vacuum pump,why pull off valve covers

[nyesgym]

Finally got to test and tune at Numidia dragway. Disappointed. with new vacuum pump on, 12 oz and new intake, car only ran 9.43 at 139 mph, last year it ran 9.12 @ 147mph. So what happened . I could feel the car stop pulling at 1000'. my 60' time went from 1.27 to 1.33 . It has to be the intake. the runners are bigger and it is higher. My fuel mix is 12.9. but I also switched fuel from sunco 110 and went to sunco 112 . could that have hurt me. can't be the vacuum pump. any want took off the hurrican plus intake and put back on my wilson super victor. I will make a pass this sunday and see.If that does not do it, I will switch back to 110 fuel. any thoughts.

[Chevelle156]

Hi new member here. I have never seen a forum with such a wealth of info. About your disappointment with your ET; Did you look at your torque numbers while at the dyno? Horsepower is great but with only a 1/4 mile to use them you need torque to get those horses working faster.

[nyesgym]

Well went to cecil on their new cement track, every one was bouncing at about 330 mark and losing traction, needs rubber down on track. but i went back to wilson super victor intake, et went 9.34 at 142, so yea the hurrican plus was holding me back. but still i am not back to 9.12 i had last year. It just can't be that vacuum pump ? i am pulling 12 oz when i cross traps. so next i will switch back to 110 vp fuel , from sunoco 112 and see what that does. Then, If that does not get my et back, I will take the vacuum pump off,then the car will be as it was last year, If I find that pump was holding me back, I am driving to Moroso and sticking up their !!!****@@.. I know dyno time gives you info, but the proof is at the track, I know that, so next saturday I try again. I want to buy some better heads, anybody have some, that will not brake the bank, need 456 ford 9" 3rd member 33 spline [anyone have that. how about 434 sbs with 800 hp any body have that

[Strange Magic]

The difference between Numida and Cecil is exactly the difference in your et. To draw conclusion, your manifold swap made no difference and they both make equal power. Depending on the ring package, your vacuum pump might contribute to ZERO POWER INCREASE. If you carry a 1/16th, 1/16th 3/16th package that has a conventional radial wall thickness (D wall) than your gains will be zero when compared to an evac system.

In order to truely evaluate your gains and losses, you need a clear understanding of DA and track conditions. Without this understanding, you are in the same boat as Stevie Wonder would be, if he was driving a car.


I'll go back and read this entire thread when I get a minute and comment accordingly. I just read page 5 only.

P.S. You should not have a dip stick or tube in this engine, you are looking for trouble. Block it off completely with a pipe plug. If you need to check your oil level frequently because the engine is either consuming it or leaking it, then those issues should be addressed first and foremost. I don't remember the last time an engine left my shop with a dip stick. Not even a street/strip combo.

[nyesgym]

i do have a dip stick in it. it locks in place and is O rined sealed. I thought that would work. I mean at idle i has 5 oz of vacuum, so my motor is sealed. Is there another reason ? You are right about the difference at numind and cecil. But when I raced at numindia is was 54 degrees low humd. when iu just raced a cecil it was 80 degrees high humd. So I figure the air would be about the same, might be wrong, just my way of thinging. But the thing that was really different was the way the motor was pulling, with the other intake, the motor quit pulling at 7300 rpm, I could feel it and see it on the tack. but with the wilson super victor, it quit pulling about 7600, but was hard to feel ,but i saw it on my tack. I think you are right about the vacuum pump. My ring gap is tight. I have no blow by. Guess I was hoping it would help.

