[mgarblik]

We ran limited vacuum as well in the system with an adjustable valve. 12"HG for us and we monitored it with the data system. Real high vacuum in the crankcase with wet sump oiling and pump in the pan, the pump is working against the vacuum. Our Moroso consult felt the 12" HG was a safe max number for a stock Melling pump which we were running at the time. He mentioned the dry cylinder wall and pin oiling issues at high vacuum, but didn't really believe it was a factor nor did he have any hard data. I tend to think that's mostly speculation as well. When you have a guy like Langer running 19" HG at speed with no issues, at what I assume is high RPM's, that tells the story IMO. Picking up vacuum from the front of the valve covers for drag racing seems like a fine idea and worked for us through a baffle system. For our road race engine, picking up in the center, inboard, high in the cover I like because of the high acceleration forces as well as high braking forces. Nice compromise.

[chuckies76ta]

(For our road race engine, picking up in the center, inboard, high in the cover I like because of the high acceleration forces as well as high braking forces. Nice compromise. )

Great info. Thanks. I could see where that makes sense as the oil flying back and forth throughout the road race . Also, like you said HIGH in the cover.

[Dave Polichena]

I've tried many baffles and locations. I ended up welding a bung at the top in the center and made my own baffle inside. Welded some flat stock in a few spots, the ends are wide open. I pull 16-18 at the stripe.

[mgarblik]

Originally Posted by Dave Polichena

I've tried many baffles and locations. I ended up welding a bung at the top in the center and made my own baffle inside. Welded some flat stock in a few spots, the ends are wide open. I pull 16-18 at the stripe.

That looks nice as well. Not sure we have room for quite that much of a baffle. Going to be running some big, clunky stainless steel rocker arms. (Crower)

[gman005]

Yes i run the adjustable relief valve. I will post a picture of that.

[gman005]

Here is the valve.

[Bob with the 66]

I added the adjustable valve last year to my EVAC pump.

With mine adjusted to 14" at the big end, at 2021 Norwalk it had maybe a table spoon in of oil in the catch can after each run compared to years past of a cup or more.

Also added a sweat band around the catch can breather which worked great.

Bob,

[Don 79 TA]

Originally Posted by John Langer

A hair over 13.1-13.4 at an idle and around 19 in the lights.

how the heck are you getting that much at idle?
must be a super sealed up engine or spinning a pump like crazy
i get about 3 with the GZ102 pump at 5k altitude idle 1100-1200
what pump are you running?
first time i've heard anyone getting that high

[slowbird]

Originally Posted by Don 79 TA

how the heck are you getting that much at idle?
must be a super sealed up engine or spinning a pump like crazy
i get about 3 with the GZ102 pump at 5k altitude idle 1100-1200
what pump are you running?
first time i've heard anyone getting that high

A good pump makes a big difference, my star pump will pull around 10 at idle.

[69Goat1]

Now my question is what is the best pump to use? I have a 14:1 535 I would like to add the best pump I can afford to because I have no windage tray or crank scraper and I have low tension rings. I want it to live a long life and I want the advantage of the increased power!

[slowbird]

Star or 4-vane Moroso are the 2 best imo

[cgeise]

Haven't seen it addressed here yet so here goes --- If your engine has any leaks -- or excessive blow by the vacuum the pump will pull oil mist and fill the tank -- It has to be sealed --- think off it like this -- put a straw in an open glass of milk and suck -- you get lots of milk -- put a straw in a tight sealed container -- and the straw sucks shut and you get no liquid --

[cgeise]

Oh -- and 69 goat -- the Star pump wants to be run with no or very little oil going thru it -- Moroso is more oil forgiving

[grandam1979]

Can someone post a picture of where you are checking vacuum? Does anyone ever use a breather on other cover to control vacuum?

[gman005]

I pull from the valve cover. I am using the GZ pump. I have around 5 at idle and 11 at WOT.

[gman005]

Here's the picture.

[Bob with the 66]

I tapped into the valve cover cap for a temporary set-up just to adjust the EVAC valve.

[chuckies76ta]

Originally Posted by grandam1979

Can someone post a picture of where you are checking vacuum? Does anyone ever use a breather on other cover to control vacuum?

Go back and read post #20. In a word NO.

[Dragncar]

Originally Posted by Bob with the 66

I tapped into the valve cover cap for a temporary set-up just to adjust the EVAC valve.

Wow Sir, I can see have some Marcella stuff going on there. Can we see some more pics of the car/engine ?
From what I can see, work of art.

[John Langer]

Originally Posted by Don 79 TA

how the heck are you getting that much at idle?
must be a super sealed up engine or spinning a pump like crazy
i get about 3 with the GZ102 pump at 5k altitude idle 1100-1200
what pump are you running?
first time i've heard anyone getting that high

Most in my class pull over 22 in the lights. I run the Moroso 4-vane enhanced pump. I guess I could pull more if I was a dry sump. My motor is sealed up tighter then a submarine. Great ring seal and no leaks are key. If my vacuum starts to drop off during a run but has great pressure until then, its time to replace the rear main seal. I don't spin the pump too hard. I have a blow off valve but it is screwed all the way in and I have duct tape over it.