# Oil pressure at higher revs RB26



## FRRACER (Jun 23, 2013)

Just been watching a few videos of a couple of cars that are being revved beyond 8000rpm. While I watched the Mines R34 earlier version hovered between 3-3.5bar at over 8000rpm but I suspect they updated the pump later and that is certainly holding 4-4.5bar of pressure.

Also Nicholas Kiesa on his famous 10k pulls pressure seems to be dropping back a fair bit. One of the videos its in the 3.5 range also. But one where he is at 10k rpm pressure is dropping down to 2.5? If I have read it right... Not sure what oil pump he is running for sure most of his components were Jun but this picture below looks like an older spec Nismo with 81mm outer drive gear but there was a thread of his engine build and specs here iirc.

I guess the viscosity of oil will have some impact also.

Would be good to get some real life data for the current pumps available logged if poss as the gauges are not always accurate.


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## FRRACER (Jun 23, 2013)

And revs at 10k rpm


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## FRRACER (Jun 23, 2013)

Mines R34 a later video


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## David (Apr 25, 2003)

Nice piece of work with the screen captures and I am interested in the replies you get, I guess Matt j is pushing past 8k.


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## FRRACER (Jun 23, 2013)

Aside of oil pumps breaking, pressure is another thing people overlook. MattJ uses a dry sump setup. Another factor that I forgot to mention are bearing clearances as seems the case some tuners go a couple of steps bigger on tuned engines over 500 bhp. See below


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## David (Apr 25, 2003)

I know Matt J uses a dry sump but his oil pressure would still be relevant to understand what pressure is necessary at high rpm and high bhp. From speaking to Rich many years ago I thought it was much lower that my expectation.


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## David (Apr 25, 2003)

FRRACER said:


> Aside of oil pumps breaking, pressure is another thing people overlook. MattJ uses a dry sump setup. Another factor that I forgot to mention are bearing clearances as seems the case some tuners go a couple of steps bigger on tuned engines over 500 bhp. See below


That is interesting as I have been involved in the detail study of bearings to understand factors that increase oil film strength and going looser on tolerances decreases the oil film strength.

I can't publicly release the detail of the project I was involved with but we ended up spending considerable amounts of money improving clearance and improving flow which you have not mentioned directly yet(reduces temperature and therefore seizure limit)


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## R32 Combat (Jan 29, 2004)

You all know why the RB26 idles higher than the RB25 right?
I'd hazard a guess that also the issue you see with oil pressure.
People bang on about revving the tits of an RB engine without the faintest idea what the issues are. You can overcome this fairly easily but not of you don't know what your doing.


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## Dan ep3 turbo (Sep 29, 2013)

My tomei oil pump has really good oil pressure I would think that would be good enough for high rpm, I see over 3 bar on idle at about 5 k it stables to around 5.5-6 bar if I remember correctly.


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## Dan ep3 turbo (Sep 29, 2013)

R32 Combat said:


> You all know why the RB26 idles higher than the RB25 right?
> I'd hazard a guess that also the issue you see with oil pressure.
> People bang on about revving the tits of an RB engine without the faintest idea what the issues are. You can overcome this fairly easily but not of you don't know what your doing.



What do you think would be the issues Andy? Crank harmonics a good balance and ati damper and obviously your engine would need a good cylinder head with big cams and fairly large rear housings on the turbos so the power doesn't drop off early?


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## matt j (Oct 19, 2001)

David said:


> Nice piece of work with the screen captures and I am interested in the replies you get, I guess Matt j is pushing past 8k.


My redline is 9300 with the GCU set at 9200, we've been over 10k in testing but it's not necessary. I have oil pressure logs I could post but they won't help as I had a restriction causing the pressure at the sensor to be higher than the engine.


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## R32 Combat (Jan 29, 2004)

I expect cavitation occurs in the oil pump.


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## matt j (Oct 19, 2001)

There were no symptoms or signs of cavitation in my pump when I serviced it Andy.


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## C7 JFW (Jun 25, 2006)

R32 Combat said:


> I expect cavitation occurs in the oil pump.


Would you be kind enough to elaborate a little more and explain the difference in idle please?

What are the solutions?


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## R32 Combat (Jan 29, 2004)

matt j said:


> There were no symptoms or signs of cavitation in my pump when I serviced it Andy.


I would not expect to see any physical signs of cavitation in your engine Matt. It forms over hundreds of hours.
There are lots of factors that effect cavitation and a good oil system with good oil will not do it.
I than think of no other phenomenon that causes a loss of pressure over a certain pump speed.
Expecting a pump to work across a speed range of 10,000 rpm is a fairly big ask. The water pump you can gear with pulleys. The oil pump, unless chain driven, is a big more tricky to gear. If you reduce the operational range I'm sure it would be easier.


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## matt j (Oct 19, 2001)

Surely you'd expect to see physical signs of cavitation in the oil itself, i.e. a running sample would be cloudy.


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## R32 Combat (Jan 29, 2004)

Not always.


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## matt j (Oct 19, 2001)

I can't see any visible signs in the engine, pump or oil. There's no excess temperature or noise that we can see/hear. I'm not 100% certain but I would presume the SKM could be targeted to filter for the frequency of cavitation noise as with any audible vibration analysis; I'd have to research or ask MoTeC about that one though - I suppose it's probably not something they get asked to often. I hadn't thought cavitation was an issue until now, so I'll take a closer look when I get chance. Cheers Andy.


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