vacumm pump tech needed

[69b1dart]

just installed a vacumm pump on my mopar 440,what should the vacumm be set at at idle or wot,also where should the reading be taking from,theres a place wheres theres a pipe plug used for the fuel pump rod,or should it be higher,i have a relief valve on the pump,using a moroso 22644 pump

[sg3526]

I usually take them from the valve cover. And from what I've been told you shouldn't exceed 20 inches of vacuum at WOT.

[69b1dart]

moroso tells me 10-12,had a guy on another forum says he runs his at 19,how much hp can i see or if any over the header vac

[sg3526]

Not really sure. I have never taken the belt off while at the dyno so I cant say for sure. What I do know is that since I went to this system my oil is a lot cleaner because it seems to pull more of the moisture out from the alcohol. Some people say you can get as much as 25 hp by putting the vacuum pump on it and the guy that runs the dyno says pretty much the same thing, but like I said we never pulled the belt on mine to verify it.

[69b1dart]

thanks for the input,have a new one on and will give it a go this year,i do run alky too

[doughboy692]

When I first put the pump on mine it only picked up a few HP. But the oil was much cleaner and it had absolutley no leaks. Where before it seemed to always have a little seapage from the rear main seal. After I went to the lowtension rings it really picked up. As far as how much to pull I myself have 12 when staged (footbraking) and over 20 at the stripe. The biggest place you need to look out for if you decide to run alot of vacuum. Is the wrist pins need more clearance, Weld a nut on the bottom of the oil pump pickup or pan so that it cannot suck the pan up against the pickup and make sure you have enough oil pressure because once you start pulling vacuum the oil pressure drops a little. I pull my vacuum from the front of the right valve cover and have fitting installed in the back of the left valve cover that is plummed to a gauge on my dash. Also make sure the fitting in the valve cover is not right over a rocker arm or it will pull alot of oil into the catch can. Hope this helps

[548h]

About vacuum pumps.

Important! If using a wet sump oilling system you must limit the vacuum to 11" or less at WOT with a race quality pump and 7" or less with any oem type pump.

The vacuum will "pull" on the oil at the pick up and fight the pump. New vacuum pumps "break in" so check the vacuum after a few pulls it may go up. It is wise to install a guage in drivers view to monitor it on a regular basis. It is a useful diagnostic tool as well.

If running a dry sump oiling system you can go up to 20" at WOT. Above that you can run risk of galling the piston pins.

Not all pumps are created equal. Our preference is Star Machine. Nothing wrong with Moroso.

Bottom line ask your engine builder what he likes for what you have in your engine. Oh yeah and don't forget to drain the tank!

[sg3526]

Been running a 4 vane Moroso pump since 1999, pulling 20" of vacuum and have never had an issue with wrist pins and I run a wet sump system. That being said I also run straight 50W Valvoline Oil and that may help with that issue. Like I said I haven't really seen any type of performance gains but the oil is a lot cleaner when I change it (usually after 10-12 passes)

[sg3526]

And always remember to drain the tank every pass, when running alcohol it fills up rather quickly.

[69b1dart]

i run a wet sump with a alum pan and swinging pick up,im going to try 10-12 at wot and go from there,i know it will be a learning curve

[69b1dart]

havent got to run it at wot yet,will at a test and tune,at idle pulls 5 on the gauge,and had a lot of water in the tank,i understand why they want you to clean the pump after use,to keep it clean and not to rust