Orange4boy's Rescue and Revival of a 2003 Prius

[orange4boy]

I seem to be making some mileage headway with the pre warming. 6.3 L/100K cold 5.3 L/100K warm. So far this is what I have done:

Grille blocks. Upper is two pieces of closed cell 3/4" pipe insulation. they fit right in woth some judicious slots cut for the little grille tabs. Lower is an internal coroplast piece screwed to the honeycomb. there is a 6" section left open for a bit of cooling. I'd like to make this adjustable.

Engine blanket. This is 3 pieces of sound deadening material with foil on the engine side and a layer of rubber between. This is great at keeping the engine warm during stops.

Gap sealing around headlights and hood. This keeps the warm air from escaping and it really helps.

Front belly pan in coroplast. Keeps drafts out.

Passive inline coolant heater. AKA lower radiator hose heater. I have this installed on my upper hose though because the Prius has it's thermostat where the lower hose enters the engine. Gives me about +20˚C coolant temperature.

To do:

Block heater

Tank/circulation engine heater for the transaxle. Since I already have the engine preheat sort of worked out I will try the circulation heater in the tranny because it hasn't been tried AFAIK. (plus it's easier to set up) As Bob and others have documented, the cold tranny eats a lot of energy. Since I already have the synthetic WS ATF in there, warming is the next step.

Oil pan heater for both the transaxle and the engine.

Better get going...

[MetroMPG]

That must have been satisfying to see those 80+ mpg segments in pulse & glide mode. Congrats.

Keep reminding yourself: in general, the purpose of winter is to give you a deeper appreciation of fine summer weather.

[orange4boy]

Transaxle pre-warming thread

That must have been satisfying to see those 80+ mpg segments in pulse & glide mode. Congrats.

It was gratifying, while it lasted. I was beginning to think there was something wrong with the Prius... or my foot.

[orange4boy]

Found a very useful graph of tire radius vs inflation pressure for anyone interested in correction factors for tires.

Like me... I just went from the stock size/pressure of 175 65 14 @42psi to 185 65 14 @ 51 psi. I found the revs per mile but not with pressure compensation.



1.5mm change in RR between 35 and 50 psi that works out to:
1737.99mm Dia @ 35
1747.41mm Dia @ 50
difference is .5% rolling diameter. meh.

Original tires Bridgestone RE92 175 65 14 xl: 902 rev/mile
New tires: Nokian WR g2 185 65 14 xl: 884 rev/mile

2% correction for tire size and .5% for pressure= 2.5% total correction.

[MetroMPG]

That's worth its own thread... I'm going to copy it over.

[KrautBurner]

I know this is an old thread,
but I wanted to be in here if there are any updates

[orange4boy]

Almost five years later...

The circulation tank heater worked well for the engine until the plug that connects the cord to the heater burnt out. I have to take it apart one day soon to try to fix the problem. I will probably solder up a permanent cord.

The transaxle heater worked OK but I just noticed that I had hooked it up wrong and most of the hot coolant was going through the radiator. D'oh! Kind of a vaudevillian outcome. The tank is furiously heating up the coolant and the rad is furiously cooling it off.

I'm going to reroute the hose to splice in at the top of the circuit, bypassing the rad. When I originally installed it, I spliced it into one of the coolant hoses near the bottom of the tranny expecting the hot coolant to flow upward into the passage. I now think that exactly the opposite was happening.

I just replaced the WS transaxle fluid with Redline D6-ATF which is fully synthetic and has better cold weather performance than WS.

I originally thought I put in T-IV when I installed the tranny but the leftover bottle I have was WS. Oddly it mentions T-IV on the label as though it IS T-IV. Anyway, 160,000 KMs and it was still red, if a bit murky.

[MetroMPG]

Delayed response: thanks for the update / status report.

It's good to hear how mods have fared over time... even if not so well.