Grille Blocks in the Summer
 

Sad day a few weeks ago. My Lexan aero grille block had to come off because the car was getting hot enough to kick in the fans doing 65 mph on the freeway. :mad:

The temperature is forecast to break 100 tomorrow afternoon. Something says the grille block is staying off to keep from overheating.

That stinks. Do you have a picture of your grill block? There may be a few tricks you can use so you don't have to take it off. Something like blocking air so it has to go through the radiator instead of around it.

http://i207.photobucket.com/albums/b...i/CIMG3267.jpg

http://i207.photobucket.com/albums/b...i/CIMG3268.jpg

My first thought: I'm in New York, and I don't think we've seen 80°F, let alone 100°F. It's 60 outside my window now, and my mom's running her furnace at night.

Ah, looks like you've got a full grille block, and no lower radiator grille opening at all. I'd trim it back, or remove half of it before I set it aside. No, that grille block is too beautiful to sit in the garage all summer.

I'm in Columbia, SC for another year. Moved from Buffalo, actually.

There are lower grille openings that aren't quite as big as the top ones. Since I have my ScanGauge to tell me coolant temperatures, I just may put on the half that covers the corner of the radiator without a hose. And pick up a radiator comb to straighten the fins of the A/C condenser mounted ahead of the radiator to improve airflow.

Daox, GM put in a rubber surround ahead of the radiator, so it's not as bad as it could be.

Your Buick, has the smallest lower grille out the three brands using our chassis. The Olds 88 and my Pontiac are bottom breathers.. I wonder if you could get the dimensions of the grille and lower grille. I'm kind of interested to see if my car has the same amount of total grille surface area as yours. I have six 2x9 openings equalling 108 Square inches. BTW, I like how it looks. Nice job on that. I hope you work something out so you can keep it.

I'd take half of the cover off. Leave the other half on. Theres no way that whole thing needs to be open.

I put on the left half of the block. Over what I think is a "dead" area of the radiator, since there are no hoses there.

Perfect test tomorrow on a road trip in 100 degree air temperatures.

The two lower openings are 16" by 3" each, for 96 square inches.

The top is roughly 24" by 6", for ~144 square inches.

Together it's roughly 240 square inches, of which I'm blocking roughly 70 square inches with the left grille block in the photos currently, or 29-33% of the total grille area.

I ought to be all right.

Hmm. My openings are 45% less than what you have. My nose is not as blunt as yours. I wonder if the aero is really that different between our cars. As you know, mechanically we are identical so I would think you would be okay. But you never know.. Might need Aerohead on this one.

I went out for a brief drive tonight, and all was well. Tomorrow will tell on my afternoon drive back through downtown, and then on a 2.5 hour drive to the coast.

My car is a lot blunter than yours in the front. I'm not sure how the Cd differs. Mine probably gives up a few hundredths to yours.

I wasnt as concerned with the cd number but rather how the different shapes affect flow. I don't understand why you are having a problem. You still have more open grille area with your blocks than I do with no blocks.. Its a bit of a puzzler. But now you have me glued to this thread LOL.

FYI: The low speed fan relay kicks in at a coolant temp of 215deg and the high speed kicks in around 225. I forget the exact temp on the high speed fans though. They run all the time with the A/C on.

With further reflection, I was blocking the area of the radiator where the upper hose connects to with the full block. So part of the blocked area did have an effect on cooling.

Also, I installed a 180* thermostat and a re-tuned computer that kicks in the fans at 186*, among other things. That had completely slipped my mind that this was the case until seeing the fan settings on your car. Seeing how my car runs at 177*, there's not too much room before the fans kick in. Much less than the same car with a 195* thermostat running at 193-200*, with the fans set at 215*.

Quick, that should make it less puzzling why I'm having issues.

Yep, Those other mods would make all the difference. Makes total sense now. I am glad I brought up the fan temps.
Thanks

Hi,

I doubt that the way the hoses attach matter very much. How is the area under the chin: is it blocked off, so it can act as a duct to the radiator -- or is it open?

If it is open, I would try enclosing (the majority) of the chin opening, so the air tha is coming in the lower intakes actually goes throughthe radiator?

It's blocked off. The only airflow the radiator gets is through the upper and lower grilles in the car.

A brief test drive through downtown revealed that the car is okay when it's moving above 20 mph.

Onto the highway test!

Do you have fan indicator lights or do you hear them turn on? Your car came with an undertray from the bumoper cover to the radiator support or did you make one? Mine has some holes on the front side of the radiatpr support that seem like they would be used for that but my bumper cover has no way to mount anything. I wonder if thats how they made up the difference in grille sizes

I keep one slot on my ScanGauge to water temp. When it spikes to 186 then quickly drops, I know the fans have kicked in.

