It's well known that the Achilles' Heel of road-racing LS engines is oil pressure during hard turns.
A quick explanation of what the problem is:
During hard turns, the oil in the pan is kicked away from the oil pickup.The oil pickup is unable to bring in oil, and brings in air instead, resulting in a loss of oil pressure.
Above is the result of low oil pressure.
What should we see? Recommended oil pressure from John Bouchard Racing Engines is 10 PSI per 1000 rpm. So at 5000 rpm you should have a minimum of 50 PSI; at 1000 rpm we need at least 10 PSI.
Before we start the project, let's cover some common oil starvation myths with LS engines.
"Oil starvation is only a problem with LS3 engines."
Nope! Our little LS1 was seeing 20 PSI at 4500 rpm, which is 25 PSI less then what we need. This was while pulling 1.4 Gs at Turn 12 of Road Atlanta.
"A bat wing will fix everything." This is the myth that early C5 corvettes didn't have oil starvation issues due to their "bat wing" oil pan.
Nopes! Vengeance Road Racing reported on their bat wing-equipped C5. They had 7 PSI on some corners at Barber Motorsports Park.
For those that don't know, this is what a bat wing oil pan looks like. It came on early C5 Corvettes.
"It's OK I have an Accusump."
Kinda. The Vengeance C5 and our car both ran oil accumulators. The Accusump did keep some pressure, but not enough. If we did not have Accusumps, the engine would have failed much sooner.
If you're looking for a Band-Aid, this is a good one, but it's still a Band-Aid.
ALRIGHT!! On to the build. This is how we did it.
Step 1: The tank.Tanks are chassis dependent. If you have a lot of room, get a big tank. If you have less room, get a smaller tank. I'm testing an 8-quart Z06 tank in my car. This tank is a bit small, and nobody should go smaller. We will report back if we run low on pressure.
If you run the LS7 tank, get yourself a set of these fittings. They adapt the factory fittings to an AN-12. You can buy them here: http://www.hotrodlane.cc/
We found the LS7 tank for 300 bucks. If you have room for a larger tank, go for it. We also found used NASCAR tanks on ebay for the same money. Search for "nascar drysump."
Step 2: The pump.
We went with an Aviaid LS-A pump. We did this for a few reasons.
- It's considered a "Stage 1" dry sump setup. It uses the internal OEM oil pump for pressure. This is fine for LS engines running under 6000 rpm like our car. The pump itself is a two-stage scavenge pump (meaning there are two places where oil can be drawn in) that mounts to the cylinder head.
- It came from Aviaid for with everything we needed for $852 and does not need any special crank pulley.
- If this setup ever fails, we can just bypass the dry-sump scavenge pump and run it home on the OEM pump.
This is the mounting point for the LS-A Aviaid kits. It sits way up high.
Step 3: The pan.In our car the oil pan is critical. Our chassis is very small. We could buy a pan from ARE but it wouldn't clear the steering rack, so our only choice is to modify ours. That was also the cheapest option.
We took our pan over to Vengence Road Racing for some modification. It cost around $300 in labor plus $140 for two Peterson aluminum pickups.
They did an excellent job adding in two pickups and a baffle that will push the oil to each pickup dependent if we are braking, accelerating, or turning left and right.
Step 4: The install.
The next thing we need to do is get the oil from the tank, through the pan and to the main pickup. Vengeance welded the pickup tubes to take an AN-12 line, We ran Earl's caps to a flared piece of 3/4" aluminum tube we bought on Amazon.
We ran all that tubing to a 90-degree AN-12 bulkhead out of the side of the block.
Aviaid recommends screens on the oil pick up. This is in case a large object gets into the pan (think trunnion bearings) that those items won’t screw up your nice fancy little pump. We got ours from Earl's. These are part number 23012ERL.
You can see how the filters are hooked up to the pan’s scavenge ports.
Then we built the lines using Earl's AN-12 hose. It’s important to use AN-12 to get adequate flow. Some Trans Am teams told us to run this size, let’s not fight them.
To finish the plumbing we followed a diagram much like this one.
Here Is the pay off video. It holds steady pressure. We will report back after the first race weekend.
AVIAD pump, brackets, bets and fittings ----825
Vengeance modifying a V8 Roadsters pan -- 300
Earl's lines assorted ----------------------------- 200
LS7 oil tank and fittings ----------------------- 400
Grand total $1,725