So as my username states I have an old DD 2 stroke (well, the motor/truck only has 18k) I'll be running it OTR hauling cargo trailers on a wedge. I'm a car mechanic by trade, and somewhat new to diesels.

My question is: would using the coolant to raise the temp of the fuel help atomization for better mpg? Are these temps too hot? I Googled diesel boiling point and it says 360F but other sources on here say 150F flash point. While I do want to process WMO, for now a heat exchanger would be more practical. I also know fuel temps can get pretty warm from the fuel returning, but not 180. I guess if this was a thing, manufacturers would have done it by now.

 

Well, after more searching, I found some articles and studies that seriously suggest this would be a bad idea. One study concluded that while you would get better atomization, you're not going to get better mpg because you're getting less HP. In turn you need more throttle to compensate.

In conclusion, I think running a fuel cooler during the summer would be beneficial. A good portion of the heated fuel returns to the take where it might not be able to cool down before returning to the engine again. Add high ambient temps and your fuel temps are going to be pretty high. Note: a good portion of this is educated guesses.

 

Good to know.

Keep that detroit screaming!