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Re: Header evac tubes- how do they compare to vac pumps? [Re: 68LAR] #624332 02/26/10 04:23 PM 02/26/10 04:23 PM
Joined: Jan 2003 Posts: 21,751 A collage of whims topside Too Many Posts
topside Too Many Posts Joined: Jan 2003 Posts: 21,751 A collage of whims	Ring seal improves, especially with lower-tension (lower-drag) rings. It's also arguable that as positive pressure increases in the crankcase, it's harder for the undersides of the pistons to compress on the downstroke; note that the underside of a piston is shaped like a scoop. My experience with my 368" drag-race SB with low-tension rings: Open headers, standard rt & lt pan-evac hoses, minor blowby Adding Dynomax bullets & short 3" exhaust, more blowby Changing to electric pump system, zero blowby Mine is a simple GM electric pump, pulls about 7".

Re: Header evac tubes- how do they compare to vac pumps? [Re: topside] #624333 02/26/10 06:14 PM 02/26/10 06:14 PM
Joined: Jan 2007 Posts: 3,695 nc E emarine01 master
emarine01 master E Joined: Jan 2007 Posts: 3,695 nc	Hey Mr P, ya got a pic of your evac with the e vac tube square with the header tubes, we found the most vac 5.5" that way

Re: Header evac tubes- how do they compare to vac pumps [Re: topside] #624334 02/26/10 06:23 PM 02/26/10 06:23 PM
Joined: Jun 2004 Posts: 1,496 Sask, Can. 7 72demon416 OP pro stock
72demon416 OP pro stock 7 Joined: Jun 2004 Posts: 1,496 Sask, Can.	Topside- what is this electric GM pump off of? Any pictures of it?

Re: Header evac tubes- how do they compare to vac pumps [Re: 72demon416] #624335 02/26/10 06:57 PM 02/26/10 06:57 PM
Joined: Dec 2007 Posts: 10,542 BROOK PARK, OH WILD BILL Senior Member of the Junior Dragster Club
WILD BILL Senior Member of the Junior Dragster Club Joined: Dec 2007 Posts: 10,542 BROOK PARK, OH	Quote: Topside- what is this electric GM pump off of? Any pictures of it?

Re: Header evac tubes- how do they compare to vac pumps [Re: WILD BILL] #624336 02/26/10 07:09 PM 02/26/10 07:09 PM
Joined: Jan 2003 Posts: 21,751 A collage of whims topside Too Many Posts
topside Too Many Posts Joined: Jan 2003 Posts: 21,751 A collage of whims	'80s GM F-car (Camaro/Firebird). Corvettes, Mustangs, and several other cars use them; my '97 Mustang GT has one. A little bigger than palm-sized. You'll need a relay, a switch, a puke tank & related hoses & wiring. Total weight maybe 8 lbs. Doesn't pull as much vacuum as the "real" pumps, but I'm in the whole deal maybe $75 including the used pump, and it works for my setup. I measure the vacuum using a fitting on the opposite valve cover. Crank end seals & anything that can weep needs to be sealed as tightly as is reasonable, so no pop-off breathers.

Re: Header evac tubes- how do they compare to vac pumps? [Re: emarine01] #624337 02/26/10 07:09 PM 02/26/10 07:09 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Hey Mr P, ya got a pic of your evac with the e vac tube square with the header tubes, we found the most vac 5.5" that way I think I have a pic at home but I'm not home, you might have a little better sealing rings or a less accurate gauge but its still close to my findings

Re: Header evac tubes- how do they compare to vac pumps? [Re: MR_P_BODY] #624338 02/26/10 08:02 PM 02/26/10 08:02 PM
Joined: Jun 2009 Posts: 644 Minnesota Barnstorm mopar
Barnstorm mopar Joined: Jun 2009 Posts: 644 Minnesota	I know some SS/AH guys are pulling vac thru the fuel pump plate. Good "quiet" part of the motor. No valve cover hoses. The little old lady from Pasadena is back!

Re: Header evac tubes- how do they compare to vac pumps? [Re: Barnstorm] #624339 02/26/10 08:12 PM 02/26/10 08:12 PM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: I know some SS/AH guys are pulling vac thru the fuel pump plate. Good "quiet" part of the motor. No valve cover hoses. That is a good place to pick up from but you need to put a BIG hose on it if its a single hose coming off that point, you have 2 hoses coming off the V/C, you need to move a fair amount of air EDIT it would take a 1 1/8" to give you the same sq in of area as the 2-3/4 hoses... so your looking at a tube of maybe 1 1/4" to weld to the cover and I would put a baffle on the inside of the plate Last edited by MR_P_BODY; 02/26/10 08:36 PM.

