I am new to the group but have owned a 2005 Chevy Express 3500 6 liter for 100,000 miles. I haul race cars in a 20 foot trailer from east coast to the west coast.

The Chevy Van has been a rock, no breakdowns! We maintain it religously, with Amsoil 5w-30 Synthetic High-Mileage Engine oil, oil charges every 5,000, full rotation of the tires every 5,000, tune ups, braker service, trans service (changing of fulids).

The one area we would like improvment is in fuel economy. Hauling a trailer, with a loaded van, running about 65 MPH, easy throttel, easy braking is 9.5 MPG. I would love to get it to 12-13 MPG.

Has anyone tried
1.) The plug-in ODE-II controllers that claim to help fuel economy or performance
2.) The replacement high-flow catalytic converters
3.) upgrading to a 2010 and later 6 speed transmission
4.) Changing the crown wheel and pinion to a lower ratio

Thank you in advance,
Jack

 

I w ould be pretty happy with 9.5!

 

It's hard to change the fact that you are pushing a barn through the air. I've seen a post somewhere about swapping on a taller air dam and seeing a meaningful change in mileage from that. It was either a Tahoe or 'Burb of similar year to yours if I remember right. The van 2500 and 3500 air dam used to only cover about half the front bumper width, so just putting in a full width van air dam might help too.

 

Found it...
https://www.gmtruckclub.com/threads/...r-dam.1478384/

 

We installed the air dam under the stock Express 3500 front bumper with the recommended part about with great success. Not towing a trailer but driving expressways at 63-65 mph, we averaged better than 15 MPG.

This up grade pays back your investment quickly!

thank you forum!

Jack

 

Nice! I might have to try it myself. Where did you buy it and how much was it?

 

We purchased the air dam using the GM part number on eBay.
Jack

 

Amazon has the spoiler on sale right now. Cheaper than anywhere I could find and with free shipping.

I received it last week but haven't installed it yet. It's obviously not the GM part but it looks really good.

 

Thanks for the advice!