[Diesel_Dave]

I can see the advantage of this, but have since learned that the ECM is "locked" by Smarty tuning. Even removing it still leaves their version of the OEM "tune" versus the genuine factory item.

I'm not 100% certain, but I believe the stock cal is actually uploaded from the ECM. By reasoning behind this is that I know the cals are different for the manual vs. auto tranny equipted engines, and there's no option in Smarty to select which option you have. I might be wrong about that, however. Either the Smarty may be able to read the tranny option, or they may just use the auto cal on the manual trucks--it may still run okay.

I'm holding out for EFI-Live when it becomes available for the '03-'05 CTD, and the person who can write tunes for longevity/economy. Leaving the engine stock just means that emissions, not economy, engine timing advance is in place.

Calibrations (tunes) are incredibly complicated pieces of technologies, with literally thousands upon thousands of tuneable parameters, each of which can potentially have some impact on longevity, emissions, & economy--and many, many thngs are interconnected.

So the engine cooling is via the "gap" from grille to bumper cover, and bumper opening, correct? This was DIY, IIRC. No longer a winter front installed under the hood and adjusted?

Actually, I filled the "gap" too with a piece of pipe insulation. The whole thing was DIY. Here's the thread: http://ecomodder.com/forum/showthrea...wer-19810.html. I've since made the lower grille block quickly removable via two hand pins that fit through the tow hooks. I do leave all the blocks on year around (keeping a close eye on my coolant temps and listening for the fan kicking on). Due to my driving mods, mostly the EOC, I've found that I can run (unloaded) in 100+ deg F ambient temps and never have the fan kick on, therefore, I leave everything in place all the time. If I were to need to tow something or really work the truck, I'd get out and at least remove the lower block. I also removed my previously-installed radiator block (actually between the radiator and charge air cooler)--I found that kept the fan from kicking on (because some air still circulates through the radiator), but the grille blocks still provide all the aero advantage and most of the warm up advantage.

FYI, I've also found that there's an OEM "bumper filler panel" that can be used in place of the lower grille block. Part number is 55077896AC. I think it comes stock on some of the 1/2-ton trucks.

I've forgotten what brand/size are your tires. And, high pressure like this is rather a way of "pre-heating" them, in a manner of speaking. Have you tried lower pressures? (What is the door placard recommendation?) I recently weighed my CTD on all four corners (at 7,950-lbs, but within 40-lbs at all four corners interestingly), but haven't yet been to a MICHELIN dealer to check the RMA book to see what the LTX A/S needs as to load percentage versus CapriRacers advice on pressure rise after 1.5-hrs of steady state driving [no more than 3-5 psi pressure rise in that time]. Whatever my changes I'd like to keep in mind how much "over" I may be. I currently run 55-psi FF and 60-psi RR (stock, at 6,860-lbs, is 50FF & 50RR)

My tires are 265/70/17 Scorpion Pirelli STRa, E load rating (80 psi max sidewall). They're the ones that we on the truck when I bought it (~30k miles ago). Originally I did run the door sticker recommendation (can't remember what it is right now, but I think it's like 50/55). Going up to 75 psi, definitely helped the FE, however, the ride is quite a bit rougher. I've never quantified it, but I can definitely feel the increased RR at lower speeds if the pressures are lower.

I do keep a close eye on them. I keep a pressure gauge in the glove box. If ambient temps or up, or if I do carry a load I'll let some air out to get the pressure back down to 75. I also have to keep a close eye on them because I have one tire with a slow leak, that needs.

Tire wear is still somewhat of an open question. I got a tread depth gauge a while back when I rotated my tires. I was concerned that running my high pressures might cause higher wear in the centers, but the tread depths didn't show that. That tire with the slow leak did show some higher wear overall and in the center. The other 3 showed just slightly more wear (~1/32 more) on the outer side vs. the inner and middle. I suspect the unusual wear on the odd tire may be an allignment issue, or possibly a problem with the tire itself. I've been meaning to go get my allignment checked for a while, but haven't yet.

AH64ID notes that 90-minutes of on-time equates to 90% of full warm, IIRC. Is this your practice? Will the trans and differential also receive heaters?

As far as the time it takes to get to "full warm", that's going to vary greatly on operating conditions and ambient conditions. Most of my miles are on trips that are about 45-60 minutes long. I woiuld say it typically takes 20-30 minutes to get the coolant temp up to full operating temp. Oil temps will lag that, but I haven't measured them on my truck. The heaters definitely help warm up times in the morning--time to get the coolant temp to full warm is ~30-50% lower. Heaters for the tranny and differential are on my to-do list, but haven't been installed yet.

Engine oil: Amsoil Series 3000 Synthetic 5W-30 HDD
Differential oil: Amsoil Severe Gear Synthetic Extreme Pressure Gear Lube 75W-90

I believe you quantified this as being a notable change in another thread. Is the transmission slated for a "fluid upgrade?"

Yes, the 5W-30 synthetic boosted FE by about 5-10%. Differential oil wasn' really all that noticeably, but I suspect it may help more in the winter when the cold temps roll in. I suspect my % gains from the low weight oil be be higher than many others because of the warm-up issues. If someone ran for 8 hrs a day I suspect the % change might be lower because the % benefit is greater during warm up than when one reaches full-warm.

And, yes, the tranny fluid is slated for an upgrade to Castrol ATF+4. I was very preased with Amsoil, but they don't make an acceptable ATF+4 fluid. Based on my research, Castrol had the ATF+4 with the lowest viscousity, higher viscousity index, and best wear characteristics--at least among manufacturers who release their specs. I definitely want to get the tranny fluid changed before winter.

As an endnote I am pleased to see that my seat-of-the-pants recommendation to others about maintaining 27-mph or higher (yours, 26.1 mph) as an average is critical to best overall mpg.

I'm not sure that there's an "optimal" average speed for best FE. It's tough to compare average speed on two different routes/duty cycles. Average speed numbers can be low due to low highway cruising speeds (which helps FE), but may also indicate lots of idling (which is bad). Also, I started doing EOC and that's going to play games with the average speed numbers too--avg speed may be exactly the same as engine-on, but obviously the FE is different. Also, when doing EOC, slower is pretty much always better from a FE perspective, however, when doing engine-on coasting, very low speeds will hurt FE, because fuel flow is still equal to idle fuel flow, but mph is very low. Generally I try yo avoid engine-on under 10 mph.