Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

dancam · 02-17-2017, 08:41 PM

Hi, a word of caution on changing radiators. If you go too large the velocity decreases and coolant goes from turbulent to laminar flow. You get a stationary film sticking to the walls of the rad and that insulates the coolant thats flowing. Water pump has to be sized to the system volume to keep up velocity. If the rads your looking at flow all the coolant through 1 core and then back through the second it needs to be twice the volume of the original rad to not reduce flow or increase velocity. If half the coolant goes through one core and half through the other that is less efficient than a single core and you need a larger rad but have to watch that you dont get too big.
A water to air intercooler on a truck would add too much heat to the rad, i doubt you want to do that. Anytime you add heat from an intercooler or trans cooler to a rad it becomes less efficient and needs to be larger.
For fans- look for thick fans, slim fans move substantially less air. However the shroud is almost more important than the fan. You can have the best fan there is and with no shroud or a poor one it wont cool properly. It will cool less than a moderatly good fan with a well designed shroud.
- your looking mostly at aero solutions which is good. I cant comment much on them, but here are a few more suggestions. Anytime your oil is thicker than it should be it increases your losses, doesnt matter if its synthetic or not. Find out from the manufacturer what viscosity is best for engine, transmission and diff oils and what acceptable ranges for efficiancy and protection are. Its common here for engine oil to run too cold. In my opinion optimum engine oil temp is 212-220f. Hotter it last less long but you need it to burn off water and some of your fuel dilution. Do you have actual temperature senders in your oil pan or oil gallerys? Some temp gauges are just computer extrapolations based off pressure. If your ideal viscosity is xx.x cst which oem oil reaches at say 220f and say 220f is what they designed it for and the same weight grade but different brand oil you use is a little thicker and your oil only gets to 200f then you have losses. You need to insulate, install a thermostat in your oil cooler or a hotter temp one or run thinner oil so that its the same viscosity at your 200f as oem oil is at 220.
Same goes for the trans and diffs. Get good temperature gauges if you dont have them. Find what operating viscosity should be, what temperature it takes for oem oil to match that and what temp your oil meets that. You may need insulation, thinner oil, thicker oil, heat sinks.... depending what the readings are. I find oil runs too cold most of the time. Maybe not in your case but you should find out.
This would be dependant on each truck and what weights of loads they haul and the terrain and ambient temps. But if you have a bigger truck thats typically hauling smaller loads and the engine and diff oils dont get warm enough you will see gains by changing things.

For cost measures- have you looked into bypass oil filtration, oil analysis and extended oil drain intervals? Big potential savings there.
How about tire pressure monitors? It was asked before but i didnt see you reply to it. You dont want underinflated tires but on truck and single axle trailers a tpms with 6 sensors costing $150 will pay for itself if it saves you from one blowout. They have audible alarms if a tire starts loosing air fast. I havent looked at costs for systems for rigs but it cant be cheap to have a blowout, rip a fender off, treads/fender going through windshield of car behind you, downtime of truck and driver...

02-17-2017, 08:41 PM	#103 (permalink)
dancam EcoModding Lurker Join Date: May 2016 Location: Alberta Canada Posts: 16 Thanks: 0 Thanked 10 Times in 5 Posts	Hi, a word of caution on changing radiators. If you go too large the velocity decreases and coolant goes from turbulent to laminar flow. You get a stationary film sticking to the walls of the rad and that insulates the coolant thats flowing. Water pump has to be sized to the system volume to keep up velocity. If the rads your looking at flow all the coolant through 1 core and then back through the second it needs to be twice the volume of the original rad to not reduce flow or increase velocity. If half the coolant goes through one core and half through the other that is less efficient than a single core and you need a larger rad but have to watch that you dont get too big. A water to air intercooler on a truck would add too much heat to the rad, i doubt you want to do that. Anytime you add heat from an intercooler or trans cooler to a rad it becomes less efficient and needs to be larger. For fans- look for thick fans, slim fans move substantially less air. However the shroud is almost more important than the fan. You can have the best fan there is and with no shroud or a poor one it wont cool properly. It will cool less than a moderatly good fan with a well designed shroud. - your looking mostly at aero solutions which is good. I cant comment much on them, but here are a few more suggestions. Anytime your oil is thicker than it should be it increases your losses, doesnt matter if its synthetic or not. Find out from the manufacturer what viscosity is best for engine, transmission and diff oils and what acceptable ranges for efficiancy and protection are. Its common here for engine oil to run too cold. In my opinion optimum engine oil temp is 212-220f. Hotter it last less long but you need it to burn off water and some of your fuel dilution. Do you have actual temperature senders in your oil pan or oil gallerys? Some temp gauges are just computer extrapolations based off pressure. If your ideal viscosity is xx.x cst which oem oil reaches at say 220f and say 220f is what they designed it for and the same weight grade but different brand oil you use is a little thicker and your oil only gets to 200f then you have losses. You need to insulate, install a thermostat in your oil cooler or a hotter temp one or run thinner oil so that its the same viscosity at your 200f as oem oil is at 220. Same goes for the trans and diffs. Get good temperature gauges if you dont have them. Find what operating viscosity should be, what temperature it takes for oem oil to match that and what temp your oil meets that. You may need insulation, thinner oil, thicker oil, heat sinks.... depending what the readings are. I find oil runs too cold most of the time. Maybe not in your case but you should find out. This would be dependant on each truck and what weights of loads they haul and the terrain and ambient temps. But if you have a bigger truck thats typically hauling smaller loads and the engine and diff oils dont get warm enough you will see gains by changing things. For cost measures- have you looked into bypass oil filtration, oil analysis and extended oil drain intervals? Big potential savings there. How about tire pressure monitors? It was asked before but i didnt see you reply to it. You dont want underinflated tires but on truck and single axle trailers a tpms with 6 sensors costing $150 will pay for itself if it saves you from one blowout. They have audible alarms if a tire starts loosing air fast. I havent looked at costs for systems for rigs but it cant be cheap to have a blowout, rip a fender off, treads/fender going through windshield of car behind you, downtime of truck and driver...