0w-5 Oil @ 10,000 rpms

[buster]

http://www.mpt.org/motorweek/goss/2313.shtml


Thanks to batterycar for the link. I think this should dispell some of the "thick is better" myth and make us all realize it's all about the chemistry used and not necessarily the viscosity.

 

[DockHoliday]

Interesting article. These guys rebuild their engines after every race, so their goals in choosing a motor oil are HP first, and only require enough lubrication to get the engine through one race. That is why they run a different oil for qualifying that for the actuall race. I would venture to guess that synthetics allow them to run a thinner oil.

For me, I am more concerned about using an oil that will protect my engine well enough to go for 300K + miles.

 

[ToyotaNSaturn]

quote:

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Originally posted by buster:
True, but they are running 0w-30 for the whole race now, not 50wt oils.

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It's amazing to me to see such thin oil stand up to such abuse without the engine self destructing.

quote:

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Plus a Datyona 500 running a 0w-30 ror 500 laps at 175 mph more then exceeds anything you guys could do to a street car.

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You haven't driven any expressways in Chicago lately! LOL

 

[JohnBrowning]

buster their rings are usualy worthless after one race! I double dog dare you to run a 5 viscosity oil! I belive NEO and Redline make a true 5 in single weight. You think you little 1.8 eats oil right now!! Viscosity is about preventing metal to metal contact through hydrodynamic means. I am sure we might need to come up with a detergent package to add to that though. Maybe if we over based with calcium add and some LC you could try it for 5000 miles?

 

[Patman]

Just like Dock said, racing conditions and street conditions are two different scenarios. Just because that viscosity oil works well for a race, doesn't mean it's going to work in a street engine and allow you to get 300k out of it. Most engines would probably burn a quart of oil every 1000 miles if they ran that thin of an oil too.

 

[buster]

True, but they are running 0w-30 for the whole race now, not 50wt oils. Plus a Datyona 500 running a 0w-30 ror 500 laps at 175 mph more then exceeds anything you guys could do to a street car. So it's not viscosity always, but the make up of the oil. Technology has allowed lowere wt. oils such as the 20wts we are now seeing be very effective. I'm sure you could get 300k miles using a 20wt oil with no problems.

 

[DockHoliday]

quote:

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Originally posted by buster:
I'm sure you could get 300k miles using a 20wt oil with no problems.

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That is the $64,000 question.

[ January 02, 2004, 01:02 PM: Message edited by: DockHoliday ]

 

[Leo]

They probably use extensive oil cooling so that a 30wt during the race wont be as thin as we would expect! But one thing for sure, the engine is relying badly on EP/AW additives.

 

[Patman]

quote:

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Originally posted by Leo:
They probably use extensive oil cooling so that a 30wt during the race wont be as thin as we would expect! But one thing for sure, the engine is relying badly on EP/AW additives.

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Here is a quote from that article which shows they do see high oil temps often though:

quote:

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I've had cases where this might, my oil temperature gauge is pegged at 320 degrees, because we've got a piece of paper on the front of the grill. Heck, I've run 200 and 300 mile races without having any problem whatsoever. In fact, I've won races before at the oil temperature gauge peg, and you could never do that with non-synthetic oils. This stuff is really pretty bulletproof nowadays.

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[buster]

I'm surprised this oil isn't all ester based. I'm guessing it will have to have a lot more ester content then M1. Othewise it should resemble S2k quite a bit.

 

[wulimaster]

I believe he said the tolerances were made closer which means the bearings can float on a thinner film of oil. Also, the cars run consistant high rpms which also helps. A large dry sump with high oil flow doesn't hurt either.

If you want to compare racing cars with street vehicles then at least pick a type race where the car is changing gears constantly, the engine rpms go from low to high on full throttle or mid throttle to high as you row through the gears. How about 24 hr Le Mans or Paris to Dakar or Baha 1000 or Grand Prix.

Anybody know what type of oils are used in the above races?

[ January 03, 2004, 07:45 PM: Message edited by: wulimaster ]

 

[XS650]

quote:

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Originally posted by wulimaster:
I believe he said the tolerances were made closer which means the bearings can float on a thinner film of oil. Also, the cars run consistant high rpms which also helps. A large dry sump with high oil flow doesn't hurt either.

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How thin a film of oil the bearings float on is more a function of rpm, load and oil viscosity than tolerances. The oil film on the loaded side of the bearing is way less than 1/2 the total bearing clearance.

I've designed journal bearing systems that used water as a lubricant. The had greater clearance than normal automotive practice. All they required was a good supply of water, but the actual running clearance on the loaded side was microscopic.

One of the problems with low viscosity oils is the reduced clearances on the loaded side makes them more susceptable to damage from smaller particles of dirt. Less clearnce on the loaded side means that a smaller piece of dirt can damage the bearing.

It seems like the xW-20 oils are chasing a very small economy gain at some real increased risk of damage or increased wear down the line. As long as everything is just right, xW-20 is fine. Let something get out of tolerance, like the size of dirt particles in the oil, or oil temperature, and an engine with xW-20 is going to be more susceptable to damage.

[ January 03, 2004, 11:20 PM: Message edited by: XS650 ]

 

[Robbie Alexander]

quote:

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Originally posted by ToyotaNSaturn:
It's amazing to me to see such thin oil stand up to such abuse without the engine self destructing.

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no doubt... what about the motors that go many more RPM's ???
what is their lifespan
I hear the average Joe that races rebuilds every season maybe twice... If they didn't would it still make it another season or would it blow apart>???