Dual Ignition Heads

miniman82 · Posted: Mon Oct 05, 2009 8:32 pm Post subject:

Jake: you're right. I'll never understand people that want all kinds of performance, but who also have no interest in modern technology, or what that technology means to their vehicle. When I was 8, something about how the VCR recorded moving pictures drove me nuts, and I just HAD to figure out how it worked. What did I do? What any curious 8 year old would do- I disassembled it! Only after tearing it apart and putting it back together did I understand all of it's intricacies, but I didn't need to do that to understand that it's leaps and bounds better than an old 8mm projector...
Same goes for engines, and engine management. Why don't people just use the Glenn Doctrine? Drive the old skool VW when you get that 'missing the 60's feeling', but then revert to driving the Honduh for reliable DD duty? People that use VW's for DD duty but use the 'I don't like computers' argument are fooling themselves. DD VW's and carbs should be a oxymoron.
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Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747

Jake Raby · Posted: Tue Oct 06, 2009 5:15 am Post subject:

Not everyoone who wants a fast car or something unique wants to build it themselves... Historically the VW has been a prime vehicle for DIY sorts of people, but there are exceptions that are evolving with the times and ages of the VW following.

Carburetors also have their place and their own following. I'd rather provide a carb savvy Enthusiast with a pair of well prepped Carbs as try to make them conform to an EFI system with its vast differences. The same goes for someone who has no idea about carbs but has experience with EFI..

I've gone 60,000 miles with a pair of carbs, never synched them and never had them apart for even a dirty idle jet, but I also appreciate EFI.

Thats why I create the engine for the DRIVER and the application- there are no rules except satisfaction and simplicity.
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Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell"

Bashr52 · Posted: Tue Oct 06, 2009 8:58 am Post subject:

Jake,

Have you, (i'm sure you have) or can you, do a run and then post up some dyno results from a dual plug application with only one set of plugs firing, and then both? I'd love to see the results!

Jake Raby · Posted: Tue Oct 06, 2009 9:13 am Post subject:

Any engine that takes the most advantage of the twin plug arrangement will be absolutely twin plug dependant, not able to sustain life on pump gas with only a single plug.

Thats why this comparison can't be done on the same fuel.. every engine I build thats twin plugged is dependant fully on both plugs.
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Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell"

Bones 53 · Posted: Wed Oct 07, 2009 5:58 pm Post subject:

Has anyone thought of using a compufire ignition system with a two plugs per cylinder head and using four coil packs, one for each plug. Question is can the compu-fire be made to fire four individual coilpacks. I have never used a compufire system so I'm trying to get info. Thanks.

miniman82 · Posted: Wed Oct 07, 2009 6:29 pm Post subject:

I'm sure it's possible, but the pertinent question is whether or not the ignitor section can sink the current of twice the normal amount of coil packs. Double the coils means half the coil primary resistance, which means the current through the ignitor will roughly be doubled. It would probably be a good idea to drive the coils with individual ignitors to take the load off of the Compufire parts. That, or find a coil pack that has twice the resistance of what the Compufire normally drives and parallel them, or even dropping resistors.
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Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747

Jake Raby · Posted: Wed Oct 07, 2009 6:36 pm Post subject:

The company I coupled with to make the latest arrangement was computronix... The same designers of the compufire DIS set up..

The standard compufire will not handle the load of twin coil packs.. I tried that in 2001.. It would run but the units failed almost at start up.

Computronix worked for a year to enhance the module to allow the higher loads.
_________________
Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell"

miniman82 · Posted: Wed Oct 07, 2009 6:42 pm Post subject:

I figured as much, Ohm's law still applies. Cool

It's not hard to build coil drivers, but I think it's probably over most people's head. I just as soon use an off the shelf solution, you guys already know what that is.
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Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747

Bones 53 · Posted: Wed Oct 07, 2009 7:12 pm Post subject:

Thank you miniman 82 and Jake for the info

tncsparky · Posted: Wed Oct 07, 2009 7:22 pm Post subject:

miniman82 · Posted: Thu Oct 08, 2009 9:39 am Post subject:

Bones 53 · Posted: Sat Oct 10, 2009 6:45 am Post subject:

Does anyone know who can drill for the second plugs? I called http://www.greatplainsas.com/sccylheads.html but their jig is fixed for the stock valve size and my heads are 48 x 37.5 so their jig won't locate the plugs accordingly. Thanks

ALB · Posted: Sat Oct 10, 2009 8:05 am Post subject:

Bones 53 · Posted: Sat Oct 10, 2009 9:17 am Post subject:

What's the largest sized valved head anyone has done with the dual plug head? What is the optmum placement for the plugs in relation to valve placement?

1946vw · Samba Member Joined: April 02, 2007 Posts: 74

BAE heads have two pulgs and 2.500 intake and 2.000 exhaust or bigger

1946vw · Samba Member Joined: April 02, 2007 Posts: 74

4 cam head

Image may have been reduced in size. Click image to view fullscreen.

Bones 53 · Posted: Sat Oct 10, 2009 11:21 am Post subject:

Are those type one vw heads or some other? They look like some CNC'd aftermarket heads, very nice.

1946vw · Samba Member Joined: April 02, 2007 Posts: 74

CNC type1, I have put two plugs in 44 x 37 type 1 heads also. Brian

Juanito84 · Posted: Mon Jul 15, 2013 2:09 pm Post subject:

It looks like Bug Patch is gone. I guess a guy could use Great Planes to do it for $250 a pair.

Could a guy just machine his own heads at home or a local shop?
It seems there's nothing more to it than clearing out some fins, drilling, tapping, and perhaps clearing out some combustion chamber material, other than getting correct measurments and presice machining.
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If a water cooled engine cools its water with air, isn't it just an overcomplicated air cooled engine?


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