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Computer Controled Timing. Help me build ignition timing map

Posted: Mon Jun 10, 2013 12:32 pm
by luftvagon
Load (manifold absolute pressure) based Computer Controlled Ignition timing map

I need your help in designing a load based ignition timing map. I will be working off these charts to build a a base map, and tune it for performance at max load, and economy at cruising load. In addition, the system will sport a knock sensor to help-out when it needs to. :salute:

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Re: Computer Controled Timing. Help me build ignition timing

Posted: Mon Jun 10, 2013 10:00 pm
by SlowLane
Why don't you just start with the advance curves given in the Old Volks Home distributor specification list?

For the '80 - '83 Federal Vanagon, that's:
Advance/Retard Range: Vacuum: 8-12deg Adv @ 7.9 In. Hg; Centrifugal: 9-14deg @ 1600 rpm, 21-25deg @ 3400 rpm

Re: Computer Controled Timing. Help me build ignition timing

Posted: Tue Jun 11, 2013 5:41 am
by luftvagon
I am. That will be my base map. :bounce:

Re: Computer Controled Timing. Help me build ignition timing

Posted: Tue Jun 11, 2013 8:57 am
by SlowLane
Okay, then what sort of help are you asking for, exactly? :scratch:

Re: Computer Controled Timing. Help me build ignition timing

Posted: Tue Jun 11, 2013 10:44 am
by luftvagon
I'll need your opinion on what it should look like at light/medium load cruise... how much advance it should have... i feel that with distributor you don't get to take advantage of what this motor could do.

Re: Computer Controled Timing. Help me build ignition timing

Posted: Wed Jun 19, 2013 9:56 pm
by Amskeptic
luftvagon wrote:I'll need your opinion on what it should look like at light/medium load cruise... how much advance it should have... i feel that with distributor you don't get to take advantage of what this motor could do.
"What this 'motor' could do" at light/medium load cruise is just what any engine does at light/medium cruise. Note that the 205P has the best curve for stock output, lots of advance in the vacuum signal under light loads and it ramps up then stops the centrifugal advance seriously around the 3,000 rpm range while that svda is lagging.

Tuning for maximum load is the province of the centrifugal advance since your vacuum signal will be out.
Tuning for maximum economy will be the province of the vacuum advance, off-throttle overrun stock is at 38-40* total advance, dropping back as the vacuum drops.
Colin

Re: Computer Controled Timing. Help me build ignition timing

Posted: Mon Sep 02, 2013 4:18 pm
by luftvagon
Here is my current running ignition map:

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Current engine layout (mind the lack of distributor):

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Let me know how you'd like to see the ignition map. I can load it and test it, and document it.
I idle at 40 kpa. Stady state light load cruise is at 80kpa. =) Everything past 85kpa is load.

Re: Computer Controled Timing. Help me build ignition timing

Posted: Sat Sep 07, 2013 7:42 pm
by Amskeptic
luftvagon wrote:Here is my current running ignition map:
Please label the Y axis.
Colin

Re: Computer Controled Timing. Help me build ignition timing

Posted: Sun Sep 08, 2013 5:14 pm
by luftvagon
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AFR to match:

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