vaccum pump?

[hansj3]

The Pros and Cons of Racing Vacuum Pumps

having worked with a friend who used to drag race his mustang with a 460 he used to go on and on about how he loved his vaccum pump.

long story short for him it controlled oil leaks due to blow by, and gave him 32 hp. the theory behind it is if you have more than 4 but less than 15inhg it will cause the rings to seal better.

maybe a cheap way to pick up a few mpg

[RobertSmalls]

An engine at full throttle makes very little vacuum. A vacuum-powered crankcase ventilation system is therefore pretty much inoperable during a race. I don't know where his +32HP comes from, but hey, he needs vacuum at full throttle anyway. I wouldn't expect a MPG boost in a road car, since few ecomodders are at full throttle for extended periods of time.

When I drive to my buddy's house, I switch off the engine a quarter mile from his house, make a few turns without power steering, and coast into his driveway. I almost hit his front porch a few times, since my vacuum brake assist was inoperable. I'm probably going to install a vacuum capacitor or pump on my Insight so I have power brakes during extended EOC.

[ConnClark]

The crank case vacuum pump works by removing air and vapors from the crank case, thus reducing pumping work imposed by these gases. This does have potential to increase mileage provided the parasitic draw to operated it isn't to great. It will provide the most benefit at higher rpms.

[Peter7307]

As mentioned above the pump operates via a belt drive and creates a relative vacuum in the crankcase. The power required is not a lot but there needs to be some sort of separator catch can for the vapour from the oil.
This in normally a metal cylinder with a drain back to the crankcase and a vent to atmosphere and the associated valving to make sure it all operates as it should.
Not a lot of weight but some space required to house it all.

For the MPG side there would probably be some gains but if the extra complexity (and costs) are worth it that is a question for the owner to sort out.

Interesting thread.

Cheers , Pete.

[hansj3]

JEGS 52210 - JEGS Crankcase Evacuation Kit

it takes the cost and complexity out of it. if you could weld it could be put in for less than $50 or so. even if you cant, it probably would come in at under $100

exhaust crankcase evacuation....it works - Corvette Forum

according to this thread they say it works best under 4500rpm but it seams that they think that bigger motors cause it to be less effective.

people have thrown down c-notes on less proven things...

[RobertSmalls]

Since we're talking about road cars here, it would be illegal (and unenvironmental) to vent those hydrocarbons to the atmosphere. The catch can can drain to the sump, but the gasses must be circulated into the intake to be burned. I favor the existing PCV valve and hose arrangement.

There are electric vacuum pumps, too, which would draw less power, be easier to mount, and run only when necessary. Jegs has one for $250, but eBay has them for $60+ used, out of diesel applications.

[hansj3]

but would they even make it on a warmed up car? most of the extractors are mounted square in the headers. they would probably burn up before they hit the cat and the cat would take care of the rest... presuming there is still a catch can. however a pump would be another story
if i did it i would drill out a new bung and weld in a baffle on the valve cover and still leave the pcv system in place, as it seems to pressurize at high rpm.

[Peter7307]

Originally Posted by RobertSmalls

Since we're talking about road cars here, it would be illegal (and unenvironmental) to vent those hydrocarbons to the atmosphere. The catch can can drain to the sump, but the gasses must be circulated into the intake to be burned. I favor the existing PCV valve and hose arrangement.

Robert ,
Yes, agreed.
That would be a much better approach.

Cheers , Pete.

[AXMonster]

IIRC the exhaust extractor PCV system is there to ensure the crank case remains at negative pressures during WOT conditions. This is something that isn't really useful for us (unless you're running a Diesel engine) as the stock PCV system should be pulling a vacuum if it is connected to the intake manifold post throttle.

On a Diesel engine it may well be of use as Diesels do not run an intake vacuum, and therefore can only plumb the PCV system into the air intake, which will not pull much of a vacuum at all.

I have an exhaust extractor valve, a catch can and a PCV valve that I may well put to use on the Focus Diesel

[hansj3]

but from what i have read, the extractors create vacuum regardless of throttle position, just not as much.... i can see the diesel advantage though
i guess there is only one way to find out, i wish all of my beaters weren't flat 4's now...