Block Heater or Grill Block?

The block heater is a small cylindrical metallic item that just slips into a recess in the block, it requires no attachment mechanism, and requires routing it's wires to a spot easily reached with an electric plug.
It's safe and won't void your warranty.
The grill block is up to your own creativity.
A quick search should show various versions.
If your mileage is in a downward spiral everyone else's is in a death dive

 

The block heater is a Toyota product; it is a specific design for the Prius. The part is relatively cheap, but the install is a bit of a bear. In your shoes I'd just get them to install it. That's the route I went. I believe the warranty would be more sound if there was a problem, after going that route. That said, a number of DIY'rs have put them in, but it is a bit tricky.

When ours was installed they just left the plug-in wire coiled and taped inside the engine bay. I ended up running it under the front trim, down the front of the radiator, and out through the lower grill opening. I'd suggest double zip-tying it (two locations, an inch or two apart) to the grill slats. Also: try to use an extension cord that pulls out easy, and secure it. It is very easy to forget to unplug, plan on it happening eventually.

Grill block is dead easy. What most people are using is styrofoam tubing, the type designed for insulating domestic hot water pipes. It has an inside diameter of about .75" and outside diameter of about 1.5", and a longitudinal slit. You just push it onto the car's grill slats with this slit. The percents for III'rd gen, and where to block, are discussed in this thread:

http://priuschat.com/forums/gen-iii...62556-2010-prius-grill-blocking-strategy.html

And I think there's some mention of second gen blocking strategy as well. I've been conservatively following Ken's guideline. I actually have a question of my own on it though:

How does grill block affect AC efficiency? We're in that in-between weather, some days cool and wet, and then sunny with climbing temps. I do think grill block is going to impact AC efficiency, not sure by how much. Anyway, I've pulled ours off for now.

You can also put short sections of that tubing on the lips of the engine bay, along the sides above the wheel wells. They get pinched by the hood when you drop it down. This helps the car warm up faster, and also holds the heat in when it's parked.

 

You are not going far enough to get your Prius to operating temps.. I don't feel either method will help you in the end? If you don't need the car for anything other that to get you 4 Kil. to work , then I would just walk that distance! Good for you and the Prius as well. Hal

 

I agree with Hal: with your very short commute the car is not going to warm up completely. Depending on your particulars maybe you can adjust: carpool, bike, walk, at least on some occasions. Your mileage is still very good though.

Our trips also include a lot of short runs. At least they are multiple short runs during the day, and sometimes longer trips, so it gets completely warmed periodically. Our in-town, we're lucky to get 4.8~4.9 (displayed).

 

His commute is 5 miles round trip. He may need a car during the day. He may not be able to walk 5 miles due to health, time, or other factors.

Grill block is really cheap (under $5) with pipe insulation. No reason not to do that if following the guidelines and watching water temp with scangauge or similar.

Should see noticeably faster warmup and measurable mpg improvement.

Get a new baseline, then consider block heater which has more cost and will usually only help on the morning commute (unless can plug in at work, too). This one unlikely to pay for itself.

 

Member 2009prius has an elaborate parameter monitoring system described here:
http://priuschat.com/forums/gen-ii-...-trip-record-fun-early-problem-detection.html

One of the first things he noted was "It looks like full grill block is not a good idea even in the middle of winter", because short-term temperatures can spike quite high at unexpected times. Maybe Toyota engineers really did know what they were doing. I'd definitely go with the block heater, which is completely safe and effective even for very short trips.

 

You are getting great mileage. The block heater is best used when the temps are around 0 C or lower. At your temperatures I doubt it would make much of a difference. I could take years before you recovered your investment in a block heater.

 

I can't tell you that. I live in seaside California and think 55 F is cold.

I don't even think you will find a block heater in stock in your country. I would go to the dealer and see if they can order one. You will then need to buy a timer since you don't want to waste energy running the heater all night. Do a search on PriusChat. Some of out members have done extensive tests and can tell you how may hours to run the heater.

 

Block heater does save fuel by shortening the S1 warm up stage, during which the engine does not produce much driving power and fuel is burned just to heat up the catalytic converter. The shorter the drive, the higher the overall percentage of saving. (I haven't factored in the cost of electricity though.) A two hour plugging in time should be good.

Another strategy to consider is to wear warm outdoor clothing and turn off the heat (otherwise the engine would keep running to warm up the coolant in order to provide warm air to the cabin). Good luck!

 

I've been using a block heater in the UK for a few months morning temp about 10`C and it lifts my first 5 minute bar from about 30MPG to about 60. After the first five minutes the improvement is much less. It warms the ICE to about 50`C in a bit over an hour, so avoiding S1! I had to buy it from the USA and use a power controller to step down the voltage to 110V.

