The reason that a strong vacuum signal is needed is clearly shown by
this chart;
http://www.ratwell.com/technical/FAQ/images/DizzyCurvesVac.gif
You can see that it requires more vacuum to get more advance, the
problem appears to be even greater with the 043 SVDA dizzy. I looks
like it needs more vacuum, and gives less advance for the same amount of
vacuum, than the other stock dizzys. You should measure your vacuum
signal strength and check your advance with a stroboscopic timing light
to get the whole picture on what you've really got going on there.
The next chart shows the mechanical advance curve of those dizzys;
http://www.ratwell.com/technical/FAQ/images/DizzyCurves.gif
In this chart, the 043 SVDA dizzy appears to need more rpm's to give as
much advance as the stock dizzys. This is the currently available stock
Mexican dizzy. This is also sold by aircooled.net, but with their own
proprietary modifications for improved advance operation. I bought one
from John at Aircooled.net (with the Pertronix module already installed)
a few years ago for a friend's Beetle, it was a great improvement over
the 009 that was paired-up with a 34PICT-3 carb.
Mike B.
On 12/25/2012 11:48 PM, No Quarter wrote:
Thanks for this bit of wisdom Mike I run an SVDA in my 86 Brazilian
DC, but I'm only pulling it off from one carb. I bet it's running
more or less as a 009 dizzy and I think I'll just get me a new 009 and
put on there and keep my SVDA for something with a 34-PICT-3. I never
thought I'd say I liked a 34-PICT-3, but with the SVDA, it's my
favourite combo. There is an electronic igntion you can get called
Accel I believe it is. It's the cheaper chinese version of a
Pertonix. They will not work stock in an SVDA due to the entire stack
of the trigger disc and rotor being too tall causing the cap to not
sit flush on the distributor. I did manage to make it work though. I
took apart an old junk distributor and put it in my lathe. Then I put
the rotor on the end and using the lathe took off about 3/32" off the
bottom of the rotor. The entire stack fits nicely inside the SVDA and
so far so good! :)
NQ
----- Original Message ----- From: "Mike B" <mbucch...@charter.net>
To: <vintagvw@googlegroups.com>
Sent: Tuesday, December 25, 2012 9:43 PM
Subject: Re: [vintagvw] Re: 34Pict-3 article.
The other reason that many volks use the 010, 019 and 009 is due to
running aftermarket dual carb setups. These setups have no central
vacuum source for both carbs. The 009 works better on this setup
than most any vacuum advance unit would.
The factory dual carb setups like late bus and earlier type 3 and 4
had a large diameter balance tube that ran between the intake
manifolds to even out the gas pulsation due to the boxer design. But
the vacuum signal needs to come from the carb vacuum port that's
tapped off near the throttle plate level for the advance diaphragm.
If you just tap vacuum from one carb, the strength of the vacuum
signal isn't as strong as the centrally-mounted single carb setup.
Some people recommend running a small diameter vacuum line between
both car ports and teeing off to the distributor advance. The retard
port on a DVDA would be even harder to correctly hook-up as most
aftermarket dual carbs have no port for this specifically-timed
vacuum signal. Hooking up the retard port on the dizzy is only
necessary for reduced emissions on deceleration, so most people don't
use this anyway.
Mike B.
On 12/25/2012 9:28 AM, No Quarter wrote:
The use of the 009 was originally born out of frustration when
replacement factory distributors couldn't be found or were too
expensive to buy. They worked better than a non-functional
distributor, but were a compromise at best.
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