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Looking at the Mallory Unilite, there is one with and one without vacuum advance. Which is better in your opinion? I feel with vacuum adv. is better and that's what I've read. Do your dyno results show the same? Which do you use? Thanks.

This has been discussed many a time.
Jake prefers the unit WITHOUT vaccum, and says he hasnt seen a difference with/without the vac advance.

I run the vac advance mallory unilite optical on my 2L T4 and definatly CAN feel a difference with the vac advance connected. Makes it nicer to drive when pulling away, and gained my about 2mpg on my normal runs (short local hops)

Personally I would get it WITH vac advance, and if you decide not to use it simply disconnect the hose! gives you the choice in the future rather than having to buy a whole new dizzy!

Cya,
Sam C

Oh, its also easier to change springs on the NON vac advance unit.
Although personally I have changed spring sets twice and it only took me 10mins start to finish second time around (because I knew what I was doing... not learning like the 1st time which took more like 30 mins)

Remember though, once the engines all together and working nicely then you wont be interested in swapping springs.

Two grey springs is what most people reccomend in the T4.

Cya,
Sam C

there will be no difference on a dyno at full throttle, since a vac advance stops working at 1/2 throttle. But from off idle to 1/2 throttle, the additional timing of the vac advance gives better throttle response, cooler running, and more MPG.

How many NEW cars out there have no provision for a timing change WRT load?

Check them at 15hp and 3500 RPM to see the difference.


John
Aircooled.Net Inc.

Is there a way to run a VAC dizzy with dual carbs?
I've heard you can weld in a nipple on one of the intake manifolds, is this correct?

you can NOT run a nipple on an intake, the signal is wrong. Most DRLAs and the newer IDFs have the correct port already in them for a vac advance distributor.

John
Aircooled.Net Inc.

JohnConnolly wrote:the newer IDFs have the correct port already in them for a vac advance distributor.

really??? that's awesome...

John,
Can the signal be taken from one carb (DRLA) or do both have to be linked ?
DD

i have a 45 dell with the ports (with the nipple connectors) on only one carb. i've been wondering the same thing as well.

Ace Thraen told me that only one side was needed for vac advance so he kept the other carb's nipples (?).

thanks.

bj

I like pulling vacuum from 2 cylinders. Whether that's 2 ports on IDF/DRLA, or 1 port on Kadron/ICT/FRDs, same thing.

Not required, but smoother. If you had to modify the carb like an IDA, I'd only do 1, but for carbs that already have it, run both and T them together.

John
Aircooled.Net Inc.

My daily driver is running a vacuum advance Mallory Unilite (from aircooled.net) with dual Kadrons, one being modified for the vacuum port. I've never run it with another distributer, so I have nothing to compare it to, but it does run very well with the Mallory.

cool. no worries then.

thanks all

bj

i can only compare my vacuum mallory dizzy to a 009 which is what i had before. the difference is amazing and im only getting half the advance since my vents are too big on my bug. climbing hills requires no more throttle than cruising since the load kicks the vacuum advance it. this is on a 1776 with 44 IDF's. i will be putting 40's on with 32 vents and im sure that will make it even better.

SAM

Speaking of the Mallory Unilite, other than switching to the grey/grey spring combo, is there anything else I need to do to dial it in(other than setting the timing, obviously)?

Thanks,
Andy

Thanks for the input. The Vac adv. sounds like the one for me since it's a daily driver motor. More mpg is always welcomed.