Advice on whether or not I should block my grills

Though I don't think grill blocking would help your situation much, I don't think it would hurt. At least as far as blocking the lower grill. With those temps I wouldn't close up the upper grill all. With that distance, you will pretty much make up for the initial warm up.

I block my lower grill 100% up here in the winter. I can't say it makes a big difference in FE... though keeping road grime out of the engine compartment it does a great job.

Going slower if possible would probably work best for you. IMO of course.

p.s. what are you running your tire pressures at?

 

That's pretty low pressure. I keep mine ~42F/40R and found that it makes a bit of a difference over the recommended. I don't personally want to go any higher than that, since the city "roads" on which I drive will beat the car to death if I do, but I've heard of many here who do go higher.

I'm also interested in the grill-blocking--both for FE and for warming the interior faster--and will probably try the bottom half this winter, although I'd be more comfortable doing so with an actual temperature gauge or a scangauge. I might guess that in Las Vegas you might experience the occasional warm to hot day even in winter? Something to think about if you go that route--although from what I've heard, the gray 1/2" foam pipe insulation is perfect for the job, and I'd imagine you could remove it and replace it at will.

Good luck,
~T

 

timo27,

You can start by blocking the upper grill "smile."
I'm running with it blocked year 'round.

AS to the lower grill, right now here in our beloved Ballamer I've got
the 3 full size openings in the lower grill blocked. When daytime temps
fall below 40 degF I'll block the half-size openings at top and bottom.

I do have a SanGuage to keep an eye on coolant temps. From 3
winter's experience, once temps are down around 40 degF, there is
little chance of overheating, at least in my routine driving.

My one-way commute is ~16 miles; ~50/50 urban streets at 30 MPG
PSL and freeway at 50 MPG PSL. The blocking makes a difference of ~3
MPGs.

I go a little farther to try to keep things toasty warm under the hood
with a radiant heat block around the ICE:

http://priuschat.com/forums/gen-ii-...radiant-heat-reflector-gen-ii.html#post979632

If you're really interested in high(er) MPGs in cold weather, you need
to cut way down on use of the heater and defroster until coolant temps
get up to 157 degF. That means S4, when the car will go into a no arrows
glide on its own. Above ~110 degF, you can get the ICE to shut down
when stopped by turning off cabin heat and/or defrost. This alone can
keep you from loosing massive MPGs when you're stopped.

Hope this helps.

 

CAREFULL NOW folks!!! Timo27 drives a Gen III. I believe the inverter is in the upper grill on a Gen III and you don't want to block it.

 

D.O.

Definitely room for improvement there: the recommended pressure something like 34~35 with the 15", and most mileage cognicant drivers go higher, say at least 42 front /40 back.

I think your drive is an obstical: steep grades are generally rough on hybrids. Try slowing down a little?

 

If you really have to block, block the lower grill for the city drive, stop and remove for the hwy drive, especially the uphill part.

I personally installed a steel mesh in the lower grill for rock protection and it's doing 50% blocking. No more blocking for me.

 

As others mentioned, I think you will see improvement with higher pressures. It is all a matter of what kind of ride you can handle. I am even running my studded winters @ 38 psi.

 

Hi All,

Never block the upper grill on a Gen III completely. DP should not be blocking it at all driving at speed up mountains.

DP, I would not block the driver's (transmission) side lower grill either. The only cooling the transmission and MGs get is from air flowing over the transmission.

Being in a dry desert, at some altitude, driving up and down mountains, I think its best you get a scan gauge and learn how to use it before you do much than more than a 6 or 7 inches of grill blocking on the engine side of the lower grill in 30 F weather. Its not like you are pulse and gliding your way home across a metropolitan coastal plane, like many of on PriusChat that grill block.

Oh, get your heat on (AUTO ON 70F, or more) once your on the highway if your grill blocking.

Yep, and definately get those tires pumped up. You could get a blow-out with such low pressures at high speeds. And they will aquaplane easily too.

 

slowing down a little will always have a pos affect on gas milage

 

Is grill blocking safe? Why doesn't it damage the vehicle?

 

The point is to help retain heat, allowing the engine to work less.

100% blocking of the lower grille on a 2010 in a location where you experience real winter (well below freezing), you'll notice an efficiency benefit... without exceeding normal opertating temp.

197°F is the highest I ever see in the summer, totally block free. Most of the time it's 195°F. During the winter with lower blocked, the common temp I see while cruising is 191°F. So, you could imagine how much lower it could be without.

205°F is the acceptable temp many comment about... way higher than I've ever seen. So, I'm not worried.

 

I drive a Gen II Prius, (totally different vehicle by the same vendor that looks similar) and I find that the tire wear is more even across the thread at higher pressures. (42f/40r) Toyota biased their recommendation for comfort, not wear. (I drive in straight lines, not sure what happens in an area with curves)

While I think the Gen III Prius is the same, I am not sure anyone has worn out a set of tires yet .

 

Ah, I see! Thank you.

I live in a relatively warm area where this would probably be a bad idea.