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Discussions about the RB26 oil system crop up pretty often, so we'd like to pull together some good information to guide GTRCers.
Feel free to contribute within the following guidelines:
1 - No internet fear mongering or repeating stuff you heard somewhere. If you've had bad experiences with a particular component, please post them along with relavent details about the application. (Max revs, hitting rev limiter or not, lateral or longitudinal g's, etc)
2 - Opinions are fine, but experience and sound reasoning are even better!
3 - Don't take it personally if someone disagrees with you. Differing perspectives make for great learning opportunities.
I'll start out with a summary of my own thoughts on this topic.
Eric (XSDAILO) has been kind enough to provide a summary of XS Engineering's guidelines.
Dan's thoughts:
I've heard some guys correlating problems with oil systems to high power engines, but to my thinking the problems follow this path....
Most common common oil system failures are pump hardware failure and oil pickup starvation. The second can cause the first, as pointed out here.
s13 diff will it work???
----N1 oilpump side discussion---------
Almost every N1 oil pump failure story I've read (and I've read 'em all) includes either reving over 8000 rpm and/or bouncing off the rev limiter. Bolts need to be lok-tighted in too.
Every component has it's limit and the N1 pump isn't made to spin over 8k or rattle off the rev limiter.)
----back on topic----------
Mechanical pump failure is usually caused by over revving and 'shocking' the pump. Shock is best minimized by staying off the rev limiter, balancing, and perhaps by running an upgraded crank dampener. (Perhaps because I've yet to find any hard data support the reasoning behind this claim.)
On the oil starvation side,
1 - Wet sump oil system failure correlates to the pickup sucking air or foamy oil. This correlation may not be 100%, but I'll bet it's close enough for our applications.
2 - Low oil level at the pickup results from a combination of low oil level in the sump (more on that in a second) and both longitudinal and/or lateral accelleration.
Low oil level in the sump is caused by either not enough oil in the system (easily avoidable!) or oil pooling in the head and therefore not sitting in the sump. The restrictor orifice will help here, but free oil return from the head to the sump is a key for extented high rpm operation.
The sump baffle will delay the onset of accelleration related grief, but there are definately limits. I don't know what they are, but the laws of physics dictate that there's combination of accelleration magnitude and duration that will expose the oil pickup. The baffle will significantly raise the magnitude of the tolerable transient g force, but if you spend more than X seconds sustaining high g's the oil will still run past the baffle and ....
I'm pretty sure about the basic info I've written, but I've only got limited info on acceleration limits for:
- no sump baffle (1.0 g 80% lateral, 20% longitudinal OK, 1.2 g not so much)
- sump baffle
- extended sump (not sure if a baffle is necessary here)
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Eric's input:
I don't know if I can give you any "definitive" information, but I can tell you the guidelines which we (xs) typically use for deciding what pump to use for which application. This is not THE word. This is simply how we decide based on our RB26 GT-R experience. If people disagree, so be it. Let them.
BNR32 stock pump = less than 7500rpm, less than 500whp street/drag & 400whp road race, stock restrictor. If doing a new build, I immediately throw the stock pump away.
BCNR33/BNR34 wide drive stock pump = less than 7500whp, less than 500whp, stock restrictor. If doing a new build, I immediately throw the stock pump away.
N1 pump = I never use it. It's a stock pump with a higher rate pressure relief valve spring. I've never used the Nismo pump either.
Greddy pump = less than 8000rpm, less than 600whp, 1.5mm restrictor. I generally do not use this pump unless the customer is cheap and supplies it himself.
HKS pump = less than 8500rpm, less than 1000whp (if street or drag), less than 800whp if road raced, 1.5mm restrictor
Tomei pump = less than 9000rpm, less than 1000whp (if street or drag), less than 800whp if road raced, 1.5mm restrictor. I generally use this pump on almost all of our builds.
4 or 5 stage dry sump = the absolute best for any configuration
When doing a build for a road/canyon racing application, at the very least I use the Nismo baffle. On a serious effort car, we run the Greddy sump with a custom modified Nismo baffle.
An oil cooler is an absolute MUST on the RB26 at any stage of modification. The RB26 is a long engine with MANY bearing/journal surfaces and a cramped, poorly flowing engine bay so oil temperatures are high in general. Even the Nismo bearings cannot handle sustained 110degC oil temperatures. I am excited about the new Cosworth bearings because they will handle the higher temperatures without the surface flaking.
On an engine with sustained 6000+ rpm use in mind, namely road racing, I typically use the HKS ATI dampener. I've only used the ATI USA dampener once before. In my opinion the ATI USA model is too narrow and uses one less o-ring than the HKS unit. The HKS unit is based the thicker small block Chevy unit and does NOT overdrive the A/C compressor to 50,000,000 rpm like the ATI USA unit does.
Those would be my tips for the oiling system. I hope this can help out.
Thanks
Eric
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Originally Posted by BeeGTR
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