Grand Master

GTRgeoff

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Good stuff. I had been led to believe the N1 was just a higher spring rate on the relief so it's good to see some testing.

What I have confirmed from FAST is that the RB25DET and RB26DETT oil pumps flow exactly the same amount, but it doesn't detail any defferences in construction, so to all intents it is the same pump. I can't recall if the part number was different.

The Alchemist Collaborator

The Alchemist

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$850 NZ.

The Rb25 and the R32 GTR pump are indeed the same. We also happened to have one off a dead Rb25 and compared the two.

Interesting how the relief spring have the same spring rates eh?

Isn't the HKS pump worth a small fortune ??

Mike

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