Drag Pan - Pantried

[Ed Blown Vert]

Drag Pan - Pantried
We prefer the term "inexpensive" over cheap," but when we're on a budget, we're just as likely to try to save a few bucks on an oil pan as the next guy. This was the case in "A Game of Rat and Mouse" (July '07), where we had to build hi-po big-block with a strict $6,500 budget. Just as most of you would do, we put as much of our money as possible into power parts, then installed a Summit Moroso oil pan kit, which includes a pan, pump, and pick-up for a paltry $200. There's nothing wrong with this setup; the parts are all of good quality and the y keep our fat-block properly lubricated. On the other hand, we couldn't help but wonder if upgrading our basic pan-or instal ling a better piece-would release a few more ponies. Question posed, we headed back to the dyno to find out.
The Enemy Below
We went for a case-study approach rather than trying to slog through theory, making changes to a proven engine combo and measuring the results. But we do want to define our goals, and Mike Johnson of JMS Racing engines puts the issue at hand succinctly: "Oil, first of all, needs to lub ricate," he tells us. "Then we'll control it for horsepower." The enemy of oil control is wind age, which is, according to Moroso's Brint McLellan, "the action of the oil getting whipped up by the crank." The term also refers to the piston-churned air in the crankcase, which does quite a bit of oil whipping itself.
The crankshaft must be properly lubricated, of course, but any oil it must carry beyond this need exacts a performance penalty, aka parasitic loss. We want every bit of horsepower available, just like you, so that's bad enough. Aeration, how ever, affects the quality of the lubrication itself. As the oil is whipped about by all that air in the crankcase, the two begin to mix; "The oil actually gets air bubbles in it," Johnson observes. "And you don't want that." Oil infused with air doesn't lubricate as well as air-free oil, and that's not a good thing for engine bearing longevity.
Step One
With either concern, the goal is the same. "The objective is to keep the oil under control by getting it down in the pan and keeping it off the rotating assembly," says Johnson, defin ing our task. We began by upgrading our basic street/strip deep-sump Moroso pan by installing a windage tray. Simply put, a windage tray separates the crankshaft-and its windage-from the oil in the sump. At the same time, it allows oil coming off the crank to drain back into the sump. Con versely, it also prevents the sump oil from getting tossed up into the rotating assembly. In theory, this cuts parasitic losses and frees up some horsepower.
In practice, we didn't see a horsepower gain or an appreci able loss; peak torque stayed the same, as did the average num bers. What we did see was a nominal 2-3 psi increase in oil pres sure over the course of our dyno pull. We were sur prised that Moroso's McLellan wasn't surprised. "By having a louvered windage tray installed too close to the rotating assembly," he explains, "the oil has a way of whip ping back up, causing a power and engine-acceleration loss. Installing the tray lower in the pan allows the oil to get farther away from the rotating assembly and will reduce the windage in the pan."
And that's where we ran into the street/strip pan's physical limitations. The windage tray was installed 1/4 inch below the rotating assembly, and that was as low as we could go. We would have liked to have seen a power gain, but the increased oil pressure indicated to Johnson that oil control was improved and our engine still benefited from the work. "The oil's not getting as aerated, which is better for the bearings" he observes. Dyno pulls are very brief, and the increases may look mini mal. Running on the street-or the track-and for extended periods of time, however, this improved lubrication will help engine longevity. We'll take it.
Quick Notes
The Job
Compare a windage tray in a street/strip pan and a drag pan on a big-block
Bottom Line
Improved oil pressure and gained power
Cost (Approx)
$96 (windage tray and studs)/$440 (eliminator pan)
THE WIND IN WINDAGE
