Voltage output?

[jeepzj]

I installed an Accel Super Coil a few years ago for my 1998 Jeep Grand Cherokee Laredo 4.0L. This coil outputs 42,000 volts. Anyone know the voltage output for the OEM coil? Also, besides wearing out the cap and rotor faster, and maybe even the spark plugs, are there any other dis-advantages using a higher output coil like the one I have? Thanks


http://performance.thepartsbin.com/basket.php?makeid=14&modelid=151&year=1998&partid=10&brandid=368

 

[andyd]

you should be able to widen the spark plug gap to .045" This allows for better fuel burn. Only real dis-advantage is to your wallet

 

[jeepzj]

To my wallet?.... meaning worse fuel economy or the purchase of the coil? I have the spark gap to .040....OEM is .035 I was also wondering if there will be any premature wear\damage to the pistons or valves.

 

[TheLoneRanger]

JeepZJ, that Accel's a cool coil, and should be a good upgrade. (I need one for my XJ.) Since the stock plug gap is .035", I'd suspect the stock coil puts out about 30-35Kv, which is about standard for that gap. There's absolutely no disadvantage to running the Accel, other than watching out for arcing due to the higher voltage. Upgraded plug wires might be a good idea.....

Better idle, throttle response, MPG, are all benefits of a higher output coil. As Andy says, you could probably go up to .042-.045" on the plug gap. I wouldn't go over .045"; the rule of thumb is to keep opening the gaps until misfires occur, then back them down .005".

TLR

 

[tom slick]

actually the coil puts out **up to** 42,000 volts. the coil will only put out enough to jump the gap to ground. that means if 20k is needed it puts out 20k, if 15k is needed it puts out 15k. it is possible your super coil is putting out the same voltage as your stocker.

 

[Dave H]

I had one on my '78 Camaro (305), and I did notice crisper throttle response with the Accel coil. I didn't track mileage, and any power increase wasn't enough to be noticeable. But the throttle response and quicker starts were definitely an improvement.

I was running AC Delco stock plugs gapped at .044 with no problems. I even tried Splitfires, but they lasted less than 6 months. And when they went, they went quick. One day they're fine, the next the car ran really rough, and the following it wouldn't start. My buddy's '76 Blazer did the same thing at the same time, and we got our plugs together. We both went back to our old AC's, and both vehicles ran like new again. Amazingly, we were both running the Accel Super Coils also. Maybe they burnt out the Splitfires?

Anyways, the Accel coil never had any detrimental affect on my wires or stock plugs. The Splitfires may have just been a bad batch. I do wish I had kept better track of my mileage back then, though.

Dave

 

[Chris142]

"actually the coil puts out **up to** 42,000 volts. the coil will only put out enough to jump the gap to ground. that means if 20k is needed it puts out 20k, if 15k is needed it puts out 15k. it is possible your super coil is putting out the same voltage as your stocker. "

I second this.

 

[unDummy]

The gap was increased. Wouldn't that require more juice?

There is more to a coil than voltage.
Rise time, all around better performance, tighter manufacuring, higher quality coil parts.....will lead to better and more reliable sparks throughout all temp ranges and loads.

Accel also makes caps/rotors that would complement your coil. Iridium/platinum plugs will last longer then copper ones. They also will tolerate a larger gap better utilizing that coil.

I find that thorough ignition mods are very noticeable. That says a lot for stock systems. You got the coil, now get some good plugs/wires/cab/rotor/ignition!