First Morning with a Blocked Grill

OK! I've gone ahead and started the winter prep!

I opted for the "FEO Schaefer" method, with my own minor alterations. Thanks to Tony Schaefer for starting the post and Wayne, our F.E. for coming up with the idea.

The following picture shows the split pipe insulation inserted in the top grill parts (folded in half and inserted for a compression fit) and in two of the lower grill parts (No.s 2 & 3 from the top down). From my perspective, the great thing is that you really can't see it unless you're looking for it:

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Here is a close-up of the top grill pipe insulation inserts:

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And this is a look at the two inserts in the lower grill:

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I've only had this in for an afternoon, but it seemed to make a difference in that I was able to reach stealth mode so much more quickly. Of course, today the temps reached up close to 60, but still the car seemed to warm up faster!

 

Quick update: Now I've had MY first morning with a blocked grill, and I can't yet say whether there is much of a difference. While it was a bit chillier this morning, it wasn't really cold (just under 50). My commute is only 4 miles, but this morning I had to make a detour, so I went 6 miles. MPG for the trip came in at about 52.7.

It could be better, I suppose, but it does appear it is providing a quicker way to get to a higher stage. Again, it is pretty hard to tell in just a short commute. Driving further last night, I noticed very good gas mileage, but I'll have to wait until next week when I can compare MPG on a known, longer drive to earlier performances.

 

Has anyone with CAN-view ever noted inverter over-temp. prior to reaching the high range on coolant temp.? Just wondering, as my grill is blocked and I'm only using Scanguage to monitor. My coolant temp. is running 185-195F.

 

<div class='quotetop'>QUOTE(galaxee @ Nov 10 2007, 11:46 PM) [snapback]537884[/snapback]</div>

Girl power !!!!

 

we have daytime temps 45-60... morning temps lower 40's. i block top and bottom, done it for 2nd winter now. never had an issue.

not until we get temps consistantly in the upper 60's do i even THINK about removing half the upper grill

 

Thanks for the responses. I'll sleep better.

Cheers,

Geoff

 

Just wanted to say thanks for all the technical advice on this forum. I just blocked my upper grill today. It's getting cold here in central Indiana; high in the 20's today. My car is usually in my fairly warm garage at nights, unless I'm working night shift (I work 7 nights every 7 weeks). Well, tonight I'm working, and it's down to 12 deg F already. I'm assuming my MPG will not be so great on my 25 mile drive home in the morning, but I hope the partial blocking will help.

 

Bill,

Congrats on your new Prius! And, welcome to PC.

You could go ahead and block the rest of the grill, keeping in mind the warnings and concerns posted in the thread. You may also want to keep up with other threads on grill blocking. The Knowledge Base section will point you to the Summary Article on Grill Blocking, and there are some valuable follow-up postings to read there.

If you haven't already given it some due consideration, please think about adding an Engine Block Heater.

Drive safely in this weather!

 

Thanks. I will definitely be blocking the lower part later today. I'd like to keep my mileage up near or at 50 mpg. I'm looking forward to the spring thaw to see what kind of mileage I can get in warm weather.

 

If you'll come to Gurnee, you can do mine and I'll buy lunch!

Tony can even come along!

 

Inspired by this thread, I went to Home Depot and Canadian Tire today, bought some pipe insulation and blocked my grill. Since it rarely drops below 0 Celsius, I haven't done it to extremes, but I bought some dark grey 3/4" pipe insulation from Home Depot (6 feet long - $1.47 for one) and some black 1/2" pipe insulation from Canadian Tire (3 feet long, $0.42 each).

The 3/4" I cut in half lengthwise, to make the "C" shape, and then cut to the proper length for the upper grill (simply pushed in after making the "V" shape). For the top part, I cut it in half again lengthwise, to split it at the center vertical spacer - I may redo this with a notch instead of a cut... I find that the bottom part is a little more recessed, so there was no need to cut it lengthwise.

The 1/2" I used as is, wrapping around the 1st and the 3rd horizontal spacers, with black 11" zip ties at the sides and the middle. The 11" zip tie is able to go around both 1/2" tubes, as shown in the close up photo below.

The bottom-most part of the grill area is not blocked off. It got down to 2 Celsius (36F) today, and ScanGauge never registered water temp above 90 Celsius (194F), even up a hill at highway speeds.

Here's a variety of photos, one with my cellphone, some at home with the camera (cellphone was outside, so better lighting, camera has much better resolution).

This was incredibly easy to do, and completely reversible at any time. (Like when it eventually warms up...)

