Mustang Ignition Coil Replacement Upgrade

Next, the electrical plugs... 

   

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Next, the electrical plugs are disconnected. With these two steps accomplished, gently pull the OE coil pack off of the engine--wash, rinse, repeat for the remaining coil packs. If your Mustang has some serious mileage on it, now is also the perfect time to drop in a fresh set of spark plugs.

The dyno showed an incredible improvement of 27 hp and 33 lb-ft of torque. We were all surprised by the substantial gain. JR checked every variable to see if anything was impacting the outcome and everything checked out normal. Remember, JR predicted an improvement in the 8 to 10 horsepower range. There was certainly nothing wrong with the car on our baseline test, as the GT/CS wound up smoothly and made respectable numbers. We decided to retest the car, this time hot, to simulate actual operating conditions rather than cooling down to obtain the best test numbers. We ran the car again.

A little dielectric grease... 

   

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A little dielectric grease is used on the spark plug end of the cable. A small amount was also used at the coil end. It's a good idea to use dielectric grease as it promotes optimum conductivity. The dielectric grease keeps corrosion and moisture at bay, for a long lasting connection and is included with the coil kit.

Here the car provides almost the exact same result. In fact, the horsepower figures are identical while the torque figures are down by 9 lb-ft, but still 24 lb-ft better than the OE coils. JR explained that torque figures are the first to suffer when the heat factor goes up. However, the value of the new coil pack ignition was reaffirmed as the same horsepower figures were maintained. We're not kidding here folks, and these tests were carefully conducted. While we're interested in every extra horsepower we can muster, a gain of 8 or 10 ponies is one thing, but an improvement of more than 25 horses is quite another, and we'd be willing to take the bet on the GMS kit without a doubt. We're not saying that a 27 hp gain is guaranteed on every car. What we are saying is that on that day, JR's kit was worth 27 hp and at least 24 lb-ft of torque on a new '08 Mustang GT/CS with 1,180 miles on it.

Next, the coil pack assembly...        read full caption Next, the coil pack assembly is installed into the cylinder head. There will be a small click as the cable end passes the detent of the spark plug tip on its way to seat.	Here's the completed GMS Xtreme...        read full caption Here's the completed GMS Xtreme Pro Series coil pack installation. The whole procedure took about an hour with photography, so figure around a half hour or so in your own driveway.	Working our way to the rear...        read full caption Working our way to the rear of the engine, the same procedure is repeated seven more times. Once every coil pack is in place, all wire connections will be reestablished and any other components removed (for photography) replaced. As noted earlier, the coil pack and injector connectors are short enough to only reach their correct coils/injectors, so there's no need to worry about attaching the wrong connector.
With the coil pack seated,...        read full caption With the coil pack seated, install the original coil pack fastener to secure the new coil pack. Be sure not to over tighten it or you risk breaking off the ear of the coil pack.