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You are speaking about crank case vacuum? Doesn't matter if the engine is boosted, it lowers the pressure on the case side of the rings/combustion. So it would be used as you normally would a naturally aspirated engine. I would ask your engine builder if you should use it. Usually boosted cars have wider ring gap and more blow by so I would imagine it would help
I've never had an issue just using a catch can plumbed to both valve covers. I imagine at some boost level that won't work anymore but that level is somewhere over 22-24psi of boost so I'll probably never find it.
Thanks, I have a JAZ -10 with filter on top to 1 valve cover now. Haven’t fired it up since going turbo, doing fuel system & chassis work so to much spark so far but close so was just wondering if crank vacuum pump might help. Also have oil separator that’s not installed. Just thought about pump cuz my buddy has one!
Thanks, I have a JAZ -10 with filter on top to 1 valve cover now. Haven’t fired it up since going turbo, doing fuel system & chassis work so to much spark so far but close so was just wondering if crank vacuum pump might help. Also have oil separator that’s not installed. Just thought about pump cuz my buddy has one!
A vacuum pump could very likely help, but be aware they have their own set of nuisance issues. The only time I tried one I had a nightmare of a time getting the belt alignment just right, and even then it was not remotely worth the hassle of an extra set of potential failure points. I decided a catch can and the 1 extra lb or less of boost it would take to equal the gains of the vacuum pump made much more sense.
I've also heard that running a vacuum pump on the street pulls oil out of components that would normally be saturated.
You could of course just remove the belt on the street.
That -10 should be enough, I ran a single -12 on my old car with a single MM PCV can at 700whp and it worked great.
I personally ran a vacuum pump on my twin turbo sbc set up on the street for years. Never had an issue with oil being drawn out of any parts. I'm sure you could do that if you over vacuumed it but as long as you run a vacuum relief I don't see it as an issue. I don't think it is necessary but if you have it use it.
I currently run a mighty mouse can on my camaro and have never needed a pump on my lsx but I wouldn't say running one is a bad idea either.
Thanks for all the info, I probably won’t need it but now I got a better idea just in case. May fry to hook both valve covers after I fire up, still finishing tool bar up then fuel system as soon as welding is finished. Might have to use 1 gal fuel cell just to fire up for incentive to finish in this 90 degree heat!
Vacuum pump helps prevent blow by, crank seal issues, and adds "free" HP. The belt doesn't have a lot of tension on it... never had issues with it coming off. We run e85 so the oil is changed every 1000 miles as the fuel does bring in some xtra moisture into the oil system vs other fuels
... but those are VERY hard miles.
Why not just have the crankcase well vented so too much pressure does not build up in the case? Whats the negatives of just being vented, with no pull of any vaccum?
Without some kind of active venting,, its really hard to burn off condensation or fuel entrainment in the oil.
Way back I helped with a engine dyne setup and we got 10 HP bump on a 650HP sprint motor with a vacuum pump.. At 9800 RPM..
Without some kind of active venting,, its really hard to burn off condensation or fuel entrainment in the oil.
Way back I helped with a engine dyne setup and we got 10 HP bump on a 650HP sprint motor with a vacuum pump.. At 9800 RPM..
How does a vacuum pull on the crankcase add power? I would think a tighter crankcase would push back on blow-by....if anything.....
I underdstand toxins and moisture in the oil should be evacuated, but not seeing how power is added by the addition of vacuum, or more vacuum.
But it sounds to me like they feel the vacuum in the crankcase helps ring seal and removes pressure below the pisons. I'd say ring seal does more for power then anything else but I don't believe anyone has proven beyond a doubt why a vacuum pump add hp. It has been proven over and over again that it does though. Usually only on big hp engines already but who knows maybe it does on a stock 5.3 too I just don't think alot of folks are gonna buy a 1000 set up just to check. Check out the engine masters episode with the 1000hp 598 inch BBC. Adding the vacuum pump added 15 hp if I remember right. On an already stout combo adding 15 hp can become harder and harder. Now I can already hear someone saying add 1 pound of boost but if it helps keep oil clean, helps longevity and adds a little hp then why not. Besides price it seems like a win/win to me.
Yea we were testing a Dry sump setup that could be set up with or without a pure vacuum stage..
We found over the season that the vacuum setup really reduced methanol in the oil.
Much less ring wear too, for who knows what reason, maybe the reduction in contamination helped it lube better. ??
Also seemed to help reduce windage in the engine just based on looking
NA 408 GM Sprint motor with Kinsler mechanical injection, 1/4 mile ovals turning up to about 9500...
I've also run a vacuum setup on a road race NA 2.0(Early OHC pinto) Ford..
It was good for about 5HP and on a heavily restricted < 200 horse motor that ain't bad.
Considering what the car owner was paying to build the spec engines..
But it sounds to me like they feel the vacuum in the crankcase helps ring seal and removes pressure below the pisons. I'd say ring seal does more for power then anything else but I don't believe anyone has proven beyond a doubt why a vacuum pump add hp. It has been proven over and over again that it does though. Usually only on big hp engines already but who knows maybe it does on a stock 5.3 too I just don't think alot of folks are gonna buy a 1000 set up just to check. Check out the engine masters episode with the 1000hp 598 inch BBC. Adding the vacuum pump added 15 hp if I remember right. On an already stout combo adding 15 hp can become harder and harder. Now I can already hear someone saying add 1 pound of boost but if it helps keep oil clean, helps longevity and adds a little hp then why not. Besides price it seems like a win/win to me.
Ok cool, thanks.
Is there a psi rating for the belt driven vacuum pumps? I ask because there are many different small electric vacuum motors the size of a cigarrette pack up to the size of a tennis ball can.....that a create different levels of vacuum. They can all be powered by wiring it to the battery or alternator so it only runs when the engine runs.....however the electrical gurus do it.
I have one of the cigarrette pack sized vacuum and it pulls better than the factory strength coming off the intake line. I wonder if thats enough pull on the case. I bought it awhile ago to use on my N/A 436ci stroker engine. Never used it, maybe I'll put it on my current 390ci thats most likely getting an F-1A-94.
Last edited by Cant_die_LOL; Jun 14, 2021 at 09:25 PM.
I have never actually seen an electric pump work for this. It's not the psi that is a big deal but the amount of air they can flow. I saw someone try a pretty big electric pump and it just couldn't keep up. Flow rating is gonna be your limiting factor for the size pump you are describing. Think of it like this that small pump will pull a vacuum on a coke can pretty fast but not a nitrous tank. An engine just produces to much air for a small electric pump like the size your describing.
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