Volume 3 Issue 3 - Diesel Articles
Written by Joel Paynton Monday, 21 February 2011 14:05
I haven’t been this excited about a new truck model since the Duramax engine debuted in 2001. Back then, the new GM diesel powerhouse represented an exciting leap forward in torque, horsepower and reliability. GM market share leapt forward as well, from an abysmal three percent to 30 percent. Looking for improvements in the new 2011 LML Duramax vehicles, we might expect to find them in the engine and transmission. The truth is that while there are some significant improvements to the powertrain, the Duramax engine has become a very refined engine with little refinement necessary. Why am I so excited then? The chasis!
The chassis of the 2011 GM 2500 and 3500 “Heavy Duty” trucks are markedly stronger - and stiffer – than previous years. © GM Corp
Pretty well all of my complaints of the old chassis have been addressed. And GM has again, in my opinion, left Ford and Dodge behind with plain intelligent engineering. Yes, I live and breathe GM products, but there is a reason I am a Chevy man! Perhaps someone over at the competition will wake up and realize what “unsprung weight” is and get rid of the clunky floating axles that they insist on using in their four-wheel drive heavy-duty trucks.
A little explanation: unsprung weight, or more accurately, unsprung mass, is basically the mass of the suspension components that are in contact with the road. When a wheel approaches a bump in the road, it attempts to accelerate these components upward. The heavier those components are, the more resistant to this acceleration force they are. However, they have to yield to the force applied by the road surface and move upward. When the bump levels off, the acceleration force applied levels off, but now these components have momentum and their upward motion has to be stopped by the springs. The heavier the suspension components, the stiffer the spring has to be to keep the components under control. Naturally, the stiffer the springs, the more of that force is applied to the chassis and eventually to the passengers, contributing to a rougher ride.
