Well,

I think I have made up my mind to get a racing vacuum pump for my motor.



They are available in street/strip versions to keep the oil recirculating through the pump. The main purpose for the install is to clean up my intake that sucks oil out of the covers and into the plenum. And also they claim 1.5-.2sec gains with standard tension rings. More with low tension - I wish I would have decided to do this a few weeks ago when the motor was on the stand - it would have been pretty easy to put a set of low tension rings in then. Maybe next year.

The purpose of these pumps is to create a vacuum in the crank case and allow free movement of the rotating assembly. When there is air present or blowby from the rings (every engine has it) - this can cause a pulsing that needs to escape and or it will blow the seals out of your motor and can also cause resistant to the pistons on the downward stroke.

With our VERY large strokes in relatively the same area as a 350, this becomes more essential. Last year I bandaided the problem with a vacuum line to my plenum that drew vaccum on anything under WOT, but at WOT there is no vaccuum when you need the pull the most.

Furthermore, with the new cam I am only getting about 8" of vacuum on the plenum at idle So I will T off the line use some for my power brakes.

I think the pump is the only way around this so I am going to purchase one today from Greg at www.gzmotorsports.com

Going to get the pro pump(purple in graphs) - a step up from the sportsman cause I am going to use the pump to assist with the brakes as well.

Here is a chart of the CFM these pumps can move:



And a breakdown of the vacuum they can also pull at given RPM ranges.

Going to need all the help I can with my quest to the 9sec range.

Now all I need is for it to do is quite snowing out!

I will keep you posted on how the install goes with it. I have a feeling its not going to be as easy as he claimed, particularly with the crank pully. Maybe I will luck out.

PS: Ralph you will be getting one too...

 

my friends mustang used this pump, the car went from 10.0 to 9.7 that sound like a lot of ET but its the truth. the only thing that sucks is you have to find a way to run it and to be able to unhook it on the street. if you use it on the street i think you have to rebuild it regularly and yeah his motor is a 427 windsor

 

Just install a vacuum break valve. It is basically a pressure safety valve in reverse. When vaccum exceeds X it opens to releive. A lot of the Super Comp guys here use them, sometimes them damn vacuum pumps suck so much that it can collapse a sheet metal valley pan or suck in gaskets. One time a guy was push starting his dragster and it sucked in a valve cover gasket. As the engine was not running there was no crankcase pressure developed by the engine to offset the amount of vacuum the pump was pulling and it sucked in the gasket.

 

Are you saying that a vacuum break valve will help with longevity? Pardon my ignorance it has been a long day.

 

I heard about these, supposedly they can only make vaccum for so long, then you need to rebuild them as it's been said because internal seals or some such start wearing out, is that right? Anyway very neat idea. I was always a fan of getting better power:weight ratios without increasing power output through traditional means (stroking it into a tank motor namely) but rather decreasing weight of the vehicle, increasing volumetric efficiency, or doing something like this (which I guess would fall under decreasing drivetrain power losses?)

 

I know this is a little redneck.... but use your A.I.R. Pump as one of those! It does work! and it doesn't need rebuilding like those do! I'm sure it doesn't "suck" has hard, but it helps nonetheless!

 

Yes these can suck a lot of air, much more than a typical air pump. Remember even if you have vacuum at idle, once the RPMs start to increase it must keep up with the blowby - and suck even harder to remove that introduced air to keep up with the vacuum. That is why these specialized pumps are used.

I ran my vacuum gage on the motor yesterday, and it only pulls ~4-5" of vacuum! Looks like open loop 100% of the time is going to be the way to tune this puppy.

I just can't get over the exhaust note. Before it was a loud low rumble. But not its a more cracking, with notes of silence inbetween. We'll see how the stock ECM makes out, but I may have gone overboard now. lol.

Back to the vacuum pump. The pump in question here is built specifically with street use in mind. Observe the return line of the pump to recirculate oil from the canister back to the pump to assist in lubrication. He said they will last for years with lubrication and he will cover the rebuild if it wears out sooner, so long as its apparent that oil was present.

The pump I think should help, and I needed to put something on there to assist with the power brakes. 5" is not going to cut it. So I figured I might as well go the extra couple hundred dollars and get the benefits the pump might give in HP at higher RPMs.

Red98, you are not the only one stating .1-.2 sec gains with these things. But I am looking for zero gains and if some come then awesome. On one hand I find it hard to believe it would yield that much on a fresh motor, and on the other when you start thinking about resistance at 3000+ rpm from crank pressure building up and resisting the pistons downward movement, i can easily see 20 HP being gained or even more. I have seen littler things make that much difference and its usually the small things that yield the larger gains. Put a step up header size on thinking it will help and get nothing. Do something like this and gain .2 sec.

Also one MUST run a vacuum relief valve someone alluded to in the post. The pumps can and WILL produce too much vacuum and will result in other problems occuring. The information they supplied to me said that most power gains happen in the 10"-15" range with gains of up to 15% - what that tells me is that 12" is what you want to run, and on a worn motor you could see 15%. Cause on our ~650hp motors they are not picking up 97hp from this thing.

Well it should be here earlier in the week and with any luck I can have it on by the close of the week.