Dual Ignition Heads

[miniman82]

In a word: distributorless.
That, or 2 distributors.
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Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747

[Mr. Electric Wizard]

Gotcha.
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"Saying what we think gives us a wider conversational range than saying what we know."
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(T)exas (C)oalition (B)uses
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[Jake Raby]

or a twin plug distributor..
I have done it 5 different ways.
It's worth the hassles!
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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"

[gears]

I used to do this mod in the early 90's for various performance VWs and 4-cyl Porsches. ("New Products" April '92 Hot VWs)

heads and distributor:

various Type I heads"

[Twntrbo]

Is there a available distributor for twin plugs?

[Unkl Ian]

[Jake Raby]

[craigman]

I would be interested in a twin plug ignition also.
Jake, any chance your going to sell this "conversion" for the 009 dizzy?

Craig

[gears]

Jake, I installed a simple pair of mini switches beneath the dash on my Ghia, one for each coil ... a simple way to demo the difference between single plug and dual plug.

My original dizzy was just an adapter plate whittled from an old cam gear, heat shrink onto an 009. The dizzy in the photo is a later 1-piece billet body. I'd merely use a shaft assembly with weights and bits from 009, 010, or 031, along with my own body and adapter parts.

The early rotors would fly apart at 6000 engine rpm, ruining the cap too. It wasn't until the rotor material was changed from cheap plastic to strong Zytel that the mod became worthwhile.

Gary Peloquin may have been the first guy to use dual crank fire for a drag car (with the Scat heads in photo) ... if I recall correctly, dual ignition was promptly banned.

[bdkw1]

[Jake Raby]

Gears,
Yep, they always ban the things that "Do not work".. I had a heated debate about the usage of twin plugs with another well known builder last year on this topic..

I've never really been able to gather back to back data on the twin plug benefits on an N/A engine because to get the max from the technology I have always ran higher CR than the single plug would support on the same grade of fuel, so the variables were too great.. The least I have ever ran with twin plugs is 10.8:1 CR.

The bigger bore TIV engines REALLY see a big gain from this with their larger bores and chambers as the two flame fronts dramatically reduce the optimized total timing of the engine.

The twin coil 009 driven kit is through testing and is being employed on my turn key engines now.. Not much of this technology is sold otherwise as I am afraid of someone applying the components improperly would occur. Its a guarantee that not adhering to the dramatic differences in tuning and engine design will create a failure that could stain the reputation of the technology.

All it takes is one. With a turn key I have quite a bit of control over these complexities.

Its a different world, not many conventional VW people are open minded enough to accept it. Thats why I LOVE it!
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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"

[gears]

I pursued the twin plug thing in 1990, after being told how a Big Name shop had tried it, failed, and proclaimed it couldn't be done. There's probably still a few guys running around with my twin-plug conversions today. I kept the last 1-piece dizzy for my display case, and I think Pele Bug still has my original 2-piece.

The reason twin plugs were banned when Gary showed up at the track was because it worked too well. He told me his already high horsepower engine gained an additional 20 hp, but I was never able to verify numbers or take it to the next level, as my role was really just as the underground machinist. I even contemplated a sectioned waterboxer head ... now there's a head with which "it can't be done" ... way easier to start from scratch with a new design.

[Jake Raby]

[Jimmy111]

Twin Plugs can and do create a faster and more directed burn. They work best with a pent roof combustion chamber like in a 4 valve per cylinder chamber but they also work well in a wedge chamber such as a VW chamber. I have some photos taken from different types of combustion chambers and they clearly show that the twin plug setup does compleate the combustion event 30% faster than any single plust setup. Jakes heads are well designed and he does have the data to prove that they work well in VW applications.

[tencentlife]

I have an '82 Datsun pickup with the twin-plug Z22 engine. Long ago when it was my daily it gradually got to running off, big loss of power. Started looking around and found one of the two coil-to-cap HT leads had rubbed against a hose and the juice had carbonised the rubber until it was grounding out that way, cancelling one bank of plugs. Isolated the wires and it was like adding a second engine, the jump in power was HUGE! Two sparks in a chamber designed for them makes an amazing difference, and without the second spark is a dog.
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Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[66zeke]

Rolls Royce used to use dual plugs but they had one set coming out of a magneto. the reason behind this was the distributer would provide great low rpm spark and the magneto would handle the higher rpms. so I think Mr. Raby should use a crank trigger dis. and a vertex or somthing

[Bones 53]

I can see how using a coil pack for each plug would work but how does the distributor fire two plugs at the same time for each cylinder? Does anyone have some pictures of the distributors being used and the wiring setup?

Is there a distributor / ignition system available to purchase for twin plug applications?

[Jake Raby]

We just finished the testing of the simplest method yet.. It uses any VW dizzy and acts as a trigger to fire a pair of copil packs that are connected to the two banks of plugs.

Its a 689.00 set up, but it works well and makes the dual ignition arrangement a true bolt on with all off the shelf parts.
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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"

[miniman82]

Sorry to be like this, but...

$690? Pffft.


If all you're doing is firing pairs of plugs in parallel (at the same time, a la Alfa Romeo TS engine), the same thing can be accomplished for much less money. Just use 2 EDIS systems in parallel, with a Megajolt/Megasquirt controlling it. If you want a REAL twin plug system that has some real tuning power (perhaps you already do), all you need is another Megajolt. Then you can have 2 entirely separate spark maps, so you would be able to experiment with leading/trailing schemes like the rotaries do.
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Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747

[Jake Raby]

Sure it could be.. and we have done it and have probably experienced every way to fire twin plugs ever available..

Thats because I have been pushing this technology for over a decade with the ignition system being THE achilles heel from day one and the limiting factor.

Fact is the twin plugs don't make any more power with lead/ trail settings for the plugs as I have went to the ends of the earth to apply these sorts of changes and test the changes. What has worked best is simultaneous firing with high enough voltage to overcome the static from the elevated cylinder pressures that we love to use with twin plug arrangements.

BUT the majority of who I cater to wants nothing to do with any system that requires computer interface..

What may be simple to you isn't simple to others... The majority of those I deal with don't have a tool box, or I supply them with tools to assemble their engine kit. Some of these people want the simplest, easiest to understand system possible that snaps into place in a few minutes..

Its a different world.
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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"