FCA Announces Updated Pentastar V-6 for 2016 Jeep Grand Cherokee
Six Percent Greater Efficiency, Better Low-End Torque
Fiat Chrysler Automobiles (FCA) announced it would update the excellent 3.6L Pentastar V-6 for the 2016 model year, giving the engine greater efficiency and better power delivery. The company achieved this through several clever tactics, including cutting engine weight wherever possible and adding a few features. It will make its first appearance in the Grand Cherokee.
Key among those features is a redesigned Variable Valve Lift (VVL) system. As with most variable valve timing systems, VVL operates in an efficient, low-lift mode until more power is needed, when it switches to the high-lift mode. However, it now operates in a 70-degree range, up from 50, which helps prevent engine detonation and allows the Pentastar’s auto stop-start to operate more efficiently.
Cooled exhaust gas recirculation (EGR) is another trick FCA engineers used to improve efficiency and reliability. EGR has long been known to be effective at reducing emissions, but in the Pentastar, it also helps prevent knock at high engine loads and reduces parasitic pumping losses. EGR alone accounts for 0.8 percent of FCA’s claimed 6-plus percent efficiency gain.
A higher compression ratio (up from 10.2:1 to 11.3:1) and high-powered ignition coils and spark plugs promote a clean, thorough fuel burn, which not only improves efficiency but responsiveness as well. Although FCA didn’t quote exact numbers in its press release, the company claims that certain applications of the Pentastar will see torque increases of 14.9 percent between 1000 and 3000 rpm. Horsepower in the Grand Cherokee is now 295, up from 290 for the previous Pentastar V-6.
Notably, the engine will soldier on with multipoint port fuel injection (contrary to what we'd previously reported), featuring eight-hole injectors for improved atomization. That will ensure a more complete burn, which will partner with the powerful ignition system and higher compression ratio to reduce emissions.
With so many manufacturers switching to direct injection, it’s surprising to see Chrysler stick with what they got. However, the Pentastar is nevertheless an efficient, powerful engine that has no problem moving the Grand Cherokee through traffic, and its newly broader torque curve should only add to its already reasonable performance. We find ourselves agreeing with FCA North America Vice President Bob Lee when he infers that the added cost, complexity, and weight of a direct-injection system wasn’t worth it for this update.
Low-friction engine internals and extensive weight-saving measures help with both efficiency and performance, and the Pentastar V-6 now comes in at 326 pounds, 4 pounds less than it weighed for 2015. That slimming comes in spite of 13 pounds of added equipment (VVT enhancements, EGR, et al). As an added bonus, all FCA engines, except for the Dodge Viper’s 8.4L V-10, will be at least E15-capable for 2016, which will help prevent any compatibility concerns as that fuel continues to proliferate gas stations.
Source: Fiat Chrysler Automobiles