Ignition timing mechanisims, centrifugal and vacuum.

[mikedjames]

1641 on a bus - home made black box, about £150 parts. Timing curve from firmware I wrote to provide an SVDA function but with multiple vacuum curves.
Based on a 205 distributor.

The engine never goes above 4800 rpm, and generally around 4000 rpm max, so the timing starts to retard a little at high RPM.

The up-tick in the timing down from 750 is so that it picks up when the engine starts.

[Infidel]

[quote="Ohio Tom"][quote="Ohio Tom"]

[Ohio Tom]

[Ohio Tom]

[quote="Ohio Tom"][quote="[email protected]"]
. That's where the 28-32 "rule" comes in. That rule always applies, even if you have vacuum advance. But the rule does NOT apply to part throttle, which is where the additional timing of vacuum advance will actually kick in. This is because at Full Throttle there is no manifold vacuum to pull any advance in anyways! So vacuum advance has the additional benefit of "load sensed timing adjustment" that is not possible with centrifugal only distributors.

if some asshat is timing, or telling you to time, a vac advance distributor to 28-32 total timing, they have no clue what they are doing and you need to find another "mechanic", because we have no idea what other false information they are working on your car with!!!!!


I see a contradiction here:
asshats are doing exactly as you describe in the paragraph prior..
Same exact thing recommended is now an asshat trait?

Perhaps a clarification that Asshats need is to un-hook the vacuum line when setting full timing...

[Ohio Tom]

123

[oprn]

It's not quite as simple as that, so much depends on your C/R, fuel used, air/fuel ratio, combustion chamber shape, altitude and of course driving style. You need to keep an eye on engine temp too when making timing changes.

Is it a type 1 or type 4 engine? Type 4s tend to tune a bit different.

My timing curve will not be of much value to you because it's in a 1400 pound car with vacuum advance.

[vw666]

Hi Guys ,
Hope you all doing good and safe ,

I recently bought and fitted a 123 tune+ on my 2276 ( on my Bus)
Was wondering any of u have a similar set up
And would love to see some timings u guys using ,
(I’m not using vacuum)

Currently these are my timings

Rpm. Degrees crankshaft
500 5
1100. 11
1400. 16
1600. 18
1800. 20
2000. 22
2200. 25
2500. 29
2700. 34
6000. 34


Was wondering what numbers you all running ?

Regards
Jay

[Onceler]

[Glenn]

[oprn]

On the VW performance side the real issue I believe is there is such a variety of engine build and carb combinations that it would be virtually impossible to build a vacuum distributor pot to match them all. Even if you did produce one adjustable enough very few would take the needed time to understand it and tune it right. That would result in a lot of negative feed back.

When it comes to timing on performance VW engines the mentality that has existed for about 50 years now (Just put a 009 on and forget it) is going to be pretty hard to overcome in the market place.

[ST Dog]

[Lingwendil]

The late vanagon electronic system but curved for a beetle would be a lovely product to use for many of us- give it a single vacuum advance and it would basically be an SVDA with high quality OEM pick up circuitry, no cheesy pertronix.

That, or if MSD bothered to continue producing the vacuum advance equipped Mallory. Those were nice.
_________________
73 super beetle thread http://www.thesamba.com/vw/forum/viewtopic.php?t=649622 Back on the Road!

Modify your Kadrons for SVDA http://www.thesamba.com/vw/forum/viewtopic.php?p=8115884#8115884

Cast iron VJU4BR8 SVDA reference thread- https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

Need replacement filters for original Kadron aircleaners? WIX #42087 is a perfect fit, as is Napa Gold #2087!

[Onceler]

I’m dreaming here, but this is what I want in a distributor: a fully adjustable, fully rebuild able (without ever more scarce components) Mech/vac. Advance plate that can be dropped into a Bosch housing ( maybe a few mod.’s required, but that’s fine) and no janky electronics. Set it and forget it for 20 years except for maintenance, then rebuild it (even the vac. can)
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1972 Karmann Ghia

[ST Dog]

[heimlich]

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[ST Dog]

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[ST Dog]

[daos]