My T-100 grill blocks over the past few years...
 

Here's quick photo history of my grill blocks... :D

Grill block using Coroplast shutters (one closed)
http://i164.photobucket.com/albums/u...Picture013.jpg

Grill block using Coroplast shutters (both closed)
http://i164.photobucket.com/albums/u...Picture007.jpg

Grill block (open) using Coroplast shutters (painted black) and tape
http://i164.photobucket.com/albums/u...Picture021.jpg

Abandoned the Coroplast shutters as the tape failed over time and I didn't have a good way of securing the shutters at the pivot point. :(

With my new T-100, I started out using pipe foam insulation. Just ziptied in place. Found out the foam shrinks over time when exposed to the sun and engine heat. Reinforced the center with PVC Schedule 40 pipe. Foam insulation breaks down over time due to the environment... :(

Grill block using foam pipe insulation (33%)
http://i164.photobucket.com/albums/u...0/IMG_7138.jpg

Grill block using foam pipe insulation (67%)
http://i164.photobucket.com/albums/u...0/IMG_7388.jpg

First iteration of the Coroplast grill block (67%) taped in place. Gorilla tape eventually started pulling off over time.
http://i677.photobucket.com/albums/v...s/IMG_8053.jpg

First iteration of the aluminum grill block (67%) taped in place. Duct tape eventually started pulling off over time.
http://i677.photobucket.com/albums/v...s/IMG_8187.jpg

Last iteration of the aluminum grill block (67%) screwed in place. I used 1" PVC PE200 pipe fer the backing support.
http://i677.photobucket.com/albums/v...s/IMG_9084.jpg
http://i677.photobucket.com/albums/v...s/IMG_9100.jpg

Since pulling the aluminum grill block since it was gitting pretty hot here, I only had the top 1" PVC tube doing grill block duties. So I went and custom cut a new tube and painted it black. Ziptied it to the grill. Seems to be a winner... :D

I didn't use Schedule 40 PVC...I used the PE200 since it's thin walled and easier to shape/work with. I ground the ends to shape by rubbing it against the cement road... ;)

33% grill block...wide view.
http://i677.photobucket.com/albums/v...s/IMG_0999.jpg

Close up view...
http://i677.photobucket.com/albums/v...s/IMG_1002.jpg

What happened to the aluminum one? seems like the best solution.

It's sitting under the aero cap fer now. It will probably git reused into something else down the road. It was too involved just to revert it to a 33% grill block when it got too hot. :(

I'll use 2 more shaped pieces of PVC pipe painted black to bring it to a 67% grill block once the temps drop back down. When the road chips git too bad on the pipe, I can touch up the looks with more flat black paint. :D

I might eventually go with a locking mechanism on the backside of the tubes to lock them down vs the zipties I have on there now. ;)

It might be possible to resurrect the shutters method using a different material like aluminum instead of the Coroplast. The Coroplast shutters flexed too much when they were in the open position. I first worked with the shutters about 4 years ago and I believe my experience in building things has grown since then. ;)

I'm thinking about adapting a spring loaded method that keeps the shutters open when the truck slows down enough and doesn't prevent the shutters from closing at speed. The pivot of the shutters behind the grill will be key to how well it responds to the air flow. :D

My original concept thread...over at GasSavers.org. :D
Adjustable grill block...fer a T-100! - GasSavers.org - Helping You Save at the Pump Hypermiling and Fuel Efficiency Forum

Went with a 50% grill block. Daytime drive to Dallas was uneventful...until I got into rush hour traffic. Ambient temps were around 108 degrees! Stop and go traffic pushed the coolant temp to 230 degrees! The stock coolant temp gauge needle was just past halfway. Didn't blow up or lose any coolant...whew!

Pulled the grill blocks after I got to Irving and didn't have any problems with temps from that point on. Drove home later that night without any grill blocks. Cruise set to 60mph and the indicated MPG was around 25mpg.

Now I'm thinking about going back to my original concept design with the shutters. Time to do some more work... :D
_________________

temps
 

In the 1970s I took an engine rebuilding course at Lancaster Community College and some of the students brought up the topic of coolant temps to our instructor (Factory-trained Volkswagen Master Mechanic) and he didn't think we needed to sweat it too much.
At the time,I believe it was Buick which was running over 20-lb cooling systems with 'normal' operating temps of 255-degree F.
He said that as long as the system was clean,the coolant wasn't over-age,system pressure was holding,and heat-exchangers clean,that there shouldn't be any alarm with temperatures well in excess of boiling point.
Engine oil can go over 350-degrees F without trouble.This would be in the normal operating range for a Beetle or Ghia.
Maybe 230-F isn't a problem.Manual might say.

