Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Pre-heating the Prius Transaxle and Engine for better fuel economy

orange4boy · 03-04-2010, 05:31 PM

Well, I have been driving for a while with the transaxle preheat. It makes a noticeable difference in coasting between warmed and cool.

Testing will have to wait.

I have just finished installing a tank heater for the engine. I got a 750 watt unit for the transaxle and have swapped the 1500 watt unit to use with the engine. The nipple that came with the kit fits the rear block coolant drain just fine.

Instead of hooking into the heater core line, I plumbed into the top rad hose. Actually, I just removed the wimpy passive inline heater I had installed earlier and put in a T junction that I fabricated out of stainless. The heater return hose tap would have required me to take the inverter out completely but this way I just had to prop it up and I could leave it mostly still installed. Another down side to the heater hose is that it takes a steep upslope just as it leaves the engine which is a no-no for a tank heater set up.

I took some pictures this time so I will post those when I get a chance.

Just for testing , I also installed the factory block heater.

I also finally finished installing the last two aero wheel covers, but that's for a different thread.

03-04-2010, 05:31 PM	#47 (permalink)
orange4boy Master EcoModder Join Date: Aug 2008 Location: The Wet Coast, Kanuckistan. Posts: 1,275 The Golden Egg - '93 Toyota Previa DX 90 day: 31.91 mpg (US) Chewie - '03 Toyota Prius 90 day: 57 mpg (US) The Spaceship - '00 Honda Insight Thanks: 100 Thanked 306 Times in 178 Posts	Well, I have been driving for a while with the transaxle preheat. It makes a noticeable difference in coasting between warmed and cool. Testing will have to wait. I have just finished installing a tank heater for the engine. I got a 750 watt unit for the transaxle and have swapped the 1500 watt unit to use with the engine. The nipple that came with the kit fits the rear block coolant drain just fine. Instead of hooking into the heater core line, I plumbed into the top rad hose. Actually, I just removed the wimpy passive inline heater I had installed earlier and put in a T junction that I fabricated out of stainless. The heater return hose tap would have required me to take the inverter out completely but this way I just had to prop it up and I could leave it mostly still installed. Another down side to the heater hose is that it takes a steep upslope just as it leaves the engine which is a no-no for a tank heater set up. I took some pictures this time so I will post those when I get a chance. Just for testing , I also installed the factory block heater. I also finally finished installing the last two aero wheel covers, but that's for a different thread. __________________ Vortex generators are old tech. My new and improved vortex alternators are unstoppable. "It’s easy to explain how rockets work but explaining the aerodynamics of a wing takes a rocket scientist.