Oil pumps questions

[Chris Wilson]

I have had engines apart with the "N1" oil pump fitted, as well as stock oil pumps, and I have stripped both stock and N1 pumps. The *ONLY* difference i could see and measure between the two was a longer relief valve spring in the N1 pump, giving higher operating oil pressure. the flow must be the same between them as the rotor widths and teeth numbers were identical. Someone said the metallurgical construction of the rotors differed, i find that very hard to believe myself...

My question is who makes a genuinely higher *FLOW* oil pump with a totally redsigned rotor assembly, probably a wider one? This would demand a new casting as the stock casting hasn't enough material to accomodate a wider rotor assembly.

Thanks.

[japtaxi]

JUN makes rb oil pump with higher volumn/flow at same pressure I think... mariogtr (aka exvitermini.com) would know more about it specification wise.

[cokey]

Hi Chris

I bought the Tomei pump, it has all the features your after.

V Expensive though. Got it from Rod Bell, took a whilst to persuade him to order it though.

cokey

[R32-GTS]

I got the Jun oil pump. feels alot heavier duty.

[600hp]

i 've got the JUN as well, a bit pricy but it does the job and yes it does have more pressure just call CRD and they can tell you more.

[R31Nismoid]

they cost a fortune when most guys run the N1 pumps and they are making some very good power with no issues at all.

from what i remember your power goal etc wont require a big $$ aftermarket one

[Duncan]

Chris, do you have pics of the standard and n1 pump internals and their springs?

[benm]

Merli has had some experience with both pumps, 1 of them cost him some $$$

[R32-GTS]

N1 pump can fail if your going to rev it hard. I heard no more than 8500rpm on n1 pump or you are risking it.

[Chris Wilson]

Sorry, no pics, but the rotors were identical (one set would fit the other pump and vice versa, with same number of "teeth". The only way to get more volume is a wider gear set, or (maybe) more teeth or a tooth form change, at any given pump RPM. I had a Tomei one in my hand yesterday, that was a totally different casting with the relief valve accessable externally, not buried in the sump, and with a wider gear set. A nice thing, but at a nice price too....

[SootyR32]

I bought the Tomei pump, it has all the features your after. V Expensive though.

How much is very expensive? I have one ordered with my Nismo N1 block.

[Chris Wilson]

How much is very expensive? I have one ordered with my Nismo N1 block.

On the Tomei Japan site they are listed at 178,000 Yen, over here in the UK they seem to sell for around 700 UK pounds.

[SootyR32]

WOW! Apparently, mine is only going to be AU$1200 to $1300, but that's a special price from the supplier as he is mates with my mechanic and is keen to see how my rebuild turns out.

[Warpspeed]

I am curious Chris, why do you require more pumped oil volume ?

The oil pump volume increases directly with engine speed. The only time it really becomes an issue is with a very low idle speed setting ?

As others have said the N1 pump has the same swept volume as the standard GTR pump. A high RPM engine can really use a SMALLER oil pump if the idle speed is suitably increased.

[Sydneykid]

I have had engines apart with the "N1" oil pump fitted, as well as stock oil pumps,  and I have stripped both stock and N1 pumps. The *ONLY* difference i could see and measure between the two was a longer relief valve spring in the N1 pump, giving higher operating oil pressure. the flow must be the same between them as the rotor widths and teeth numbers were identical. Someone said the metallurgical construction of the rotors differed, i find that very hard to believe myself...

My question is who makes a genuinely higher *FLOW* oil pump with a totally redsigned rotor assembly, probably a wider one? This would demand a new casting as the stock casting hasn't enough material to accomodate a wider rotor assembly.

Thanks.

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.