Re: Header evac tubes- how do they compare to vac pumps? [Re: 72demon416] #624340 02/26/10 08:59 PM 02/26/10 08:59 PM
Joined: Nov 2004 Posts: 2,121 sc T tjmarcus1 top fuel
tjmarcus1 top fuel T Joined: Nov 2004 Posts: 2,121 sc	Quote: thanks Raff, It looks like it's almost pointless to run a header evac system when running a exhaust system. the good part is you just saved me some time and money didn't i say that?

Re: Header evac tubes- how do they compare to vac pumps? [Re: MR_P_BODY] #624341 02/26/10 09:11 PM 02/26/10 09:11 PM
Joined: Dec 2008 Posts: 1,200 UK 6 602heavy pro stock
602heavy pro stock 6 Joined: Dec 2008 Posts: 1,200 UK	I've yet to get the motor running to see if the ex evacs are going to work (fire up tommorow) , i'm using the Moroso ones with the 'bird beak' cut out of the tube , i thought this was 'an aid' to create more vac across the evac tube , i also heard a few others mention this , i was trying to get my head around how this 'bird beak' would help , turns out it is just a refference point when welding the evac tubes into the collectors , the instruction shows it to be flush with the outside wall thickness of the exhaust pipe to aid in correct protrusion of evac pipe into exhaust. Last edited by 602heavy; 02/26/10 09:13 PM.

Re: Header evac tubes- how do they compare to vac pumps? [Re: tjmarcus1] #624342 02/26/10 09:16 PM 02/26/10 09:16 PM
Joined: Jun 2004 Posts: 1,496 Sask, Can. 7 72demon416 OP pro stock
72demon416 OP pro stock 7 Joined: Jun 2004 Posts: 1,496 Sask, Can.	didn't i say that? Yes you did, thank you for your input! Actually- thanks to all contributors! Last edited by 72DEMON416; 02/26/10 09:21 PM.

Re: Header evac tubes- how do they compare to vac pumps [Re: topside] #624343 02/26/10 09:18 PM 02/26/10 09:18 PM
Joined: Jan 2005 Posts: 866 Winnipeg ,Mb. CA. chryco super stock
chryco super stock Joined: Jan 2005 Posts: 866 Winnipeg ,Mb. CA.	Quote: '80s GM F-car (Camaro/Firebird). Corvettes, Mustangs, and several other cars use them; my '97 Mustang GT has one. A little bigger than palm-sized. You'll need a relay, a switch, a puke tank & related hoses & wiring. Total weight maybe 8 lbs. Doesn't pull as much vacuum as the "real" pumps, but I'm in the whole deal maybe $75 including the used pump, and it works for my setup. I measure the vacuum using a fitting on the opposite valve cover. Crank end seals & anything that can weep needs to be sealed as tightly as is reasonable, so no pop-off breathers. 5832513-IMG_5771.jpg (200 downloads) Gas is fer washin' parts ....Alky`s fer drinkin' ...Nitro`s fer Racin'!

Re: Header evac tubes- how do they compare to vac pumps [Re: chryco] #624344 02/26/10 10:46 PM 02/26/10 10:46 PM
Joined: Nov 2004 Posts: 2,121 sc T tjmarcus1 top fuel
tjmarcus1 top fuel T Joined: Nov 2004 Posts: 2,121 sc	i had one customer that wanted to run evacs on a street truck. i recommended if he were to try it he should put the valves downstream past the mufflers and run longer hoses. but, i stick to my guns and say they don't work too well with full exhaust. what we have to remember is this: they pull 3 to 5" of vac EACH. so that is more volume than you might think

