waste spark thought
Turbo Mini Forums

i was just making some new leads for the spud ,
and thought of this ,,

if a waste spark system runs the current from coil to plug...

plug tip positive charge to earth strap...

then earth strap to plug tip neg charge on shared cylinder,

is the cylinder that has the pos charge at the tip going to have a better quality spark ?

,,and if so , with a mini ,do the middle cylinders have a greater need for a better spark than the outer two ,because of mixture bias making the inner ones run lean ,and so harder to light up ?.,

following this , i wondered if it would be worthwhile not following the 1234 marks on the edis coil pack ,but finding out which leads were positive spark ,and sticking those ones on the middle cylinders .

or is this all mad ?

regards
robert

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Intersting point,

If you look at tig welding the electrode is negative, the electrons flow from the negative electrode to the positive work peice, sommthing like 80% of the heat is then at the workpeice (positive electrode)

I also wondered about a silghtly different amont of advance for the inner and outer cylinders.

Edited by Joe C on 24th Nov, 2006.

These kind of ideas are interesting to think about and mull over, but surely an extra pound of boost would have a far greater effect on power output?!

True, only so much boost you can run though

also this could potentially have a positive effect on the effiency of the engine. Although, i'm the first to admit that most of that post went way over my head!

Has anyone got a circuit of how the coils are wired (HT side).

as the explanation above isn't how I thought it was.

I have gooogled, but no joy.

Cheers

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I personally thought that the coil packs (as per Fiesta type) are two individual coils, that fire both cylinders at once, in the "normal" positive way.

yes EDIS coils are really two coilpack, like Tom wrote above.

Ive worked on a lot of Subarus which have coil packs.

All of them wear 2 and 2.

One set of plugs will wear the plug tip itself, the other the plugs electrode bit.

Apparently its just the nature of wasted spark

Here is a pic of some NGK racing iridium plugs from a Subaru, you can clearly see the wear difference.
I dont see why all wasted spark system s wont be the same. Individual COP will probably be normal ( at least mine are )

Big pic, so its linked.


And a brief thread where I queried it
http://bbs.22b.com/cgi-bin/ultimatebb.cgi?...t=001065#000000

Edited by stevieturbo on 24th Nov, 2006.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Basically in the coil pack there are 2 coils, I think everbody knows that. Each coil is charged and discharged in the normal way, i.e remove voltage from the coil and the magnatic field brakes down and a high voltage is produced. The difference in the wasted spark coil is that the coil is centre tapped, so that when you get the HT pulse you get one +ve pulse and one -ve pulse simultaneously.

As spark plugs are designed to spark electrode to case the -ve pulse can give a slightly weaker spark because it goes case to electrode. not worth worrying about though.

I have heard it described that the -ve spark is weaker because it has to go through the +ve plug first. As I understand it this does not happen.

Feel free to correct me if I am wrong.

Ben

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

I blew up a coil pack a while ago and chopped it up for a look, wish i'd paid more attention now!!

One thing you could do is run 4 bike coils (or similar) I'm pretty sure the primary's tend to be about double the impedance of a ford coil so you could probably run a pair in parrallel off of the EDIS box giving the same polarity on all cylinders.

As spark plugs are designed to spark electrode to case the -ve pulse can give a slightly weaker spark because it goes case to electrode. not worth worrying about though.


Ben[/quote]

i think that was the point ben ,whether it is actuallyworth worrying about ...i know that having the coil wired up the wrong way around is deff supposed to be a mortal sin in my sun analyser books giving a weaker spark , i v also read that ford made a special coated plug for edis ,and at first coated just the side electrode for one bank of cyl ,and the centre for the other !!to get round the problem stevie shows us with his pic.seems to me that ,if the plug is earthed so negative ,then a spark thats neg will be lower v than a pos spark cos the potential difference is less ,but as you say .would it make a diff ,specially on a high boost engine puttling a lot of demand on its ignition system with mixture bias ...

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Coil on plug is the way to go IMHO

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Old Legacy coils are prone to failure in their old age. The nose cracks, the rubber insulator gets damaged. These are COP systems, so all 4 will fire the same.

The strongest coil pack is supposed to be the 97/98 version, which is dual coil, wasted spart setup.
99/00 versions are similar, but have a built in ignitor.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

With coil on plug if one fails you still have three to get you to the finish at least.

LS1 coils are appearing everywhere. Factory fit coils, that have a huge reputaion for serious sparks. Built in ignitors too and very compact, which can be handy for some ecu's ( not when I built mine though lol...ended up using some cheapy Bosch coils instead )

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will