Windage is most often talked about as a function of oil getting whipped up and slung about by an engine's rotating assembly. But as it turns out, one of the primary causes of this whipping action is the piston-churned air in the crankcase; i.e., wind. Each piston pushes air into the crank area as it moves down and sucks it back up on the return stroke, eight times per engine revolution. The more revolutions your rotating assembly is turning the more windage you have whipping oil all over the place. When JMS' Mike Johnson wondered out loud about a way to illustrate this, we returned with a 1,400-watt hair dryer...and promptly made a mess. Oil went everywhere, especially up, right where the crankshaft would be. You already knew windage is a bad thing; now you can see why.
Installing a windage tray in this application requires swapping to a set of standoff main studs (left). We ordered ours from ARP, and the torque specs are the same as the regular studs we replaced (90 ft-lb with moly lube). It's easiest to do this while building your engine, but it can be done after the fact; we did it with our engine on the dyno.
We began this experiment by making baseline dyno pulls with our Moroso PN 20460 street/strip oil pan in place. This 8-quart pan is notched to accept our 505ci stroker's 4.250-inch crank throws and has a stock-style baffle mounted in the sump. It's a good, basic pan and works well; we wanted to see if it would work better with a windage tray.
The windage tray is mounted on the standoff studs using serrated lock nuts--these were included with the studs. The tray itself is Moroso PN 23030. The louvers allow oil thrown off the crank to drain into the sump, and the tray cuts down on airflow that can whip the oil up and into the rotating assembly. It's also Teflon coated to further aid drainage.
The idea, according to Moroso's Brint McLellan, is locate the windage tray as far away from the rotating assembly as possible. If the tray is too close, oil thrown off the crank may not have enough opportunity to drain through to the sump and can get whipped back up into the crank. Note the cut-off studs; this is as low as we could get within the confines of our street/ strip pan. Moroso warns that "some trimming" may be required when installing a windage tray; we had to clearance the dipstick area.
The minimum clearance between the rods and the windage tray, according to JMS racing, is 1/8 inch; with the tray at its lowest possible position, we had 1/4 inch.
Our Summit Moroso oil pan kit came with a assembled high-volume pump/ pick-up combo. To facilitate our on-the-dyno oil pan swap, we ordered a comparable high-volume pump from Federal Mogul, along with new oil pan gaskets. The matching pick-up for our new pan was a convenient bolt-on design.
After removing the windage tray from our big-block mule and reinstalling the standard ARP main studs, we lifted our new tray into place...and couldn't quite bolt it on. Moroso designed the main cap partitions on this pan to work with the main caps and bolts on Dart and Merlin big-blocks. When using a factory block with studs, clearancing is necessary--and normal.
Step Two
Our plan had been to try and further enhance our street/strip pan with a crankshaft scraper, but John son strongly suggested we'd be better off upgrading the pan itself. We try to listen to the voice of experience, and we're especially glad we did in this case. McLellan recom mended Moroso PN 21047, an eliminator pan for Bracket and Super Stock cars. The advan tages of this pan's features are better illustrated than explained, so we'll get right to the point: We bolted it on and made an extra 17 hp, along with 11 lb-ft torque. The averages also improved by 10 lb-ft and 6 hp. The drag pan costs about $270 more than the street/strip pan, which sounds like a lot, but it actually provides a good power pay off. "That kickout and win dage tray they've got built into that pan works," John son sums up. "And we're not even talking about how much better that is for your bearings." Sounds like a win-win scenario to us, and we'll take that too.
A main cap baffle can help improve oil control in a stock or street/strip-type pan. It mounts between the rear main bearing cap and the oil pump, and it keeps oil from the sump away from the crankshaft under acceleration. "A wedge of oil forms between the front and the rear of the sump," McLellan explains. "This piece blocks that wedge off and redirects it to the oil pump." This doesn't happen on a dyno, so we only show it here. When this bullet makes it into a vehicle, we'll install it.
