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440 Vacuum advance, hook up ported or constant vacuum? #718008
06/06/10 11:23 PM
06/06/10 11:23 PM
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Posts: 6,005
Reno, Nevada
NV69B7RR Offline OP
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NV69B7RR  Offline OP
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I trying to figure out where my vacuum advance goes from on my 440 (512) elect ign dist to carb. The edelebrock carb has either ported or constant vacuum ports. So which port would it go to ported or constant?

My guess would be ported?

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: NV69B7RR] #718009
06/06/10 11:35 PM
06/06/10 11:35 PM
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So Near, Yet So Far
topside Offline
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Ported

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: topside] #718010
06/07/10 12:07 AM
06/07/10 12:07 AM
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CT
GTX MATT Offline
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I say manifold vacuum but alot of people will disagree with me. If you want it to idle better and you tune your mechanical advance correctly use manifold vacuum. Ported vacuum is basically doing the same thing that your mechanical advance does. Nothing at idle and more advance at WOT/high rpms.


Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: NV69B7RR] #718011
06/07/10 01:27 AM
06/07/10 01:27 AM
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Carstairs, Alberta, Canada
dave571 Offline
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Ported is correct.

Manifold ads timing when you don't need it.

Vacuum advance is to give more advance at light cruise to improve economy. Ported vacuum accomplishes this, and it's how the factory dist is designed to work.

IMHO especially on a stroker, you should be running a dist that has been set up to use the most initial timing you can get away with, and bring in the mechanical when you need it.

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: dave571] #718012
06/07/10 07:16 AM
06/07/10 07:16 AM
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Cookeville
Chilort Offline
Will Work For Mopars
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Cookeville
ported

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: GTX MATT] #718013
06/07/10 07:28 AM
06/07/10 07:28 AM
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Ontario, Canada
Dodgem Offline
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Quote:

I say manifold vacuum but alot of people will disagree with me. If you want it to idle better and you tune your mechanical advance correctly use manifold vacuum. Ported vacuum is basically doing the same thing that your mechanical advance does. Nothing at idle and more advance at WOT/high rpms.




Anyone who would try to get better idle this way is an idiot!

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: NV69B7RR] #718014
06/07/10 08:22 AM
06/07/10 08:22 AM
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
Mr.Yuck Offline
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what is the build? Unless it's a mild or stock 440, I wouldn't even hook up a vac advance.


[IMG]http://i66.tinypic.com/pui5j.jpg[/IMG]
Coming soon!!!!
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: Dodgem] #718015
06/07/10 05:24 PM
06/07/10 05:24 PM
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CT
GTX MATT Offline
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Quote:

Quote:

I say manifold vacuum but alot of people will disagree with me. If you want it to idle better and you tune your mechanical advance correctly use manifold vacuum. Ported vacuum is basically doing the same thing that your mechanical advance does. Nothing at idle and more advance at WOT/high rpms.




Anyone who would try to get better idle this way is an idiot!




Alright call me an idiot, I could really care less and don't feel like arguing with you. Ported vacuum was introduced as one thing to produce better emissions. Cars ran manifold vacuum for years to operate vacuum advance. Manifold vacuum is indicative of the load on the engine. Running manifold vacuum will drastically improve part throttle performance and have no effect on full throttle performance. As I said use manifold vacuum IF YOU TUNE YOUR DISTRIBUTOR FOR IT.


Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: NV69B7RR] #718016
06/07/10 07:34 PM
06/07/10 07:34 PM
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Rio Linda, CA
John_Kunkel Offline
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My advice....ignore all the advice and try it both ways, see which works best for your setup.

By "try it both ways" I don't mean just move the hose, tune it around both ways and see which drives the best.


The INTERNET, the MISinformation superhighway
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: GTX MATT] #718017
06/07/10 08:49 PM
06/07/10 08:49 PM
Joined: Mar 2008
Posts: 5,746
Ontario, Canada
Dodgem Offline
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Anyone who would try to get better idle this way is an idiot!




Alright call me an idiot, I could really care less and don't feel like arguing with you. Ported vacuum was introduced as one thing to produce better emissions. Cars ran manifold vacuum for years to operate vacuum advance. Manifold vacuum is indicative of the load on the engine. Running manifold vacuum will drastically improve part throttle performance and have no effect on full throttle performance. As I said use manifold vacuum IF YOU TUNE YOUR DISTRIBUTOR FOR IT.




