Coil NEAR plug ignition

[MNGSX]

Some engines. GM pushrod V8's for example use a coil near plug setup.

That got me thinkning.

I pulled the spark plug cover. Unbolted the factory coils from the mount and layed them in the VC valley. Yep allot lower than the oil cap... then shut the hood.

Cleared perfect. Hmmm.

No major modifications are neccessary. Just extending the factory coil wires and shortening plug wires. If you know what you are doing putting coil end terminals on is easy. So simply changing length of the wires and that is it. A lot of 4 cylinders with waste spark have two double ended coils mounted on the VC.

It will take some thought as to exactly where to best mount them but this still would cut spark plug length atleast in half. A custom deeper preferably ventilated spark plug cover could be used to cover every thing.

The 1&4 coil should be centrally located as these pairs are farther apart. This appears to be the best arraingement I have found yet. I'm just in the mock up stages. It was just one of those things that hit me all of a sudden. You know I wonder". Will the wire lengths be completely symetrical. No. Are they in stock form... no. This would be handy for those with a sheet metal intake who are'nt ready for a full individual coil COP system. With a well designed cover it would also greatly streamine the look of the engine compartment.

 

[RipperXX]

Um, not to burst your bubble, although you are on the right track, and I am sure this does technicly help. I doubt this will make any real deference on our cars. The loss of power in that little bit of wiring is insignificant.


For instance if you take a 10' extention cord and then a 50' and you cut them both in half. You would see vertualy no improvement in the now 5' cord however in the now 25' you would probly see a good improvement.

 

[MNGSX]

Even full COP has VERY minimal gains. A good ingnition coil is a good coil regardless of where it is mounted.

For those with a sheet metal intake going.... Ok now where do I put these f&ckers its probably a good idea.

It is not going to matter alot as far as actual spark energy. Just someplace else to put them for those who need to relocate. If done properly with a good cover it would look pretty good so the bling bling guys might like it.

The best system would likely be full COP with 4 individual coils and an aftermarket ECU with four coil drivers.

You can also do 4 coil waste spark with 2 drivers.

This is just a DIY low buck way to relocate off the manifold with the least hassle. DSM-ers are a bit frugal so it might catch on.

It needs to be 2g coils as they are two seperate coils and can be split up.

 

[RipperXX]

I see now, your mainly doing it just to relocate it, not to improve the heat of the spark. OK! now I got yea

 

[pneumo]

To be technically correct our stock plug wires have a resistance of 10,000 to 22,000 OHMs. That's a lot of resistance. It's built that way to reduce noise in the electrical system, so any reduction in plug wire length means more energy to the plugs, which means you can run a bigger plug gap without misfires. A bigger plug gap will ignite more of the mixture at the same time, instead of igniting a small part and letting the fire spread from there. It's sort of like having the power of more advanced timing without being more prone to knock. It's all good!

 

[MNGSX]

I'll have an update later. I found something even cooler.

 

[Defiant]

I can't think of anything it'd hurt, unless you're getting more vibration or heat to the coils, but the stock DSM ignition is good for more than 350hp with its long-distance wires.

 

[MNGSX]

It is very possible to swap or EVO/3g 2.4 coils. The EVO has direct COP on two cylinders with short plug wires to the other end of the coils to the other two.

But for gain per dollar I think just moving the factory coils beats it. Youd have two really short wires and two "long" ones. The "long" ones would still be shorter than the shortest factory coil wire.

I did a resistance check on the longest OE wire and the shortest. It's about a 1.6-1.7 K ohm difference. 5k vs 6.7k

I can't think of anything it'd hurt, unless you're getting more vibration or heat to the coils, but the stock DSM ignition is good for more than 350hp with its long-distance wires.

The vibration ought to be the same. The intake is connected to the head too. As long as the person who designs the mounts puts some though into making them secure. You could put rubber isolators on the bracket. Something the factory mount omits.


Alot of engines make good power with long as hell wires. Just look at a top fuel V8. Long as heck. It's just a simplification issue.

http://www.meaa-mea.com/products/p_ignition.asp

Evo's are the bottom double ended coils. But just moving the factory coils should get about 90% the same gains.

The ultimate would be using the pencil coils with a 4 driver ignition system. Thats the most efficient coil design.

 

[pneumo]

Thanks MNGSX for the inspiration. I got up off my butt and measured the resistance of the new NGK wires on my Talon; 5k to 8k OHMs.
Then I measured the resistance on my 90 Laser equipped with Accel Thunderbolt 8 mm wires. They say," 150 OHMS per foot" and they measured 170 OHMS for the shortest wire, 245 OHMs for the longest.
Big difference.
So how much power is lost with 5k to 8k resistance?
I'd have to guess the Accel wires would not benefit very much from being shortened with the coil near plug mod.

 

[MNGSX]

I found a OE coil and wire set which is identical to what the EVO's run for $45 at a local yard. Stratus/ 3g eclipse. A few cars have these.

I'm still waiting for the EVO wiring diagram from my buddy but were both pretty sure its a negative trigger system like the stock DSM coils.

A coil goes directly on two cylinders with a lead on each to its mate at TDC.

They are a DECOP system. Double ended coil on plug. This should be easily adapted to a DSM and DSM-ers should be able to find ample coils in yards as more 3g's and other cars with these parts factory get wrecked.

You can run magnacore or NGK or what ever with these coils but you only really get two wires and the distance and difference is quite short.

What you do get with better leads even if the resistance drops are not that great is better durability and dielectric (insulator) strength. So they last longer and transmit more power because less tries to bleed out the sheilding.

I'm just going to try the OE wires on those coils. So far it looks pretty straight up and bolt on.

 

[MNGSX]

Voltage drop

V=I x R

Voltage = current x resistance

Actual power drop

P=V x I

Power (watts) = Voltage x Current

I guess I'll have to bust out my fluke (dataloging ) and do before and after measurements for a tech article.

See just how much more energy makes it to those NGK's

 

[MNGSX]

I sent my buddy to pick up the coils since he lives near there. They goofed they were std bracket mounted coils. Someone put in the wrong # in their computer.

I've got a couple yard looking out for and searching for the right coils. The EVO and 2.4 3g, certain mirages and stratus's have the same coils. So some will turn up somewhere.

 

[alexg1323]

nice idea but 3g coils wount work, well technically they would work but because of the set up of the 16v sohc head the coil is much to long and sits well above the valve cover. 3gs also have 3 wires going to each coil. Possibily an evo coil would sit at a better height in a dsm as its also a 4g63 dohc. But evo and 3/gs are not the same part number nor shape. New evo coils are $100 per at the dealer, then your next challenge is getting pigtails for it.

alex