Building a Dry-Sump System: Making Room for Everything | Project C5 Corvette Z06

J.G.
Update by J.G. Pasterjak to the Chevrolet Corvette Z06 project car
Jan 19, 2021

One thing that we’ve learned in 35 years of project car editorial is to be flexible with our plans. Our recent dry sump installation in our now-LS3-powered C5 Corvette Z06 is the perfect example of that.

Our original plan was to install the dry sump tank in the rear of the car, which would necessitate long, oil-filled lines running all the way to the front of the car. You can read about all that, and the initial phases of our Aviaid dry sump install here and here.

Once we got the engine and drivetrain back in the chassis, however, it just all started to seem overly complicated. Lines running through the interior, or through the already tight driveline tunnel, lots of extra materials, and difficulty with routing all started to become clear with our plan.

The solution: Do what Chevy already did with the LS3-powered C6 Grand Sport and move the dry sump tank into the engine bay.

With the battery out of the way and moved to the rear, it leaves a nice hole for an oil tank, which is exactly where Chevy located their OEM units. It did require us to downsize to a 2-gallon tank and do a little grinding and cutting to remove the battery mount.

Also making our decision easier was a friend’s similar project. A local Orlando shop–Speedworks Racing–fabricated a bracket to hold his dry sump tank in his C5. Speedworks’ solution was simple and clever, and bolted to the existing holes used by the hood latch. All it will require is drilling a few holes and attaching our Aviaid tank for final mounting.

Now came the task of routing all the lines for the system and, no lie, things are tight in there with the engine in place. Keeping lines away from rotating or heat hazards, and maintaining adequate ground clearance takes a little creativity, but it certainly can be done.

We decided to remove the washer fluid tank, which gave us an easy spot on the top of the inner fender to mount the remote oil filter.

With the main pieces in place, we used some household 120v wire to build mockups of our main hoses we’d need to connect. The copper wire could be bent and shaped and hold its form and made a great prototyping media to figure out hose routing.

Once we figured out the rough routing of the hoses, we started playing with our assortment of Fragola hose ends to point the hoses in their correct direction when the exit their respective device. This is where clearance issues really start to rear their heads, and we had to swap out some of our original ideas for different configuration ends to get everything to work properly and point where it needed to.

We’ll also have to do a small bit of grinding on the subframe, just to add a bit of safety margin so there’s no chance of metal-on-metal contact with hose fittings and subframes.

Next step will be to actually route and cut the hoses, then send the hoses and fittings back to Fragola for cleaning and crimping.

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Comments
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Papabear
Papabear Reader
1/18/21 9:53 a.m.

I'm curious on how you address the PVC system on the top of the engine when switching to the dry sump. If the valve covers etc are vented to a catch can now do you seal all this off for the dry sump?

kb58
kb58 SuperDork
1/18/21 10:08 a.m.

That's correct. One of the benefits of a dry sump is pulling a vacuum in the crankcase, which reduces windage losses. The only way that can happen is by blocking off all avenues for air entry. The catch can ends up being connected to the dry sump reservoir.

Papabear
Papabear Reader
1/18/21 10:37 a.m.

In reply to kb58 :

Why I was curious was in some of the install instructions it shows the sump tank going to a catch can and another line running to the valve covers. 

Kubotai
Kubotai New Reader
1/18/21 10:53 a.m.

In reply to Papabear :

Depending on the sizing of the scavenge side of your particular pump and the blowby on your engine, you may find that at high rpm, there will be more blowby than the scavenge can handle.  In that case, you need to be able to vent the crankcase to the sump tank or you'll build pressure.  You can put a check valve in the line between the valve covers and the sump tank so that excess pressure can vent but when there isn't as much blowby, you can still pull a vacuum.

 

bentwrench
bentwrench SuperDork
1/18/21 11:32 a.m.

If you vent the valve cover to the top of the dry sump tank, you will allow condensate in the tank to be drawn back into the motor. Better to have fresh air drawn into the motor than dump condensate laden air back into the motor.

If you are going to seal the motor you need more than 2 scavenge stages. (not enough vacuum)

Many dry sump setups have multiple pickups in the pan and one in each head.

Some will block off hot top end oil from falling down onto the rotating assembly and draw oil from the valley instead of the heads.

We run a vacuum pump on the wet sumped big block we drag race for crankcase vacuum.

My Hoonmobile V6 has a 4 stage pump.

kb58
kb58 SuperDork
1/18/21 12:14 p.m.

On my custom car, due to the 3-stage dry sump, crankcase vacuum remains between 13-18 in Hg regardless of rpm and load (atmospheric prs is ~30 in Hg). Wouldn't be possible with any valve cover vents.

350z247
350z247 New Reader
1/22/21 7:56 a.m.

I would love to have a dry sump set-up, but I just can't see it offer ten times the benefit over an accusump and oil pan baffles. 

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