roadhard1960
Veteran Member
Backpressure is not variable. Here is an article that sort of explains the basics of exhaust flow. http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/
The thing is that the intercooler is doing good in low temperature but when in idle or light load it's cooling the air too much. Naturally it's no big money to save to retrofit a liquid to air intercooler just to gain some winter mpg. But if you combine it with other mods or want to increase your intercooling capacity any way the liquid to air intercooler could be worth looking in to. Especially if you often drive in cold climate.I know this is an old thread, but anyway.... Regarding switching to an air-water intercooler with the goal of not intercooling in the winter, wouldn't it be a lot easier to just bypass the existing intercooler in the winter?
You know, make it so the air comes out of the turbo and goes to the intake directly? You'd need a charge pressure sensor in the pipe, because it is normally in the intercooler.
Anyway, that would be a simple way to test out whether not having an intercooler does any good.
In Sweden almost all cars have coolant or block preheater installed. Up in the north when temperatures fall to -30 deg. C a Diesel engine have a big difficulty starting with out.IMO the best thing for winter MPG's is to put a coolant heater on the car. Put it on a timer so that the heater runs for about 1hr prior to your trip.
The first 5-10 min of running a car that is not warmed up kills the most MPG for your trip. The MPG is so bad in the first few min that even after the car gets warmed up its difficult to offset those first few min unless you have trip time that is +45 min.
I have a 20 min drive to work. In the summer I average 45 mpg on that trip. In the winter with a coolant heater I average 43 mpg. If I forget to plug the heater in, I would be lucky to get 36 mpg.
This is not the case on older TDIs with no DPF. VW did that to help get the DPF up to temp quicker.IMO the best thing for winter MPG's is to put a coolant heater on the car. Put it on a timer so that the heater runs for about 1hr prior to your trip.
The first 5-10 min of running a car that is not warmed up kills the most MPG for your trip. The MPG is so bad in the first few min that even after the car gets warmed up its difficult to offset those first few min unless you have trip time that is +45 min.
I have a 20 min drive to work. In the summer I average 45 mpg on that trip. In the winter with a coolant heater I average 43 mpg. If I forget to plug the heater in, I would be lucky to get 36 mpg.