Background

I have had my '92 GMC Suburban for about 2 ½ years now and it has served me and my family well. The truck is used mainly as a daily driver for my wife on the short hauls of the kids to and from school and all their other various activities on their busy social schedule. Once my wife got used to the size, an upgrade from a 94 Ford Explorer, she has enjoyed the roominess and seating capacity of the Suburban. On the weekends the truck turns into a real work horse hauling various items related to projects around the house as well as acting as a tow vehicle for our 20 foot family ski boat and our 18 foot Weekend Warrior with a gaggle of quads inside. The 454 with just under 80K miles is still strong but as I have learned in the past any help in the towing capacity can't hurt. I have read about Jacobs Electronics systems in the mags and heard a number of testimonial ads on the radio. The system always sounded too good to be true. Improved gas mileage (to keep the wife happy) and an increase in horsepower and torque (for me and my towing) all with a simple ignition upgrade that would take about an hour to install. After opening up the breathing of the power plant with a Banks RamAir intake system I decided to go for the Jacobs ignition upgrade.

Selecting the System

My initial contact with Jacobs order line was very pleasant. The sales staff was knowledgeable and courteous. After asking for the standard year, make and model information, they also asked me what type of coil, internal or external. For those not familiar with these types of GM coil systems, it is simple to identify. If there is a wire running from the center of the distributor cap to another external electronic component (the coil), it is an external coil. If it has no center wire running from the distributor cap, the coil is internal. We then discussed what I was attempting to achieve with the upgrade. I wanted what they promised in all the ads: improved performance with and increase in gas mileage. The sales rep went through their product line and we settled on an Ultra Team system. This included a Jacobs Ultra Coil, a Pro-Street Energy Pak and a new set of spark plug wires.

The Jacobs Ultra Coil is the top of the line, highest output coil that Jacobs produces. The Pro-Street Energy Pak is the brains of the system. This patented computer ignition controller modifies the spark output in response to changes in operating conditions for each cylinder on every power stroke. The Jacobs plug wires are thicker than Stock GM wires (8.5mm compared to 7.8mm) providing better electrical energy transmission from the distributor to the spark plugs. They come in factory OEM lengths with boots fused at both ends to prevent any type of water contamination. About two and a half weeks after I placed the order the kit arrived at my doorstep.

Installation

On initial inspection the kit seemed to be very well laid out. All the wiring connections for the Coil and Energy Pak were pre installed and clearly marked. It also included very simple instructions on each of the components including mounting and wiring diagrams. All the literature has plenty of listings of Jacobs 800 tech numbers to call if I had any problems. Also included was the Jacobs Warranty which gives a 30 day money back, 120 day replacement and an option to purchase an extended one-year warranty. Pretty generous considering that most electrical parts from your local parts store have the "as long as we see you" warranty meaning as soon as you disappear outside the door the warranty is up.

The first step I took was to follow the tech tip of replacing the spark plugs. The kit came with a special hand written sticker that listed the recommended plug brand and model as well as the starting gap. In all case the starting gap is .005 to .010 inches increase over factory gap settings. After installing the new plugs I placed the sticker on my fan shroud for future reference.

I then replaced the plug wires. This was about a 30 minute project. The hardest part was matching the new wires to the factory wire lengths and then installing the new Jacobs wire separators. But it went without a hitch. I then did a quick start up test with the factory coil to make sure I had all the wires installed correctly. The final step was to install the Ultra Coil and Energy Pak components. I picked suitable mounting locations on the wheel wells and connected the two main wires. One from the factory wiring harness and one to the factory coil. I then connected a ground wire and the positive and negative battery leads. It only took minutes.

The install was finished by plugging in the included fuse and turning the key. The status lights on the Energy Pak lit and the engine immediately fired up.

Outcome

The real test was out on the road. I immediately notices a new peppiness to the 454. Anyone that has driven a pre Vortex 454 knows that peppy is not usually used when referring to this power plant. With the new ignition, acceleration off the line was smooth and consistent. You could really feel the difference when merging onto the freeway. I have not yet verified these numbers on a dyno but the Jabobs guaranteed power increase is at least 12 horsepower for this application. That should give me 242 up from the stock 230.

The next test was on a weekend trip down to Pismo. We had the 18 foot Weekend Warrior full of quads and gear. My estimates on tow weight is somewhere above 5000 lbs. It is about a 200 mile treck from my home in San Jose to the Pismo dunes. There is only one major grade which is worse coming home. Everywhere but on the grade we averaged a bit over 60 miles/hour and pulled strong on the hill only dropping down to second at about 45 miles/hour. I noticed that maintaining the speed with the trailer in tow was much more comfortable with the new ignition. The improvements in torque and horsepower really helped.

Final Thoughts

The only problems I had with the kit was the battery leads. In my opinion it is a weak link in what is otherwise a very high quality setup. My battery has side bolts. The leads from Jacobs are just brass spades designed to go between the bolts and the terminals. Initially it went together fine but the extra space that this setup allowed in the bolt to terminal connection causes corrosion on the leads. I lost power in the vehicle once and had to clean the leads. I tightened things a bit more following this but will have to work out a better battery connection for long term use. This is not a show stopper by any means and only is a minor complaint. At this point I am very satisfied with two out of the three Jacobs promises. It was a very easy install and the power increases are very apparent and worth the cost of the system. I will be analyzing my mileage over the next several months to get a good picture what the post ignition upgrade delivers on the third promise. What I expect is to see an increase from the 10 or so MPG that I get now to somewhere closer to 12 MPG. It may not sound like much but with a 43 gallon tank that should increase my range about 85 miles. Once the numbers are in, I will post them here on this page. Stay tuned……. Even without the milage number factored in I would recommend bumping a Jacobs Ignition system to the top of your performance upgrade list for your vehicle. For more information contact:

Jacobs Electronics
(800)627-8800
www.jacobselectronics.com