N1 Oil Pump

[Guilt-Toy]

I am thinkin of buying a N1 oil pump to replace my RB25DET pump in my RB30DET, it has around 360+ rwkw and I keep hearing shock storys of them breaking into pieces on the drag strip or sometimes out of the blue.

Is there a reason for this ? I do have a crank collar on my crank (stupid thing caused all sorts of drama's which destroyed my previous crank) but anyway....

The old RB25DET pump has done me well and still works but its had close to 300,000 km's on it so i am thinking its time to change it and cannot really afford a Nismo or JUN pump at this time.

Anyone have any luck with these pumps ? is it just that they dont like the rev limiter too much ???

Anyways who has used them or is using them where they are working well? is that talk all just bullshit or should i just keep the 25 pump ?

[bubba]

I've heard it's something to do with high revs.. myself and my mechanic both run one on our 30s but on his 26/28 drag motor he is going to run a Jun pump because it will be seeing much higher revs.

[Guilt-Toy]

ok to add to this, i am only going to be pushing a MAX of 7200rpm. it will hardly see more then 7000rpm. Dont need more revs then that.

[bubba]

From what I understand 7k is fine, significantly more than that is likely when you would see failure.. this 26/28 is being built to rev to 10k so no scrimping on the oil pump there

[Guilt-Toy]

what setup do you have in yours? what are you like with the rev limiter? i need to use the rev limiter because sometimes its just sooo hard to catch the revs before hitting it, some gears its near impossible.

[SATO GTS]

you will have no issues with the N1 if you bottom end is all balanced well with light weight good quality rods .

i think all the talk about N1 smashing drives is because ppl put heavier aftermarket rod's in and try and rev them then the harmonics really start to happen and the weakest link is the oil pump gears.

[Bliksem]

AFAIK the only difference with the N1's is the different casting and the pressure relief valve uses a higher rated spring.... In other words it wont actually flow any more, It will just hold pressure longer before the relief valve opens at higher rpm.

The same can be acheived on the RB25/26 pumps by removing the relief valve and installing an extra washer. My engine builder informed me that a 1mm washer will bump pressure up approx 5psi.

Edited January 31, 2008 by MintR33

[Guilt-Toy]

can you measure an engine for harmonics?

[SATO GTS]

The gears of the N1 oil pump are made from a harder grades metal then std , they also have a lesser amount of teeth on the oil pump drive gears allowing the pump to flow more and the backing plate has a 8 bolt pattern instead of the 7 , its also thicker .

Not sure about if you are able to measure harmonics. I am sure there would be some expensive machine out there that would measure harmonics.

[Bliksem]

Thats interesting SATO are we both talking about N1 pumps, not getting confised with Nismo?? both my engine builder and SK are saying the same thing, heres a direct quote from SK

Hi Merli, having measured quite a large number of RB pumps what I have noted follows;

*N1 GTR pumps run at higher oil pressure but the same flow as standard GTR pumps.

*I have "adjusted" the pressure relief valve on a standard GTR pump and achieved the same oil pressure as an N1 pump

*N1 pumps are the same dimensions as standard pumps therefore can not flow any more oil than a standard pump does at the same rpm.

*HKS GTR pumps are thicker across the impeller, therefore flow more oil at the same rpm.

*HKS GTR pumps have adjustable oil pressure, so you can run higher, lower or equal to strandard pressure but at higher flow rates.

On our circuit race cars we always increase the capacity of the sump and fit wings and one way baffles. Anybody who spends any time on a circuit should do the same.

Hope that helps

[Bliksem]

Heres a more recent reply from SK re N1 oil pumps:

Absolutely correct Chris, all the N1 pump does is run at a higher relief pressure. Jun, HKS, Trust and a couple of others make pumps that actually flow more. I don't know what prices you get over there, but I can buy a complete Peterson 4 stage dry sump system for less than Jun want for a replacement pump. Both still require sump mods, so it pretty easy to understand why I go for the dry sump option on the race cars. On the road cars I simply fit a stronger pressure relief spring to the standard GTR oil pump, then it's the same as an N1 pump, costs about $2.

[HR31DRFT]

I went the Tomei h/v pump for my build, cost a bit but works good with my 7ltr sump.

[bubba]

what setup do you have in yours? what are you like with the rev limiter? i need to use the rev limiter because sometimes its just sooo hard to catch the revs before hitting it, some gears its near impossible.

My limiter is set to 6800rpm but I never hit it due to the small assed turbo on there (rb25 turbo) it falls over about 5800rpm and drops down to 90hp by the limiter. I just make a point of shifting up ~5500rpm.

[Sydneykid]

There is a further complication, there are 7 "standard" RB26 oil pumps available from Nissan;

1 .R32GTR Early

2. R32GTR Late

3. R32GTR V Spec

4. R32GTR N1

5. R33GTR S1

6. R33GTR S2 + V Spec

7. R34GTR all models

#1 is not the same as any other RB26 pump, plus it has the narrow drive flange, and it is the same as RB20, RB25 and RB30 (late)

#2 is the same as #5

#4 is the same as #6 and #7 except that it has a higher pressure relief spring

I have yet to see/measure a guaranteed #3, although I suspect it is the same as #4

So when I say a "standard" RB26 oil pump is the same as N1 oil pump except for the pressure relief spring, I am not talking about #1. That should be obvious as #1 has the narrow drive flange whereas #2 and all subsequent RB26 oil pumps have the wide flange drive.

Thinks that's complicated, but wait there is more. Don't expect to be able to go into a Nissan dealer and order #2, #3 or #5 as their part numbers have been superceded by #6 and subsequently #7.

Cheers

Gary

[Sydneykid]

Not sure about if you are able to measure harmonics. I am sure there would be some expensive machine out there that would measure harmonics.

We don't "measure" harmonics, we feel them. The gear lever is not bad for that.

On the engine dyno, you can feel it through the flooor.

Cheers

Gary

[benm]

Where can I get a 'pressure release spring" and what does it look like?

Also, I didn't think standard oil pumps could be bought new anymore, only N1?

[Bliksem]

Where can I get a 'pressure release spring"

I would also like to know this...

[STATUS]

I am thinkin of buying a N1 oil pump to replace my RB25DET pump in my RB30DET, it has around 360+ rwkw and I keep hearing shock storys of them breaking into pieces on the drag strip or sometimes out of the blue.

Is there a reason for this ? I do have a crank collar on my crank (stupid thing caused all sorts of drama's which destroyed my previous crank) but anyway....

The old RB25DET pump has done me well and still works but its had close to 300,000 km's on it so i am thinking its time to change it and cannot really afford a Nismo or JUN pump at this time.

Anyone have any luck with these pumps ? is it just that they dont like the rev limiter too much ???

Anyways who has used them or is using them where they are working well? is that talk all just bullshit or should i just keep the 25 pump ?

when you say you cant afford a JUN pump, what have you been qouted for it? and what have you been qouted for a nissan N1?

i usually pay around 70000 ($750) yen plus shipping for a JUN 1013M-N001G unit. RRP is 98000 or $1050 worst case..

[The Mafia]

hasn't it also got something to do with the harmonic balancer?

[Simon-S14]

RB25 oil pumps are 500 from nissan, so you'd be silly not to pay a few hundred more for a jun 26 pump... tho that said i cant understand how they are so expensive.... a water pump has the same sort of casting required to make it... the only expensive part i can see being is the gear set... but stil!