Daox's Grey 2004 Prius

[Daox]

In preparation for winter, I splurged and bought myself a ECT spoofer (coolant temp spoofer). It fakes out the coolant temp signal so you can get through the warmup stages more quickly and get to engine off operation faster. It will also allow me to use a bit more heat in the car this winter which should be nice.

More info on the install here: http://ecomodder.com/forum/showthrea...ius-27125.html

Here are some images:

[Daox]

On the way to work this morning I definitely could tell a difference with the spoofer in place. I was able to engine off a fair amount earlier, if I had to guess I'd estimate 1/2 mile earlier than normal.. This comes in handy for me especially since my commute is only 7 miles. My warm up time eats up my mileage pretty badly. Anything to reduce warm up helps my mileage out.

[Daox]

The coolant hack is still working nicely. I definitely notice that I can engine off sooner. I'm also able to use my heat more aggressively now that its getting cold out which is really nice. This alone is worth it to me.

[Daox]

Now that its ridiculously cold out (-14F commute this morning), I'm still really liking the coolant hack. It definitely allows me to get heat sooner in the car, and it also allows me to use the heat more aggressively. When it is this cold, its really nice to be able to sit at a light with warm air blasting you in the face, and your engine isn't running. However, I will note that you can tell that the heater air doesn't get as warm. Still, warm is better than the engine on, or no warm air. So, I am quite happy.

[Cobb]

It almost sounds like there is a disconnect between getting warm air vs having warm coolant? The Insight heats the coolant and in turn gives you heat. When the engine stops, the warm fluid quits flowing. In your case getting the engine to cycle off faster thinking its warm up produces more warm air???

Originally Posted by Daox

What is a coolant spoofer you might ask? Well the Prius goes through 4 warm up stages before you can get it to turn off the engine every time like you'd like to do. Most of the stages are controlled by the coolant temperature. So, this little circuit tells the ECU that the engine is warmer than it really is to get you through the warmup process quicker. Also, if you have the heat turned on in the Prius, depending on the coolant temp, it will keep your engine running or not. So, the coolant temp spoofer basically allows for more engine off operation.

[mechman600]

Originally Posted by Cobb

It almost sounds like there is a disconnect between getting warm air vs having warm coolant? The Insight heats the coolant and in turn gives you heat. When the engine stops, the warm fluid quits flowing. In your case getting the engine to cycle off faster thinking its warm up produces more warm air???

Prius heaters are not that simple. I'm not sure what generation used what exactly, but battery pack powered heating elements and vacuum insulated coolant "thermoses" were part of it. I think Gen 3s use the pack powered A/C pump as a heat pump as well.

[Cobb]

I knew the EV Rav 4 used the ac in reverse as a heat pump, but didnt know they did that on the prius too. I knew it used a thermos to store 3/4 of the coolant for quicker start ups and it ran at start up to get the engine up to operating temp and also runs as needed to maintain temp along with a host of other factors.

I knew a few gen 2 prius owners who would complain of not being able to beat 43 mpg when winter came and they used the heater. I can see the heat effect mpg in my insight when it gets cold out on level surface I can crank it up and down temp wise without touching the blower speed and watch my mpg.

[Daox]

The 2nd gen Prius does have an electric resistance heater for the front windshield defroster and one for the front foot vent. They are operated under certain circumstances. The 2nd gen Prius also uses a coolant thermos that holds warm/hot coolant when you switch the car off and dumps it in when you turn it back on. The 3rd gen got rid of the thermos and instead uses an exhaust heat exchanger, so it can scavenge exhaust heat to warm the engine. The 3rd gen doesn't use the A/C in reverse for heating. There is no need to when there is free warm coolant to be had. There was a heat pump on the prototype PHEV Prius, but it was dropped for the production model.

There is no disconnect between having warm coolant and warm air. They're directly connected. If there isn't warm coolant there isn't warm air. By using the coolant hack it allows me to keep the engine off more often. The Prius uses an electric coolant pump so you can have heat while the engine is off. But, having the engine off doesn't warm things up as much, so things just stay cooler. Its not horrible by any means, but I thought I'd mention it because it is noticeable.

[Cobb]

So you are increasing auto stop so to speak and using what heat is available in the cooling system? The Insight you can easily run out of heat in auto stop and when at idle you can watch the temp noise dive to 130 degrees with the heater on. I tend to drive more aggressively in colder weather til the cold is worn off inside the car, so short trips just do not have good mpg.

[Daox]

Originally Posted by Cobb

So you are increasing auto stop so to speak and using what heat is available in the cooling system?

Yep, thats basically it.