Vacuum Advance 3000m Essex V6
Discussion
I have the original Motorcraft distributor fitted which has vacuum advance but not connected.
The car is being raced with a standard engine and the distributor has considerable wear so a couple of questions:
1. Would there be any gains to be had fitting a Powerspark electronic ignition module, which should negate the distributor wear and need for adjustment of points?
2. Does the vacuum advance not being connected have any impact on performance or just fuel economy?
The car is being raced with a standard engine and the distributor has considerable wear so a couple of questions:
1. Would there be any gains to be had fitting a Powerspark electronic ignition module, which should negate the distributor wear and need for adjustment of points?
2. Does the vacuum advance not being connected have any impact on performance or just fuel economy?
I'm no expert but if you're racing it then I'd want decent control of timing at high revs.
Appreciate it's not the cheapest option but have you considered a 123 distributor? Gives you chance to play with advance curves and vacuum advance. As well as solving your wear problem.
Works well on our road car.
Appreciate it's not the cheapest option but have you considered a 123 distributor? Gives you chance to play with advance curves and vacuum advance. As well as solving your wear problem.
Works well on our road car.
GadgeS3C said:
I'm no expert but if you're racing it then I'd want decent control of timing at high revs.
Appreciate it's not the cheapest option but have you considered a 123 distributor? Gives you chance to play with advance curves and vacuum advance. As well as solving your wear problem.
Works well on our road car.
Thanks GadgeS3C, but dont think that would be legal in my series.Appreciate it's not the cheapest option but have you considered a 123 distributor? Gives you chance to play with advance curves and vacuum advance. As well as solving your wear problem.
Works well on our road car.
Tech info -
Vac advance really only does anything at small throttle openings, so if you are racing around the track (mostly at full or medium throttle) you won't see any difference.
At light throttle, vacuum advance does what it says - high vacuum in intake mfold/plenum causes timing to be advanced to get better combustion with light cruise, which compensates for [typically] weaker fuel mix to get better economy. Some engines never had it in first place.
As an example from my Cologne 2.8i engine (yes I know, but Ford recommend disconnecting vac advance on this engine for unleaded gas, and retard timing by 3 degrees. On mine I got away with 2 degrees.)
Engine does feel slightly 'flat' on throttle response, but it only lasts a short time. Economy drops from 29-30mpg on a run to 26-29, but otherwise not much overall difference on acceleration.
If you want total control over ignition curve, an aftermarket unit is probably the best, a digital one. Something like Megaspark, with a 3 coil unit and 'wasted spark' setup allows you to ditch dizzy altogether.
Vac advance really only does anything at small throttle openings, so if you are racing around the track (mostly at full or medium throttle) you won't see any difference.
At light throttle, vacuum advance does what it says - high vacuum in intake mfold/plenum causes timing to be advanced to get better combustion with light cruise, which compensates for [typically] weaker fuel mix to get better economy. Some engines never had it in first place.
As an example from my Cologne 2.8i engine (yes I know, but Ford recommend disconnecting vac advance on this engine for unleaded gas, and retard timing by 3 degrees. On mine I got away with 2 degrees.)
Engine does feel slightly 'flat' on throttle response, but it only lasts a short time. Economy drops from 29-30mpg on a run to 26-29, but otherwise not much overall difference on acceleration.
If you want total control over ignition curve, an aftermarket unit is probably the best, a digital one. Something like Megaspark, with a 3 coil unit and 'wasted spark' setup allows you to ditch dizzy altogether.
Edited by RCK974X on Thursday 16th November 19:03
RCK974X said:
Tech info -
Vac advance really only does anything at small throttle openings, so if you are racing around the track (mostly at full or medium throttle) you won't see any difference.
At light throttle, vacuum advance does what it says - high vacuum in intake mfold/plenum causes timing to be advanced to get better combustion with light cruise, which compensates for [typically] weaker fuel mix to get better economy. Some engines never had it in first place.
As an example from my Cologne 2.8i engine (yes I know, but Ford recommend disconnecting vac advance on this engine for unleaded gas, and retard timing by 3 degrees. On mine I got away with 2 degrees.)
Engine does feel slightly 'flat' on throttle response, but it only lasts a short time. Economy drops from 29-30mpg on a run to 26-29, but otherwise not much overall difference on acceleration.
If you want total control over ignition curve, an aftermarket unit is probably the best, a digital one. Something like Megaspark, with a 3 coil unit and 'wasted spark' setup allows you to ditch dizzy altogether.
Thanks for clarifying, again race series would not allow a digital unit. Vac advance really only does anything at small throttle openings, so if you are racing around the track (mostly at full or medium throttle) you won't see any difference.
At light throttle, vacuum advance does what it says - high vacuum in intake mfold/plenum causes timing to be advanced to get better combustion with light cruise, which compensates for [typically] weaker fuel mix to get better economy. Some engines never had it in first place.
As an example from my Cologne 2.8i engine (yes I know, but Ford recommend disconnecting vac advance on this engine for unleaded gas, and retard timing by 3 degrees. On mine I got away with 2 degrees.)
Engine does feel slightly 'flat' on throttle response, but it only lasts a short time. Economy drops from 29-30mpg on a run to 26-29, but otherwise not much overall difference on acceleration.
If you want total control over ignition curve, an aftermarket unit is probably the best, a digital one. Something like Megaspark, with a 3 coil unit and 'wasted spark' setup allows you to ditch dizzy altogether.
Edited by RCK974X on Thursday 16th November 19:03
Erich Stahler said:
Thanks for clarifying, again race series would not allow a digital unit.
Oops, sorry, missed that.Is it allowed to have original dizzy with an extra control unit ??
I ask because what you can do with some units is to 'lock' the dizzy internals, and then control advance with the control unit.
This isn't visible without looking very closely at the dizzy internals....
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