Just changed my plug wires yesterday with some new Summit Racing 8mm spiral/mag core ones. I was having some rough idle issues that I thought was because of the old plug wires, and so far the idle is perfect. The old ones were Bosch Premium 7mm, also spiral/mag core.

I tested the resistance of the old wires, the actual plug wires seemed ok, but the coil wire had what seems to me like very high resistance. I know the old style carbon core wires had high resistance, but the most information I can find on the mag cores is that they should have significantly less resistance. Anybody have information on this?

Here's one article I found about it: Understanding Spark Plug Wires

Old coil wire: 6900ohm


New coil wire: 770ohm


Old plug wire: 952ohm


New plug wire (same length): 441ohm

 

definitely seems to me like the coil wire was shot, i wouldnt worry about it since you changed them and it seems to be better now.

 

Hopefully when I get gas on Friday I'll see normal gas mileage again too.

 

I like MSD 8.5mm Red wires, only about 40-50 ohms per foot resistance.

http://www.msdperformance.com/product.aspx?id=6149

 

They look nice, but they're about double the price of the summit wires though. I forget which company makes the summit wires, I think it starts with an M. Mallory maybe?

 

Well the plug wires definitely fixed the low gas mileage I was getting lately. I had only been getting between 11 & 12mpg going between school and home recently (about 70% highway and 30% city) but just topped off the tank a little bit ago (had to make an extra trip home, so that made it the same distance) and I got 17.6mpg. Not too shabby. Guess those old plug wires, especially the coil one, were bad for sure.

 

I don't know who makes Summit's wires? Judging from the cost comparisons I would suggest Mallory does not, but who knows????

 

When i replaced my wires several months ago i switched to the Red 8mm summit wires. While i was on the phone with there tech guy i asked him who made there wires and he told me they where re-badged Taylor Spiro wires so i would say that Taylor makes them. I have always used Taylor wires in my C10 Chevy w/ 350 v8 and the Silverado w/a 454 in it in the past and always have good luck with them. I have had good luck with the summit wires as well since they where installed.

 

I have those same summit wires as well. I put them in about 3 years ago and had to get a second set for spares. For some reason my plug wires like to stick to the plugs extra hard, even with tune-up grease on them. That occured with both the E3s (which worked well til they started to fall apart at the top and cause misfires after 8000k miles) and the NGK vpowers (actually runs better with these than the E3s). But they seem to be well constructed with decent performance.