Granahan378 wrote:
In Colorado i block the radiator on my dodge cummins 100% with cardboard to help with heat and it does help with MPG but the colder the intercooler the better your MPG will be so if you can leave the intercooler open do it. I put cardboard inbetween the liberty's radiator and electric fan but the clearance is to little and the fan blades will hit the cardboard. I didnt really see any advantage either becuase the liberty has that viscous heater which warms the coolant which does the same as blocking the rad to increase heat. Its a toss up and i didnt see the return.
That's only true in engines at operating temperature. I don't know the exact figures, but when you're dealing with a cold engine and a cold air-fuel mixture, a diesel engine is not running at peak efficiency, thus the richer fuel mixture needed to keep it running. The whole idea behind an intercooler is to keep the air temperature from getting HOT going into the engine. This is done to take advantage of the volumetric efficiency of cooler air. The more air in the chamber, the more oxygen. More oxygen in the air-fuel mixture, the hotter the fire, to a point. HOWEVER, putting super-cold air into a cold engine is a HUGE problem with diesels. The following sums it up better than I can.
"Diesel engines perform significantly better at a steady state with regards to temperature. Typically, a colder intake air charge will allow the engine to produce more power thereby providing for better operating conditions. However, it is possible for a significantly lower intake air temperature to decrease combustion temperatures, producing an adverse effect. The cold air actually affects engine operation in several ways. The first is in the combustion process itself. A diesel engine uses no external source of heat for ignition and must therefore rely on the heat of the reactants (fuel and air) to aid in the combustion process. Cold incoming air and cold fuel cause the combustion temperature to be even further reduced in the idling engine resulting in increased carbon and tar buildup. Cold air also causes fuel detonation instead of deflagration (explosion instead of burning) resulting in burnt pistons. This phenomenon, at its most severe, can cause a diesel running at low speed to fail to idle due to its inability to maintain combustion temperature." - By: Michael Kelley and Jeremy Coatsworth, Marine Design Center, US Army Corps of Engineers (COLD WEATHER PROBLEMS OF DIESEL ENGINES)
http://www.nap.usace.army.mil/mdc/newsl ... ne_wet.htmIN A NUTSHELL, warming up the air by blocking off the engine compartment partially and using warmed compartment air is a good thing for a cold engine, especially in cold environments. Your inter/aftercooler will cool it sufficiently anyway at winter temps.
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tend to hang the caliper up. I removed them from my last CRD and had much less rolling resistance. Unfortunately, I totaled it 2 days later (unrelated) before I could see any MPG improvement. 
But I will be checking the new CRD and doing the same thing.