Video: How much horsepower does your oil pan rob?

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It's a "known fact" among prius drivers that running 1/2 quart low (from the top pip of the stick) has MPG gains.
 
Originally Posted By: eljefino
It's a "known fact" among prius drivers that running 1/2 quart low (from the top pip of the stick) has MPG gains.


And draining half of your blood supply can make you lose weight.
 
Originally Posted By: eljefino
It's a "known fact" among prius drivers that running 1/2 quart low (from the top pip of the stick) has MPG gains.


This has been common knowledge in engines for years.

Many racers in "stock" (very strict rules) classes will only run 3 quarts in a 5-qt V8 engine oil pan.
In a 12 second drag race, you only need oil pressure for the 12 seconds of run time. If 2 quarts would do the trick, they would do it.

"Crankcase windage" can kill 10HP easily - at rated RPM.

Normal "grocery getter commuter cars" typically will never see a difference in anything if run a whole quart low.

Yes, I am serious!
Did you ever think the new Nissans with only a 3 quart capacity might have other reasons for their decision ?!?!!? Everyone is trying to get better MPG across the fleet.

EDIT: OK, I just watched the video. That was no surprise at all.
If they keep pulling oil out, HP has to go higher. It ALWAYS does!
 
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I wanted them to put 0w-16 in there and see if power was gained!
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Originally Posted By: eljefino
It's a "known fact" among prius drivers that running 1/2 quart low (from the top pip of the stick) has MPG gains.
I don't know about that "fact," but I'm careful not to refill mine with more than the specified volume---which incidentally does not bring the level all the way to "the top pip of the stick," only about 90% of the way up from the lower pip.
 
How much horsepower does your oil pan rob? - Er, none. Trick question? Or maybe stupid question?

How much horsepower does your oil amount rob? - Er, none. unless the oil level is excessive?

How much horsepower does an excessive oil level rob? - Er, quite a lot, because the crankshaft hits it.

This is not news.

The assumption in the above discussion that Less=More seems unlikely to be generally valid. I;d expect there to be a cutoff below which you wouldn't gain much if any horsepower but might loose your engine
 
The after market oil pan must be poor quality. Too much drama for a mans program.
 
With a well designed windage tray, there should be little or no difference in high to low on the dip stick.

If you really want to save HP at RPM, you go dry sump and vacuum pump. You pay something for the pumping losses, but not as much
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Originally Posted By: Linctex
Originally Posted By: eljefino
It's a "known fact" among prius drivers that running 1/2 quart low (from the top pip of the stick) has MPG gains.


This has been common knowledge in engines for years.

Many racers in "stock" (very strict rules) classes will only run 3 quarts in a 5-qt V8 engine oil pan.
In a 12 second drag race, you only need oil pressure for the 12 seconds of run time. If 2 quarts would do the trick, they would do it.

"Crankcase windage" can kill 10HP easily - at rated RPM.

Normal "grocery getter commuter cars" typically will never see a difference in anything if run a whole quart low.

Yes, I am serious!
Did you ever think the new Nissans with only a 3 quart capacity might have other reasons for their decision ?!?!!? Everyone is trying to get better MPG across the fleet.

EDIT: OK, I just watched the video. That was no surprise at all.
If they keep pulling oil out, HP has to go higher. It ALWAYS does!


I don't understand. The oil is still pumping regardless of the volume in the sump. I can see the 3 quarts warming up faster, but I would assume the engines would already be hot.

Also, some cars fitted for drag racing (obviously not stock) have over sized sumps.
 
Thinking about it a bit more, I think I not sure exactly what was going on here either.

I'd always assumed that the issue with over-filling was the crank actually hitting the oil surface, but I guess the term "windage" implies its actually rotating air entrained by the cranks motion and blowing oil off the surface.

If that's the case the horsepower loss may be partly due to air resistance, and maybe there won't be a sharp cutoff like there would be if hitting an oil surface.

I'd also assumed the dry-sump thing was to avoid oil starvation due to the oil going sideways due to lateral G's, and pumping losses from the piston underside pushing air around. Hadn't thought of air resistance to the cranks riotation.
 