Cars never ran manifold vacuum unless they had a idiot for a mechanic.
if you are pulling 15 deg of vacuum from manifold and 35 total you floor it you have 0 vacuum so you have 20 total all through your lets say pass so way off your power. makes no sense when most power is at 35 total.
vacuum advance is a crude gas mileage device meant to pull light cruise advance up to 46 to 56 degree. new fuels don't allow that much but it will still work with some tuning.
so when morons put it on manifold vacuum they do not even get the benifit of a little better cruise gas mileage as it is all taped out at 35 and not getting the benifit vacuum advance was designed for!
Red a few books

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: Dodgem] #718018
06/08/10 12:28 AM
06/08/10 12:28 AM
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Posts: 6,545
Downtown Roebuck Ont
Twostick Offline
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You might want to "red" that book again. If you set your mechanical at 35 total, the vacuum advance only adds to it at part throttle ie 35*+15* vac = 50*. At WOT it will still be 35. FYI ALL cars with vacuum advance use manifold vacuum. The only difference is ported shuts off the vacuum when the throttle is closed so no advance at idle. Strictly an emission control deal.

Kevin

Last edited by Twostick; 06/08/10 12:52 AM.
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: Dodgem] #718019
06/08/10 12:51 AM
06/08/10 12:51 AM
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CT
GTX MATT Offline
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Quote:



Anyone who would try to get better idle this way is an idiot!




Alright call me an idiot, I could really care less and don't feel like arguing with you. Ported vacuum was introduced as one thing to produce better emissions. Cars ran manifold vacuum for years to operate vacuum advance. Manifold vacuum is indicative of the load on the engine. Running manifold vacuum will drastically improve part throttle performance and have no effect on full throttle performance. As I said use manifold vacuum IF YOU TUNE YOUR DISTRIBUTOR FOR IT.




Cars never ran manifold vacuum unless they had a idiot for a mechanic.
if you are pulling 15 deg of vacuum from manifold and 35 total you floor it you have 0 vacuum so you have 20 total all through your lets say pass so way off your power. makes no sense when most power is at 35 total.
vacuum advance is a crude gas mileage device meant to pull light cruise advance up to 46 to 56 degree. new fuels don't allow that much but it will still work with some tuning.
so when morons put it on manifold vacuum they do not even get the benifit of a little better cruise gas mileage as it is all taped out at 35 and not getting the benifit vacuum advance was designed for!
Red a few books




No distributors pull 5 degrees of total mechanical advance. I believe a Mopar Performance distributor comes with 24 degrees of mechanical advance built in to it. Set intial to 11 degrees. At WOT you will have your 35 degrees of total timing. At light cruise with 15 degrees of vacuum built in you have 50 degrees of advance.

Your theory that I would only have 20 degrees of timing at wide open throttle is completely wrong because the first rule when setting timing is that you DISCONNECT THE VACUUM ADVANCE. Ported vacuum is an EMISSIONS DEVICE.

Before you start calling people morons maybe you should get off your ass and read a few books yourself (and maybe learn how to spell the word "read" too). No need to break out ignorant name calling because of a disagreement over tuning methods, but I even said in the beginning that people will disagree with me, apparently because distributors come with 5 degrees of advance built into them now. Sorry I missed the memo. Either method can be correct based on how you tune the distributor.

If you dont believe me go disconnect your vacuum advance. Set total timing to whatever youd like. Then connect your vacuum advance to manifold vacuum. If you have 35 degrees of total timing right now with the ported vacuum disconnected your engine will pull much better over 3500 rpm because you have too much timing right now. The ported vacuum is ADDING to it at wide open throttle, giving you TOO MUCH ADVANCE because ported vacuum is based off of the amount of air flowing through the venturi of the carb. Not only will your engine run correctly at WOT with manifold vacuum, it will deliver much better part throttle response and idle much smoother. Ive tried both vacuum sources on every engine I've tuned and everytime manifold vacuum works best. If you dont want to try it thats fine but theres not need to come on here calling people names because you don't know how ported and manifold vacuum work and dont know how to argue your point. Im sure that the oil companies and global warming activists will both be happy.

Last edited by GTX MATT; 06/08/10 12:55 AM.

Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: GTX MATT] #718020
06/08/10 01:10 AM
06/08/10 01:10 AM
Joined: May 2003
Posts: 6,545
Downtown Roebuck Ont
Twostick Offline
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And now you're both wrong. The only difference between ported and manifold is ported shuts it off at idle. Crack the throttle and they are the same. Easy test, get 2 vacuum gauges and hook them up, 1 ported 1 manifold and you will be enlightened

Kevin

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: Twostick] #718021
06/08/10 08:31 AM
06/08/10 08:31 AM
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Posts: 15,500
Norwich CT USA
moparts Offline
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Quote:

And now you're both wrong. The only difference between ported and manifold is ported shuts it off at idle. Crack the throttle and they are the same. Easy test, get 2 vacuum gauges and hook them up, 1 ported 1 manifold and you will be enlightened

Kevin




Thank You

On a pre emission car the vacuum was hooked up at the base of the carb,

The vacuum advance is on top of your normal timing settings, gives you that 50 plus degrees of timing at light throttle to help with gas mileage

All timing is set with the advanced unhooked


Tom ,

2011 Ram 3500 C&C Diesel
2009 Challenger R/T
1971 Challenger Conv. 511/4 speed
1970 Challenger R/T 503/727


Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: moparts] #718022
06/08/10 08:42 AM
06/08/10 08:42 AM
Joined: Jan 2003
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Brookeville, Md
Mr.Yuck Offline
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Quote:

Quote:

And now you're both wrong. The only difference between ported and manifold is ported shuts it off at idle. Crack the throttle and they are the same. Easy test, get 2 vacuum gauges and hook them up, 1 ported 1 manifold and you will be enlightened

Kevin




Thank You


On a pre emission car the vacuum was hooked up at the base of the carb,

The vacuum advance is on top of your normal timing settings, gives you that 50 plus degrees of timing at light throttle to help with gas mileage

All timing is set with the advanced unhooked





hence my quest why even hook it up? Isn't this a 512cid wedge? Set it for performance and have fun.

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: Mr.Yuck] #718023
06/08/10 02:32 PM
06/08/10 02:32 PM
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Oregon
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Quote:

hence my quest why even hook it up? Isn't this a 512cid wedge? Set it for performance and have fun.




And why not hook it up? If tuned correctly you won't know it's there, except for the mileage increases.


If you ever find yourself in a fair fight, your tactics suck.
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: hooziewhatsit] #718024
06/08/10 02:39 PM
06/08/10 02:39 PM
Joined: Jan 2003
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Brookeville, Md
Mr.Yuck Offline
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Quote:

Quote:

hence my quest why even hook it up? Isn't this a 512cid wedge? Set it for performance and have fun.




And why not hook it up? If tuned correctly you won't know it's there, except for the mileage increases.




doubt you'll see much. Not like it's going to easy to kep ur foot out of 512 cubic inches.. I couldn't anyway

Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: Mr.Yuck] #718025
06/08/10 03:30 PM
06/08/10 03:30 PM
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I just had my dizzy recurved again by Don at FBO. The reason I had it done again is because this time I NEEDED to add back the vacuum advance to get my 440 to run right with the stock cast iron manifold & correct 4640SA Carter AVS carb.

Don added the advance mech & curved it to use MANIFOLD vacuum to give me 34º all in by 3400 rpm at WOT. This eliminates the possibility of detonation at high RPM's due to overadvancing.


1MYTGTX
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: 1MYTGTX] #718026
06/08/10 05:32 PM
06/08/10 05:32 PM
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Joplin, MO USA
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Quote:

I just had my dizzy recurved again by Don at FBO. The reason I had it done again is because this time I NEEDED to add back the vacuum advance to get my 440 to run right with the stock cast iron manifold & correct 4640SA Carter AVS carb.

Don added the advance mech & curved it to use MANIFOLD vacuum to give me 34º all in by 3400 rpm at WOT. This eliminates the possibility of detonation at high RPM's due to overadvancing.




I realize the factory did it differently, but when I got my FBO ignition it says in his book to hook it up to manifold or constant vacuum.....which I was going to post a question about it....cause I never have done it that way. In his book I'm taken it that the motor is going to run more efficient this way, but...............like I said I've never done any of my motors this way. Other than didn't GM do this way back in the 60's? I need to send my dizzy to him and have him put it on his machine.


Moparlee
Re: 440 Vacuum advance, hook up ported or constant vacuum? [Re: 1MYTGTX] #718027
06/08/10 06:02 PM
06/08/10 06:02 PM
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Someplace you aren't
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SomeCarGuy Offline
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Quote:

I just had my dizzy recurved again by Don at FBO. The reason I had it done again is because this time I NEEDED to add back the vacuum advance to get my 440 to run right with the stock cast iron manifold & correct 4640SA Carter AVS carb.

Don added the advance mech & curved it to use MANIFOLD vacuum to give me 34º all in by 3400 rpm at WOT. This eliminates the possibility of detonation at high RPM's due to overadvancing.




That doesn't seem right at all there. 3400 RPM, vaccum advance to get 34 degrees, at WOT.

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