Chevy & GMC Vans

Air dam that is.

Interesting reading:
http://www.dieselpowermag.com/features/ ... index.html

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

Got me thinking about trying an air dam on Grumpy. What do you guys think, worth a shot?

Grumpy already has one. They've been standard on vehicles for some time.

Unless you have a long daily commute of open highway driving with no stop and go traffic, you would never see any real difference in your gas consumption. You might see a slight improvement when cruising, but the question is: how much of your drive time is 60 mph or higher?
For example, I have a 26 mile commute one way. Part of it is stop and go traffic, part of it is 65 mph+. Over a typical week, my average speed for a weeks worth of commuting is 27 mph. This was actually kind of surprising to me as I had no idea it was so low.
Besides that, why would you want to put that Frankenstein's Monster of an air dam on the front of your van?

My commute is 25 miles each way with 22 miles of it being on the interstate, plus Grumpy was bought specifically for a 3000 mile road trip.

If I can do something like that cheaply and gain mpgs it might be worth having something that ugly out front.

Well in that case you might see some positive result. I've pondered the idea of fabricating a custom air dam to replace the stock piece on my van. My thought was to make one that was similar to the stock air dam but to make it deeper. The theory bouncing around my brain was to create more negative pressure under the van to assist air flow through the radiator and engine compartment.

I've thought about having something adjustable, hydraulic or just cable controlled, as you pick up speed adjust it out or lower or both,

The same with body... higher speed, smoother roads, lower to the ground (especially with all the crack heads crawling under vehicles cutting off catalytic converters... when parked, a low rider, so unless they bring a jack, they cant get under....)

Once again, there is an air dam already installed on Grumpy.

Sure there is the stock air dam that's like what 6-8" off the ground, not very efficient. I'm thinking much closer, in the neighbor hood of 1.5-2" and made out of conveyor belt material. It will probably rub during hard breaking, but it should be flexable enough that it won't matter.

i vote for lowering the van until the stock air dam is 1-2 inches off the ground...

ihatemybike wrote:Sure there is the stock air dam that's like what 6-8" off the ground, not very efficient. I'm thinking much closer, in the neighbor hood of 1.5-2" and made out of conveyor belt material. It will probably rub during hard breaking, but it should be flexable enough that it won't matter.

I guess I just don't see the point in that. Grumpy is an AWD van right? Why put something on it the will hinder ground clearance? Then you gotta wonder how long it will be before you suck up a plastic bag that seem to be flying all over the roadways these days. Or any other debris on the road, rainwater, the list goes on.

It's just not worth the hassle in my opinion...

Moreforles wrote:I've thought about having something adjustable, hydraulic or just cable controlled, as you pick up speed adjust it out or lower or both,

The same with body... higher speed, smoother roads, lower to the ground (especially with all the crack heads crawling under vehicles cutting off catalytic converters... when parked, a low rider, so unless they bring a jack, they cant get under....)

with the exception of tweaking the torsion bars a little mine is basicly stock height and i still cant get under it without a floorjack i wouldnt worry too much about bums stealing your cat. on a side note tweakers here in oregon have actually been breaking into electric plants lately and stealing the large copper boots from the ends of the ground wires, i dont even want to know how, anything for a fast buck i guess!!

d3athm3talh3ad wrote:i vote for lowering the van until the stock air dam is 1-2 inches off the ground...

Two votes!

astronut74 wrote:I guess I just don't see the point in that. Grumpy is an AWD van right? Why put something on it the will hinder ground clearance? Then you gotta wonder how long it will be before you suck up a plastic bag that seem to be flying all over the roadways these days. Or any other debris on the road, rainwater, the list goes on.

It's just not worth the hassle in my opinion...

Yes, Grumpy is an AWD. It's all about increasing the MPGs, plan is to make something that can be removed fairly quickly for going off road or driving in snow. I don't see debris being a problem, as it doesn't effect the van's air intake (currently upper passenger side of the grill).

Over the rally's 3000 miles it could be worth the hassle.

3000 miles @ 16 mpg (Grumpy's last recorded tank MPG) = 187.5 gallons * $4.16 (last price I paid for gas) = $780

For every 1 mpg increase I can squeeze out I'll save about $45.

Ideally I'd like to hit 20 mpg or better.