My ignition program

[racydave]

Matt suggested a interest in this. It was adjusted with a lap-top. On the fly! http://www.flickr.com/photos/wwwfiatspi ... 260785334/

[mdrburchette]

Hey Dave, I like the colors! Btw, can you explain a little of what we're looking at?

[ga.spyder]

Enlighten us ,oh wise man! And whats Jay Leno doing to that bear in the other pic?
Craig

[mdrburchette]

Tickling his fancy...bet you didn't know that's where Sam's fancy was, did you, Craig?

[ga.spyder]

No...but obviously you and Sam have become''close'', when Ron is out of town
Craig

[pope]

Is that performance before and after Viagra?

[rlux4]

Pope and Craig, you guys were able to understand that table? I don't have a clue what I was looking at.
Ron

[racydave]

The horizontal bar is rpms. The vertical bar is Kilopascals which we usually measure in inches of mercury or vacuum. Vacuum represents the load the engine is under. Load can also be determined with a throttle position switch for cars that have wicked camshafts and poor vacuum at the lower rpms. As the car is driven the individual squares will be hi-lighted. IE, 800 rpms at 54 kilopascals will yeild 30degrees BTDC. The timing value is adjustable allowing you to tune the ignition advance. With my partner in crime at the lap-top I would say, Tim it feels flat right about here. He could see which square was hi-lited, and adjust the timing at that location, and the relationship to squares next to it. It is 2 dimensional so you can tell, the timing is not just at one set value at a given rpm.
Lets look at 6,000 rpm with a total advance of 34 degrees BTDC, and target of 18 degrees ATDC for when we want max cylinder pressure to develop. At 6,000 rpm this would give us (6,000 rev/min)/(60 sec/min) = 100 rev/second, the inverse of this (1 sec)/(100 rev) = 0.010 seconds for one revolution of the engine. But we only have (34 BTDC)+(18 ATDC) = 52 degrees of crankshaft rotation available to develop maximum cylinder pressure. In order to change degrees of rotation to time, we now take our (0.010 sec/rev)(52 deg)/(360 deg/rev) = 0.00144 seconds, or 1.44 milliseconds from spark to when we need peak cylinder pressure!

If we subtract out 8 degrees for pre-kernel development and 2 degrees for flame development, we only have 52-10 = 42 degrees for the flame propagation, or actual charge burn. The length of time would now be (42/52)(1.44 ms) = 1.16 milliseconds. So the actual combustion of the charge is completed in only 0.00116 seconds.

[mdrburchette]

It sure is a colorful picture!

[racydave]

OK, so I "borrowed" a little info... The main reason to develop this system for my 2L is to bring the ignition into modern specs. The ignition event is critical to a properly tuned engine. The events occur quickly, and in a distributor system, there are many opportunities for mechanical play in the timing belt, dist drive gears and in the distributor. With a reluctor wheel at the crank pulley, and a pick up sensor, it does away with the mechanical play and gives a 2 dimensional approach to the spark event. I have found that the overall performance from idle to balls-out is smooth and powerfull, and even the exhaust note has improved.

[racydave]

Denise, if you installed this on your race car, I would probably "need" to come down and help you tune it!!!

[mdrburchette]

I'll get the guest room ready! How much do you think you have in this setup, Dave? Is this a distributorless ignition setup?

[racydave]

I always forget how much I spent just before Carol asks! You can buy the Mega-Jolt module pre assembled, or get a battery operated cold solder gun and make your own. I opted to save a few bucks and made mine which is not that difficult. You will need some Ford parts from the junkyard. A EDIS module, the pick-up, coilpak and plug wires. After it runs you can replace with new, or not. Millers Mule made my Aluminum crank pulley with the reluctor, and fixture for holding the pick-up sensor, and dummie plug for the unused dist hole. Also necessary to tune is an old lap-top which I got for 50 bucks. A quality crimping tool ( ask Pope ) and home-made wiring harness. $o actually, its very affordable! And yes, this is the Distributorless system. Ron could possibly make the parts for you too! But the alum crank pulley is much lighter, and a performance mod in its own...

[racydave]

Actually, its not that complicated. Many people alot smarter than me came up with the idea. Alot of information was posted and shared for my project ( many thanks ) The really smart ones develop fuel delivery programs.

[mdrburchette]

Definitely something I'd like to consider with the SCCA racer and maybe even my 72.