Gregory

iTrader: (4)

So what is the RPM limit of an LS engine using a high capacity oil pump? I want to make sure make sure my 7700 RPM top end isn't short lived because of an oiling problem somewhere. I've heard about oil cavitation and want to avoid it.

ARE Racing of Loomis, CA gave me a quote of approximately $3,200.00 for a dry sump system that uses my SLP oil pump.
I'd rather just use a large capacity oil pan, with an Accusump.

But, I'm not one to take unnecessary chances. So, give me your feedback on high RPM oiling systems.

Thanx!

Beaflag VonRathburg

iTrader: (176)

For my high RPM setup I'm going with AFR 8000 1.54 OD valve springs, an LS7 dry sump setup, and crank. I'm going to rev it until the power drops off.

For my Formula I am sticking with the wet sump. I have a Canton oil pan that is going on the car and eventually an accusump. If you are going to stick with the wet sump setup I would go with a Canton or Moroso oil pan. The Canton I have has a thin flange. I really like the Moroso one a lot better, but it is more expensive.

Gregory

iTrader: (4)

I've got a late model GTO and my choices are very limited.
Below are pictures of one oil pan I'm interested in, but the Australian manufacturer does not respond to inquiries.
Nevertheless, I want to make sure these factory style pumps work properly at continuous high RPM that road racing entails.

427

iTrader: (3)

The one problem that always worries me is the ability of the pumps suction side to fill at the higher rpm since the LS pump runs at crank speed. I have been using the wide gear GM pump in some higher rpm engines with good results, although I do see pressure trailing off a bit in the higher rpm bands. I seem to lose 10 psi between 7800-8500, but using the yellow spring keeps me above 70 psi so I still sleep at night!

Kurt

Beaflag VonRathburg

iTrader: (176)

I honestly don't think you'll have an issue with 7700 rpms as long as the oil pump is setup correctly. I've seen a lot of people take a HR / wet sump setup to crazy RPMs a la 8300. Kurt has you pointed in the correct direction.

KCS

iTrader: (20)

What is the wide gear GM pump? I'm not familiar with that.

GMLSX

iTrader: (12)

The new GM LS9 oil pump has a thicker pressure section than the old LS7 pump for the piston squiters. Also Katech sells a blueprinted LS7 and LS9 pump with a 30% larger scavenge section, check it out!

Shawn @ VA Speed

iTrader: (3)

we have used a melling oil pump with an accusump to 8200rpms with no issues

kelp

RE: LS7 (old) vs LS9 (new ver) - No it does not. I have both. I disassembled and compared them. Who claims this? I'll write them.

I like the Katech pump, but only the ports are ported and they are mostly straight, so what. Also the vein size does not change. Also, note this is the scavenge side. It does nothing for the engine side, where the oil squirters are. BTW I just ported and internally powdercoated my LS7/9 oil pump tonight, both scavange and engine sides. That works for me.

Regarding your oil concern, the ARE will not help oil starvation over a conventional Z06 type dry sump. Search the Z06 section on CorvetteForum.com for the studies and data.

Piston squirters will help piston cooling, but that is not a problem under 900 HP. Top engine builders do not use them as they take away from essential lubrication.

Oil starvation will result from high G Force when using slicks under sustained lateral acceleration > 4.5 sec. I have not seen any other condition showing data indicating a decrease.

The solution is a larger sump tank. Data from the Lingenfelter shows this problem is resolved with this device. It is simpler and cheaper. There are other larger sumps on the market.

Don't take anybody's word for anything, including mine, do research, get data, verify everything.

ATVracr

iTrader: (5)

Same here ... Melling pump, moroso pan 8,500rpm

427

iTrader: (3)

The pressure section is about .100 thicker in the pumps I call the wide gear, about 25% wider gears. They seem to come in the cylinder on demand engines the most, thats what I order them for when I need one. They keep up well even when using piston oilers. I have ran the stock pumps over 9000rpm at times, but they will start to lose oil psi normally somewhere above 8000. It might be better if you stay with lighter weight oils, I never did this testing.

Kurt

racer7088

Depends on drag race VS road race. The bigger oil pan and Accusump can fix both if you stay under 7700 most of the time.

You also can change out the front pump every year on a road race deal or use an oil pump that has billet gears that won't break as much.

I am not familiar with the Katech pumps gears as that is an issue with constant high rpm use. The gerotors will eventually crack and fall apart from constant cavitation.

mikey

iTrader: (6)

We use Melling Pumps with a custom designed pan (made by Moroso) as well as some other tricks. Multiple drag and road race cars past 8000 rpm. No problems so far.

crb99ws6

iTrader: (7)

I'm using a wet sump oil pan with an external belt driven oil pump for my new 427 c5r. Dyno next week or so to see where rpm is. My guess is around 8500.

KLJohnson

Hi Kelp,

I am rearranging a couple parts of your reply:

I agree this is very important. Not always possible with time, money constraints, of course.


