Reputable links for horsepower from windage tray/crank scraper

[ptuomov]

...
Remind me if SR20 is a large displacement V8?

Willem Weertman -- he only worked on large displacement V8s right?

Oh, crap.

I don’t believe that all the solutions that are good for a two liter four cylinder engine are good for say 6.5L cross plane V8. The issues are different.

In a big cross-plane V8 with a wet sump oiling system, the gas flows due to piston pumping pulses are the big problem. Those pulses need to communicate between bays. Some fraction of that pressure equalization happens thru the heads via head oil drains, some fraction in the oil pan and below the crank shaft. Yet some of it happens thru the breathing holes in the webs above the crankshaft. The car factories don’t want to put any “scrapers” or things like that too close to the crankshaft in these kinds of engines because they often make the primary problem worse.

Car factories today are pretty good at coming out with fully baked products. When one then hot rods them with longer stroke and higher rpms, one sometimes up outside what factory solution can handle in terms of crankcase gas flows. Sticking “scrapers” right next to the crankshaft in a hot-rodded large displacement V8 sounds insane to me, because I believe it makes the primary gas flow problem worse.

[Kevin Johnson]

Hey, let's take a big cross-plane V8 and divide it in half.

Oh, man. It inherited the dynamic fluid distribution problem in the bedplate.

Pumping exchanges are a big issue for I4 engines as well. That is why Toyota took the trouble to switch the orientation on the ZZ engines.

If you follow the longitudinal development of Nissan straight fours you can see the pumping problems introduced by a engineering swing -- that is related to, gasp, the ZZ engines.

I know you are working on the big Porsche V8 -- that's great and you and Herr Kuhn are doing lots of amazing and impressive work. However, you are trying to jump into a bigger pond without doing the requisite background research. I certainly should not have to school a professor on that, correct?

[ptuomov]

I’ve researched this a bit and talked to people designing software that is specifically used to design windage trays. That’s the opinion I’ve ended up with. It’s not guaranteed to be correct, but it’s a considered opinion that I’ve ended up with a lot of background research.

[Kevin Johnson]

Yes, well, to return to what I stated previously. I can accept that you cannot accept that.

[ptuomov]

Hey, let's take a big cross-plane V8 and divide it in half.
Oh, man. It inherited the dynamic fluid distribution problem in the bedplate.

The problem is much smaller in the four because the cylinder displacement per bay is often something like factor of 6.5L/2L larger in the V8. This is because half the cylinders and balance allowing larger cylinders in the V8.

[Kevin Johnson]

Funny how Porsche kept increasing the size of the scraper array in the floor of the I4 engine.

Poor software.

[ptuomov]

Funny how Porsche kept increasing the size of the scraper array in the floor of the I4 engine.

Poor software.

They did in fact have insufficient software for this problem at the time.

However, even today, it is the case that sometimes factories stick things relatively close to the rotating assemblies in four bangers.

Those oil guides in the ancient Porsche four banger oil pan bottom aren’t that close, however.

And in today’s factory V8s, they don’t ever have anything too close to the rotating assembly — they don’t want to block the gas flows.

[Kevin Johnson]

Funny how Porsche kept increasing the size of the scraper array in the floor of the I4 engine.

Poor software.

They did in fact have insufficient software for this problem at the time.

All that empirical testing Porsche did. From the Audi L4 to the 968, the ribs growing and growing in height, lastly being added to the sump cover. Just pitch that.

However, even today, it is the case that sometimes factories stick things relatively close to the rotating assemblies in four bangers.

Those oil guides in the ancient Porsche four banger oil pan bottom aren’t that close, however.

I imagine they went right up to the limit in their design manual. Like Mercedes did. Gotcha.

And in today’s factory V8s, they don’t ever have anything too close to the rotating assembly — they don’t want to block the gas flows.

Well, the domestic battle seems to be between Ford and Mopar. In 2009 I designed a system for the Coyote that managed gas flow and had a dedicated scraper. That was because I looked at it in my mind and saw a problem. Several years later I was contacted by race teams who tried the system because they ran the engine beyond the modeled design. It solved the engine destroying problems proleptically. I will do my best to stop thinking so much. Oh, I think some wise asses call that a solution looking for a problem.

I am wasting too much time on this.

[ptuomov]

Funny how Porsche kept increasing the size of the scraper array in the floor of the I4 engine.

Poor software.

They did in fact have insufficient software for this problem at the time.

All that empirical testing Porsche did. From the Audi L4 to the 968, the ribs growing and growing in height, lastly being added to the sump cover. Just pitch that.

However, even today, it is the case that sometimes factories stick things relatively close to the rotating assemblies in four bangers.

Those oil guides in the ancient Porsche four banger oil pan bottom aren’t that close, however.

I imagine they went right up to the limit in their design manual. Like Mercedes did. Gotcha.

And in today’s factory V8s, they don’t ever have anything too close to the rotating assembly — they don’t want to block the gas flows.

Well, the domestic battle seems to be between Ford and Mopar. In 2009 I designed a system for the Coyote that managed gas flow and had a dedicated scraper. That was because I looked at it in my mind and saw a problem. Several years later I was contacted by race teams who tried the system because they ran the engine beyond the modeled design. It solved the engine destroying problems proleptically. I will do my best to stop thinking so much. Oh, I think some wise asses call that a solution looking for a problem.

I am wasting too much time on this.

I think some of the gas flow commentary in your write up on Coyote was insightful.

