First Morning with a Blocked Grill

I think I'm a believer in this thing. I noticed a significant improvement in my mileage with the upper grill blocked, and half of the lower grill. Outside temps about 50F.

To address those of us thinking about overheating: Am I right in thinking that some sort of engine warning light would appear on the panel if in fact the engine were getting too hot? It wouldn't just fry itself without warning, would it?

54.9 mpg on a 25 mile trip in 50F weather seems pretty good to me; normally, I'd get about 43-45 mpg.
B

 

<div class='quotetop'>QUOTE(Bob Allen @ Jan 9 2007, 05:36 PM) [snapback]373337[/snapback]</div>

Count me in too. I went the TonyPSchaefer route, and got pre-slitted 3/4" pipe insulation (6 feet for about $2), cut in half lengthwise to get two C's, then cut into sections to fit into the grill. I didn't want to block it up entirely, so I left some small gaps on the top, and had enough left over for two long lengths on the bottom.

Hopefully the picture will upload okay. I got the gray because that's what they had. It looked pretty good when I installed it in the dark garage at night, but in the morning it's pretty obvious it doesn't match my silver paint. Still, it's not too noticeable, took about 10 minutes to install.

Last week with temps in the 40's (about 6'C) I was struggling to reach 43 mpg (I have a 17-minute commute, the first 5 minutes really kills my mileage, even though I can P&G for several miles). This week with temps around freezing or slightly below, I'm averaging 44.6 mpg. A little better, with 15' F temperature drop. I would say at least 3 mpg improvement, not bad for $2 investment and a few minutes of my time. Blocking off the rest of the grill might help more, but I don't have CANview or the like, so I want to play it safe for now. If I was in a place with real winters, like back in northern Minnesota, then I'd take that route, but it's relatively balmy here in the Chicago area.
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if you could have a look at the belly pan just behind the air dam on the 2k6 and see if there is at least 2 holes approx 4x6" in the pan in front of the rad. If there is I don't think you can ever over heat a Prius in 40F (6C) weather. I have the wife's 2k4 completely blocked off and it will barely get to 85C in +6C weather no matter how far you drive it. Even up steep hills. The function of the two holes in the pan is to allow the Inverter section of the rad to get air flow if the temps switch turns the fans on because of an inverter overheat. I've never had the fan on, even on a 2000' 3 mile climb at 50 MPH. These are the most cold blooded cars I've ever owned.

 

with only scangauge, i can only check water temps. but have done one trip to Raymond that was mixed freeway speeds (two lane mountain road actually) but periods where speed was as low as 40 mph uphill. that was 55 miles and temps were 50-53ºF and max water temp was 209ºF.

i have both upper and lower completely blocked off. now i would feel a lot more comfortable reporting converter temps before saying that no one has anything to worry about, but i am pretty convinced that the risk is pretty minimal.

i have also did a trip to Seattle when temps were 57ºF. that was 60 miles at 60 mph on I-5. no issues there either. one of the things that kinda still amazes me is that i will see water temps drop to 195ºF on freeway downhills...

 

<div class='quotetop'>QUOTE(DaveinOlyWA @ Jan 11 2007, 08:27 AM) [snapback]374107[/snapback]</div>

Hmm.. I haven't gotten mine above 192 F, but then I haven't had any really long uphills after the car was alreaady warmed up. Generally, I don't see a lot of difference between water temperature and ICE temperature. But, then it's awkward to switch between the different screens with CAN-View fast enough to really track.

Unfortunately, I didn't have CAN-View installed the last time I came and went to/from Olympia, so didn't have a chance to see what it did on longer uphills to the Snoqualmie summit.

Dave M.

 

a lot of concern has been voiced over converter temps as well. do you see any changes on those with a blocked radiator. not sure what the temp ranges are from MG1 and 2 but i seem to remember that they were not the same

 

Nerfer,

Go ahead and block the whole thing off. I have a 45 minute in city commute, at 55F outside temp. Scangage never reads above 200F, well below the fans kicking on. Also taken a warmed up car from downtown, down the DanRyan at 55MPH (yeah I was going slow) onto I-57 off at 119th, never above 195F.

Wayne

 

<div class='quotetop'>QUOTE(Frank Hudon @ Jan 10 2007, 10:19 PM) [snapback]373963[/snapback]</div>

I don't see those holes on my belly pan (2006). But even so, it sounds from other respected voices that it'll be safe to block off more. I might do that this weekend again, spring for another $2, since next week is supposed to finally get really cold around here. We've had something like 33 straight days of above normal temperatures (often 10-15'F above normal) in the Chicago region, but that's going to change soon.

<div class='quotetop'>QUOTE(TonyPSchaefer @ Jan 10 2007, 09:22 PM) [snapback]373926[/snapback]</div>

Thanks Tony. I didn't make the last one, it would be good to schedule another.

 

<div class='quotetop'>QUOTE(nerfer @ Jan 11 2007, 01:57 PM) [snapback]374218[/snapback]</div>

My 2004 has them. They're much easier to see if you remove the top decorative plastic trim that goes between the grille and the radiator support.

 

This was the first morning with my upper and lower grills blocked. And I drove on a new route in to work this morning. I'm very excited:

The first 5 minutes were great (for a cold start up)


Mileage for the trip (according to ScanGauge)


Sorry for the picture quality. My cellphone was all I had with me.

 

what was the OAT?
Edit: that's darn nice mpg! for winter

 

where do you get the pipe insulation at?

 

great job sky!!

my morning commute...

37.4 mpg... OAT 21ºF..BRRRR!! Max Water temp....161ºF

trip was only 5.2 miles...but same trip that i can get 48-51 mpg in normal winter weather which is about 45-50ºF

 

<div class='quotetop'>QUOTE(poodlemaster @ Jan 12 2007, 05:56 PM) [snapback]374982[/snapback]</div>

Home Despot or any plumbing supply store.

 

<div class='quotetop'>QUOTE(Frank Hudon @ Jan 12 2007, 11:38 AM) [snapback]374692[/snapback]</div>

I'll answer for him, since we're both in Central VA. It was in the low 40s.

 

I am maintaining at 50.0 MPG in this winter so far....

 

just can't seem to break the 5.3 mark on account of all the slush and ice and then getting stuck in a 2 hour traffic jam because people don't know how to drive in snow and ice. If it would just get back up above freezing for a while I could probably get it down to 5.1 or 5.2 But as usual climate change is precluding that. So I guess I'm paying extra for sitting in my car trying to get to work.