Most of the controllers also offer a simple way to toggle between two different calibrations. For example, you could have calibration A set up with a performance orientation with aggressive upshift speeds and higher line pressures, while calibration B could be used for towing or light-duty daily driving applications. The controllers with this feature include a single wire that is grounded with a simple toggle switch to switch calibrations.
The Painless Torc and others also require saving the changes you've made to the ECM to write the new commands into the controller. Otherwise, when switched, 12 volts is turned off, the changes will not be saved, so it's best to get into the habit of saving all changes to ensure they are not lost.
HGM Compushift II ($1,136.08)
HGM Electronics created the original CompuShift electronic controller soon after the original GM 4L60E began appearing in Chevrolet cars in the early '90s. The new and improved CompuShift II controller uses a separate handheld module from the transmission control unit (TCU). The remote can be permanently mounted within reach of the driver or retained as a portable unit. The CompuShift II is advertised as "No Laptop Required," and that's the way we used it, but you can connect a PC to the box if desired. The CompuShift II can also be used in conjunction with a paddle shifter or pushbuttons mounted on the steering wheel. The harness connections are clearly marked, which makes installation easy. In lieu of a laptop, it uses a separate display module with a good-size screen and seven buttons used to navigate the program to change shift points, shift firmness, and other variables. This made the initial work on the controller very simple.
The GM system offers multiple tuning screens, and one you will certainly want to investiga
This is a laptop screen photo demonstrating the data-logging capabilities. There are liter
The CompuShift II display can also indicate vehicle speed, engine rpm, trans temperature, and gear position in large digits that are very easy to read. One aspect we liked and saw in only one other controller was an input for vehicle weight. This input takes into account the mass of the vehicle for more accurate shift parameters.
Among all the nonlaptop controllers we tested, the CompuShift II was the easiest to navigate, and its program was as close to optimal as any of the others we tested. The only thing preventing this controller from making the top of our list is the absence of a data-logging feature. But that takes nothing away from its overall performance and excellent adjustability. The feature that most impressed us (under Advanced Setup) was Shift Tables, in which each screen offered shift pressure tuning down to 1 percent changes in TPS. That's very cool. Most people probably wouldn't bother tuning that precisely, but we thought it was a great feature. The only other systems that offered that kind of precise control were the laptop-driven programs. It offers outstanding finite control from a handheld unit.
GMPP Supermatic ($1,139.33)
The GM Performance Parts (GMPP) controller is the only controller we tested that requires a laptop not only to configure the software but also to make changes to the shift values. This requires some basic computer skills, but the software is designed to be easily modified. Setup data is critical to optimized operation, so details such as tire diameter, rear gear ratio, engine cylinder count, and TPS open and closed voltages are essential inputs. The software also offers two shift schedules that can be easily swapped merely by grounding the Shift Schedule Selector wire with a toggle switch. We should also note that the box came with a basic program already in place (as do all the controllers apart from the PCS Simple Shift), so once you have accurate input data and have configured the TPS range, no further work is necessary to make the trans shift acceptably. The initial configuration was nearly ideal and only required a couple of minor part-throttle upshift changes.