dizzy mods when using a turbo?

i know that in the air cooled vw world (not sure if that is a bad word around here sorry if it is) and you use a turbo the timing is locked out at around 27 degrees. what about ford 6 engines are any mods needed?

Pretty much exactly the same!

Looking out the distributor works just fine. But in my Wife's car we modified the Duraspark II distrubutor by welding up the "advance slot" so that the mechanical adv. swing is only 10 degrees or so. We also removed the vacuum adv. entirely.

Also we are using a MSD BTM to pull out some more timing under boost.

I still feel we are leaving some power on the table by this method. It works, yes, but it would make more power if we can add in some timing back in at the higher RPMs.
So a programmable ignition is probably in our future.

Later,
Will

Will, do you have any pictures of the dizzy mod?...I have read others doing this mod but no one has done a DIY thread on how to mod the dizzy.

I was actually looking at the crank trigger that Summit sells...it looks like it would be a simple mod with an adapter or re-drill the center to bolt directly to the pulley.

It also seems like the more power you go after, the more money it takes...LOL...it's a simple math equation...engine X horsepower=money or engine + desired horsepower =money...it also seems like you're headed into the megasquirt category...I personally prefer a MASS air system as the stock Ford unit is almost undetermined on how much power it will support...the guy who sold me my system from Dunn-rite Racing installed a stock ECM on a older 390 and added bigger injectors and air meter ant got a dyno reading of 670HP!...as long as the injector duty cycle envelope is not pushed, the stock ECM has a lot of great potential for a in-expensive mod.

Dave 8)

revisiting this old thread, this website shows modding the mechanical advance, i think the 'welding up' is pretty obvious once you see what he's doing or look at the mechanisim.

http://www.bob2000.com/dist.htm

i'm curious about the vacuum retard mod, or boost retard that some people are talking about... using an emissions '2 vacuum' dizzy to retard under boost. (i guess one of the vacuum cans is going to get used for pressure) i'm junkyard diving this weekend, gonna see if i can find one of those to play with.

anyone have experience with the 2 vacuum dizzy? what models of 240/300 would they have been on? any more info on where to plumb them in? should they both get inlet vac or from somewhere else?

check check... is this thing on?

just ordered a brand new DS dizzy from rockauto, it was 55 bucks with a $5 core charge... its probably going to cost $5 to ship my dizzy back so screw it, i might want to rebuild it anyhow and just have it on the shelf in case. I just bought brand new points, cap, rotor anyway.

i got the '2 vacuum' unit, which looks like it just has a tap for both sides of the vacuum can. Unfortunately the can itself is crimped on, so no adjusting of the springs there. Maybe i can use some kind of bleeder orifice if i have to adjust the boost-dependent retard.

So i'm thinking, hook up the main (advance) port to the manifold vacuum and hook up the secondary (retard) port to the carb hat/ inlet piping so it sees only boost. Do i need a check valve in the main line to manifold so it doesn't see boost?

I'll probably hook it up with compressed air and plot out the advance/retard curves based on vacuum/pressure.

EDIT: ok, so i guess i was a bit confused on this, the vacuum advance pulls the timing more advanced at high vacuum? hence being called 'vac advance' duh... so wouldn't pressure on the opposite side of the membrane, where the porting is on the '2 port' dizzy cause the same effect, pushing on the membrane and increasing timing with boost?

If the vac advance works the way i think it does, you'd want to put a heavier spring in it and set it so '0 vac' is somewhere advanced of stock, say 10 degrees or so, then you would have ten degrees of travel in the pressure direction (retard) and 10 degrees in the vacuum direction (advance) and clock your distributor so at idle you are 25 degrees or so. That way high rpm, low pressure means you are advanced mech. plus advanced vac. High rpm high pressure means you are advanced mech plus retarded vac. Low rpm means retarded mech, and advanced/retarded the same for vac/pressure.

Now i'm wondering what the mechanical limits and parameters of this thing are and whether it wouldn't be a lot easier to go TFI using a microcontroller, manifold pressure sensor, and temp sensor... I'm looking at some projects people have done with Arduinos and it is pretty slick!

i'll post more on this soon, but i accidentally purchased the yellow grommet DS2 module, the one with a retard sensor for emissions/altitude.

I'm thinking i can hook this up to a pressure switch to retard under boost for another degree of tune-ability.


Going to have my neighbor look at the schematic as well, but i think this thing might be proportional too, as in, sending it less than 12v will cause less than full retard. We shall see.

motzingg":2rt10qo2 said:

sending it less than 12v will cause less than full retard. We shall see.

Click to expand...

Haven't you seen Tropic Thunder? You never want to go full retard.