Boost Retard Dizzy

[camerondownunder88]

Hi,

Been googling about and can't find it there.

 

But I KNOW you can make a normal dizzy off any car work as a boost retard dizzy. I need this in my mm coming project to stop blowing head gaskets and I want to not lock my dizzy to a set angle so any help appreciated?

 

Or if anyone has the how to can you plese post it?

 

Cheers

Cameron

[pozman]

how does a vac advance dizzy work, cos by the name of it to me it soungs like it advances with vacuum, so there for retarding at ozero pressure?????

 

i may be a long way off track too

[camerondownunder88]

I am thinking that to but will a vac part on a dizzy hold 14PSI also I have an electric dizzy on my K motor so it has dual vac diaphragms so use both one or boost to one and vac to the other?

 

Also will I need to say regulate the boost to it or what? As from what I have heard it is not as simple as putting boost to the dizzy at all needs mods but is still easy to do.

 

Cameron

[doityourself]

the dual diaphrams are vac advance and vac retard.

if you want to retard you remove the hose from the advance side to the retard side. The way the pick up for the vac source is positioned makes it near impossible for it to pressurise.

[Taz_Rx]

Hey cam, I can explain this to you, might even give you some drawings with my awesome mspaint skilz!!

 

your just gunna have to wait for me to go have a coffee with the missus first. :P

 

stay tuned. :D

Edited February 5, 2007 by Taz_Rx

[Taz_Rx]

ok, you seem like pretty clued on fella so you should be able to understand the concept of this.

bascially you need to get the diaphragm to the other end of the solenoid so it can be pushed in, not pulled out.

 

 

I tried doing this to a couple of spare solenoids I had.

hardest thing to do it drill through the back of the solenoid WITHOUT GOING STRAIGHT THROUGH THE DIAPHRAGM, which is what i did twice. diaphragms with holes in them don't tend to work to well!! :P also need to right sized spring that is stronger than the original one so that it pushes it back. :D

[Trev]

Ha thats pretty much what i told him to do (thru MSN) but i was a bit lost on how to decrease the boost into the diaphram.

[camerondownunder88]

Hi,

From what I have found yes all you need to do is do what Taz_RX told me to do and what Trev suggested. BUT...

 

Doing Taz_rx way as he said fidlly and mm he needed to drill into the vac chamber so also time consuming. Also I am running n electric dizzy so don't want to go start modifying it and break it..lol

 

But on the electric dizzy it has 2 chambers one is vac advance one is vac retard. And I want to retard my timing. BUT with boost. So I was thinking there should be a pressure drop on my SC14 intake when it is on? So can I plum the line from the intake to the vac retard chamber and hope fully it will mm retard it enough? But what mm vac pressure does the K motor vac system run at? As on my turbo pumping 30+ PSI boost I get a bit over 2PSI pressure drop on the intake so the SC14 running oh 14PSI at the most will it make enough vacuum in the line to retard the dizzy? As I am running a SU suck through setup here so I'd imagin there will be a good vacuum as it has to have vacuum behind the SU to make it work.

 

But if the SC14 intake line isnt big enough can I find vacuum some where else on the motor that when boost comes on it increases? As if I can ill jsut run a line from that spot to the vacuum retard on dizzy and have the advance part left venting to space.

 

Cheers

Cameron

 

P.S. Cheers for the drawing Taz..

[camerondownunder88]

Just been looking and found info on boost retard dizzy's:

 

Apparently CB on there old turbo kits they sold the kit came with a standard bosch 205 dizzy. This dizzy is like all other bosch units but has dual vac cannisters one vac retards one vac advances. Apparently stock spring inside the canister it would give 7 degrees retard by just boosting the SC/turbo boost into the vac advanced port and running the vac line to the vac retard side. As with boost it will push so if vac on the retard side retarded it boost will advance it so they were simply swapped hoses and whalla worked with 7 degrees retard. But if you changed the spring inside the canister you will get up to 32 degrees retard.

 

So I might just run my boost line into my electric dizzy and see how it goes and well wait to see if I blow a head gasket..lol

 

But looking at Angela's famous KE10 and noticed under the hood she is running a standard electric K dizzy with no vac lines but has it turned on a modded mount future to increase retard under boost so now I know ti can be done like that but i don't wanna do it that way as needs mounts and blocks off the oil filter adn stuff so want to avoid it

 

Cheers

Cameron

[love ke70]

considered getting spark control?

[camerondownunder88]

Hi,

Love_ke70 I have a MSD CDI kit here BUT it can't do spark retard :D so thinking easier to run the electric dissy but if i use kit wont kill points either so might switch to a points setup on 5K if I get a 5K points dizzy..lol and just fiddle around with a points dizzy getting it to boost retard so I can have 14 sparks a cylinder at idle and wont wear my points out :P

 

 

Cameron

[Taz_Rx]

I reckon if you put the line to the vac retard solenoid in between the carby and SC, you will actually have a vacuum drop. Even though it's got the SC behind it sucking away, it will also (provided on full throttle) have a fully open butterfly in front of it!! as soon as the butterfly is them closed vacuum will increase.

 

I think your best bet would be to do some research on other cars that came from the factory with a carby turbo setup. I was going to look into this myself, but just haven't got around to it yet. Couple of examples would be the turbo MG's or the turbo 1.5lt Lasers. If these have standard boost retard solenoids on them them it may be easy to modify one to fit the dizzy you are using.

 

Also in regards to the elec dizzy, Boost+K in NZ runs an unlocked elec dizzy - with normal mechanical advancement. He said that the elec dizzies only pull about 12o max mech advance, were as points dizzies, like I run, pull up to 40o!!!!

[camerondownunder88]

Hi,

Taz you are right about electronic dizzy's The outer chamber if connected there will only pull 12 degrees advance. But if I connect the hose up to the second chamber closest to the dizzy it will pull 18 degrees. So with it in normal position and a SC on the car it should be fine as didn't you only run 20 degrees with a zip tie when you ran the CT12?

 

Cheers

Cameron

[Robert]

I'm pretty sure hes talking about mechanical advance.

 

so the electronic dissy only advances 12 degrees frome base setting mechanically, whereas the points dissy has a lot of mech advance

[camerondownunder88]

Taz do you mean the mechanical weights inside the dizzy? As If you did it is still hand to know if I keep the vac line on the most it will advance there is 18 degrees or 12 so..

 

Cameron