Makes sense. LOL I'm still to cheap to buy a ScanGauge but I really should invest. Sorry I edited my last post as you were reading what I originally posted.

Umm... What's the main object of a grill block? To block the cooling airflow so the engine gets up to operating temperature faster (or in my case, period) in winter, right? So if you're not getting enough cooling in summer, you take it out.

I know a lot of us are using grille blocks to clean up the aerodynamics rather than to have the car heat up faster. I am unsure if this is 100% true for for 99LeCouch... I cant speak for him

Mine is both. It fastens outside the grille to divert air from the grille. Also has the side effect of warming up the car a lot faster in the winter.

Currently I'm running with half on to keep the engine from triggering my cooling fans.

To update: With the left half of the grille block pictured earlier in the thread in place, my engine temperatures on a 95-97 degree day at highway speeds peaked at 184*, or just under the temperatures the fans trigger at. So no worries there.

Also set a trip record at 39 miles per gallon over 147 miles. I was up to 39.5 at one point, but several complete stops in the final 7 miles kiboshed the all-time record.

I was thinking maybe you can make a half height block.. Starting from th highest point and ending up mid emblem-ish. That way you still have the 50% of the grille blocked and you are directing a smoth even flow of air over the hood. Awesome MPGs you are getting.

That's an idea that hasn't occurred to me.

Although, how does that differ from blocking one half fully for aero benefit?

I don't know how to explain it. I think you would get a more direct cleaner flow to the radiator. Air slows down as it expands. Trying to fill the right side of the radiator the air will slow a great amount taking that unnatural turn. Symmetry would be a big thing in my uneducated opinion. As far as the aero I am thinking side to side balance and you would split the air better over the hood because of the now equal pressure wave. If anyone has an opinion or a better explanation than me please chime in. I can't figure out how to describe what I mean for some reason.

Blocking the top half makes sense, because that air will be directed over the hood. If you block the bottom half, the flow will just hit the unblocked part and create even more drag. That's why I'll never understand why people do bottom blocks but leave the top grill open. They're doing it backward.

That's a way I can modify my block. I'd need another package of mounting hardware, and a spare minute or two to cut it.

I'd be interested to see what the effects are of having 3/4 of the grille blocked. The car's doing fine in the 90+ degree temperatures with half blocked so far.

What thickness is your material (lexan?) and where did you get it. I might use that for mine instead of the paint it myself plastic I am working with.

It's thin, like 3mm/ 3/32nd inch or so. And it's not true Lexan, but generic polycarbonate (IIRC).

I got it at a hobby shop. Most of the dedicated hobby shops should have a display of the various kinds of polycarbonate sheets you can get. I got some 12"x6" sheets, I think. Shaping was done with a Dremel and a heavy-duty cutoff wheel.

Okay, I sawed my grille block in half, and am going to install the upper half that will hopefully direct flow over the hood shortly. So 3/4 of the upper grille will end up blocked.

Quick, we'll see what effect this partial block has. Thanks for the idea!

Cool. I'm excited to see. I hope it works well. How did 3/4ths end up blocked?

My grille block is in 3 pieces instead of 2 now. Referring back to the pictures of the block earlier in the thread, the drivers side block was cut in half horizontally.

Attached to the car right now are the passenger side block and the upper drivers side block. That's how 3/4 of the grille is blocked.

It is 100 here in Louisiana too. Man, you have to have *some* way for air to touch the radiator.

99LeCouch -

Just want to say the execution was great. On first glance you get to keep your chrome grill. It's stealthy + a little bit "butch" from the fasteners (rivets make me think planes and steam-punky look).

CarloSW2

I'd like more details on how you made the grille block. It looks amazing!

There are 2 lower vents I haven't touched yet. And the part left open is where the top hose comes in. So airflow hits the hottest coolant first, then hits it again right before it flows out the bottom hose.

To make the block, all I did was buy 2 12"x6" sheets of polycarbonate and 12 spring-loaded fasteners, then made a template, taped it to the poly sheets, and started Dremeling. Then came test-fitting the grille and finally drilling holes for the fasteners in the grille block.

Thanks... do you have a link to the spring loaded fasteners?

They attach by drilling the polycarbonate and then threading something on the back?

I've added a second bay to my radiator air inlet to reduce the amount of time that the cooling fan kicks on in summer driving. The new opening is in-line with the original opening below the stagnation point and is on the passenger's side of the nose. It has a shutter ganged to the original shutter so I can adjust the opening as needed.

The Civic has it relativley small sized radiator offset to right am I correct?