Fuel economy trials & tribulations

It seems I'm going to have to start over on all my figures.

I just got my truck back from Kenworth in Dearborn, and besides my unplugging the EGR throwing a whole slew of codes that mucked with the ECM & derated the engine, I also had a sensor in the exhaust that was bad, and the cherry on top, my charge air cooler was badly cracked & leaking roughly half my boost into the atmosphere.

So, one week and $3500 later , I'm starting my baseline out again. EGR plugged back in, everything as it was stock. I'll run it this way for about a month & see where I'm at. Once I get a consistent baseline, then I'll start trying a few things, one at a time.

I think that this time, I won't just unplug the EGR. Both my father & I are welders and fabricators, so I believe we'll pull of the tubular intake manifold, and just weld up where the EGR dumps into it. As far as the ECM will know, the EGR will be operating as normal, & shouldn't throw any more codes.

After that (possibly before, depends on when I manage to get up to see the old man at his shop again), I'll change the stack muffler to the straight-through Donaldson model. I can't see a downside to this one.

I'm sitting right on 509k miles right now, and I know an overhead is looming in my future, but the #### thing is running so smooth now, and I just dropped so much $$$ into the truck, that I'm going to hold off for a while on this one.

Anyone know about how much running the overhead on a post-EGR ISX is going to cost me?

Tires: My drives are all brand new virgin Goodyear 362's. Not the greatest for rolling resistance (150), but until I get a couple hundred thousand on these, they're not leaving my truck. When it comes time for as change, I'm seriously thinking Super Singles again. I liked them on my flatbed truck, and the old girl could stand to go on a diet anyways (20,020 lbs. full of fuel w/ my fat #$$ in the seat.)

My steers will be getting replaced in a few months, and I'm not sure what I'm getting. I've got some research to do here.

ECM: I see this one a while down the road. Still not sure which way to go. PDI-reprogrammed ECM (either $2150 or $2700, not quite sure how their pricing works), Bully Dog Power Pup ($2800), or the Pittsburgh Power box ($2395). Would love to hear from people who have used any of them on a post-EGR ISX.

Any thoughts, comments, or advise is welcome.

 

116 looks & Noone has a comment? I know it's a little long winded, but I figured this was better than postwhoring 5 or 6 different new threads...

 

Thank you for the feedback and info, Pappa Bear.
I'm interested in hearing more about that Bully Dog.

 

CAC just got replaced. Old one was cracked & leaking WAAAAYYY bad. Couldn't get more than about 18psi on a hard pull before, now it will hit just under 40psi at times.

Truck is running smooth, but as far as good mpgs, I just am not sure just what this truck should be capable of. I'm hoping for high 7's without a lot of work.

Depending on how much time I have to complete a load, I'll set the cruise between 55 and 62. Doing a steady 55, and with 25k in the box, from Wilkesboro NC to Indianapolis IN I averaged 7.2 (math # fillup, not by dash display numbers). Maybe I'm just expecting too much, but that just seems a touch on the low side to me.