I have to disagree here. GM uses squirters on both the LS7 (cast piston) and LS9 (forged). I assure you that extensive testing went into this. The new Coyote V8 from Ford (400hp) uses oil squirters on the modular engine in order to keep hypereutectic piston temps under control.

If top engine builders are eliminating the use of oil squirters simply because they "take away from essential lubrication" then I suggest they need to do a little more homework on available stock oil squirters. For decades, many OEM high performance engines have used small slots on the connecting rod sides to direct oil from the bearings to the underside of the pistons. This does not affect the pressure gradient in the bearing shell as the oil has already passed out of it. This is efficient design -- putting what would be a waste product (oil as an expelled lubricant which needs to be scavenged) to a secondary use (as a cooling medium -- which then also needs to be scavenged).

See the connecting rods from a BMW S50 or the rods from a Honda B16, for example.


Heavy braking has also been mentioned.

I think this is treating a symptom not a cause but that is just my opinion.

racer7088

No LS7 I have even seen has piston squirters? The rods already throw a lot of oil under the pistons as do all engines. I don't think the LS1 in general needs even more oil or windage at all on any NA engine.

KLJohnson

I apologize -- the LS9 is indeed the only LS engine so far to introduce piston squirters for its forged pistons. The extra cooling was needed for the aimed 100 hp per liter. I cannot imagine a modern professional engine builder shooting for 100 hp per liter in an NA engine. Oh wait. Alpine offered a very streetable bolt-in kit for the 807 Renault engine about thirty-five to forty years ago that brought its output to 100 hp per liter NA (designated the 807-G, for Amédée Gordini).

The architecture of the Porsche 928 engine (neglecting the bedplate) is similar to both the LS and Modular V8 from Ford. Porsche was forced to withdraw piston oil squirters from the 928 because of the increased windage and subsequent build up of additional heat/aeration. Perhaps this is why Porsche never took that engine to 100 hp per liter NA. Certainly it is possible (and in fact has been done but with improved windage control).

Ford went with a gasket integral windage tray for the Coyote (with squirters, which are needed for the 100 hp per liter NA engine [Edit: correction, 80 hp per liter]) which harkens to the windage tray for the Ford GT block. The modular engine shares the terrific windage and pumping issues with the LS. The modular engine has a steeper hurdle, though, because of the asymmetric and handed pumping pattern introduced by the drain passages from the heads and timing cover. See the Toyota UR V8 for a way to address this issue. Also see the Ford GT block for a way to address this issue.


I think the LS has a problem with windage. I think that's why GM developed software to model raindrops. I think the need or desirability of oil squirters is independent of that problem though dedicated galley fed squirters would increase it. If you are utilizing rod beam slots the amount of oil ejected does not increase but the underside of the piston is cooled more. In the Honda B16 (100 hp per liter) there are four galley mounted squirters and sixteen rod based ones making a total of twenty for a four cylinder.

Why would GM leave off slots which would have no cost impact and not introduce any greater amount of oil? Probably because different generations of engineers come with different sets of background knowledge and ways of viewing problems. In some instances it is a higher level version of the car enthusiast who figures that if he doesn't see a technology implemented on his engine it must not be beneficial (or the factory would include it).

Earlier versions of the slotted rod face were used to direct spent lubricating oil at particular targets. Look at the slant six and the interior cam -- that's going back about fifty years now.

Really no excuse for lack of piston oil squirters.

Pwebbz28

iTrader: (31)

Moroso pump and pan here. 8000+ no problem

CamaroSS22

iTrader: (1)

Melling Oil Pump and stock pan to 7800 no prob.

KLJohnson

You need to check the G-rating of the wet sump you want to use to be able to compare it with your projected use. Calculate the amount of oil that is in the pan under normal operating conditions. Fill the pan with that much water. Tilt the pan in all directions and measure the angles at which point the rotating assembly begins to strike the surface of the water. This is the maximum allowable angle of repose of the oil. A pan will normally have a different G rating for different directions of acceleration. If you are drag racing and your wheels/body lift be sure to include that figure for the rear tilt(subtract it).

Most pumps fail because of high amounts of air entrained into the oil. This shocks the gears. It is not the same thing as cavitation though cavitation can certainly occur with aerated oil. You can run an engine on the dyno at extremely high rpms and never see the stress loads presented when the vehicle is in motion.

You will want to perform these steps because your rod bearings will likely fail well before your pump gears will or maybe it will be an interesting race to failure. Note that scavenge pumps on dry sumps can and do take a lot of abuse.

BMW had problems with gerotor pumps failing. I suspect this was related to the low viscosity oil recommended. I have read that there are low viscosity oils that have an inverse relationship with air entrainment and temperature versus higher weight oils. This means that if the oil is not up to operating temperature it is more likely to be carrying a lot of air in it -- this is not the same as foaming. The shock loads on the gears caused failures of the sintered gears. This is just conjecture -- maybe if you ask BMW they will tell you. Take home lesson -- make sure the oil you use is up to operating temperature before nailing it.