Adding a sandwich type oil warmer to the Mirage

[Daox]

I am thinking about adding a VW TDI sandwich type oil warmer/cooler to my 2014 Mitsubishi Mirage.



Of course, the first question to ask is why? Short and simple, for increasing fuel economy. We know warmer oil is thinner. Thinner oil is easier to pump, and it reduces friction more when thicker oil. This is why OEMs continue to design engines for thinner and thinner oils over the years. There is efficiency to be had by thinning out the oil. Add that to the fact that all the Honda high fuel economy vehicles had these (Civic VX, HX, Insight), and it lends some credibility that there is a benefit to be had. There is actually a pretty lengthy thread on EcoModder that talks about the benefits of this mod.

Great, so warm oil is good. Why do we need a heater? Oil flows through the engine block and should warm up with the rest of things, right? Wrong. Oil temperature warm up lags considerably behind engine coolant temperatures during warm up. Below shows some testing from a BMW forum user. I'm not sure why he was testing this, but it is useful to me. You can see that the engine coolant temperature is maxed out within the first 10 minutes (600 seconds) of driving. However, the oil temperature takes a full 25 minutes to max out. By the time 25 minutes have passed, my car is parked in the parking lot at work.





Testing from a member of EcoModder also showed that oil pressure didn't drop until well after the engine was fully up to temperature. The whole time your oil pressure is high, your pump is doing more work, and that consumes more fuel. This also means your piston rings are scraping thicker oil off the walls of the cylinders, your crankshaft and camshafts are spinning through thicker oil, and more.

The final reason to try this mod is because I already have a VW sandwich style heater kicking around. A few years ago, I swapped out the engine in my sister's Jetta TDI with one that didn't have a broken timing belt. I kept a bunch of parts off the old engine, and parted out the rest of it. Amongst those parts was the sandwich style oil warmer/cooler that all TDIs of that era (ALH engine) have. So, I am thinking about slapping it on the 'ol Mirage.