I honestly hate the concept. I would like to know if anyone has heard of a way to remove it from the stock programming. Eventually I'll be buying products from Craig Motes and doing some grassroots ecu hacking. I will not go into how a wasted spark ignition works or why it is in use, just let you Google it and read. I will say this though, it is a frase and only used to apease the EPA (along with many other emissions related componets).
So the question is, how can we get rid of a wasted spark ignition?
John
Wasted Spark . . .
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IMINHELL
Well I guess I might have to explain how/why wasted spark works, then you may understand why I want to dump it.
When your ignition fires on the compression stroke it also fires on the other near TDC cylinder (exhaust valve open). I believe it fires at full voltage and duration, not sure though, lack of available info at current. In theory it is used to lower the actual HC (fuel) emissions out the tail pipe (same can be said for the cat). There in lies the problem. Assuming that you are using ALL available fuel and air there should be little to no HC remaining in the exhaust (or at least a small enough amount that the cat can easily handle). So why was Wasted Spark invented. Simple, to fool the EPA into thinking that the Zetec is actually a SLEV or ULEV (I forget which). That basically means that the emissions out the exhaust are so low that they barely register on a sniffer. Granted it is a good design from a engineering point, but . . . Wouldn't it be easier to actually burn the correct amount of fuel from the get go? I guess I would think so, but I'm not the brightest bulb in the box I guess. I have this theory in the back of my mind that having an O2 sensor and a wasted spark ignition sort of defeat each other. In my theory the O2 measures the AFR after the burn and reburn, there is really no way to know how much goes to what whithout some serious in cylinder tools (ion sense or cylinder pressure tools). I'm sure the Ford/Mazda engineers did some serious R & D with MBT and VE for a stock setup. But do we really know if we are going about it right with mod'd engines? Not really. You figure even if you tune with 5 gas, your still getting after reburn results. So your left with pen and paper to figure the MBT points from the fuel volume and assumed VE tables.
That outta have you thinking for a little while.
John
When your ignition fires on the compression stroke it also fires on the other near TDC cylinder (exhaust valve open). I believe it fires at full voltage and duration, not sure though, lack of available info at current. In theory it is used to lower the actual HC (fuel) emissions out the tail pipe (same can be said for the cat). There in lies the problem. Assuming that you are using ALL available fuel and air there should be little to no HC remaining in the exhaust (or at least a small enough amount that the cat can easily handle). So why was Wasted Spark invented. Simple, to fool the EPA into thinking that the Zetec is actually a SLEV or ULEV (I forget which). That basically means that the emissions out the exhaust are so low that they barely register on a sniffer. Granted it is a good design from a engineering point, but . . . Wouldn't it be easier to actually burn the correct amount of fuel from the get go? I guess I would think so, but I'm not the brightest bulb in the box I guess. I have this theory in the back of my mind that having an O2 sensor and a wasted spark ignition sort of defeat each other. In my theory the O2 measures the AFR after the burn and reburn, there is really no way to know how much goes to what whithout some serious in cylinder tools (ion sense or cylinder pressure tools). I'm sure the Ford/Mazda engineers did some serious R & D with MBT and VE for a stock setup. But do we really know if we are going about it right with mod'd engines? Not really. You figure even if you tune with 5 gas, your still getting after reburn results. So your left with pen and paper to figure the MBT points from the fuel volume and assumed VE tables.
That outta have you thinking for a little while.
John
<--its a foot print in a yellow cake!IMINHELL: I have this theory in the back of my mind that having an O2 sensor and a wasted spark ignition sort of defeat each other.
You obtained a little bit of info on wasted spark ignitions without completely understanding how ignition systems work. The wasted spark on the exhaust stoke is doing nothing, and nothing to upset the o2 readings because that small spark is made to ignite the compressed gas/ fuel vapor and will not "reburn" exhaust gases. I doubt the engineers who developed the ignition system missed something this big. There are many Foci making good power above 300hp who use the stock ignition system, wasted spark and all.
2001 Infra-red ZX3
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focinite
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i think the wasted spark is just some thing that happens. the focus coil is a dual coil setup and 2 cyls witch are called sister cyl, fire at the same time. the reasone i was taught is to make sure the next cyl to intake has a empty chamber so fresh mix can be burned eficently. but i could be wrong. and its pzev= practicly zero emissions vehical, and to my knowlage the new mazda/duratec motor is a coil on plug witch fires per cyl, it may have a bleed over voltage to the next cyl for that same reasone. but if one were to set valve overlap proporly and the compression bumped a touched you wouldnt need half the emissions crap to begin with. most the time if a motor is making more power it is actually being more efficiant. what it comes down to is the manufacture is trying to mix durability with comfort and performance and economy, it cant happen like that. look at europe, there cars are stiff and noisy and they have half the shit on em. the svt/st170 motor has no egr all of it emissions are contoled by valve overlap.
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IMINHELL
GearHead wrote: The wasted spark on the exhaust stoke is doing nothing, and nothing to upset the o2 readings because that small spark is made to ignite the compressed gas/ fuel vapor and will not "reburn" exhaust gases.
True and untrue. If there is no air left for the extra fuel to burn it will not ignite (zero overlap). As far as I know our cams are built with about 23 degrees of overlap. Which provides the residual fuel with enough air to reignite, burn and be extinguished before it reaches the O2 sensor (assuming the actual AFR is on the rich side and not overly rich-slower burn). There by fooling the O2 into reading a false AFR reading.
John
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IMINHELL
By doing nothing (as you stated) it is hurting tuning. Creating a unneeded draw on the ignition system. So if it as you said (does nothing) then why in the world is it needed?
John
John
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the wasted spark is not hurting or helping. grab a scope and test the igniton, you will have yer first spike, that is main spark, then you get a little spike that is wasted spark. and trust me you are not taxing the focus or any ford edis ignition system they are good for 100,000 volts as long as yer batt is good. the wasted spark is a good thing it zaps the cyl with like a 1/8 of normal voltage to clean the chamber.IMINHELL wrote: By doing nothing (as you stated) it is hurting tuning. Creating a unneeded draw on the ignition system. So if it as you said (does nothing) then why in the world is it needed?
John
wink wink.....bitches