Another thing is there were V-8 engines, (Oldsmobile and Buick among them), that had issues with the oil pump starving out because the oil couldn't drain back into the oil pan fast enough. Forcing the oil pump to basically to suck wind instead of oil. This led to bearing failure as oil pressure would fall to zero if the engine were run for any length of time at high RPM's. (Above 4,500 RPM). Like in jet boat applications. There were even kits that could be installed in these engines that would somehow prevent this from happening.

When I lived in Lake Havasu City, my neighbor had a race boat with a 455 Oldsmobile "Rocket" V-8 in it. He told me about this, and showed me the kit he installed in the engine to prevent it. He warned me if I was ever in the market for this type of boat, (Oldsmobile / Buick V-8 powered), and it did not have this kit installed, to run, not walk away from it. Running an engine of this type low on oil would make an already bad condition even worse. Deliberately running any engine with less than the rated oil capacity just seems foolish.

http://www.hotrod.com/articles/0302phr-oldsmobile-455ci-engine-build/

"The narrow passages from the stock heads do not allow oil in the valvetrain to return to the pan in an efficient manner. This condition can lead to instant death for a 455 that is run wide open for extended periods of time."
 
Originally Posted By: billt460
Originally Posted By: eljefino
It's a "known fact" among prius drivers that running 1/2 quart low (from the top pip of the stick) has MPG gains.


And draining half of your blood supply can make you lose weight.


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Part of the role of a sump, in addition to being a recepticle of oil, holding sufficient to supply the engine is to:
* give enough residence time for bubbles to separate out (hydrodynamics and air bubble don't work together)
* give enough surface area that the bubbles have the smallest path to the top
* keep surfaces away from the spinning assembly so that drops/streams don't hit a floor and either splash oil up, or break up and return as a mist.
* hopefully shed oil from the spinning assembly in the most efficent manner.
* do all of the above during any and all operating angles of the engine (including unertial effects from acceleration)

Air in the oil doesn't lubricate and pushes you quickly into boundary lubrication...the pressure and power loss is likely demonstrative of that...

If it sucked the sump dry, engine is toast on a dyno, although some drag racers will do that through the traps for that last poofteenth of shaft power for a second before shut-off.

If the crank runs into the oil, then it's really bad bad news, and poor design...LOL, saw an idiot when I was in the service stations put 3 gals in a 2.6 mitsubishi and drive off...sounded horrid, smoked badly.

In order to do what the video shows, the sump is grossly overfilled.

Regarding sumps, oil control, and G forces, I LOVE this video
 
When I worked on an advanced 5.3L V8 at GM, we did an experiment with oil levels to see the effect on fuel economy on the FTP-75 cycle. Stock oil fill on the L83 is 8 quarts, and we did tests at 6 and 4 quart fill levels. Fuel economy on the cycle improved at the lower fill levels, and was repeatable. We showed about 1% improvement at the 4 quart level. We did not attribute the improvement in economy to lower churning, but to the more rapid rise in oil temperature during the test. The FTP-75 test has to be started with the engine fluids at ambient temperature.
 
Originally Posted By: Linctex
Originally Posted By: eljefino
It's a "known fact" among prius drivers that running 1/2 quart low (from the top pip of the stick) has MPG gains.


This has been common knowledge in engines for years.

Many racers in "stock" (very strict rules) classes will only run 3 quarts in a 5-qt V8 engine oil pan.
In a 12 second drag race, you only need oil pressure for the 12 seconds of run time. If 2 quarts would do the trick, they would do it.

"Crankcase windage" can kill 10HP easily - at rated RPM.

Normal "grocery getter commuter cars" typically will never see a difference in anything if run a whole quart low.

Yes, I am serious!
Did you ever think the new Nissans with only a 3 quart capacity might have other reasons for their decision ?!?!!? Everyone is trying to get better MPG across the fleet.

EDIT: OK, I just watched the video. That was no surprise at all.
If they keep pulling oil out, HP has to go higher. It ALWAYS does!
When my friend was racing stock eliminator, he always said reducing oil level by a quart was worth a tenth.
 
Originally Posted By: mjoekingz28
More time in the garage for a tenth less time on the track?


Why would you say that ?

If it's windage induced power loss, then the oil is potentially aerated, and of far poorer performance as a lubricant...How do you equate more garage time ?
 
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