vacuum advance

[skep419]

I have a accel 59301 dist in the dart. I had the car dyno tuned last summer. The tech working on it said that the ported vacuum would be the best but since my holley 4150 hp dp only has a manifold vacuum port it would have to do. From what I have read the only difference between manifold and ported vacuum is with ported vacuum there is 0 vacuum at idle. So after a bunch of reading I would like to know at what vacuum my accel 59301 vacuum can advances the timing. I have a large cam and at idle it only pulls 5" I have read a bunch on it and its hard to decipher who is right. Having such a low reading at idle it shouldn't matter if I am using manifold vacuum because it shouldn't engage until at least 8"-15" right?

 

[bigdemo1]

I run manifold vac.seems to idle smoother and cooler,still does what it is supposed to at cruise.Of course I've got more vacuum.

 

[skep419]

Are you using vacuum advance at idle?

 

[bigdemo1]

Yup

 

[skep419]

what are the odds of finding a vacuum canister that engages less than 5".

 

[bigdemo1]

I'm not really sure,but you will have some at 5" anyway,just not full stroke of the dashpot.

 

[the wall]

you are correct it wont move the dash pot till about 10 inchs or so. run it there its fine in my opion. thats the way i have it on my RR it idle at about 5 inchs also. it help keep the plugs cleaned up and not fouling and its a milage increase and my engine runs slightly cooler.