First Morning with a Blocked Grill

<div class='quotetop'>QUOTE(prius biker @ Jan 24 2007, 05:42 PM) [snapback]380318[/snapback]</div>

On mine I had to use 2 zip ties together to wrap around the upper grille and the foam.

So far I really cant say I have seen an improvement but I'm only half way through this tank and the temps are around 36F. The engine has not gone above 199F and the rest of the temps ( MG1 MG2 ect... ) are around 75F or below and on a long highway trip they are about 80-110F. Anyone know what the max temp should be for the other parts of the engine?

 

When I had the entire upper and lower grill blocked, I saw that the engine reach 170 F a lot sooner, but the inverter temps were up to 120 F and MG's were up to 140 F after 20 min on the highway. So I unblock the lowest slot on the lower grill, the radiator for the inverters is behind the lower grill by the way, and the inverter and MG temps are a lot lower, in the 60 - 90 F range. Outside temp is around 30 F. I don't know what the max temp for the inverters and MG's should be, but I would like to keep them cool.

EDIT to make it clear I did not unblock the entire lower grill.

 

thanks for the info Scott. i will unblock my lower grill as well. i think you are the first to post any data on inverter temps that i have noticed. to be honest with ya, i dont know the range of inverter temps either, but to my memory and i wish i would have tracked those temps, i dont remember the temps going all that high when i had my CANVIEW in my 04. i do remember one inverter going higher than the other, but seems to me, it was just barely into the 120's or so and this was summer temps

 

ok cool... thanks for the headups. i guess i will leave mine for now. it occasionally gets to 50, but mostly daytime highs only get to around 45. as for me...baaaadd memory

 

<div class='quotetop'>QUOTE(DaveinOlyWA @ Jan 25 2007, 11:53 AM) [snapback]380613[/snapback]</div>

I didn't unblock the entire lower grill, just the lowest slot. That kept the inverter and MG temp way down. Yes, MG1 is usually higher temp then MG2.

 

Since Dallas was "blessed" with ice and <32º temps, I have tried blocking about half of my grill intake. I used HomeDepot Foam Insulation designed for ½" copper pipe. It came already split and stuffed easily into the upper grill and into the center two horizontal grill members of the lower grill - seems about 50% of the intake area thus blocked. The 3' lengths were perfect for the job. All I did was trim the upper grill ends at an angle for a better fit. The pipe insulation was left over from protecting my outside hose bib piping, so the Prius cost was about $1.50.

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<div class='quotetop'>QUOTE(theforce @ Jan 24 2007, 05:58 PM) [snapback]380327[/snapback]</div>

Two zips ties together - duh - I should have thought of that. Thanks.

<div class='quotetop'>QUOTE(ScottY @ Jan 25 2007, 12:34 PM) [snapback]380639[/snapback]</div>

I think for now I'll just keep the lower grill part way blocked - better safe than sorry.

 

Boy - wish I had seen this a couple weeks ago.
I have pipe insulation lying in my basement and it has been pretty darn cold up here in Maine.
The car spends the night outside - no garage.
It warms up OK - even today when it was zero - but the MPG is down to 40.

Maybe a block heater as well. I have to look into those.

I also take 2 hour drives to the ski area and 5 hour drives to NYC. Should I unblock the bottom grill for those - or only if it is over 50 degrees?

 

<div class='quotetop'>QUOTE(Actual Mileage @ Jan 26 2007, 09:24 AM) [snapback]381183[/snapback]</div>

on your hiway drives if it's over 45F I'd unblock the lower grills if below that I'd unblock only the lower portion otherwise block it up and drive it. As far as the block heater goes put one in and enjoy even quicker warmups.

 

My apologies for jumping in late. I've been extremely busy the last couple months, and pretty much had to curtail my board participation.