Re: Header evac tubes- how do they compare to vac pumps [Re: tjmarcus1] #624345 02/27/10 07:29 AM 02/27/10 07:29 AM
Joined: Jan 2003 Posts: 4,852 KENTUCKY 69CHARGERMD master
69CHARGERMD master Joined: Jan 2003 Posts: 4,852 KENTUCKY	Good thread.... Question: 1) WHERE do you mount the fitting on the header ? ( is there a measurement to use,,certain distance down the header ? any tips/tricks/troubles/ people have had installing them) The instructions i have say on the TOP surface of the header, just beyond the TRANSITION area. 2) NO MORE POP OFF BREATHERS ? ( this is what i have now,,Moroso sells a "screw" on type deal,,,would that be ok ? ) 3) BAFFLES ? (just for the inside of the valve cover?) 4) HOSE TYPE (what are you guys using ?,,,is there a particular type recomended?) I have the motor out of the car,,,so the headers can be worked on,,,, I have the Mr Gasket Evac kit ( sitting on the shelf ),,, Might be a good time to install them.... thanks. DOUG............ Moroso sells these,,,which i was thinking of getting,,, Just noticed they are about $50 EACH !! (yikes) they are the screw in style,,, i have seen some other styles that look super nice,,billet,,etc,,,

Re: Header evac tubes- how do they compare to vac pumps [Re: 69CHARGERMD] #624346 02/27/10 07:48 AM 02/27/10 07:48 AM
Joined: Jan 2007 Posts: 8,121 Mt Morris Michigan mopar dave master
mopar dave master Joined: Jan 2007 Posts: 8,121 Mt Morris Michigan	i tried one of those electric vac. pumps last year. did'nt pull enough vac. for me and pulls alot of amps. i tried it with and without it on the chassis dyno and lost a few hp with it on. these pumps came on s10's and corvettes that i know of. jegs sells this very same pump for $250, i'll sell mine for $75, used one season. mine pulled 3.5" vac. http://www.youtube.com/watch?v=aIxaesJ190U http://youtu.be/lCZAaN7fFLg

Re: Header evac tubes- how do they compare to vac pumps [Re: 69CHARGERMD] #624347 02/27/10 10:19 AM 02/27/10 10:19 AM
Joined: Dec 2008 Posts: 603 Central Oregon R Rodney mopar
Rodney mopar R Joined: Dec 2008 Posts: 603 Central Oregon	Quote: I have the motor out of the car,,,so the headers can be worked on,,,, you may want to mock up the headers in the car so you weld the pipe in the correct place to not interfere with things under there I've used both steel braided, black rubber hose and push lock hose

Re: Header evac tubes- how do they compare to vac pumps [Re: 69CHARGERMD] #624348 02/27/10 10:27 AM 02/27/10 10:27 AM
Joined: Jan 2003 Posts: 26,418 United Socialist States of Ame... T tboomer Too Many Posts
tboomer Too Many Posts T Joined: Jan 2003 Posts: 26,418 United Socialist States of Ame...	Doc...I made my own..I used 5/8" heater hose..MrPeabody sent me the check valves...Maybe he had a part#..I used a pair od Moroso valve covers from Summit that already had baffles in them...Also make sure that the pipe nipples are welded in the right direction...I put mine in backwards! Lonemopar noticed that and re did them for me!! Need your rear end checked out? Contact Grizzly!!

Re: Header evac tubes- how do they compare to vac pumps? [Re: 72demon416] #624349 03/03/10 12:26 PM 03/03/10 12:26 PM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	Dumb question maybe, but what if one were to either run cut-outs or space the exhaust back from the collector? I have seen guys that will run full exhaust then unbolt at the collectore (like un-capping) then use a nut to space back the pipes. This would seem to help reduce the back pressure problem. [IMG]http://i66.tinypic.com/pui5j.jpg[/IMG] Coming soon!!!!

Re: Header evac tubes- how do they compare to vac pumps [Re: 69CHARGERMD] #624350 03/03/10 12:58 PM 03/03/10 12:58 PM
Joined: Feb 2010 Posts: 1,377 Ohio Todd pro stock
Todd pro stock Joined: Feb 2010 Posts: 1,377 Ohio	what is the best position for the tubes in the headers? Ive seen them installed a couple of differnt ways.

Re: Header evac tubes- how do they compare to vac pumps [Re: Todd] #624351 03/03/10 01:09 PM 03/03/10 01:09 PM
Joined: Jan 2003 Posts: 24,562 Brookeville, Md Mr.Yuck Not enough dumb comments...yet
Mr.Yuck Not enough dumb comments...yet Joined: Jan 2003 Posts: 24,562 Brookeville, Md	I think it's in the instructions...I've always seen then welded into the collector either on top or on the side depending on clearance.

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