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Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/13/14 12:18 a.m.

So, I've got an LS3 in my track car. Which means I might have a little bit of a time bomb in my track car due to their oil control problems on sustained left turns. I've got a really good oil pan, but if oil is trapped elsewhere in the engine the pan won't help. I'm starting to think about a dry sump.

I don't have a lot of space, and I have very, very tight clearances between the crank and the steering rack. So an off-the-shelf pan probably won't work. I'm thinking of taking my current pan and modifying it for a scavenge pump.

I was originally thinking of retaining the stock pump for pressure (like an ARE Stage 1), but it would actually be easier to feed pressurized oil into the engine via the fittings for my external oil filter. So that's easy enough. So is the basic plumbing.

I figure I can pick up a 3 or 4 stage pump and a tank, and build my own bracketry. ARE will sell me what I need, but it's expensive stuff and I can build brackets easily enough. Pump location will be in the AC compressor spot, I have room there. I'll probably pick up an ATi damper with a toothed pulley to drive it. Not cheap, but an ATi isn't a bad idea anyhow.

Looks like a typical dry sump pan has a very small sump with 2-3 AN fittings welded in. Anything I need to know? How many stages should I run for scavenge?

What do I do with the stock pump? Just let it thrash around in there with no pickup, or should I pull it and plug off the output passages?

ARE Stage 2 schematic.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/13/14 12:45 a.m.

More questions about fundamental system design!

How fast should I be spinning the pump? I see the drive gears come in a number of sizes, so this is obviously adjustable. I don't plan on high revs, just the factory redline of 6600 would be more than enough.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/13/14 1:07 a.m.

Interesting, it appears I may be able to use the old ASA oiling system for a budget setup. They used a single stage scavenge pump driven by a ribbed belt, so I could keep my existing pulley. If I can find one of those, it would be a relatively easy thing to put together. What do more scavenge stages get me if I've got a big oil tank?

fastoldfart
fastoldfart New Reader
7/13/14 1:21 a.m.

This site has a good tech page. I have see one of thier pumps and was impressed with the quality and price. http://nutterracingengines.com/racing_oil_pumps/dry_sump_oil_pump_products.html

fastoldfart
fastoldfart New Reader
7/13/14 1:33 a.m.

Raceline has developed an interesting, self contained dry sump system for the Duratec/MZR that uses the stock pump for the pressure side and second pump for scavenge inside the pan. http://www.raceline.co.uk/products/part_section.asp?SectionID=23&CategoryID=1 It seems to me that retaining the stock pump for pressure with a belt drive 1 or 2 stage scavenge pump would be fairly straightforward and more budget friendly solution.

Dr. Hess
Dr. Hess MegaDork
7/13/14 7:28 a.m.

Billzilla once built his own dry sump pump from two SBC pumps fused together and driven by a belt off the crank pulley, if you want to go grass roots.

44Dwarf
44Dwarf UltraDork
7/13/14 8:16 a.m.

Why not just use an accumulator like an acusump? It keep the motor in oil during the time the pump cavatates and refills when on the straights.

Yes dry sumps are nice and would be best for long term but designing a system on the go is difficult. Add the accumulator now right in to the remote oil filter lines and go while you find dry sump parts that fit. I have a NOS 3 quart unit somewhere....never got around to putting it on my drag car years ago.

Giant Purple Snorklewacker
Giant Purple Snorklewacker MegaDork
7/13/14 8:22 a.m.

My racing engine builder handbook says you should seal the returns in the heads and scavenge them directly along with many other bits of minutia I can't recall. It also spends a lot of time stressing the importance of the oil tank's design in properly getting air out of the oil.

I've never done anything like designing my own oiling system but it was interesting reading about all the design considerations I hadn't thought of. There is more to it than just pumping oil. When I get home I'll snag the isbn number and post it.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/13/14 10:23 a.m.

44dwarf, I have access to an Accusump and I've considered it. They bring a number of other problems with them in my experience, such as a tendency to hide oil consumption (you can't check the level inside the accumulator) and they also just don't seem to help enough with the LS3 starvation problems.

I'm considering a system with an external scavenge pump and the stock pump for pressure. That's what the ASA engines used, as well as the ARE Stage 1. It's looking like finding an ASA pump might be the ticket, as it's already got brackets for the LSx engines - although I think it has the F-body belt alignment. They're not that common but I might try going straight to the manufacturer.

It's fairly easy to find used dry sump tanks of various sizes, so I'm not worried about the design of those.

oldtin
oldtin UberDork
7/13/14 10:54 a.m.
Curmudgeon
Curmudgeon MegaDork
7/13/14 11:11 a.m.

Dumb question: every dry sump setup I have seen has two scavenge fittings, typically at the far ends of the sump. So what keeps the rear scavenge fitting from running dry on hard braking? Seems to me that would quickly suck air with disastrous results. It also seems that if the pan were made like an upside down pyramid you'd only need one big ol' scavenge fitting, greatly simplifying things.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/13/14 11:20 a.m.