 

I live in northern california (bay area) so it gets cool, but not really that cold. I have noticed a bit of mileage drop as the winter came on, but recently experienced a trip that really surprised me. It was a trip from Santa Rosa to San Ramon (approx 80 miles) that I took early on New Years Day. Outside temp was about 40F. It is an all highway trip with moderate speeds around 55-65mph. I filled up in Santa Rosa and only averaged 39mpg. I was shocked. I never get less that 40mpg. Normally I get around 46-48 average per tank. (without really trying hard to maximize mpg). That trip convinced me of the importance of blocking the grill. So I completely blocked off the bottom grill and now my tank mpg averages are almost back up to what they were in the summer. Thanks Priuschat for the wonderfull tip.

 

This may be a long post. Sorry.

First off, I look around the parking lot at work, and other cars on the road, and I don't see any other Prius cars with grille blocking. I thought everyone was on PriusChat! Are they just not interested?

Anyway, I thought I'd post my experiences and lessons learned over the last tank or so.

Baseline:
I always had the A/C off and the cabin fan on low. Temperature was set at 74. Temps lately have been anywhere from 38F-50F during my normal commute time (~30min for 23 miles; 2 miles to freeway at one end and 1/2 mile from freeway at other end; mostly flat, just some minor grades). I typically drive under the speed limit in the slow lane, typically around 58-60 MPH. My tank averages for the last few have been usually around 52 MPG, which is about 54 MPG during commute, and shorter weekend trips driving the average back down.

First change, knock off the heater:
I had the heater on low based on posts that said this didn't have a material affect on mileage. I forgot that it was on really. I noticed that in the beginning and at the end of my commute where there is a bit of coasting and regenerative braking that I try to do, the engine comes on even with a high SOC. I was thoroughly frustrated when I would look at a green battery and still have the engine running. This had me thinking about the cabin heater, so I turned it off. For the next tank, my mileage went up to 54 MPG. I know this is only one tank, so not enough evidence to prove anything. Each trip for this tank was registering roughly 2 MPG more though, so it did seem consistent.

Second change:
Being motivated by the apparent increase in MPG from turning the heater off, I decided to block the upper portion of the grille today. Commute temp down was 50F and back home was 48F (46F at one point). For the drive down, 56.6 MPG avg. For the drive back, 59.2 MPG (these are cumulative). Not bad at all. While at the very end of the drive, the engine was still running (15 MPH, foot off petal, but was reading 60-70 MPG). I definitely did notice that the engine was not running as often, and I was able to deadband on coasts a lot more effectively.

Grille Blocking issue:
I used the compression method of blocking, and cut slits for the vertical fins. I thought that it would be easy to insert and remove the insulation as the temps start to vary wildly during the day in the springtime. As I was removing the insulation for the first time during fitting, I could tell I was starting to rip the insulation trying to pry it out. It looks like it won't be so easy to remove these at will. I am not sure I have a solution just yet.

 

The people in the chat room are a definite minority of all owners and grill blocking is done by only a (IMO small) percentage of members.

I leave the top blocked all year. This past week temps went up to 70F and the tank went as high as 59.3mpg on the MFD. I have yet to hear the fan. I can confirm your observations.

 

I figured as much. I was being a bit facetious. I am sure glad that I check in with the board though. There is a lot of good information.

Thanks for the confirmation. I don't think I will attempt to keep these in all year. It gets above 100F here in the summer. I don't have any monitoring either. I'd like to get a scan gauge, but I think I will wait until they get more of the codes figured out. It seems like it has been a while that the XGauge has been out, but they don't have a lot of new stuff figured out for the Prius.

I think I know how I am going to solve my issue of quick removal of the insulation. I will put bands of duct tape (should be close enough in color to what I bought) over a few sections to use as pull rings.

 

thanks for all the input

Gary here from boston... after reading many pages of threads for the past week, i decided to take myself to homedepot. i bought 2 6' lengths of pipe insulation... installed them like you all showed us how in past threads, and put my heat off for the first 5 minutes.... WOW WHAT A DIFFERANCE I went from 49mpg's to 56 mpg's in the first day.. also put 89 octane in the tank, as i filled up for the first time since i got the car last week.. $20.50.. HOW GREAT IS THAT...I cant thank you all enough for your thoughts on the subject....

 

EFUSCO--- Where did you get your insulation? Also what size did you buy.
It looks a lot better than what I did with my taxi's.
I cut small pieces for each section and have had problems losing a few of them. I think my drivers are washing the car with the high pressure hose and loosening the pieces. It would be better for me to have 1 piece like yours.

 

Earlier in this thread there was a discussion of 4X6 holes in the belly pan in front of (below the bumper) the radiators. This was being considered a backstop or failsafe to overheating if the lower grills are covered. My 2009 does not have these holes. Is this consistent with all 2009s?

If there are no holes, it seems that the risk of fully covering the grills, particularly the lower grills, would increase the risk of overheating.

How risky is this to do without SGii? Let's say SGii is present, what about the risk to the inverter, since its temp is not being monitored without CAN-View?

What temperature range would everyone be comfortable with in this setup, (with SGii)?