Don't Underestimate An Air Dam

[Big Dave]

Up until now i thought an air dam was just one of those things that work for racers but not the average Joe.

Normally this time of year, my tankful MPG drops to the high 23s and low 24s. It is 18 degrees and my last tankful with my air dam was in the low 25s. Only difference is the air dam.

Using conveyor belt meant I could be fearless about road debris and get really aggressive about approach the road. I set mine one inch above grade. Yes it did drag on braking but not for long. the road ground off the excess and since all dragging happened during braking or backing up, the "grinding" process did not affect my MPG.

[ajohnmeyer]

Good to hear.
I've been thinking of making a big front air dam myself. Seems like it could take care of several thorny issues in one fell swoop. (That and COZX2 has one )

[ZugyNA]

Originally Posted by Big Dave

Normally this time of year, my tankful MPG drops to the high 23s and low 24s. It is 18 degrees and my last tankful with my air dam was in the low 25s. Only difference is the air dam.

Could you say how wide (high) this air dam is? And what your ground clearance is now.

Has anyone drove along side to see if it is being bent back by the wind?

How about a pic? ...just saw your pics...now that's an air dam.........

5% gain?

Questions you might want to answer..........


Maybe you can get a gig plowing roads this winter? I used to do that with my sports car with plastic lawn edging.

[trebuchet03]

[Danronian]

Pictures? I want to see this.

[Big Dave]

Pix. I am somewhat challenged in getting pix posted but here is a link that shows the air dam and my "fastback fairing.

http://www.fokisd.org/gallery2/main.php?g2_itemId=508

Both are engineering prototypes. I am working on better-looking versions for next year.

My air dam (after some grinding by the road) has a 1.5 to 2 inch road clearance.

It does bend back a little (<1 inch) in the wind and also ripples like a clarinet reed. By putting a bend in the air dam I can stiffen it up.

When the snow flies, the air dam comes off and spends the winter in the my garage.

[Danronian]

That thing is a monster.

Just the height of that bumper is almost as high as my civic...

Nice results!

[brucepick]

Nice work!
I like the cargo cover too!

For pics in these posts, copy the pic's link address and then click the mountain scenery logo in the message building window. That gives you a place to paste the pic's address. You can post multiple pics in one post.


Big Dave's Snowplow Air Dam

[itjstagame]

25MPG from a fullsize! What'd you make the airdam out of? I have lots of things I've been planning on trying and can never get to but now I really need to increase MPG a bit.

Did you consider making it taller and blocking the grill a bit? I wouldn't mind increasing how quickly my engine heats up.

Also is that last picture the inside of the 'fast back'? I had thought a pop snap tonneau type cover/fast back like that would help a lot, I was planning on adding snaps along the cab too and not leaving any gap. Did you try making this without a frame? That is can you just stretch the material tight and get close enough? Any shrinking/stretching/billowing I would think would line up with whatever the air is doing anyway.

How much of an improvement did you see with the fast back? I was hoping for quite a bit, the reason mine got put on hold is because I didn't want to spend $100 for the tool that puts the snaps/rivets together and don't know anyone I can borrow it from. Plus my material is more like boat canvas, I wouldn't want it for winter use anyway.

[Sludgy]

Originally Posted by itjstagame

25MPG from a fullsize! What'd you make the airdam out of? I have lots of things I've been planning on trying and can never get to but now I really need to increase MPG a bit.

Did you consider making it taller and blocking the grill a bit? I wouldn't mind increasing how quickly my engine heats up.

Also is that last picture the inside of the 'fast back'? I had thought a pop snap tonneau type cover/fast back like that would help a lot, I was planning on adding snaps along the cab too and not leaving any gap. Did you try making this without a frame? That is can you just stretch the material tight and get close enough? Any shrinking/stretching/billowing I would think would line up with whatever the air is doing anyway.

How much of an improvement did you see with the fast back? I was hoping for quite a bit, the reason mine got put on hold is because I didn't want to spend $100 for the tool that puts the snaps/rivets together and don't know anyone I can borrow it from. Plus my material is more like boat canvas, I wouldn't want it for winter use anyway.

You can buy caps for trucks and tonneau covers for trucks, but you cannot buy a fastback cap. The closest thing I've found is a cap called "Top Gun" made by a company called "Snugtop" It has a rounded rear, and should improve mileage quite a bit. But they don't make one tht fits my Ford Super Duty!

It really torques me off that you can't buy aero parts for pickup trucks. I'd buy reasonably priced pre-engineered fatback tops, air dams, wheel spats, mirrors and the like. But the just don't make them. It's a conspiracy, I tell you.