When we fi rst drove the 2.8L LWN Duramax-powered Chevrolet Colorado midsize pickup, we loved it. It is a great little truck, and anyone who wants a truck, but doesn’t need a full-size, should seriously consider the Colorado or its General Motors corporate sibling, the GMC Canyon. Of course, the trucks are nice, but they are not perfect. That’s where the aftermarket comes in to make upgrades and improvements.
Like their larger full-size siblings, the Silverado and Sierra, the Colorado and Canyon feature a smooth-riding independent front suspension design that rides well but has a serious weak point: small tie rods that are prone to fl exing under power and bending in extreme cases off road or at the track. To beef up the tie rod issues, the team at Merchant Automotive in Zeeland, Michigan, developed a set of threaded stainless-steel tie rod sleeves that replace the factory jam nuts with machined stainless steel sleeves that will prevent the rod from bending or breaking in most situations. Since the sleeve must be loosened to properly align the truck, the MA team chose to use stainless steel and includes anti-seize compound to prevent the sleeve from rusting into position on the rod as could happen with less expensive metals.
Installing the sleeves on your truck is a straightforward operation and can be accomplished by most DIYers with basic garage tools and a couple hours of time. Basically, the factory jam nut is replaced with the sleeve by removing the tie rod end and nut then installing the sleeve and putting it all back together. We followed along with diesel service technician Dennis Delo in the Merchant Automotive service bay to document the installation procedure while the truck was in the air on a two-post lift. But you could certainly perform the installation in your garage or driveway using a floor jack and a set of jack stands. Delo completed the installation in just over an hour including our photography slowdowns, so most DIY wrenchers can likely finish the installation in around an hour or two. Don’t forget to get your truck aligned after the installation to prevent abnormal tire wear.
To address the power of the 2.8L LWN Duramax 4-cylinder engine, the crew at Merchant Automotive turned to the tuning experts at Duramax Tuner in Marengo, Illinois, for their EFILive tuning, and they use the SoCal Diesel DSP4 rotary switch to select from the four tunes on the fl y. The team at Duramax Tuner developed their calibrations for the baby Duramax engine and the 6L50 transmission to widen the torque curve while improving both the horsepower and torque available across the board. The tunes work with the stock components on the truck, including the emissions system, so it still operates as quietly and cleanly as before, but with more pep in its step. The broader torque curve allows the tunes to shift the transmission and engage lock-up at a lower rpm without bogging down the 2.8L Duramax engine, which ultimately delivers lower rpm and less fuel consumption.
The four power levels included with the tunes are Optimized Stock (+10 hp), Tow Tune (+32 hp and 30 lb-ft), Sport Economy Tune (+45 hp and 60 lb-ft) and Performance Tune (+52 hp and 80 lb-ft). Using the rotary selector knob, the driver can easily switch between tunes on the fl y without having to re-fl ash the truck to make changes. Duramax Tuner does not recommend prolonged use or towing in the Performance Tune, but it is fun to select the added grunt when needed. The truck seemed to still get great mileage, but we honestly were not easy on the throttle and did not have enough time behind the wheel to log definitive fuel mileage improvements. We suspect that drivers will pick up 1-2 mpg if they can control their right foot and maintain similar driving habits. But of course power is addictive, so it is highly possible that your mileage may vary!
The DSP4 switch uses an OBD interface cable that has a pass through allowing the OBD-II diagnostic port to still be used without requiring the switch to be unplugged from the truck. After Delo completed the tie rod sleeve installation he installed the DSP4 switch in the Colorado and finishd in less than 30 minutes even while we slowed him down with our photography. He chose to mount the switch below the dash near the center console where it would be out of the way yet easy to access to change power levels. He routed the cable along the bottom of the dash, securing it with cable clamps and secured the slack with zip-ties. After the DSP4 switch was installed, Bob Peterson from Duramax Tuner flashed their tune files into the truck using his laptop PC and an EFILive V2 interface.
During testing, the steering felt solid and secure and the power delivery was smooth with noticeably more grunt from the little 4-cylinder Duramax mill, especially in the high-power Duramax Tuner “Performance Tune” mode that delivers 52 extra horsepower and an additional 80 lb-ft of torque to the rear wheels.DW