windage tray

General engine tech -- Drag Racing to Circle Track

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Re: windage tray

Post by Newold1 » Thu Jan 18, 2018 7:29 am

I feel like other than trap doors baffles my inadequate education in gobbledy gook and double speak that my understanding of the descriptions of 2 phase oil flow movement is a case of , if I can't baffle them with brilliance then I will mystify them with bullshit! :roll:

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Re: windage tray

Post by ptuomov » Thu Jan 18, 2018 11:53 am

Ken_Parkman wrote:
Wed Jan 17, 2018 4:53 pm
Late to this discussion, but to add a few comments. There is some serious weirdness that can happen in an engine sump. It is not intuitive on what is going on, and to explain where the power is going you have to revert to fundamental physics. The potential power loss in a sump is huge and it does depend on oil control, even in a stationary engine. The issues relate to 2-phase flow.
It's a funny coincidence that about a year ago I asked a job candidate this same question. He had an engineering degree, and was looking to switch to finance. I asked him how does he model the two-phase flow in the car engine crankcase. Gave a decent answer, at least to the point I could understand it. It's a perk of the job to ask people explain things about their field.
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Re: windage tray

Post by n2xlr8n » Thu Jan 18, 2018 12:43 pm

I'm just shocked that we had a robust discussion of windage without Kevin and Jon. :lol:
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Re: windage tray

Post by Krooser » Thu Jan 18, 2018 4:35 pm

ptuomov wrote:
Wed Jan 10, 2018 4:03 pm
bigblockmopar wrote:
Wed Jan 10, 2018 3:08 pm
How about maybe that windage trays on modern days engine are installed closer to the crankshaft than on older engines? Or larger internal block webbing? Providing less room for air displacement/movement between cylinders.

Another thought; how about the thicker oils used in the older engines would show more benefit with a tray in draining/keeping the oil away from the crank than on modern engines with thinner oils.

Then again, why would modern manufacturers spend the resources to design and fabricate something that will limit its engine power.
There must be more (economy/efficiency?) benefits at the lower rpms that offset a little loss in the upper ranges I would think.
I think that a well-designed windage tray definitely has a real benefit in a wet-sump car engine when the car is in actual use. There's a reason why car manufacturers create these complex and expensive-to-manufacture trays. They aren't doing it for fun.

The external g-forces cause the oil to splash out of the sump. The windage tray acts as physical blocker keeping most of the oil out of the rotating crankshaft. You really don't want the oil to surge into the crankshaft, say, when braking into a corner.

The V8 windage trays also usually have devices that shield the head oil drains from piston pumping pulses that disturb oil drain. It's not an effect that one will notice in a 9-second dyno pull, but run the car hard on a track or twisty road for an hour and there's a difference in oil drain and oil aeration.

The block webs and skirts coming further down in newer engines are definitely another issue. The modern, very stiff blocks with main girdles instead of main caps and deep skirts dramatically reduce the area that is naturally available for piston pumping pulses to communicate between bays. In fact, the designed now usually accept the fact that some fraction of the bay to bay pumping gas flows are going to communicate in the valve cover cavities, via the head oil drains. All of this makes it harder to design a windage tray that doesn't increase crankcase pumping losses and reduce power. These modern engines need big breathing holes in the main webs and in the windage tray.

My opinion (not a fact) that modern V8's get a real and meaningful reliability benefit from well-designed windage trays in actual use and possibly a real and meaningful power benefit in actual use by keeping the oil from sloshing into the crankshaft because of the external g forces. My opinion is that most of those well designed trays aren't helping and may be slightly hurting power when the power is measured using a short pull on a stationary dyno.
How many remember the big Moon breathers we used down low on the block or oil pan 50+ years ago?
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Re: windage tray

Post by Mattax » Fri Jan 19, 2018 7:22 pm

Geoff2 wrote:
Wed Jan 10, 2018 3:11 am
To answer your question about Chrysler windage trays: numerous publications. This is one from my Mopar Performance handbook, published by Chrysler: 'We ran the B-RB windage tray on our new 440 dyno engine. 400 hp without, 416 hp with tray'. Engine was run to 6000 rpm.
Yes, sometimes. It also has an exception.
Starting with the B & RB Engines as that's what's been referenced. The stock pan is center sump with shallow front and rear.
From (Chapter 5) Mopar Engine Chrysler Corporation, Direct Connection p/n P4349340 1984
With the recommendation to modify Stock Pan by increasing depth of sump by 2" (or purchasing basically the same from Chrysler) the text says stock based pans must have the rear acceleration baffle sealed to sump. Illustration 5-18 states "Include Windage Tray with this Modification!" (in capital letters). So the tray is in addition to the horiontal sump baffle.
Two pages later it states "Every high performance "B" or "RB" engine should have a windage tray." Similar to the quote above, this bulletin then goes on to state "It's worth 15 Hp at 6000 rpm!"
However the same pages note that with the full Race Oil Pan (10" deep rear sump with with swinging pickup, and 6.5" deep front half) the windage tray should not be used. With this race pan "the windage tray should be removed resulting in increased car performance. If the car slows down when the tray is removed, the pan has been compromised too much and the tray should always be used with that particular pan."

So it would seem that the use of the windage tray is, at least in part, related to depth of the pan's return areas and sump. They further clarify this in the chapter on race oiling systems. Specifically stating that if the front portion has to be made shallower in one of the options illustrated, its likely that the windage tray will be needed.

It should also be mentioned that the stock 340 cid smallblock v-8s were equiped with windage trays from the factory. However, there was a bulletin or ? advising racers to open up the louvers, as the exit areas were too small. Sorry I can't find that one quickly.

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Re: windage tray

Post by Geoff2 » Sat Jan 20, 2018 4:05 am

No exception. Direct quote from MP book #4452790, page 316.

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Re: windage tray

Post by ptuomov » Sun Jan 21, 2018 9:00 am

In an unrelated thread, here’s a windage tray example from pre-computer-everything era:


Oiling problem in a shallow sump, which gets cured by either 2” deeper pan and no windage tray or a 5/8” deeper pan and windage tray. No word whether the test was under g-forces or not, or whether the screen met or only approached the deep pan power level.
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