Are the Accel Coils for the 97-98, 4.6 V-8 worth the money? Would I see an improvement in MPG or power? Will spark plugs last longer and fire better?

 

Unless you race, they are not worth the money. No reason not to run stocks. Plugs are plugs, By 20K they all have degraded. Put the money into new plugs MORE often. Money well spent(IF you do your own.)

 

I seen the very same coils in the Accel book at work. They claim 10% better voltage than stock(42000 vs 37800), IMO give or take at least 3% of that 42000 is 1260 which is not going to matter much at all. Probably the best person to ask is someone who has them, only person I know of on here is Joe T.

 

Interesting thing here, a coil is only going to fire enough voltage to make the spark jump the gap...If you are going to run wider gaps(better low end and fuel mileage) then a set of coils could be justified...

Or if you were going to run the plugs extended mileage or a higher compression, or a richer mixture...

But just stock engine..change the plugs more often...

 

Thanks for the replies. I do change my own plugs. We, a friend and I have done mine and his 5.4. I think we took a couple of hours and a few cold ones.

 

They look nice . : )

I really didn't see an improvement to be honest.

But they look nice. Oh I said that....



JT

 

Seems like that's not much of a boost for the newer coil packs.

For those that do have them, I strongly recommend trying different gaps. After puting a full Jacobs system on my '95 I found the gaps have a large effect. My current gap is .075!

The only problem I have had with the real big gaps is slightly soggy performance until the truck comes up close to operating temp. I may knock them down a little in the winter due to this. Throttle response and mileage are slightly up with the bigger gaps.

 

Now signmaster...you know what you are talk'in...widen the gaps and it will help bottom end and increase mileage...

The stock coil packs will handle that..still no need to go to aftermarket coils...

unless you like the looks...

If you want to mod the ignition go with the MSD....

 

Mach1,

You wouldn't beleive the number of posts I have seen from people unhappy with thier box/coil/wire upgrades. About the same number of people still run stock gaps!

Haven't seen as much good feedback on the boxes on the newer trucks. The old trucks seem to benefit more, but then again the old trucks didn't have as strong of a stock ignition.

 

This may be a stupid question, but how does expanding the
spark plug gap increase torque & fuel milage?

 

tkegumby,

The theory is that you produce a larger flame, which helps in the burn process. The larger flame in theory will cause a more complete burn. There is a point where too large of a gap will cause problems at higher revs, when the swirl effect of the incoming mixture could "blow" the flame out. This is even more of a concern in forced induction engines, since the mixture is pushed into the cylinder.

On my truck, a '95 5.0, the mileage increase is more noticed than the low end. The initial ignition upgrade did improve low end, but this was true even with stock gaps.

 

Signmaster--it sure is nice to respond to someone that knows...You got the spark theory down...however you did not mention --

Flame probagation..the flame front that moves evenly and controlled throught the combustion chamber...

 

yes you were right about the MSD and high energy ignitions...

they are much more effective on the older vehicles..espically the carbed models...

 

There was a series of posts a couple years ago where some guys were cutting back the side electrode to expose the center electrode and thus more of the spark to the fuel charge. I think they were have success with this technique. I guess if you cut it back too far (might not hold an arc) you'd just have to bend it down and close the gap some to keep it sparking.

 

Signmaster,

I've never tryed to mess with the gap on my plugs, but what gap do you run or suggest over the stock gap! I would love some more torque & gas mileage.