Timed or manifold vacuum advance?

[RustyRatRod]

Damn. Guess I was wrong. :-(

Lame, dude. C'mon, even I don't usually get that mealymouthed, and I'm pretty damn mealymouthed -- ask anyone.

Now: Please try to be a grownup, willya?

Well Dan the big difference here is you're mealymouthed and you know and admit it. LOL

 

[TurdFerguson]

Damn. Guess I was wrong. :-(

My mistake, lets start over.

Lame, dude. C'mon, even I don't usually get that mealymouthed, and I'm pretty damn mealymouthed -- ask anyone.

Now: Please try to be a grownup, willya?

I have seen that poster grill others harshly in other threads over the smallest things.

The way he addressed me to begin with...'his style'... is the way I responded back.


I am a very nice guy, easy to get along with and enjoy discussions where each person can respect the other and be clear about what they are asking/saying.

It's easy to simply ask...'can you explain this part to me, cause I think I know where you are going worth this but it is not clear enough for me'

While some bullying members you can see coming from a mile away....It Is better to give the benefit of the doubt, than to be jury/judge/executioner right off the bat.

mealy mouth?
I haven't heard that since the song ''dial a cliche''

 

[TurdFerguson]

Lets be clear...

I am not bashing dan, his posts are very informative.


I seem to have displaced that irritation.



I am finding it unfair to the other informative posters when members only hand thanks and credit to 1 person and seemingly brush of all others.

It just seems like suckery to me.
understand?


I hope so..

 

[slantsixdan]

My mistake, lets start over.

Works for me.

 

[cudamark]

Ported vacuum for street cars.....on race cars, it depends on many variables.

 

[moper]

Yeah, I get that sense from reading his book. And I'm not impressed with his ignition system, either; when I get time I'm going back to my standard HEI upgrade with appropriately dialled-in mechanical and vacuum advance curves.

I always try to run a vacuum advance, but at some point you just can't make it work well anymore. They are always off a ported source.
Dan, I agree with you on this. I'm not impressed with the theory or expressed "exclusivity" of his products.

 

[67Dart273]

heres the deal...

You want as much initial timing as it will start with 'fully warmed up'

Test drive trying different total/full advance setting till the best performance is achieved without detonation/ping

find a way to have both, be it by welding up the slots in the distributor or a bushing in your msd distributor [mine is custom]
Now set the rate of advance to suit the power band & or convertor stall [if equipt]
Basically have it full advance as soon as it can with out ping/detonation

Thats where the performance comes from.

If you want to get better mph during cruise [not acceleration] run the vacuum advance can.

If the car run cooler with the vac advance it might be because you don;t have enough total to begin with.

OK, now THAT was sayin somethin. And even I, "the guy with no brain" can understand that.

The way I used to do so is essentially the same:

I start with TOTAL and adjust total for max perceived HP (never had dyno, had to use 1/4mi) and use lightweight or no springs to ensure full advance.

So you check that with your light at high RPM, and winder 'er up to be sure that it's not got any more advance left, or spark scatter

Then use stronger springs to get down to initial and check that about as slow as she'll run, and adjust slots so that initial is where ya want with the previous total still in place.


Then adjust springs for best midrange/ drivability.

And last screw with or eliminate the vacuum advance. Frankly (mileage) some of the time it didn't seem to make much difference, probably because of how hard we drove them.

(If you are into the pedal a lot, the vac advance isn't gonna do squat)

Back when "we had gas" I used to be able to run as much as 38* and sometimes 40* total on about a 20-22* curve, so initial would be 16-18*

 

[jimmyray]

FWIW, I run manifold on my 408 stroker with a 236/242 .544 cam and a Thermoquad carb. Idles with about 10" at 850, and get's 14 mpg hwy through 3.73's and a 4,000 stall Dynamic conv, all on 87 octane (9.6 comp Edel heads) at 65 mph. The vacuum adv is +10 deg, and the dizzy in 16 initial 34 total at 2900, FBO ignition. Car runs 12.20's consistently at 3600 lbs with me, and a best of 12.09 @ 110.

I experimented with a variety of setups and both ports, the manifold works best for my setup. It effectively functions as a timing retarder to ease starting, then adds 10 degrees once engine is idling. Off idle acceleration is smooth at all throttle positions. I can go WOT from idle from a standstill, it flashes the converter immediately, lights up the tire, and goes. Could not ask for a better setup, just need a little more compression, cam and gear.

But then, I'm not sure I would know what to do with a brain if I had one. I just love the condescending arrogance some people put on display, often a cover for ignorance and insecurity. Especially in bold or all caps, accented by gratuitous misspelling. Comical!

 

[TylerW]

Well, you guys seem to spend a lot of time arguing among yourselves...but I thought I would contribute something to this discussion:

Here is a chart that I found on the internet several years ago that shows manifold vacuum vs. rpm and ported vacuum vs. rpm

Enjoy.

 

[flipper]

Why not try both and then decide?

 

[ir3333]

..standard mopar distributors will usually only work with ported vacuum.
..manifold vacuum is better but it requires the correct advance can for your
engine.
..google timing and vacuum advance 101 for a thorough explanation.

 

[MuddMan74]

Really late to the game here but the smallblock 360 in my Duster has unknowingly (by my own mistake) been running off of manifold not timed. This thread had me check and sure enough it was on the drivers side port on a Carter 600 (Edelbrock) instead of the timed port where Carter/Edelbrock say it should be. When I switched it didn't run well like it needed tuned. Not sure why manifold vacuum works so good for me. I drive the hell out of the car and race it once or twice a year when I can afford to. It just screams and doesn't have that hesitation when I slam the pedal from idle but it should on manifold vacuum? So confused now. My Dad always said, "Don't fix it, if it ain't broken" so I'll stay on non timed vacuum for now even though it doesn't make sense