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I've just learned about grillblocks and I was thinking about making some for my car. I was wondering if I'm supposed to block both the of the grills of the car? Also, are there any cons associated with grillblocks?

If you have made a grillblock for your Mazda3, please post some pictures.

I made a temporary grill block for one of my car club's economy run events back in August. Here's how it looked on my 2000 Protege DX.

http://img.photobucket.com/albums/v452/blownb310/DSC04807-1.jpg

The only place I left for air to get to the radiator was the small slot directly below the licence plate. I had no cooling issues at all. The gauge was in the middle where it always is. Note that it was a cool day [low 70's] and because I was hypermiling, I did not use the A/C.

Mike

Mike,

Thanks for the reply.

Did you notice significant improvements with the grillblock?

Mike,

Thanks for the reply.

Did you notice significant improvements with the grillblock?I'm confident that it helped, but I can't say how much as I did not have anything to compare it to at the time. I just got a Scan Gauge this week and might be able to glean some data from it regarding a grilll block in the near future. I will make a more permanent type grill block later this fall for the winter season.

Just watch your engine temperature. Since in many cases the air conditioner condenser is located in front of the radiator, if you blast your A/C in hot weather and have significant engine load you can overheat the engine really quickly (regardless of how fast you're traveling) dumping all that heat into the engine bay. Mine overheated while driving 55 mph with the A/C on low.

Overall, I believe it helps a lot. Some sources on this site list cooling system drag as making up as much as 30% of total aerodynamic drag. Search around for some info if you like.

Just watch your engine temperature. Since in many cases the air conditioner condenser is located in front of the radiator, if you blast your A/C....Absolutely. I would never run an A/C system with a grill block.

Agreed. Besides, it won't work very well. I've tried, just to see. :rolleyes:

I blocked off the entire grill opening on my 96 SC2. I saw no problems with heat and the coolant temp hasn't changed noticeably. It does get lots of air from underneath the front bumper because of the air dam underneath the radiator. It forces air up into the radiator/condensor. I didn't change any of that.

I MIGHT play with grill block on my 3 this fall and winter. Will do the WAI for sure.

I threw a quick grill block on my 3 in November made out of black landscape edging and zip ties (upper portion only). At what average temperature do most people take their grill blocks off?

At the point where the cooling fan starts running more than once or twice a trip. That's usually around 70 degrees for me, but I have a cool-running engine.

I threw a quick grill block on my 3 in November made out of black landscape edging and zip ties (upper portion only). At what average temperature do most people take their grill blocks off?I ran mine on my '01 Protege in August and it did not run too hot. I don't use the A/C though. In fact I think I will remove my A/C system entirely this year. Why haul the weight around needlessly?

Mike

http://img.photobucket.com/albums/v452/blownb310/DSC04807-1.jpg
An update and correction on a statement I made earlier in this thread. At our first Economy Run event last August, I added the above grill blocks to my Protege and reported that my car did not run any hotter at all. I was mistaken. This was before I owned a Scan Gauge unit to monitor actual engine temp [digitally] as opposed to believing my stock gauge. As most of us know, the O.E. gauges do not accurately display temp swings. When that needle reaches the center of it's range, the engine could be 160 degrees all the way to 215 or so! In other words, unless the car is really overheating, you'll never know it.

This past weekend I made the same grill blocks out of choroplast and reinstalled them before a trip to southern NJ. This time though, I could see what was going on from the Scan Gauge unit. My car normally runs at 195 degrees. With the grill blocks back in place I got on the Thruway and it went right to 205 and kept slowly climbing until 213 at which point I decided that was high enough and pulled over to widen the lower grill block a little. I didn't have to peel back the lower grill block much to get temps under control. I don't mind 200 to 205 or so, as a hotter engine burns the fuel more completely. So here's what I ended up with.

http://img.photobucket.com/albums/v452/blownb310/DSC05286-1.jpg

As an additional note, I now know that my electric cooling fan comes on at 206 degrees. Generally it should never have to come on when you're moving. With my grill blocks in place, mine was probably on the entire time during last August's Economy Run!

http://img.photobucket.com/albums/v452/blownb310/DSC05285-1.jpg
So how did my grill blocks do on my round trip to NJ this weekend? Well in addition to my new moon disc wheel covers and folding in both side view mirrors, I finally broke 40 mpg [40.5 actual] with my automatic equipped Protege DX. That's 7.5 mpg more than the car is rated for.

Mike