Vac advance

[millworm]

My e16se on t40s is running a 14nv dizzy witch has the vac advance unit still attached just not used, just wondering if switching to a unit with deleted vac advance is an option or weather I'd be better keeping it and plumbing it in? Car is fast road track use so leaning towards deleting it but could be wrong

[meritlover]

Why would you not want it to work?

[millworm]

At the moment it doesn't work as there's noting for it to connect to, but I've spoken with people that run without them with modified dizzys

[marc69]

I ran my 1.4 NV without the vacuum, just make sure the timing is at the right place for high revs (idle might not be the smoothest!) and it ran perfectly at knockhill, every month for ages. Oh, and 240 miles each time there and back.

[millworm]

Looks like I know what I'm doing then, modified dizzy has a different curve to standard so should be slightly better

[meritlover]

It can have the best curve in the world but thats not what the vacuum advance is for.
Without the vac there is no load sensing so its essentially only 2d timing (RPM vs adv) with vac you have 3d (rpm v adv v load/map)

At WOT it wont make much difference as there is little vac and the rpm is driving the advance. But light throttle (around town for eg) it will make a difference. Your call.

Just ask if the base timing is set with it connected or not.

[millworm]

Ok cheers defo know what I'm doing then, car don't do any podling around it only comes out to be thrashed

[boffer8]

Depends what you are using it for, daily driver, then yes keep it as it helps at low RPM's.

If comeptitition/track car then no, limits performance at the top end and as it alters ignition position will mean you wont have optimum spark where you need it most at high RPM's.

Is it a Bosch (orange dizzy cap) or AC Delco (black dizzy cap) dizzy?

[meritlover]

I dont believe thats true. There is virtualy zero effect from the vac actuator anywhere after part throttle. Even if there is, the weights should be set so that it still gives the correct adv at those vac conditions.
Its not about getting max advance, its about getting the correct timing for the conditions.

[millworm]

Red bosch

[garyc]

the only benefit be improved fuel economy. It wont change the overall performance.

[meritlover]

How do you come to that conclusion?