im running a locked dizzy but for better fuel milage i got a jdm 12at dizzy for my car,

i don't know where to hook up the vac, line for the advance and retard any help would be grate.

its a 12a with a holley 600, s4 turbo and no emissions.

 

manifold vacuum. the 12aT actually has boost retard, and not advance

 

at the manifold and carb bace i get vacum, at about 15 and drops to 0 when my carb hat sees 5 psi.

so what i need is for the dizzy to see boost, and it onley has mech. advance.
is this correct?

 

for it to work you need it to see boost.

it does have mechanical advance too. on the stock 12aT, they found it had a "knock prone zone" and they use the retard units to keep it safe. the stock EFI can turn the advances on and off, so it may not use the retard function all of the time

 

pics of a 12aT dizzy? Never seen one

 

http://www.flickr.com/photos/turbo16...7607511875867/

best pic i could find. the vacuum advances/retards are different. it might have a different mechanical advance curve too, but VISUALLY except the stamp on the distributor body and advance units, its the same

 

not familiar to the 12at dizzy but as for hooking up vac advanced to the holley, T the advance pods on the dizzy together and run a single hose to the port vac source on the metering plate right above the mixture screw. it currently probably has a cap on it.

 

thanks, i think ill just "t" the line in with the fpr this weekend

 

you should mark the pulleys and see what the timing actually does, its really easy to do

 

-- i have handled plenty of all types of electronic dizzies , and have a genuine 12at dizzy on my LPG turbo FC


12at dizzy has set screws on the end of each vac advance / boost retard unit

the obvious connotation of this is its sets a preload on a spring that is on one side of the vacuum diaphragm

 

Sorry for the nooblet question...Whats a locked dizzy? Non-adjustable distributor???

 

You can still adjust the timing, but the mechanical advance is locked(no advance). There are weights and springs inside the dizzy, as it spins faster the weights swing out and advance the timing. Remove the springs and it stays at full advance the whole time, which isn't really what you want but it's the easiest way to do the timing on a turbo motor.

I'm not sure if the 12aT dizzy uses vacuum or only boost pressure. I would think you could connect the line anywhere along the IC tubing, at the carb hat, or to a ported vacuum source(will still see boost just like regular vacuum) like the stock dizzy.