Club Cobra - Engine vacuum using side pipes

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Engine vacuum using side pipes

Anybody use the side pipes to draw a vaccum from the engine, I have a smog pump that I'm thinking about using as a vacuum pump but, I like the idea of using the side pipes. any help appreciated.

It is usually a drag race only way to draw vacuum. You need to sustain high flow rates though the exhaust, high RPM the whole time. Why do you want the vacuum pump, to generate negative crankcase pressure, or for power brakes?

You can use a vacuum pump to evacuate the block, to get an effect similar to hooking up a tube from the breathers into the collectors. If you look through a Summit catalog, you'll find the pump, and you'll also find a kit to run things into the exhaust. Make sure if you run into the exhaust, that you have a one-way check valve so you don't end up with exhaust backing up into your engine for some reason.

I too would wonder why you want to do this? Loose rings?
It is a drag race setup, effective only at very high rpm's, and is pretty messy looking under the hood (hoses, clamps, valves, and a pump?).

But a lot of things under a Cobra hood don't make a lot of sense to rational thinkers, so hey, go for it if it'll float your boat.

Perry,

I've been using side pipe hookups for years. I read an article in Hotrod magazine about this and tried it. I connected one breather from a rocker cover to the PCV valve and the other to the hoses running down to the sidepipes. It was too much trouble to run the hose to the sidepipe collector, so I just choose the handiest pipe on top of the bundle and marked a spot about three inches inside of the car body. I had to remove the side pipes. Then, I drilled a 3/8th hole through the mark and brazed a 1/2 inch tube over the hole on each sidepipe. The tube that comes with the Moroso kit is threaded and a one-way valve screws onto the end of it. I believe that it is a special high temperature smog hose (with three ribs) that pushes over the valve nipple and the other end goes to your rocker cover. I use a plastic "T" fitting at the breather cap so both hoses connect to the same side.

I do believe that the vacuum helps seal the rings and gives more power. In a dozen or so years, the only trouble I have had was once, when I over-revved the engine and broke a piston ring. The oil blowby was so bad that cars behind me complained of the smell. Since I rebuilt the engine, that is no longer a problem.

Paul

Going by 427 S/Os Sig file I would say the problem is not being able to easily plumb the intake manifold for PCV. I've heard of some of the circuit race guys using an engine driven pump to evacuate the crank case. I guess a smog pump would do the trick too providing it could generate enough vacume.

I've seen a Quad Webber manifold that had been successfully plumbed for PCV. It had a fitting in each of the runners that ran back to a common connection point. I can't imagin you would want to modify that manifold of yours. It sounds like a rare piece of hardware.

Cheers

No power brakes, no loose rings, just looking for additional HP. I know all that iron slinging around in a vacuum produces no drag, due to negative crankcase pressure, just interested in using the side pipes as a way to keep the engine bay clean. I'm going with black HPC the next time I have the side pipes replated and thought this would be a good time to add the kit, providing it works. Thanks all....

Just run a PCV from your valve covers to a breather tank. No more mess.

I made this a couple of months back, it works fine I'm just looking for a way to make more HP cause, I'm just naturally aspirated.

The Hp gains one can get from running a vacuum pump to evacuate the crankcase are very small. It is usually done with low tension rings, which free up a little power by reducing friction.

Okey Dokey...you talked me out of it.