KLJohnson,

Many engines we build make near 100 hp per liter and none need piston oil squirters.

Were you being sarcastic? Maybe on an oil dry high rpm engine like a cup deal pulling a lot of vacuum for sure but not weekend warrior drag stuff or street stuff.

I would not have a problem with some nice oil squiters that didn't use a ton of oil though so I agree they are nice but I don't see them as anything necessary at all on a street NA engine.

 

I agree that air entrainment in the oil is what we would like to reduce with better drainback.

 

Interesting and good experienced feedback. Thanks!

The consensus seems to be that if the oil is there for the engine's oil pump, things will be okay to 7,700 and more. I'm thinking the best budget way to go will be the deeper, wider oil pan and an Accusump. Those two things should keep me together on the curvy circuits.

 

We have used teh accusumps stuff as well for raod racig and it seems to work well.

 

What can I say, Ford told me about the Coyote first hand. Your 418 buildup putting out 670 hp and 540 ft-lb has a BMEP of 194.81 which compares nicely to the Coyote's 197.77. But would your build up survive a GM type durability test of 400 hours going back and forth between peak hp and peak torque. I don't know. Yes, I understand that a weekend warrior or modified street car doesn't have to meet those standards but I think you get my drift. There are plenty of OEM NA engines that use oil squirters that did survive these types of durability testing and perhaps required squirters to do so. So lots of empirical evidence.

I didn't just fall from the sky yesterday. Gene Adams and Hot Heads Research employed some of my windage control devices for the old Chrysler Hemi that came in third in the 2009 Engine Masters Contest a couple weeks back. My feeling is they would have won last year but they had a part fail at the last minute. I'll have to send them something more interesting next time.

Well, what I am saying is that the slots don't use any more oil than the non-slotted ones. That's a non-issue. They just give a better probability distribution that the oil is going to land on the bottom of the piston and do something useful rather than just being in the way and generating heat rather than conducting it out. BMW agrees. Honda agrees. Both have been around a while and have built a race engine or two.

By the way, if you do get into galley mounted oil squirters in forced induction engines take a look at the synergistic engineering of the OEM squirter and piston designed to receive it in the Nissan RB26DETT.

 

Yes, air entrained oil that goes through a pump and turns into shaving cream does flow poorly back to the sump.

 

Sorry for the harangue.

Check those pans out with water. Water doesn't have a horse in the race; you can trust it.

 

Your water test does not account for the windage tray, which behaves as a lid to the oil pan. Even though it's full of holes, the windage of the rotating assembly and directional louvers in the tray make it a one-way gate that functions as a lid to the pan. Without it, the GTO (for instance) couldn't tolerate any acceleration at all without dumping the contents of the sump to the back of the engine.

As for oil squirters, I speculate that any OEM's use of piston oil coolers of any sort stems more from a desire to run tighter piston-to-wall clearances versus any sort of possible durability advantage. This is especially true in OEM motors that run forged pistons (such as the LS9) that must allow for more piston growth than cast pistons. Strict NHV requirements call for oil squirters, not durability requirements. Pistons, especially forged, can tolerate a lot more abuse and heat than you give them credit for - just without an auxiliary cooling strategy they require more wall clearance and ring end-gap than what the OEM's consider acceptable.

 

Hi Derrick,

This is similar to the error that Porsche made with the M96/97 in presuming that their box around the pickup would prevent (reverse) oil migration under steady lateral acceleration.

Windage tray design is difficult because there are diametrically opposed requirements. The tray must allow oil to drain while preventing migration from beneath. To the extent that you strengthen the latter you worsen the former in a passive system. This is why you often see trays with multiple layers. You are forgetting the cyclic rate of the pump and the oil that is deposited on top of the tray. Aero-louvers do not function properly when submerged.


I think there are a lot of intelligent gearhead engineers out there who know how to use NVH-speak to slide performance enhancements by skeptical accountants. A lot of girdle and bedplate design comes to mind.

I think there are a lot of interesting expensive paperweights out there made from the finest forged aluminum with a topological genus increase.

 

With all due respect, I urge you to clarify every point you attempted to make in your last post. You seem to have some ideas, but I'm afraid you didn't do much to explain them.

-- Unless my ignorance of the Porsche flat-6 has bitten me, it's internal pan-baffles do not utilize windage pressure differential to constrain the oil volume as a louvered windage tray does.

-- Oil is not "deposited" onto the tray as you suggest, I don't think that this kind of passive terminology can be applied to such a caotic system.

-- Louvers work by taking advantage of the momentum (direction and inertia) of air current to produce a pressure differential. That one side of the louver might be "deadheaded" by a fluid is irrelevant. So long as a current exists normal to the louver opening, a pressure differential is produced that helps prevent reverse migration, and if the differential is great enough, positive flow to the sump.

-- NHV is a concern of the marketing dept, not the accountants. It's the marketing dept that slaps the engineers around for cold running piston slap. Besides that, you're totally missing the point: there is no performance advantage to oil squirters, only a quieter running engine - and in today's highly competitive market, a cold startup rattle would likely run some prospective customers right off the lot.

-- Your last statement really has me stretching to find any relevance to the current topic. For the purpose of this discussion we must assume competent component design that meets the minimum requirements of any particular application.

 

Hi Derrick,

Sorry 'bout that.

It is analytic within the term "lid" that it seals the perimeter. It is in this sense that I disagree. If you do a patent search for Porsche a description of the integral dry sump components can be found.

There are a number of different pans in use with this engine. The batwing pan has at least two construction variants. In one the floor of the rear of the pan is cast in aluminum and in another it has a sheet metal cover. These are both technically windage trays. I realize there is another windage tray that bolts to the block. Many times people are surprised that there can be more than one level of tray -- check out the RB26DETT -- there are at least three.

An easier example to look at is the Toyota 4AGE -- many versions of this engine come with just the windage tray that covers the running level of the oil in the sump. There is a separate piece that is used on high performance versions such as the 4AGZE, P/N 12122-16011.

If you look at the F-body LS pan the bolt in cover is a windage tray.

I hope that clears things up.

Yes, and ... ? The oil is going to be churned full of air as it circulates out and back in. This is not proper functioning for an aero-louver.

Yes, and they'll provide justification for the cost for the mods. It takes a while to become facile in NVH-speak and culture, I guess.

Silly me. I actually thought that running a piston with more consistent temps and resistance to temperature spikes facilitated a safer higher state of tune. That's why they use squirters on forced induction engines -- to stop that annoying piston slap on start-up. Aha.


Holed pistons from detonation might be related to hot spots on the piston. You're saying that skirt fatigue fractures or galling are probably more relevant, I guess.

Ok -- that took up about 20 minutes of my time. Back to work.