Our original plan was to install a crank scraper as part of this test. The premise is clear enough: Oil can rope around the crank as it rotates; this piece scrapes it off. As you can see, the scraper must be fitted to the crank--a task that Mike Johnson of JMS Racing Engines figures would add at least $150 to an engine build and, in his experience, wouldn't yield a power gain. Johnson suggests that money would be better spent on a pan with a kickout. "As the motor comes around, the kickout catches the oil in the pouch and keeps it from whipping up into the block, where it comes back down on the crank again," he explains. Did it work? Given our power gains, we'd have to say yes. CHP
MOROSO ELIMINATOR DRAG PAN
1. The solid louvered windage tray is built into the pan, keeping it--and the oil slung onto it by the crank--farther away from the rotating assembly. Oil left on top of the pan finds its way into the kickout.
2. Main cap partitions control the oil's direct path to the front portion of the pan, promoting drainage rather than windage.
3. "The power kickout adds additional area to the front portion of the pan," points out McLellan. Instead of letting oil follow the assembly, the kickout strips it away, isolating it from the rotating assembly and further reducing windage.
4. The core-based pan features a stock pan-rail bolt pattern and will accommodate up to a 4.50-inch stroke with steel rods.
The increase in oil pressure we saw by installing the windage tray in our street/strip pan was nice, but our search for more power warranted a swap to a Moroso eliminator drag racing pan, PN 21047. According to Moroso's Brint McLellan, the trickle-down theory holds true for this pan. "We usually test for 2-3 years with builders and race teams before coming out with a new pan," says McLellan. "The features in this pan stem from Pro Stock technology." And while there are certainly more advanced-and expensive-pans, he calls this piece "the best of both worlds," providing the good oil pressure everyone wants to see and freeing up some power.
DYNO DETAILS Headers 21/8-inch Hooker upswept Fuel 91-octane Carb Mighty Demon 850, 85/93 jets Timing 34 degrees Oil Torco SR-1 synthetic, 10W30
BASELINE WITH STREET/STRIP PAN RPM LB-FT HP OIL PSI 3,500 580 386 63.8 3,600 582 399 64.0 3,700 579 408 64.2 3,800 579 419 64.4 3,900 578 429 64.7 4,000 572 436 64.9 4,100 568 444 65.0 4,200 567 454 65.2 4,300 566 463 65.4 4,400 563 472 65.5 4,500 567 487 65.7 4,600 572 503 65.9 4,700 576 517 66.1 4,800 578 531 66.3 4,900 578 542 66.5 5,000 577 553 66.7 5,100 579 561 66.7 5,200 577 575 67.1 5,300 574 579 67.7 5,400 573 584 67.9 5,500 569 593 68.3 5,600 563 602 68.7 5,700 558 607 69.3 5,800 552 613 69.6 5,900 545 617 69.1 6,000 539 619 68.8 6,100 532 619 68.9 6,200 522 620 68.6 6,300 511 621 65.8 6,400 501 614 65.6 6,500 489 606 66.4 AVG 580 409
MOROSO 20460 WITH WINDAGE TRAY RPM LB-FT HP OIL PSI 3,500 580 386 63.8 3,600 582 399 64.0 3,700 579 408 64.2 3,800 579 419 64.4 3,900 578 429 64.7 4,000 572 436 64.9 4,100 568 444 65.0 4,200 567 454 65.2 4,300 566 463 65.4 4,400 563 472 65.5 4,500 567 487 65.7 4,600 572 503 65.9 4,700 576 517 66.1 4,800 578 531 66.3 4,900 578 542 66.5 5,000 577 553 66.7 5,100 579 561 66.7 5,200 577 575 67.1 5,300 574 579 67.7 5,400 573 584 67.9 5,500 569 593 68.3 5,600 563 602 68.7 5,700 558 607 69.3 5,800 552 613 69.6 5,900 545 617 69.1 6,000 539 619 68.8 6,100 532 619 68.9 6,200 522 620 68.6 6,300 511 621 65.8 6,400 501 614 65.6 6,500 489 606 66.4 AVG 580 409
MOROSO 21047 DRAG PAN RPM LB-FT HP OIL PSI 3,500 587 391 64.3 3,600 591 405 64.6 3,700 590 416 64.8 3,800 587 425 65.1 3,900 589 437 65.2 4,000 588 448 65.1 4,100 582 454 65.0 4,200 581 464 65.0 4,300 579 474 65.0 4,400 580 486 64.8 4,500 578 495 64.5 4,600 576 504 64.1 4,700 581 520 63.4 4,800 582 532 62.8 4,900 587 548 62.5 5,000 591 562 62.5 5,100 587 570 62.6 5,200 585 579 62.6 5,300 583 588 62.8 5,400 583 599 63.2 5,500 579 606 63.7 5,600 577 615 64.3 5,700 570 618 65.1 5,800 567 626 65.7 5,900 563 633 66.4 6,000 555 635 66.9 6,100 549 637 66.9 6,200 538 635 66.5 6,300 530 635 65.3 6,400 521 634 67.1 6,500 509 630 66.9 AVG 590 415

