I have begun the bracket work for the manual vacuum pump installation. I am going to run a Morosso 3-vane pump. I already have -12AN fitting on the valve cover from the old crank evac system. My thought is to run from the vc to the pump then to the air oil seperator, then the air will be exhausted to atmosphere. I am considering a vacuum break on the other valve cover, but not sure if this is overkill. The vacuum pump drive pulley will replace either one of the idlers on the blower drive system, or the idler on the drivers side where the alternator sat so many years ago. Does anyone have knowledge as to whether these vacuum pumps may be run either direction (rotation)?
With the electric vacuum pump, I still see pressure under moderate/high boost levels. I am hoping to address the situation with vacuum through to max boost. Who knows?
I have been looking at those Moroso vacuum pumps for a couple years now. The new generation one looks even nicer than the old one. I have been held back by a couple of things that have kept me from pursuing it further. First is, obviously, it's very expensive. The basic bare pump from Summit Racing (MOR-22640) is $360. After you add all the lines, fittings, brackets, oil separator/breather and trying to attach it to the valve cover it was going to get very very expensive for something I wasn't sure would even work. The other two issues on my L98 setup were, pump placement and pulley. There is no free place I can see near my drive belt to install it. Lastly it would need a custom serpentine pulley to be made as Moroso only seems to offer deep V groove pulleys for it. Again the expense is going up considerably.
The issue is of course that I don't think there has been a workable alternative found to this point. I am just putting my second motor in the car, the first got a holed piston from the crankcase pressure blowing all the oil slowly out on a sustained high speed run, and I would like to not grenade the MUCH more expensive second engine. So if this is the only way to make it work I guess I will have to bite the bullet and start figuring what it might take to get it in there. There was a article in a recent car mag, in the last few months, detailing their use of this system in one of their build up motors. It was a sidebar explaining how it worked and the results. I believe it was a 650hp normally aspirated SB Chevy. I will try to locate the article and reference it here in an edit so you can take a look at what they did and check their information on the setup. Too bad the cheap $50 Moroso header vent kits won't work on our full exhaust system cars, that would have been a nice easy way to fix it...Oh, well.
Oh, and also I do recall from that article they were very straightforward about this being a race only system. They said it needs to be torn down and cleaned and serviced very regularly, not something you would want to do on a street driven car every few weeks. Hmm, I will keep trying to find more info.
A couple of items that may not be clear from the earlier post:
1) the new type Moroso vacuum pumps are for dry sump systems, designed to scavenge large amounts of liquid. To my knowledge, they have not released a new design wet sump pump yet.
2) Expense, most of the items (fittings to vc, lines, seperator, are already in my posession, as I was previously one who ran the pan evac system. As a side note, mounting-12AN fittings to the valve covers can be somewhat tricky while retaining the factory type baffle and clearing full roller valvetrain. It can be done.
3) Drive system, I will machine a guided serpentine pulley for the pump and will mount in place of one of my idlers (preferably the one mounted under the blower, as it appears there would be less strain on the vacuum pump in that location). If I can not package in that location, then I will attempt to reverse the unit and mount on the 6 rib serpentine drive next to the alternator. There is plenty of room there.
I am currently building brackets for mocking the unit on an engine stand. One of the problems is duplicating everything while keeping the car up and running. I have two FI cars, but each uses a different drive, blower, etc. I am currently waiting on a spare ps pump, and I should be ready to proceed with the mock-up.
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Addressing the Vacuum Pump Issue