I bought my 04 Prius in the heat of last summer, used, but with only 15k miles. In the hot southern summer, I was doing great with mileage. On highway runs, even fast one, I'd rarely dip below 45 mpg. During the week with my hard-core city commuting in New Orleans, I was occasionally popping up above 50 mpg. Of course, as the weather got cooler, the mpg started dropping. And it's far from frigid down here. Most usually for the past few months, I'd see something in the 40s in the morning, occasionally high 30s, or low 50s. Pretty much the same in the evening when I leave work. This was enough to drag my mileage down into the low 40s, with occasional alarming drops into the high 30s (a couple weeks ago, on a cold windy night, I had the car loaded to the gills and made my "standard" 200 mile highway run at 80-85 because I was in a hurry -- this produced 38 mpg).

Well, I decided to try the grille stuffing I've seen here. I picked up pipe insulator at Lowe's yesterday. They had both the coarser bubble type (a little cheaper) and a tighter bubble, more pliable version (a buck or so more for the two 6' lengths I bought. I did my initial install yesterday. I used the 1/2" size, cut the "O" in half creating a "C" profile, and used the peel-and-stick adhesive to fold the "C" down into a permanent "0" profile. It creates a perfect snug fit in the gaps.

On this morning's commute, temp at 48*, my mileage is up to 49 mpg! That would have been 42-43 tops without the foam.

I have yet to do the final cosmetic work, to get it smooth and symmetrical. Here's what it looks like now. I left a little space on the left, but may open that up more if I see any signs of trouble. In "real life," it looks better than this. The color contrast is a result of the use of flash. Although it's flat not shiny, the black matches the car's black very nicely.



Any thoughts or suggestions welcome. Note: I do not have CAN View, though I've been close to ordering. This may be my excuse. . .

 

<div class='quotetop'>QUOTE(ekpolk @ Jan 30 2007, 07:40 AM) [snapback]382789[/snapback]</div>

Absolutely. You must get CAN-View. There. I've verified your need, and you MUST trust me.

I have it, and it's probably not needed. I consider it an educational toy, but a valuable one.

This a.m., the temperature was back down to about 13 F, and the engine temperature (even with the grill blocked) didn't get above 130 F in nearly 10 minutes of driving. Of course, the car had been sitting for over an hour and the engine temperature was below 70F when I started. There's a "ton" of information available on CAN-View, and I still can't keep track of all of it. I'm thinking of aiming a camcorder at the display for my next long trip.

Dave M.

 

First of all, Doc Fusco’s 60 MPG blew me away! I wish I was able to achieve that in the winter. I’ve done it on the summer, but not when it’s cold outside.

Based on these posts I decided to block off my air entries on the front of the car. I have had my two top slits blocked for a month or so with good results. The first material I used was grey pipe insulation from Lowes. However, it got to rigid in the very cold weather (well, cold for Northern VA!) and fell out one morning driving to work. I replaced it with pipe insulation that is used for AC connections. It’s much more flexible and has worked great.

For the bottom I used the same material and pretty much followed Evan’s method with the tie wraps. I blocked off three of the five slits.

The pic of the MFD shows my MPG right after I got off of I95 at Fredericksburg yesterday. It was DAMN cold for this area all day. The MPG for that trip was much better than normal.

My goal for the rest of the week is to move that MPG up to at least 55 for the full tank of fuel!

[attachmentid=6376] [attachmentid=6377] [attachmentid=6378]


Can anyone tell me where the thermometer sensor is located?

 

OAT temp sensor is located behind the lower grill on the LH side of the car. You have to get down and look thru the grill, use a flashlight to be able to see it. Small pointed piece of plastic about the size of a pencil eraser, black in colour two wires going into it.

 

<div class='quotetop'>QUOTE(ScottY @ Jan 25 2007, 11:13 AM) [snapback]380569[/snapback]</div>

Thanks for this. I blocked my entire upper grill and the lower grill, but with the exception of the very lowest slot. I didn't do this by design, but rather because I didn't purchase enough insulating material. With temps here in low teens, I was considering doing this today or tomorrow. I don't have any way to tell about my engine/inverter etc. temps, so I'll make sure to leave this slot open now.

