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Garage Project GPW Runs!

Posted in How To: Electrical on November 28, 2017
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After years of collecting parts, wrenching, procrastination, miscellaneous sidetrack projects, and other distractions we finally finished our Garage Project GPW. The most tedious part of any frame-up build is the plumbing, wiring, and all the finishing detail work. The same was true of our flatfender.

Fortunately, at least part of that was simplified for us with the use of a Team 208 Motorsports engine wiring harness and computer that were designed, built, and tuned specifically for the swapped-in ’02 4.3L GM V-6 under our GPW’s hood. The company had us take several measurements and asked us many questions about exactly what we wanted before creating the engine harness and programming the factory GM computer for us.

We took the advice of another flatfender owner who recommended not attaching any underhood components or wiring to the inner fenderwells. The fenders can be easily removed for more access if there is underhood work to do.

The result was a simple plug-and-play system that allowed the engine to start right up on the first try. Even though our 4.3L is stock, the company also specializes in wiring and proper tuning for high-horse engines via Wi-Fi as well as complete power packages. The rest of the finishing touches came together in good time, and the GPW only had a few minor hiccups on its maiden voyage. For more on that, check out the “How Does It All Work?” sidebar. Don’t forget to check out the first startup video at jpmagazine.com. Also, if you’re wondering, yes, we plan to paint the windshield frame. We simply got distracted again. However, Dr. Frankenstein would be exclaiming, “It’s alive!”

Each Team 208 Motorsports wiring harness is built to order after you provide a few measurements and answer some basic questions about the engine. The harness comes complete with a sealed Bussmann fuse block.
Every circuit is clearly labeled. You can opt for additional open circuits to add more electrical accessories to your Jeep later on.
All of the wires in the harness feature labeled plugs that simply snap into the stock engine components. The wires are protected by looming. Optional race-grade heatshield looming is also available for more extreme applications.
The use of a speed-density tune gave us the ability to remove some of the complex engine sensors, such as the mass airflow sensor. To keep dirt out of the engine, we capped our stock ’96-’04 4.3L intake tube with an aFe Power Magnum Flow Pro Guard7 synthetic media air filter (part number 72-35507).
In confined applications where real estate is at a premium, such as on our GPW, Heatshield Products can come to the rescue to protect wiring, brake lines, and fuel hoses from the hot exhaust. Heatshield Products Lava Tube withstands 1,200 degrees Fahrenheit continuous heat and 2,000 degrees Fahrenheit intermittent heat. The sleeve features a hook-and-loop seam so it can be installed without disassembling the lines or cutting wires.
We stuffed a massive Optima Batteries D31T YellowTop deep-cycle starting battery under the passenger seat of our Jeep and built a solid mount for it. The D31T can be mounted at any angle and will provide more juice than we will ever need for starting, winching, and jumpstarting other vehicles.
The factory dash holes received some modern Auto Meter mechanical gauges. A low-buck ignition switch and some universal marine-grade circuit breakers completed the chassis wiring.
To keep the heat out of the interior and further protect the fuel lines and wiring, we wrapped the exhaust and muffler with Heatshield Products Heatshield Armor and Muffler Armor. The products are said to reduce radiant heat by up to 70 percent and have proved to keep our backsides cool.

How Does It All Work?

We built this GPW using knowledge and experience we gained from building several different flatfender Jeeps and other 4x4s over the last two decades. As with any project, they are never actually “done.” We feel that there are still some things that could be changed or upgraded. The 4.3L V-6 turned out to be the right choice for us. The V-8s we have used in the past were simply too heavy and too much engine to take advantage of the lightweight and nimble flattie chassis. Still, fitting the drivetrain and installing an in-frame exhaust cleanly takes a lot of planning. There isn’t a lot of space to work with. A T-18 transmission might have been a better choice than the SM420 we used. Of course, we were able to fit the SM420, but everything is very tight under there. The Headshield Products Lava Tube and Heatshield Armor made routing the exhaust possible without cooking the nearby wiring and other vitals.

Our first romp in 90-100–degree desert temps resulted in the engine running at 210-220 degrees, which is warmer than we prefer. We’ve opted to upgrade our smallish 960 cfm Spal 14-inch electric fan with a more powerful Spal fan (part number VA08-AP71/LL-53A), which draws more than twice the airflow. We also replaced the stock 195-degree coolant thermostat with a 180-degree piece. If these changes don’t help, we may have Team 208 Motorsports reprogram the fan via Wi-Fi and the OBDII port in the wiring harness. The fan currently kicks on at about 210 degrees and off at about 190 degrees. A kick on at 195 and a kick off at 180 might be a better setup for our desert Jeep.

Our brakes have been working great. However, the combination of parts that we used for our hydraulic clutch resulted in a heavy pedal. We may dive back in and upgrade to a complete CNC, Tilton, or Wilwood pedal and master cylinder assembly with a 3/4-inch clutch master cylinder to solve the problem.

The coilover radius arm suspension rides smooth over rough surfaces. As expected, the Land Rover radius arms and 10-inch-travel Fox coilover shocks don’t allow a ridiculous amount of suspension flex. The Jeep will lift tires on extremely jumbled sections of trail, but the Eaton ELockers front and rear keep it moving forward. If you are looking for an RTI ramp champ, you’ll be better off with a four-link suspension. However, the radius arms allow the Jeep to handle twisty, high-speed on- and off-road sections with confidence. Our GPW suspension handles like a four-link suspension Jeep with heavy sway bars.

The 3- to 4-turn steering boxes found on most Jeeps are adequate in most applications, but we wanted a faster steering system on this Jeep. Adding the 2:1 Howe Racing Stealth HD steering quickener was the right choice for us. Combined with the 2.5-turn Camaro steering box, it makes the Jeep drive and handle like a go-kart, which is not something everyone likes. Our current aftermarket 5.5-inch crank pulley is underdriving the OE GM 6.5-inch power steering pulley, making the steering feel a little heavy at lower rpm. We may better match the shaft rotation speed of our stock GM power steering pump to the crankshaft with a smaller aftermarket power steering pump pulley from PSC Motorsports, which would provide something closer to a 1:1 crank/pump ratio. Making this switch should improve steering assist in the rocks at lower rpm without affecting the high-speed steering feel.

Sources

Auto Meter
Sycamore, IL 60178
866-248-6356
www.autometer.com
Eaton
Cleveland, OH 44114
800-386-1911
http://www.eaton.com
Tilton Engineering
Buellton, CA 93427
805-688-2353
http://www.tiltonracing.com
SPAL USA
Ankeyny, IA
800-345-0327
http://www.spalusa.com
PSC Motorsports
Azle, TX 76020
817-270-0102
www.pscmotorsports.com
AFE Power
Corona, CA 92879
877-512-8111
http://www.afepower.com
Wilwood Brakes
Camarillo, CA 93012
805-388-1188
http://www.wilwood.com
Heatshield Products
844-723-2665
www.heatshieldproducts.com
Howe Racing
Beaverton, MI 48612
989-435-7080
howeracing.com
CNC Brakes
(619) 275-1663
www.cncbrakes.com
Optima Batteries
Milwaukee, WI 53209
888-867-8462
www.optimabatteries.com
Fox
800-369-7469
http://www.ridefox.com
Team 208 Motorsports
208-649-6123
team208motorsports.com

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