Mike

 

Hello I would go with the block heater and for bonus a small "CAB" heater and NOT use the cars heat (use timers and less for the in cab heater)
second check with Toyota / block heater MFR as some do not power up until a certain temp is reached IE my Holden Commodore will NOT heat up until -18 BUT the CDN prius one will when ever plugged in
I know in winters (-35 is not unusual ) "winterfronts" are installed to get ANY heat but can void warranty if the car is deemed to have bean overheated
I would assume northern european countries should be able to get them for 220V Mains

 

Another thing to consider is your fuel. Cold temperatures cause the gas stations to change the formula.

Here in Canada there is a noticiable hit in everyones fuel economy when they gas companies start selling the winter blends. They don't advertise it at all. One of the easiest things for them to do is up the alcohol content. Alcohol will raise octane and lower the freezing point of the fuel but it has less energy density than gasoline.

Enquire at your gas station, you'd probably have to call customer support though because I've asked a few times and the clerks usually don't know anything about it.

I know shell premium in Canada is 0% alcohol all the time. I ran it in my saab that required premium because it returned better fuel millage. When I got the prius I just stayed loyal to shell..... Then I needed to fill up and used an Esso station. On that drive home I was showing 4.1l/100 on the prius's display, I was wowed, I usually only get 4.7-4.8. This inspired me to really try and I got it down to 3.9 after 140km. The lowest I've every got! The commute is 48km, no traffic there and some stop and go on the way back, mostly highway with 95-100km/hr speeds.

I did some research and found that in Ontario the gas companies must by law have an average of 5% alcohol in all the fuel they sell for the year. So shell that doesn't put any alcohol in the premium fuel has to have a higher amount in the regular to get that avg than a gas company that puts alcohol in all their blends.

I haven't had a chance to fill up with shell again to see if it goes back up but right now after 1100km with esso I'm avg 4.4-4.5.

So for me switching from a slightly above 5% alcohol content fuel to an around 5% alcohol content fuel resulted in a .3l/100 diff. The companies don't have to advertise how much they put in at any given time, just the maximum they can put in so it's impossible to know.

I would assume all prius are certified to run at up to 10% alcohol as some countries require all cars to handle that minimum.

If anyone has any experience in an area where they can buy 87 octane 0% alcohol fuel I'd love to hear it.

 

If the 8 mpg drop you described is really due to the change in weather and not because you started hitting the snooze and driving faster, then the ebh will noticably help with your morning mpg, most likely by somewhere in the 2-6 mpg range. I went from 36 mpg to 42 mpg on a 13 mile commute over hilly terrain. I really don't know how long your winter is or how cold it will get but if it tends to get below 0C for more than a couple months per year I recommend getting the EBH. If it doesn't ever freeze by you then it's probably not worth it. The ebh is 400 watts on 120V AC and has no feedback loop. I got a timer from amazon and set it to turn on three hours before my morning departure. There are severely diminishing returns beyond three hours of operation.

A thread here (stickied under modifications i think) was very helpful in installing my ebh, but it still took me a long time to do the first one. A second installation (on my mom's prius) went a lot faster.


Also grill blocking is a good idea below 50F, it's cheap so do it. Since you have a GenII you want to leave one slat on the bottom uncovered to ensure you don't overheat the inverter if the afternoon gets warm. For those with a GenIII they should leave a top slat uncovered (the inverter coolant loop moved up with the 2010 model). Full grill blocking should only be done when it is freezing and staying freezing all day.

 

To maximize fuel economy and make it much easier to enter S4 (in combination with the EBH in cold weather), one should consider an engine coolant temperature (ECT) spoofer. I reported on a very good one here:
http://priuschat.com/forums/gen-ii-...ect-spoofer-mcu-controlled-7.html#post1384270

 

I just had a look at the graph of Tony P Schaefer's mileage log at
http://chicagopriusgroup.com/MileageLogs/TonyPSchaefer/All.htm
and it looks to me like his 12 month average went down when he started using a engine block heater but when the heater went faulty his 12 month average started going up again? It also looks like when Tony started using the grill block his winter mileage did not fall as low as before. Maybe Tony can shed some more light on this matter from firsthand experience?

Personally I have found the grill block to make a big difference and it is much simpler to install as well as much cheaper to install and use. I have used the grill block this past winter and from April until September my average was 4.7l/100km (50.3mpg US) while my lifetime average is currently 5.3l/100km. My car is not parked in a garage and I have also found that starting and letting the engine idle on very cold mornings until it is in stage S1b helps a lot to lower the fuel consumption during the first few minutes. You can hear the engine idles very rough during stage S1a but idles much smoother when entering stage S1b. It usually takes between 30 and 60 seconds depending on how cold the night was. Now that it is getting warmer I just start and drive off.

 

Thumbs up for the radiator block, No for the block heater.

I think about it this way: 15 kwh of electricity (120 V * 400 watts * 3 hours) is 0.43 gallons of petrol. Our non-EBH'd G2 Prius spend a *lot* less than that amount in the warm-up phase. I estimate 35 mpg instead of 50 mpg for the first 5 miles, that is 3/70th = 0.043 of a gallon, or 10 times as much energy use for the warm-up distance with the EBH.

Even the Volt hog is not that bad