However, I think that you’re putting too much weight on the oil flow and too little weight on gas flow in designing V8 oil control systems. No car factory puts anything that close to a V8 rotating assembly because of the gas flows. Including Ford with their Coyote engine, even after seeing your proposal. (It’s still nice to be asked, nobody from Ford asked me.)

[smeg]

I don't care if it's a 4 cylinder, V6 or V8. I think it makes sense to scrape the oil of a rotating assembly. Oil flowing past a bearing doesn't know what engine it's in and needs to get back where it belongs so it can repeat the procedure and not rob HP.

[makin chips]

I apologize, Kevin. After much research, it appears you are correct. The OEM 3rd gen Hemi windage tray does have a 'crank scraper function' according to the pdf I came across after posting. I did my best to verify that with another source and did find it mentioned in multiple places by multiple parties that it does include a 'crank scraper function'.

Sorry again, Kevin. I thought I did my due diligence in searching for documentation before I posted initially, but apparently I did not.

I've included one instance below from BASF

http://www2.basf.us/businesses/plasticp ... odule.html

For the all-new 2010 Jeep® Grand Cherokee, Chrysler in partnership MAHLE North America, the tier supplier, and BASF developed a thermoplastic oil pan module for the 5.7L Hemi engine. The module includes the oil pan, pickup tube, windage tray with a crank shaft scraper function, oil plug, gasket and bolts. The all plastic module replaced the prior generation design consisting of a cast aluminum pan, steel pickup tube and windage tray reducing the weight by over 3 kgs, a 41% reduction! The plastic module eliminates four process assembly operations reducing engine assembly cost and complexity. Ultramid® B3ZG7 OSI, “Optimized for Stone Impact, was selected to meet the impact and road salt requirements.

[ptuomov]

I don't care if it's a 4 cylinder, V6 or V8. I think it makes sense to scrape the oil of a rotating assembly. Oil flowing past a bearing doesn't know what engine it's in and needs to get back where it belongs so it can repeat the procedure and not rob HP.

The whole idea of oil hanging on to the crankshaft at 5000 rpm is ridiculous. It doesn’t happen. You don’t have to be a physicist to understand that a 5000 rpm crankshaft immediately throws any oil on it. Not saying you claimed this, just making a point.

What a scraper or whatever you call it should try to do is to prevent the oil that is immediately and inevitably thrown off the crankshaft from bouncing back off the crankcase wall or pan back to the crankshaft. If it does that prevention well, then it’s potentially worth having it there.

For a large displacement cross plane V8s, you need to keep that “scraper” pretty far away from the rotating assembly because otherwise you’re trading off a marginal oil rebound reduction benefit against a major cost of piston pumping pulses robbing power and/or preventing oil drain from the heads.

[makin chips]

Here's an LS crank scraper. What about that will rob power and prevent oil from draining from the heads? A standard sbc crank scraper is usually even less than that. One rail with well placed edges, usually.

How would that rob power and prevent oil drain?

LS



SBC crank scraper



A crank scraper wouldn't be the thing to do that, one would think. That'd be a windage tray without the proper drainage that would be preventing oil from draining and everything else. Wouldn't it? Or common sense would tell you it would more than a crank scraper ever would.

[MadBill]

I don't care if it's a 4 cylinder, V6 or V8. I think it makes sense to scrape the oil of a rotating assembly. Oil flowing past a bearing doesn't know what engine it's in and needs to get back where it belongs so it can repeat the procedure and not rob HP.

The whole idea of oil hanging on to the crankshaft at 5000 rpm is ridiculous. It doesn’t happen. You don’t have to be a physicist to understand that a 5000 rpm crankshaft immediately throws any oil on it. Not saying you claimed this, just making a point...

And yet based on their own testing, countless people believe it does. For example In his 1983 book Smokey Yunick's Power Secrets, the legendary builder described rigging a pan with clear plastic panels and an internal light source and running extensive tests. He reported that a vortex was created around the crank: "Engine oil is swept up and collected in this whirlwind, and the crank looks like it is surrounded by a big hunk of brown taffy." (p. 113)
He goes on to describe the scrapers and baffles that he developed to counter the problem and averred that an optimized pan/baffle system could deliver up to 40 HP more than a bad one.

[ptuomov]

I don't care if it's a 4 cylinder, V6 or V8. I think it makes sense to scrape the oil of a rotating assembly. Oil flowing past a bearing doesn't know what engine it's in and needs to get back where it belongs so it can repeat the procedure and not rob HP.

The whole idea of oil hanging on to the crankshaft at 5000 rpm is ridiculous. It doesn’t happen. You don’t have to be a physicist to understand that a 5000 rpm crankshaft immediately throws any oil on it. Not saying you claimed this, just making a point...

And yet based on their own testing, countless people believe it does. For example In his 1983 book Smokey Yunick's Power Secrets, the legendary builder described rigging a pan with clear plastic panels and an internal light source and running extensive tests. He reported that a vortex was created around the crank: "Engine oil is swept up and collected in this whirlwind, and the crank looks like it is surrounded by a big hunk of brown taffy." (p. 113)
He goes on to describe the scrapers and baffles that he developed to counter the problem and averred that an optimized pan/baffle system could deliver up to 40 HP more than a bad one.

This is not the “American Gods”. Just believing it doesn’t make it true, no matter how many people believe it. Now, aftermarket parts sales are a whole different story, much closer to Neil Gaiman novel...