pcmhacking.net

lol, I do it more for the debunking but then it's a waste to not use the hardware later.

Interesting to see what a new MSD coil does as well as the various LS coils.

Extra grunt be handy for us boosted guys with gaps down at 0.9mm it kills mpg a fair bit the plugs need a big enough gap so only the cylinder at tdc firing gets the spark not the one on exhaust stroke.to small on the gap and both plugs get fired taking grunt away from the one that needs it

How did the VB go with the LS2 coils?

Never run it on the strip with them on there .this just popped up on Facebook interesting http://www.turnology.com/news/f1-tech-w ... t-ignition

delcowizzid wrote:Extra grunt be handy for us boosted guys with gaps down at 0.9mm it kills mpg a fair bit the plugs need a big enough gap so only the cylinder at tdc firing gets the spark not the one on exhaust stroke.to small on the gap and both plugs get fired taking grunt away from the one that needs it

I thought both plugs always fired? Without the exhaust plug firing there wouldn't be a complete circuit for the compression spark current to flow?

I'm interested to know what gains spark gaps or stronger coils would really have?
As long as the the spark gap isn't excessively too small I couldn't see a larger gap having a huge benefit, eg there would be no big benefit of a 1.5 gap over a 1.0 gap. I can understand a very small gain but nothing you would notice.
And for coils, as long as the coil can reliably jump the gap every time, I can't see a huge benefit of a higher power coil? Again maybe a slight gain from more spark current but nothing you would notice?
The main advantage of a higher power coil (eg. MSD coils) i can see is when the existing coil can no longer jump the gap reliably, eg higher compression ratio or boost forces you to close the gap. In which case the better coil would allow you to open the gap back up. But then, unless you have so much boost you have to close the gap right up, is there much of an advantage with the MSD coil or are you pretty much just as well off with the standard coil and a slightly smaller gap?

I'm would be interested to know if someone has done some comparison of different plug gaps etc in a controlled environment eg. Engine on an engine dyno in a controlled environment?

Also another thing I was thinking about is the ignition module. I remember from somewhere that the faster you can switch off the primary current the better the spark. If the switching is slow and primary current tapers off you get a much weaker spark than if current peaks and then instantaneously drops to nothing. One of the main advantages of solid state switching/electronic ignition over old points.

delcowizzid wrote:Never run it on the strip with them on there .this just popped up on Facebook interesting http://www.turnology.com/news/f1-tech-w ... t-ignition

Nice what a great idea

I had seen a paper on this before but also included indexing of plugs. They actually managed to record the amount of missed firings in the test engine in a given minute and reduced that considerably. Economy gains and performance gains were solely from reducing the number of missfirings in a given time. These missfirings are not noticed in normal operation but none the less happen with normal operation. I recall a figure of 77 misses per min at something like 3k rpm on a 4 cyl engine on load and was reduced into the 20s per min.

So I imagine all the gains come from increase in ignition reliability.

delcowizzid wrote:Never run it on the strip with them on there .this just popped up on Facebook interesting http://www.turnology.com/news/f1-tech-w ... t-ignition

Any intent to fit em on the VB still?

I've seen this ignition system before but I can't remember exactly where.

pman92 wrote:

delcowizzid wrote:Extra grunt be handy for us boosted guys with gaps down at 0.9mm it kills mpg a fair bit the plugs need a big enough gap so only the cylinder at tdc firing gets the spark not the one on exhaust stroke.to small on the gap and both plugs get fired taking grunt away from the one that needs it

I thought both plugs always fired? Without the exhaust plug firing there wouldn't be a complete circuit for the compression spark current to flow?

I'm interested to know what gains spark gaps or stronger coils would really have?
As long as the the spark gap isn't excessively too small I couldn't see a larger gap having a huge benefit, eg there would be no big benefit of a 1.5 gap over a 1.0 gap. I can understand a very small gain but nothing you would notice.
And for coils, as long as the coil can reliably jump the gap every time, I can't see a huge benefit of a higher power coil? Again maybe a slight gain from more spark current but nothing you would notice?
The main advantage of a higher power coil (eg. MSD coils) i can see is when the existing coil can no longer jump the gap reliably, eg higher compression ratio or boost forces you to close the gap. In which case the better coil would allow you to open the gap back up. But then, unless you have so much boost you have to close the gap right up, is there much of an advantage with the MSD coil or are you pretty much just as well off with the standard coil and a slightly smaller gap?

I'm would be interested to know if someone has done some comparison of different plug gaps etc in a controlled environment eg. Engine on an engine dyno in a controlled environment?

Also another thing I was thinking about is the ignition module. I remember from somewhere that the faster you can switch off the primary current the better the spark. If the switching is slow and primary current tapers off you get a much weaker spark than if current peaks and then instantaneously drops to nothing. One of the main advantages of solid state switching/electronic ignition over old points.

I too thought both cylinders fired but because the cylinder on the exhaust stroke presents what would be a low resistance environment it required relatively little energy to fire this plug and hence most of the energy goes to the plug firing on the compression stroke and the high resistance environment.

I've experienced loss of fuel economy going from 1.5mm to 1.3mm plug gaps on 2 engines now so it seems real enough to me.