Originally Posted by OneBadGMC
Originally Posted by doorracer
Originally Posted by OneBadGMC
Originally Posted by doorracer
Originally Posted by JEFF69Z28
How much more hp will you get putting on a vac.pump?
I don't expect to pick up a single one. If we do great, but we are running it to keep the moisture out of the motor. If it will at least keep the motor in a neutral pressure situation we may pick up a few. This motor made 702hp on the dyno and seems to have a really good ring seal so who knows?
Curtis
I'd be curious to know what type of vacuum, if any, you see at 7000-8000 RPM with it under full load.
Just make sure you don't get into a positive crankcase situation, or you may find out which seal is the weakest on the motor.
You might want to consider something like a roll over check valve in the valve cover. Something that will seal with vacuum, but vent with pressure. It'd be some cheap insurance to do that and not worry about pushing oil pan gaskets out and spraying the tires with oil.
Just food for thought.
WJ if we are pushing gaskets out we need to work on our ring package. :lol: :lol: .
I hope that was a joke.
5" of vacuum isn't that much, especially with no engine load, and that electric pump isn't going to scale as RPM increases.
I'm dead serious when I say make sure and monitor that vacuum level during your first couple passes. If it loses vacuum at any time, you need to get out of it and ditch the pump.
From all of the stuff I've read, dead minimum vacuum you want is 10", and most regulators are pre-set to 15". Most pumps can pull up to 25-30" of vacuum and their volume scales with engine RPM since they're belt driven.
I'm just saying... be careful. I have nothing against doing things on the cheap, and this may work well for you. Just don't put yourself at risk if it doesn't keep vacuum on the crank case at max RPM.
It was no joke, I think everyone is losing sight of what we are doing with this and I do understand the positive crankcase situation. This engine, as many across the country does, ran fine with just a pan evac system. This pump moves way more volume than that ever would.
it is only to remove moisture I don't think it will pull over 1 or 2 inches of vacuum on a pass.
Just to clarify something though. I have a mechanical pump on my car and we have one on the dragster that we have also. I posted this for the guys who always ask questions, which I have seen a hundred times, about how these work on an engine. I do appreciate the concern for our safety but we are not a bunch of newbs trying to do something with $12.00 dollars in our pocket.
AGAIN guys don't lose sight of what we are doing with this we are not trying to pull vacuum to make power. This car is tire limited with a 14-32 so we have to kill some bottom end as it is. I am not trying to be adversarial about this I just want everyone to understand that we do have a pretty good idea and knowledge about what we are doing, this was just for the guys who can't buy a Star or Moroso and would like some info.
Curtis