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 n…
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?
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.
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.
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.
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.
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.
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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