First Morning with a Blocked Grill

I don't have holes in the undertray between the grill and rads.
As I've posted many times, my Scangauge shows safe temps even on the highway with ambients at 20C (about 70F). There is a nice volume of air between the grills and rad so there is lots for the fans to pump through. I can't speculate on what would happen if you -sealed- the grills with tape. -I- wouldn't do that as that much sealing isn't necessary or desirable. You want -some- air leakage so the fans don't stall.
I've driven on the highway in +30C temps (80F) with both grills blocked, coolant went up to 95C. No problems with the inverter, but of course I don't know how close I was to having a <!>.
Note that the temps in the city are lower than on the highway.

I got the large ethafoam pieces at Rona, the lower one was for 1 1/2" pipe as I recall, the upper one was for 3/4" pipe. I use two zip ties to hold each of them in. High pressure washing has no effect (other than cleaning them ).

 

Hi David,

Are the presence/absence of bottom tray holes a design change, or one reflecting where the cars are destined to be driven (northern vs southern climates)?

Thanks for the follow-up. It seems consistent from most posts that using sgii shows coolant temps are ok. Perhaps temps of 60-70 f is the cutoff many use. I seem to remember that Dr. Fusco had a post regarding his inverter temps rising in a way that worried him. He uses Can-View. I can't find that post presently, but perhaps he can fill us in about what his current observations and practices are?

Pity sgii doesn't have a way to monitor inverter temps.

dd

 

I have no data on Prius with holes in the undertray between the grills and rad. and have never seen them (but I haven't been looking either). My information is that there is no difference between northern and southern Prius. Other than here, as the block heater is installed automatically (at least in Alberta Canada). I'm not sure if this is the dealer or Toyota Canada.

Perhaps we can persuade a Texas owner to look and report if they have holes in the undertray.

 

Question, why do some people not block the bottom right of the grill? Is that for the temperature sensor? If you do block this is that a bad thing?

 

I live in SC and the temps have been on the colder side all winter (under 40 in the am, low teens recently). Anyway I was wondering if it is more important to block the upper or lower grill? I plan on blocking 1 of them for the rest of this winter to see what effect it has. High temps historically are in the 60's so I don't want to close it completely off. And I will not be using cable ties so that I can pull it off whn needed.

 

I don't know that I can offer you any authoritative statement on which part to block off, but I can tell you that the upper two-thirds of the radiator is for cooling the ICE, while the lower third is for the inverter coolant.

Some folks have been much more concerned about the inverter coolant, and they have not wanted to fully block the bottom grill.

I keep the top grill covered from October to at least late May or June (we are cooler in the Chicago area than you are in South Carolina.) The bottom portion of the grill allows you to "fully" cool the inverter portion and partially cool the ICE portion. What I've done is remove half of the lower portion first (when temps are regularly above freezing), the remainder of the lower portion when temps are in the 50s or even higher, and then remove the remainer when flowers are blooming.

Hope this helps!

 

Thanks, I'll probably do the top then and see what happens.

Chicago is a tad bit colder

 

This past week is not exemplary of every winter, but I doubt you've seen many nights at -24F with highs of -6F.

Given what coastal Californians have found out with grill blocking, you'd probably be able to go a bit further than simply blocking the top grill. Still, it is better to keep within your comfort zone!

 

Well I stopped at the hardware store on my way home last night and bought some pipe insulation. I have blocked the upper grill. The temperature was 19° this am when I left the house, resetting the consumption screen before pulling out the driveway. I travel 6 miles to work but this morning I made 2 stops (1 for blood work and then to get breakfast since you can't eat before bloodwork) so this may not be a real accurate test. I averaged 25.6 this am. I will now let it ride for the rest of the tank to see if it makes any difference.

 

DAPASTAGUY, you might also put some of your insulation on the lower grill that also really takes in quite a lot of cold air.

 

I will probably block some of it tonight. I am also going to get a scanguage to monitor the temps. It looks like an interesting add on for any car, not just the prius

I blocked 1 section of the lower grill - didn't have enough materials to do more. It was very hard to do, and I will have to cut it into individual sections. I don't like the wavy look as it is now.