I can't tell if I'm saving any MPG by installing the insulation as the temps here are way lower than when I installed it. Right now my display shows around 43 MPG with temps below freezing since the last fill up, if that helps anyone judge the efficacy of the insualtion.

 

<div class='quotetop'>QUOTE(efusco @ Jan 25 2007, 08:57 AM) [snapback]380616[/snapback]</div>

I'm late into this aspect of the thread. I find it awfully difficult to track sequential posts since they are no longer in sequence.

Anyway, this weekend while heading up Snoqualmie pass headed toward home, I noted the warmer inverter temperature got up to 140 F. The grill was blocked. Perhaps the problem was that I'd inadvertently gone into B mode. I'd been wondering why I couldn't get cruise control to activate, when I finally noticed the B indicator. I'd been driving over 20 miles without being able to activiate CC, but am only assume the B mode was why I couldn't do so. However, CC did work after going back into drive. It'll probably be quite awhile until I take that trip again, but now inverter temperatures are much lower, but I'm in a lower temperature environment again. It was mid to high 40s on the west side of the pass, but dropped quickly to the mid 20s on the east side.

I'm not sure what the maximum recommended inverter temperatures are, but certainly wouldn't like to see them up above 140F again. I'm also assuming that using B mode had increased the inverter temperature.

Dave M.

 

<div class='quotetop'>QUOTE(dmckinstry @ Jan 31 2007, 09:20 AM) [snapback]383335[/snapback]</div>

Dave

I asked Norm about the temperature of the MG1 and MG2 at which I should be concerned. He replied that 180 degrees C (which I think is over 300 degrees F). Basically he said, the Toyota engineers set it up so they were very unlikely to fail.

Allan

 

<div class='quotetop'>QUOTE(Allannde @ Jan 31 2007, 12:49 PM) [snapback]383382[/snapback]</div>

Doesn't this pretty much sum up Toyota's entire design philosophy?

Seriously, I'd like to float this question, since I don't (yet) have a CAN view, but do have a stuffed grille: has anyone seen their Prius actually overheat (irrespective of whether the cooling openings are blocked)? Do you just get a warning light, or does the car have any self-protect features built in (slow downs or shutdowns, etc)? In some cars, the "idiot light" does little more than tell you, "hey fool, you just ruined your engine!" By contrast, knowing the car's behavior pattern when it is getting too hot can be a big help in arresting the process before it has gone too far. I suppose smoke and flames emanating from around the edges of the hood would be a pretty clear indicator, but has anyone observed lesser forms?

 

<div class='quotetop'>QUOTE(Allannde @ Jan 31 2007, 10:49 AM) [snapback]383382[/snapback]</div>

Wow. In that case, I don't think I need to worry about 140 F.

I probably will only rarely look at those temperatures in the future.

Dave M.

<div class='quotetop'>QUOTE(ekpolk @ Jan 31 2007, 11:00 AM) [snapback]383394[/snapback]</div>

Well I've never seen any warning indicator, but even with the blocked grill driving up a long hill (e.g. over 5 miles on a mountain pass), I've never gotten the engine temperature (or water, I don't remember which I was watching at the time, but they're pretty close together anyway) get above 195 F. OTOH, the defroster was being turned on occasionally, so that may have cooled it somewhat.

Basically, I'm not worried about overheating. But of course, when spring comes I'll watch things more closely up until the time I unblock the grill. Then the test will be climbing hills at high speed with the AC set at maximum cooling.

Dave M.

 

<div class='quotetop'>QUOTE(ekpolk @ Jan 31 2007, 02:00 PM) [snapback]383394[/snapback]</div>

Before the system overheats, the fan that blows the radiator would come on first. If that fan can not cool down then we may have an issue.

I drove to Stowe Vermont Mount from NYC, 5 hours drive with grills blocked. No problem cruising at 75-85 mph. I forgot to take my ODBII reader and figured if the ICE is making about 15-20 hp and it should not make too much heat.

Dennis