Another go at boost/retard

[GARRICK.CLARK]

So I had a timing limited 009 with points on my motor which does work but not the best way to have ignition from what I've read on here.
I have now re fit my Copy SVDA dizzy with points and a dual vac can.
This dizzy isn't limited or locked.
Using points because the petronix 3 very slowly but surely stopped working. Some of you might have read my other post, My engine keeps popping and banging, Well it was the pet 3 module. Any way
I fitted the dizzy, timed it at 10* at idle, Max mechanical goes to 32*, Plus the extra timing from the vac advance must be sending the total to 40*.
Results were as expected , It pinged at very low boost.
So now I'm using the vac can as boost retard only, taking a signal from the boost pipe behind the carb butterfly so that I don't get any vacuum advance.
Not tested it yet.
Do you think I should be getting the mechanical max of 32* down to like 25*..... ( I can weld on a little stopper to limit the mechanical total). Then the retard side of the vac advance can will lower the 25* total down even further.
P.S
if I get this working it would be an improvement over a timing limited 009 wouldn't it.

[buguy]

I wonder if plumbing in a vacuum gauge to the cockpit would be a good idea so you can kind of watch and see what's happening (and when). Might make fine tuning it a little easier.
Welding on a stopper would really make the vacuum retard unnecessary. Is the vacuum can adjustable on those? Or would you just get what you get? I guess either way, any advance it would take out would benefit it.
Also I don't think you would need much less. Most that run a distributor they limit them to 24 degrees.

[Clonebug]

If it is a true DVDA distributor you should be able to hook it up like stock at the carb below the butterfly.
The boost will retard the advance but otherwise it will run like a normal distributor which is a good thing.
Figuring out how much retard it gives you and how much you need is the tough part.

Haven't you messed around with this stuff long enough to just give in and get a real turbo ignition setup????

Go buy a CB black box or just get a crank fire setup with MS and run it ignition only while you save up for FI.

You can thank me later.........

[buguy]

I happened to stumble on some info on this last night. If I remember right it said it would pull 11 degrees out. But I agree. At the least a cb black box is $200. Seems cheap to have total control of your advance.

[rubenski]

Yup. Fully programmable on a 21x21 table.

And rev limiter and 2 step and some little datalogging.

I have onr on my NA engine now. Works perfect. And get some resistor plugs.

Lots of info on the samba.

I had a few issues with it in the beginning but that was due to some bad elec wires in my old bug.
Pat at Cb helped a lot!

Good guys!

[GARRICK.CLARK]

Thanks for the replies,
In the future a CB black box will be on the shopping list,for now I'm going to carry on tuning it the old fashioned way.
I've limited the total with a stopper.
The advance mechanism now only moves half of what it used too. I'm using the canister to retard only at the moment.
The pinging has stopped.
I'm going to reinstate the vac advance like buggsy has advised.
I'm hoping for more improvement without bringing back the dreaded PING.

[GARRICK.CLARK]

Well this has improved it down low. Take off is more lively.
No pinging up high still.
If you have too much boost retard does it affect the high end power.

[buguy]

Probably not so much. At WOT there is usually no vacuum anyway so you would be at zero advance anyway.

[GARRICK.CLARK]

AHH right.
Now that I have the vac advance and the boost retard working with no pinging my next step is to increase timing till I hear it pinging at my target 1 bar boost with water, then knock the timing back a bit.
Thanks.

[Clonebug]

I would run 30 degrees at 3000 rpm and let the rest go where it wants.

You really have no control other than that and if it doesn't ping that way you should be good to go.

The only issue you will have is you don't know what your timing is at any given load/rpm setting unless you hang out the back with a timing light.

Depending on how much boost you want to run you should have good results that way as long as it won't ping.

I wouldn't advance the timing any more than what the stock setting is for that distributor.....but you are the engineer.....

[GARRICK.CLARK]

Ok.
I'll just up the timing a couple of degrees at a time until I approach 30. I'll stop when I start to hear ping. Being on points I can easily dial in 2 degrees at a time by setting timing the static way. With windows closed and no back seat I can hear ping when it starts. As it is now although its not pinging it feels a bit dull under boost. Like its LOST its on boost crispness. It is a bit rich with an AFR of 11 but that's may safety net at the moment.
Nearly there.
I suppose then when I want to up the boost I'll have to start backing down the timing.
Before that happens I'll need to look at what my turbo will safely boost to without going POP. My static comp is low like 7.5.1 so I should be able to get the psi into the high Teens.

[GARRICK.CLARK]

I think I've come to the end of adjusting and testing my timing. It seems to be working good now. Driven round town, booted it down some long stretches getting up to some high speed. It has a solid 1 bar boost. Clone bug, I suppose when you got to 1 bar and wanted to go higher how did you go about it. Did you just increase it 1 psi at a time and test it/listen for det.

[Clonebug]

You can do a test with a little bicycle air pump and gauge on the distributor hose and slowly pump up the pressure while watching the timing with a timing light.
Make notes of how much the timing retards at 5, 7, 10 and maybe 13 lbs. or whatever your max target is. When the advance stops retarding is the boost limit you can probably run.
Ideally you want to set the timing at the stock setting of 7.5-8.0 degrees BTDC and then let the vacuum advance work in cruise and the retard function work in boost.

I ran the DVDA for about 2 weeks but never went over 6 lbs. boost that I can remember.
I ended up getting a MS-1 Ver. 2.2 used from Mario for $260.00 along with a simple wiring harness and the IAT and CLT sensors.
I had already scored on a EDIS Module and Coil along with the plug wires for $20.00.

For that price I couldn't justify messing around with the distributor anymore.

Just a note though.

For the last few years I have been buying old distributors and pulling the drive off the bottom for Mario.......and many were the DVDA distributors.
Of the probably 10 DVDA's that I checked only 2 had a diaphram that was any good.
Most of them leaked and wouldn't hold vacuum.
So keep that in mind and at least check yours for leakage.

A little Mity-Vac unit will do the job and you can also use it to pump air but the gauge won't work since it is only a vacuum gauge.
It is not ideal for pressure though.

Just make sure you don't use an air compressor on the distributor and blow the diaphram with too much pressure.

Edit......you posted while I was typing the above.....

I never went above 13 lbs with a carb as far as I remember. I just cranked my Manual Boost Controller up a bit at a time as long as my jetting was still rich.

Now with MS-2 I just change my settings in my Boost Control tab and hammer the throttle.
As long as my fuel map and ignition map go high enough the computer handles all the changes.

My limit is 23 lbs due to my clutch slipping.....I need to upgrade to a Stage II.

[GARRICK.CLARK]

Ok I'll check the amount of retard in degrees I have. The dual vac can I'm using is a new one. You can still buy them from vw parts .de in Germany. I removed the stopper on the can to allow it to retard a bit more. As I say at 1 bar its pulling good with no det. I suppose now upping the psi is my risk. The plugs are a dark colour with a lighter gray tip, so a little rich still. I'm hoping more boost might lighten the plug colour without having to weakening the mixture.
Cheers Guys.

[GARRICK.CLARK]

No problem. Just understood your above post, So if I'm full retarded at say 20 degrees that gives me a clue as to what the max psi could end up being.
IF I'm at 20* with 7.5.1/ rich fuel I should be able to get to high teens shouldn't I
talking of clutches.
I'm using a new stage 2 with a daiken disc and a new fly, well I'm sure in 3rd its starting to let go. pressure plate must be strong enough. I'm thinking its the disc material.