[clydesdale]

I currently have the 203 stat for a few years and I thought that it did help with economy, but I have had my doubts over the years. What have you guys discovered about this mod? Also, I am getting close to the end of my stock tires. Does it help to go to the narrower 235s? Thanks

 

[Dave Whitmer]

I put the 203 degree stat on my truck and documented an 0.5 MPG improvement.

I really think these engines are pretty optimized but put inot wildly overgeared drive trains. I don't think there is much fuel economy improvements to be had from tinkering with the engine. Even with a specail MPG chip, I got only a 0.75 MPG improvement.

As for tires...in theory the 235-85s should give better MPG than the 265-75s but I've had both and can't document any difference. be sure to get E rated tires and air them up to 80 psi.

I may be doing new tires in the spring and I think I'm gonna try some rib-pattern tires like the Michelin XPS Rib.

 

[txpsdcrwchf]

yea i agree i dont see a whole lot of MPG gain I run 285-75-16 and i dont notice a drop from the 245-65 i was running. with your 4wd id stick with the larger tire. It kinda defeats the purpose of having the 4wd and wont look as good on your truck.

 

[Dave Whitmer]

Going from 245s to 285s would in fact decrease your fuel mileage.