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[Kevin Johnson]

...
We began by upgrading our basic street/strip deep-sump Moroso pan by installing a windage tray. Simply put, a windage tray separates the crankshaft-and its windage-from the oil in the sump. At the same time, it allows oil coming off the crank to drain back into the sump. Con versely, it also prevents the sump oil from getting tossed up into the rotating assembly. In theory, this cuts parasitic losses and frees up some horsepower.
In practice, we didn't see a horsepower gain or an appreci able loss; peak torque stayed the same, as did the average num bers. What we did see was a nominal 2-3 psi increase in oil pres sure over the course of our dyno pull. We were sur prised that Moroso's McLellan wasn't surprised.

..."By having a louvered windage tray installed too close to the rotating assembly," he explains, "the oil has a way of whip ping back up, causing a power and engine-acceleration loss. Installing the tray lower in the pan allows the oil to get farther away from the rotating assembly and will reduce the windage in the pan."

Oil bounces off the smooth metal surfaces between the louvers. Just like heavy rain in a tropical downpour.

-snip-

[The idea is to] locate the windage tray as far away from the rotating assembly as possible. If the tray is too close, oil thrown off the crank may not have enough opportunity to drain through to the sump and can get whipped back up into the crank.

Nissan, in the SR20, has louvers within 1mm of the rotating assembly. I assure you that Nissan runs plenty of friction tests on its rotating assemblies. The embodiment of a design element counts for a lot.

Our plan had been to try and further enhance our street/strip pan with a crankshaft scraper, but John son strongly suggested we'd be better off upgrading the pan itself. We try to listen to the voice of experience, and we're especially glad we did in this case. McLellan recom mended Moroso PN 21047, an eliminator pan for Bracket and Super Stock cars.

It is worth noting that louvers are a form of crank scraper technology. I count nine crank scrapers in the tray of this pan. Technology comes in many different forms. Directional or "diamond" screening is also iterated crank scraper louvers.

Our original plan was to install a crank scraper as part of this test. The premise is clear enough: Oil can rope around the crank as it rotates; this piece scrapes it off.

This is true at low rpms or in high rpm situations where the rotating assembly is flooded with oil. In normal high rpm situations the crank scraper functions by disrupting the pressure differential in the windage cloud -- not by scraping the oil out. There is an unspoken presumption here that the crank scraper being spoken of is of the classic design that sits at the 270 degree position on the oil pan rail. There are numerous OEM examples of crank scrapers in many other quadrants and this goes back 40 to 50 years. Look at Ford, for example.

You have to understand what is happening in the crankcase in order to be able to choose an appropriate device.

As you can see, the scraper must be fitted to the crank--a task that Mike Johnson of JMS Racing Engines figures would add at least $150 to an engine build and, in his experience, wouldn't yield a power gain. Johnson suggests that money would be better spent on a pan with a kickout. "As the motor comes around, the kickout catches the oil in the pouch and keeps it from whipping up into the block, where it comes back down on the crank again," he explains. Did it work? Given our power gains, we'd have to say yes. CHP

The kickout in the pan referenced functions by giving a storage place for the oil stripped off by louver crank scrapers, yes. However, the majority of its gains are from rectifying pumping losses by providing a sort of pressurized plenum that can feed lower pressure zones in real time around the rotating assembly with less work expended. There are other types of kickout pan designs too. I am sure that an appropriately located close tolerance scraper would increase efficiency still further just as I am sure there are ways to make the kickout function more efficiently with respect to ameliorating pumping losses. As the article suggests, windage is a complex set of phenomena.