I'm back. "Soft modding" a GMC Sierra 1500 4.3 for economy.

[R.W.Dale]

I'm not going to chase absolute limits but it sure would be neat to get 25 mpg without doing a bunch of expensive mods I will never recoup in fuel savings in a truck that to all outward appearances is stock.

The truck already has a lot going for it in the way of a hard teaneau

The 3.42 gears are pretty optimal for the stock sized tires @ 55 the engine is lugging slightly at only 1500rpm but at 60-70 the revs get pretty optimal around 1700-1800 rpm. Good for mileage but damn it makes for true slug like acceleration, it's a good thing I have a more powerful truck for towing and hauling work.

I did fix the AC the other day. It'll be interesting to see how that effects mpg

[UltArc]

http://ecomodder.com/forum/showthrea...kup-21766.html

Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Profile: Diesel_Dave

[darcane]

Originally Posted by R.W.Dale

Where are you typically installing these air dams? Under the bumper or on the bottom of the radiator support?

From your description it sounds like slightly aft of the radiator

If you want an OEM look, look at the '05-'06 Tahoes. There is an air dam that clips on below the lower valance of the front bumper. I'm not sure if you need the lower valance from the Tahoe or not.

You may get some ideas from my Silverado thread (see signature)