jeffswav

Alright this topic has been covered before. How many of you use vacuum pumps? Did you see a HP increase? Are low tension rings required? What PSI do you run (10-15)? Just looking for a couple more MPH for next year and reduce blowby.

jeffswav

ttt Anyone, I know somone has to be using one.

Griswald

I used to run them on all of my drag motors. Yes, you do need low tension rings and they were good for 15-30hp on various motors. Can't say I've ever seen on in a boat though.

jeffswav

I went through some old post and found a few guys using them. Some said big gains (30HP), others said no gain. Just wanted to see if anyone else had tried it. It was also stated by a few that low tension rings were not needed, but the pressure is limited.

ezstriper

I run one in my top sportsman drag race engines, but in boat engines in the rpm we run I would say 0 h/p gain..unless you run a elec one takes h/p to turn the pump..at least in a full race type setup...Rob

SHAWN DAVIS

The problems I hear are burning up the piston pin in an endurance type application, the vaccum pump kills a lot of the oil flying around in the crankcase

jeffswav

This is a performance/pleasure boat, about 90% of the time is spent at 3K RPM maybe 10% is running hard. Just looking to tweek out a few more MPH without any major changes. Maybe not even for this winter but just somthing to plan for. The engine is running perfect and I do not want to crack it open. A Stellings box raised 2" would be cool but a bunch of money to get a few MPH.

ezstriper

don't waste your $$ there

phughes69

I think the HP gain is from running the low tension rings and a little less crankcase pressure. You probably would not see enough HP gains if you were to use std tension rings to justify the cost of the pmp and all the other associated hardware.

jeffswav

Thanks for the input guys.
I will most likley put this one on the shelf and look in other places to upgrade.