I know it's an old thread but I got to say "Thank you BamZipPow!". I have been looking for ideas for a better grill block for my truck ('93 Toyota pickup), currently I have a piece of cardboard with a small center portion cut out in front of my radiator. I know it's not the best, that's why I'm looking for a better alternative (really liking the pipe insulation). I'm thinking a 70-80% block would work for me, I have a short drive to school in the morning and the thermostat only starts to move by the time I get there.

Thanks for all the pictures! They give me alot of good ideas.

Inspiration is one of the key points to innovation. Glad to be of some help. ;)

Keep in mind that you'll probably need to insert some PVC pipe inside the foam or it will shrink up on you. Also, the foam will break down due to UV exposure so yer setup will be limited to about 6 months or so depending on how much UV hits the foam. I initially used some velcro zip ties I got from Harbor Freight to secure my first grill block to the grill. Depending on yer grill, you'll have to see what will work. Keep in mind that if you need access to remove the grill block in case of overheating, you'll need to consider that if the radiator is hot and bubbly. ;)

BamZipPow,

I notice that you have also included some serious side skirts below the body of the truck.

What has been the mileage increase from this modification?

I have considered doing the same to my F150 but was not sure if it would be worth the effort. Would you do the side skirts again?

Goldenstate

A few things I noted when I went through my series of side skirts. The center point between the front and rear wheels would scrape when encountering steep driveways/ramps/speed bumps. FRP doesn't give at all and cracked when bumped. Coroplast faired the best of the materials I used as far as durability. I think that conveyer belt material might fair better than Coroplast. I'll have to try my hand at combining the conveyer belt with some FRP. My side skirts are about 4-5" lower than the belly pan.

During high cross winds, I encountered significant steering bias which I contributed to the side skirts (without any true testing). I modified the side skirts by removing about 75% from the front to just before the bed. During a test run with cross winds, the steering bias was minimal. I'll have to do another test run with full side skirts in the future to see if the steering bias is still there. So yes...I would still do the side skirts.

I wasn't able to attribute any significant mileage gains as I didn't put them on as a separate build but in a combination with multiple aerodynamic attempts at the same time (belly pan/rear skirts/dropped air dam).

I think the key will be how you will be able to support the side skirts and allow fer road contact if you do go low enough. I think the gap between the bottom of the skirts to the road is about 5"...just enough fer my toes to fit under when I'm opening the truck door. :D

About the grill blocks, your front grill looks exactly like mine on my truck. How did you fasten the pipe insulation to the grill? And for winter months and a short drive of no less than 3 miles that the engine never gets fully warm on. What % of the upper grill should I block, tempatures range around here from 20*F to 37*F in winter. But then again winter is almost over do I really need it?:confused: :turtle:

I did mine more fer seeing what aerodynamic improvements a grill block would accomplish and still provide enough air fer cooling requirements. So you will have to experiment on what yer goals will be fer yer grill block. ;)

I found that zipties or velcro ties worked the best to secure the pipe insulation to the grill once I inserted a PVC pipe inside the insulation. I tried zipties fer durability or velcro ties fer easy removal. I did experiment with a locking cam setup behind the pipe but it was too complicated fer easy removal.

I did install a digital thermometer probe under the hood just so I could keep an eye on what was happening under the hood. Obviously...the probe placement is key so I placed mine between the top of the air plenum and hood. I've seen a range from 30°F to 80°F above ambient while driving distances over 50 miles. Fer warm up times, I can't really say it's decreased the warm up times as I really haven't paid attention/experimented with the grill blocks on or off during the colder months.

The key is to establish a baseline and then see what yer mods will do. If you establish a baseline with yer mods and then take them off...you might be able to extract what the mods did. It will depend on yer data collection and how diligent you are on yer data details. ;)

Thanks, I think I'm going to go for the pipe insulation with cheap dowel-rods held on by zip ties. The tempatures around here keep fluctuating, snowing this morning then 45*F midday. Even if it doesn't help warm up my commute should be changing to more highway so I can have better aero for that. Oh and I don't have a baseline for the truck yet, I'm working on it, I finally filled up all the way this week. I'm going to start keeping track of my MPG's and working on improving it.

I've found that PVC pipe works well as it's cheap, easy to find, and easy to work with (bend/cut). ;)

Good luck with yer experimentations! :D

Looking at my truck, I think the biggest warm up mod I can do is to remove the belt driven fan. It's always running and moves alot of air. I think an E-fan is in order when warmer weather comes my way. Hopefully it'll improve city MPG too.