Throttle Body Spacer and Engine Computer: Half a Second in Half an HourPosted in How To: Engine on March 1, 1999
Do you really need to watch that sitcom for the fifth time? Is the stack of dirty clothes in the corner all that disgusting? Because in less time than it takes to do the laundry, you can throw a throttle-body spacer ring and a high-performance engine controller from Don-A-Vee Jeep on your V-8 Grand Cherokee and really clean up.
These modifications netted us a half-second gain from zero-to-60 mph, so the half-hour spent in the garage was a bit more beneficial than watching reruns of Joanie Loves Chachi. You'll need 10mm and 8mm sockets (a 5/16-inch socket can be substituted for the 8mm) and a nutdriver or a ratchet to install both the spacer and computer. That's right: only three tools. Even if you borrowed 'em and then lost 'em, your tool credit rating wouldn't be marked poorer than medium-risk. So, start the wash, turn off the tube, and get out to the garage for some time well spent.
Don-A-Vee's throttle-body spacer is a blue-anodized aluminum ring with a machined groove that holds a rubber O-ring that seals to the factory plenum. A longer stud (included) is first installed, and the spacer is sandwiched between the intake duct and the throttle body.
The spacer raises the plenum, allowing the incoming air from the filter more room to change direction as it dumps into the throttle bores. This straighter, less restrictive path for the all-important airflow helps horsepower, torque, and mileage.
The Mopar Performance Magnum computer (or, alternatively, the "Mopar Single Board Engine Controller" in Chrysler-speak) from Don-A-Vee changes ignition timing and the fuel-delivery rates for increased power from 1,600 to 5,200 rpm. Start by removing the coolant overflow bottle. There's no need to disconnect the attached hose, just set the bottle to one side to gain access to the controller on the passenger-side firewall.
A single bolt holds the 60-way electrical connector. Remove the connector and the three sheetmetal screws that attach the controller to the firewall. Tighten the new Magnum controller in place, along with the 60-way connector, and replace the coolant bottle to complete the installation.
The new controller will require the use of premium fuel (92 octane minimum) due to the advanced ignition timing it provides. Even so, some detonation (pinging) may be evident if you use your Grand for towing. Your old computer is worth about 100 bucks as a core if you return it to Chrysler, but we chose to keep ours in our box of trail supplies as a backup. Done. Oh, and don't forget that load of wash is ready to go in the dryer now.