 

I took a trip from Sumter, SC to Charlotte, NC over the weekend with just the top grill blocked. MFD indicated 43.8. After fuel up fpr return trip (I fill at half tank all the time) it is currently showing 48.9. A big improvement.

My scanguage should be here Thursday or Friday. I looked at Can View but it looked too hard to install. After ordering the scanguage I sam the Dash HQ - I wish I had waited as it looks much neater with the visual effects.

I have searched the forums for the prius lower grill block that had the holes in it that you could plug. I know I saw it in one of these posts. I think that would be much simpler for the lower grill, and I could place and rem,ove plugs as the temperature required.

 

I'm new here and have not seen the removable plug block.
For the lower grill I cut two 3 foot sections of insulation and lined up the sections against the grill noting where notches need to be located. I cut notches out to allow the foam to slip in closer without showing the cuts. The glue on the foam seems to be holding the strips in place well enough for the few months I'll leave it on and the foam has a smooth appearance.
I'm planning on a Scanguage...What is a Dash HQ ?

 

There is a thread for it in the Mods forum - I may have the name wrong.

I did it is DashDAQ

http://priuschat.com/forums/prius-modifications/56654-dashdaq-can-we-make-new-canview.html

 

This is a sensational thread .. found it & went thru it last night.

Huge thanks to the numerous posters who led the way on this and provided volumes of feedback and advice. :rockon:

Installed the upper grill blocks this AM. Will block 1/2 the bottom later today.

I'll have another question later but the answers here have some bearing.

When fully blocked the OAT gives distorted reading. Will the OAT give distorted readings at highway speed:

1 When the lower grill is only half blocked?

2. When only the upper grill is blocked?

Edit -- did upper half of the lower grill and after it cooled took a 20 mi drive.
Seems to allow the passenger compartment to warm up quicker and better mileage by a noticeable factor. Drove by a bank temperature sign that was 4 deg cooler than the OAT indicator. 180 mi drive tomorrow in 32 to 50 deg and check temps with a good thermometer.

 

You might be thinking of hybrid effects Hybrid Effects - Grille Block I checked this out first. As I wasn't as worried about looks. I cut a piece of vinyl siding and connected it through the lower grill with toggle bolts. It's been working fine for me.
Chris

 

hi george - thank you for the picture!

i was wondering what size insulation did you get - is it 1/2" ? I bought 1" last night and i think it is too big

thank you much

-carol

 

Hi John,

I see this post is from 2006--I'm wondering what you've found out since then. I'm brand new here (though not brand new to the Prius...we had a 2002 then sold it to a friend and got a 2007). We just got ours converted to a plug-in by ReGo (they install Enginer systems) and I'm looking for ways to improve everything. Someone suggested grill blocking and I've read each thread about this. While many of the posts are from people in cold spots, none others are from Minnesota like we are. It's been really cold, and the Prius is kicking us out of EV mode or not going into it because, I think, the OEM is too cold.

What do you use for grill blocking?

Thanks,

Jeanne

 

Thanks for the info guys. I just blocked both my grills except for the bottom most slat and installed an EBH engine block heater today. With the block slightly pre-heated, I noticed a solid 10-15%+ improvement in fuel economy on a 50 mile trip at 7c(45F) vs not blocked or pre-warmed. Looking forward to seeing the average change over then next tank!

It's so effective, it's a wonder why Toyota didn't install automated vents/slats for the front grills to improve efficiency; considering they when through the trouble with the coolant storage tank/thermos for that reason.

 

I`m new here, and I live in Almere, a small city East of Amsterdam, (yep, the Netherlands) and I drive in a Toyota Auris Hybrid.
It is brand new, I got it 10-28-2010, and it has the same drive train as the Prius III.
Reading all these messages here, I decided to also have my grill blocked.
My first impression is that the ICE runs less often in city traffic, the heater is warm sooner, and I get more kilometers per liter. (no miles or gallons here).
So I like to thank you all guys, because gas is extremely expensive in Europe.
And as gas prices in the Netherlands are the highest in Europe..............
One liter costs now around € 1,55 and there are a little more than 4 liters in a gallon!
I think you guys would get a hartattack if you try to fill it up here!
Greetings to all.....

Arnold