Ported Vac or Manifold Vac

[eekvonzipper]

I'm no expert; kind of a slant 6 newbie. I'm here to learn and I appreciate ya'll for that. So let me tell you that I have a totally stock 1973 Dart with a factory stock slant. I have it connected to manifold vacuum and it seems to run perfectly at idle. I haven't had it on the road because it's apart for a restoration. Am I on the right track leaving the vac advance connected to the carbs manifold port? Oh, I'll do plenty of testing once it's back on the road, but curious to know what you guys think about this as of now.

Maybe Read the last three pages of this thread...

 

[LS&S]

I'm no expert; kind of a slant 6 newbie. I'm here to learn and I appreciate ya'll for that. So let me tell you that I have a totally stock 1973 Dart with a factory stock slant. I have it connected to manifold vacuum and it seems to run perfectly at idle. I haven't had it on the road because it's apart for a restoration. Am I on the right track leaving the vac advance connected to the carbs manifold port? Oh, I'll do plenty of testing once it's back on the road, but curious to know what you guys think about this as of now.

You are on the wrong track leaving vacuum advance connected to manifold vacuum.
Mopar cars and trucks of our era were made with vacuum advance connected to ported vacuum, so that spark is not advanced at idle.
Vacuum advance is designed to add timing advance when the vacuum is high, which typically occurs at cruise and light throttle.
Engaging vacuum advance at idle adds excessive timing advance, potentially causing a rough/high idle.
Also, I bought a car that had manifold vacuum advance connected. When accelerating off idle, the engine tended to bog on acceleration from idle because of too much advance. Problem solved when I moved the vacuum advance to ported vacuum.

 

[RustyRatRod]

Oh horseshit. Soon as you stab the gas on acceleration, vacuum drops out and there is NO vacuum advance involved. Look for your bog elsewhere, but don't blame it on MVA. Maybe a poor tuner, but not MVA. Also, plenty of cars used MVA right from the factory. There's no secret how to tune for it, or magic beans to make it work. Even stock engines can use MVA, all you have to do is tune for it. Will it benefit a stock engine? Maybe, maybe not, but you CAN use it. Just because you spew nonsense doesn't make it true.

 

[Mattax]

I'm no expert; kind of a slant 6 newbie. I'm here to learn and I appreciate ya'll for that. So let me tell you that I have a totally stock 1973 Dart with a factory stock slant. I have it connected to manifold vacuum and it seems to run perfectly at idle. I haven't had it on the road because it's apart for a restoration. Am I on the right track leaving the vac advance connected to the carbs manifold port? Oh, I'll do plenty of testing once it's back on the road, but curious to know what you guys think about this as of now.

Sorry. Too many possibilities to try to respond. I'm with Eekvonzipper. Read through the thread or even better go read the Chrysler tech info from Chrysler.
If its totally stock then how is it connected to a manifold vac source? What rpm is it idling at? Was it a California car? Is it a manual or automatic? If its automatic, put it in gear. What's the underhood sticker say? All the tune up specs are usually there. Depending on the specs, maybe I would experiment with a manifold vac source, maybe I wouldn't. Depends on what a person is trying to accomplish. If this is something your interested in get yourself a timing light and tach. And if your really interested then mark the balancer or put some timing tape on it.

 

[dodgemahal]

Maybe Read the last three pages of this thread...

Ding, ding, ding! We have a winner! I already knew the answer to my question, it's in the factory service manual(I'm still going to test both ways just for fun). I engineered that post to see if I could get a snarky jerk to respond. And it worked! You are the snarky jerk of the week. Go ahead and turn your flames on; I won't be checking back.

 

[stroker402]

You are on the wrong track leaving vacuum advance connected to manifold vacuum.
Mopar cars and trucks of our era were made with vacuum advance connected to ported vacuum, so that spark is not advanced at idle.
Vacuum advance is designed to add timing advance when the vacuum is high, which typically occurs at cruise and light throttle.
Engaging vacuum advance at idle adds excessive timing advance, potentially causing a rough/high idle.
Also, I bought a car that had manifold vacuum advance connected. When accelerating off idle, the engine tended to bog on acceleration from idle because of too much advance. Problem solved when I moved the vacuum advance to ported vacuum.

yes, you are correct ! www.youtube.com/watch?v=wfzXmBKkxVQ&t=81s

 

[junkyardhero]

Ding, ding, ding! We have a winner! I already knew the answer to my question, it's in the factory service manual(I'm still going to test both ways just for fun). I engineered that post to see if I could get a snarky jerk to respond. And it worked! You are the snarky jerk of the week. Go ahead and turn your flames on; I won't be checking back.

way to win friends and influence people.

with an attitude like that, good luck getting help down the line when you get jammed up on something.

 

[RustyRatRod]

way to win friends and influence people.

with an attitude like that, good luck getting help down the line when you get jammed up on something.

I've had him on ignore forever, but I just had to see what the hubub was about. Typical, so back on ignore. lol

 

[Newbomb Turk]

way to win friends and influence people.

with an attitude like that, good luck getting help down the line when you get jammed up on something.

It’s jackasses like that who piss me off. He’s a time burglar and I detest that.

That kind of clown show **** makes people not want to post anything.