You've got that big tank of oil feeding the pressure pump, so if one of the scavenge pumps sucks air for a moment you don't lose pressure. It's exactly like a swirl pot for a fuel system.

Kenny_McCormic
Kenny_McCormic PowerDork
7/13/14 12:50 p.m.

I like the idea of rigging up 2-3 cheap SBC pumps for scavenging, but that probably won't fly on a real actual race car.

In reply to Curmudgeon:

The engine runs off the oil tank, the scavenge pumps just keep the tank filled.

Knurled
Knurled PowerDork
7/13/14 1:48 p.m.

I thought it was expected for the scavenge pump to suck air.

Memory says that scavenging should be something like 3x the pump output.

bigdaddylee82
bigdaddylee82 Dork
7/13/14 3:00 p.m.

Anyone have a link to Billzilla's Chevy pump contraption?

Knurled
Knurled PowerDork
7/13/14 6:02 p.m.

In reply to bigdaddylee82:

Oldtin already posted it.

(I recognize the name Billzilla from my 4AGE-want days)

I read that link a bit. There's one pretty big (but understandable) error, though. They were disagreeing with the notion that the oil cooler must be on the pressure side. That would make sense if all of the heat in the oil came from the engine. With a toothed gear style oil pump, there is a significant amount of heat added to the oil by the pump itself, up to half of the total heat added to the oil. With that in mind, the oil will be at its hottest after the pump, so the cooler will be most efficient when placed between the pump and engine. (Plus you won't be pre-heating the oil that you just cooled off!)

bigdaddylee82
bigdaddylee82 Dork
7/13/14 7:06 p.m.

In reply to Knurled:

I get that, I was hoping for more info about the pump specifically. I get the core concept, but was hoping for some pictures of the construction.

Curmudgeon
Curmudgeon MegaDork
7/13/14 7:28 p.m.

Ah, it becomes clear now as a surge tank system.

djsilver
djsilver New Reader
7/13/14 11:02 p.m.

I've run across several good related threads over on corner-carvers, but I'm not an LS owner and didn't bookmark them. I remember reading about doing stuff to help oil drain from the heads, like drilling holes in the lifter valleys (?) I saw one about a Porsche 928 that connected scavenging pumps to the valve covers! Anyway, here's something I ran across related to the subject; Enginelabs.com

GameboyRMH
GameboyRMH GRM+ Memberand MegaDork
7/14/14 10:59 a.m.
Curmudgeon wrote: Dumb question: every dry sump setup I have seen has two scavenge fittings, typically at the far ends of the sump. So what keeps the rear scavenge fitting from running dry on hard braking? Seems to me that would quickly suck air with disastrous results. It also seems that if the pan were made like an upside down pyramid you'd only need one big ol' scavenge fitting, greatly simplifying things.

It's no problem if the scavenge pumps suck air, these pumps are designed to handle it. It's a problem if the pressure pump which feeds from the oil tank sucks air.

The upside down pyramid would starve relatively easily, similar to a regular wet sump but with some "reserve" capacity in the tank - ideally you'd want something like the base of a pyramid with a scavenge port on each corner.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/14/14 11:49 a.m.

djsilver, it was that Enginelabs article that started me along this line of thinking! Thanks for the 4AGE link as well. I'm starting to get a clear idea of what I want to do. The easiest thing would be to use the ARE Stage 1 scavenge pump with their bracketry, a tank that fits (that's going to be a challenge!) and use the stock pump for pressure.

Of course, doing this will mean pulling the engine or close to it. So I'll probably be in the doodling and design stage for a while.

RossD
RossD PowerDork
7/14/14 12:06 p.m.

I was brainstorming a DIY dry sump and thought the Duratec/MZR oil pump looked like a decent cheap solution for a scavenge pump. Of course, I'm not well versed on different engine's oil pumps but that one jumped out at me as being shaft driven and possibly adaptable to a scavenge pump. I don't know any specifics for flows so... maybe with some machining you could run two off of one concentric shaft.

BoxheadTim
BoxheadTim GRM+ Memberand UltimaDork
7/14/14 12:39 p.m.

Put the tank in the trunk for better weight balance? You may be able to use the lines for additional cooling, too, much like some ac 911s use finned pipes to the front oil cooler for additional cooling capacity.

tpwalsh
tpwalsh HalfDork
7/14/14 12:44 p.m.

In reply to RossD:

The question is, how do you seal it? The 911 makes for a nice shaft driven pump as well, but I I'm not sure how to seal it for external use.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/14/14 12:49 p.m.

I'd be tempted to put the tank in the passenger's footwell to keep the weight centralized and the lines shorter. But there's room in the trunk, that's true...

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