[nyesgym]

ok totally new 421 sbc in. dynoed at 730 hp. 7500 rpms. had hurrican plus intake on, 5oz vacuum at idle, 10 oz wide open. at cecil i ran 9.000 at 152 mph. 95 degrees out 45% humidity. switched to wilson super victor intake, o vacuum at idle, adjust the valve tighter, now have 5 oz at idle and 10 wide open . I do not have a leak, why the difference ? car ran better. 8.99 at 150.5 mph. but where in noticed it was my 60' time, i could feel it, with the other intake [hurrican] 60' times were always 1.29, about 6 times in a row, then when i switched intakes .it went to 1.26, might not seem like much, but man could i feel it. my headers were made for a 383, 1 3/4" to a 3" collector. i am switching to dynotech headers. staul pattern,1 7/8" stepped to 2" and into a tri Y merge collector and finish at 3.5" . will this change my vacuum ? and I am hoping like hell I go faster. Guys are telling me 50-75 hp over my too small of headers. racing at super chevy this weekend at maple grove. 1974 red vega looking for 8.90 at 153 mph

[MadBill]

Crankcase vacuum has no relationship to manifold vacuum (BTW, both are usually measured in inches of mercury, abbreviated as " Hg., ~ 30" Hg. being sea level atmospheric pressure.) and is not affected by cam, manifold or header design*, only by vac. pump capacity and condition (they wear out, some faster than others), ring blow-by and air leaks into the engine. *the exception being header vacuum devices.

[nyesgym]

was leaking around my distrubtor

[vincenelson]

When this thread first started talking about using the fuel pump block off for a vacuume connection it brought back fonund memories back in the 60's. We had a chevy 301 in a 56 chevy with the best small block heads lots of compression a Sig 990B and 5.57 gears. We decided to install some breathers on the pan to remove some of the crank case pressure. One pass down the block showed us why it was a very bad idea....took 3 or 4 hours to clean up the oil mess we made under the car. It did not take much to figure out why we moved the breathers to the valve covers....less oil in the gasses leaving the valve covers.

[nyesgym]

I can believe that, Hey I went ahead and tried several of these guys ideas, but man, that one I picked up so much oil, but hey , I gotta try ideas, some of them work and make me go faster, yes some do not, but I will never know unless I try. I work on race cars for fun, so its my time. I still have the same car 74 vega SBC in , now running 9.800 at 151 mph. and I can tell you not 1 high dollar change made me go faster, it was all old school ideas that do not cost much, just uses my time, which is mine to give. I really like motorhead cars, always have always will. This saturday I have a bet with a guy that by lowering my wheelie bars I will go from 8.90 to 8.85. Alot of people just do not understand the 1st 60' is everything. Instead of going up in the air to a wheelie, my car will move forward,cutting my 60' time down. its 1.24 now, i looking for 1.23 that will give me .05 less time at the traps. People ask me, why do you pull wheel stands in the 1st place, well to be honest ,it feels cool ,looks cool, and sometimes it scares the crap out of me.I am 62 years old, but in my head I am still that 16 year old kid who took his 4 door 57 chevy to cecil county in 1966 and won stock class and won my 1st trophy

[nyesgym]

ok some news here on my vacuum pump, ok i have been pulling from valve covers ,3oz vac at idle and 11 oz at 8000 rpms, really not putting any oil in my moroso catch can, has a filter on top of it. I was running 20-50 wt oil [crude oil] thought i would switch to 5-30wt full syn oil. i know it would make my car faster and yes it did, i went from 8.900 to 8.882. cool right ? made another run 8.886, feeling pretty good, pulled my hood off to check on everything and wow oil all over the front of my motor. Here the oil is blowing out of the filter on top of my moroso catch can. the vacuum pump is pulling up this lighter oil light crazy. 2 runs and i had a 3/4 cup of oil . ok i can deal with that but, not the oil flying. so, took the catch can apart, its empty ? and the hose that feeds it goes straight in from the side, So 1st i put heavy duty steel wool in the bottom of my catch can so it will not splash, put some at the top at the filter and raised the filter 3" with a peice of plastic pipe. then i put a turn down fitting inside the catch can to blow the oil straight down instead of straight in. went to the track. no oil leak or splash. problem fixed.