All kinda new to me:) 02' F250 PS7.3L

[skyking]

Ed, your truck is a 4x4, at least 5" taller than all of our trucks. Note that we all have 2wd.
Now add your taller-than-cab topper, and you have a bigger, square wake to contend with. I think you are doing well with the equipment you are working with. Big Dave has 2wd and has lowered his truck, added an aeroshell, front skirt, etc. to get where he is at.
I've never seen a V-8 diesel truck get as good on average as an I-6 either.
I think you could reduce by 10% with a 4' long folding boattail on the current setup. Hang some cheesy tail lights on it and fold it back up when you get where you are going, or put it inside the topper.

[slowmover]

I wouldn't over-inflate.

My mpg numbers reflect pressure-vs-load; staying inside the factory numbers (and working off of a MICHELIN Load Range E tire pressure chart). Braking and handling are adversely affected by too much pressure for the load being carried. My wear rate is consistent with 120k life on the tires (or longer).

The mpg "trick" on tires is casing and tread design as you know. Highway rib (closed shoulder) being best. A website by one of the members here is full of good tire info (CapriRacer), and he chases down some of the myths around tires to some depth with our concerns. So, even if knowledgeable about tires, Barry's Tire Tech is full of good reading. There's bound to be a "best mpg" tire for a 4WD truck in Maine that spends 50% of it's miles on the highway.

I work from certified scale numbers: "empty" truck (as is; solo, with driver, full fuel and normal stuff aboard) to "loaded" (trailer hitched and weight distribution both activated and inactivated) to find the range I need to keep in mind. The FF axle tire pressure remains constant, and the RR axle tire pressure is increased 15-psi from solo to towing (at present).

A certified three-pad scale is a great place to start, IMO, for understanding changes to the truck.

Looking forward to what you have to say on tires as 4WD trucks aren't well addressed on any forum when it comes to: tire life, performance and mpg. Seems a racer ought to be the one to nail that down.

The MICHELIN A/T2 and BRIDGESTONE Duravis m700 series have good reports as to very long life and limited offroad from those participating on commercial operator forums (and, locally, oilfield hotshot); what I would use as a starting point.

. . 26ft MacGregor sailboat

Their website indicates 2,550-lbs empty. A trailer adds 600-900-lbs [?], and then add for boat load plus truck bed load. Looks like 4,000-lbs spread from boat/trailer and truck is a fair-estimate starting point (maximum). The upgraded aluminum trailer with torsion-arm suspension, surge-type disc brakes and 200-lb weight savings is all mpg-friendly as road performance, towing, is a matter of concern.

Quite a cool boat from the descriptions offered.



.

[Ed-in-Maine]

skyking- Yep I'm seeing that all diesel tucks are not the same but heck a big old 4x4 Aero would be pretty cool I think my goal will be 25 on highway at 60mph. I did order a Scanguage to get real-time data. I've been doing tank mileage calcs for decades but never had real-time. That gauge will be worth the cost just for the fun factor

slowmover- After more searching it seems there is one group who think putting the tire to max sidewall pressure is "over inflating", then a group who seems to actually be exceeding the sidewall pressure and others s let the confusion reign. But I don't think I'll exceed sidewall pressure, I figure the engineer who came up with that number knows a whole lifetimes worth more about tires than I do.

I'll probably slap a set of the LRR tires on next time around but my Kelly's with giant lugs are anything but LRR.

Using a scale is very cool. I used to set static corner weight like that, but for the truck I've only used the IR Pyrometer. When towing, and when not but I really try not to drive the truck unless it's loaded, at every leg stretch or potty break I walk around the truck and check hub temps then tire tread temps -inner-middle-outter on both truck and trailer. Takes just a minute.

My boat is the old 26S which is much more sailboat less motorboat and it weights a bit less.


Since we're visiting for the month in Annapolis MD with limited tools now my first aero mod is going to be a simple airdam.

I tried to upload a pic but it's not letting me. The current factory air dam is about 15" off the ground.
Ed

[skyking]

Ed, the boat tail could stay on with the boat in tow as well. It would be over the tongue and out of jackknife range, I believe.

[Diesel_Dave]

Originally Posted by Ed-in-Maine

skyking- Yep I'm seeing that all diesel tucks are not the same but heck a big old 4x4 Aero would be pretty cool I think my goal will be 25 on highway at 60mph. I did order a Scanguage to get real-time data. I've been doing tank mileage calcs for decades but never had real-time. That gauge will be worth the cost just for the fun factor

Just be careful about using the Scangauge with a diesel. Some diesels(including mine as I recently found out), don't report direct fuel flow over the scan port. The only "option" you have is to use mass-air-flow based fuel flow estimates which, in my opinion, are complete trash.

[Ed-in-Maine]

Diesel_Dave: thanks for the heads up. Sure will be bummed if I can't get gph. Oh well it can always go in the Matrix, but it already gets good mpg.
Ed

[Diesel_Dave]

Some do, some don't. I know a guy with an older California Cummins that it works on, however, it doesn't work on mine. It all depends.

I'm not ready to give up yet, however, I still have a few other tricks up my sleeve.

[Ed-in-Maine]

WooHoo!! The scanguage is in and seems to be working! Just a short drive and questions, questions. The MPH seems to read higher than the speedo, which reads slower than GPS I know car makers generally calibrate speedos to run slow but how is the OBDII getting a faster speed? Must be calulated and my tires are not the stock diameter.
The most important value to me GPH seems spot on. I was suprised at the over 1gph when cold at idle. This gives credance to get the car wamed up quick as possible.
Ed

[Diesel_Dave]

What PID is it using for fuel flow? 015E? Supposedly that's the direct fuel flow (not MAF based).

[Ed-in-Maine]

Diesel_Dave, my ScanGuage has a PID "all" setting and diesela setting for fuel. My cold gph was about 1.75 which dropped to 0.44 gph after about 7miles driving. I haven't done the calibration yet but these number don't seem severely off. Doing a web search it looks like the 7.3L PowerStroke uses about 1/2 gph at warm idle.

Seeing that high cold number already got me to put a radiator block on(not really tested yet) and I've started shifting to neutral at stop lights since now I SEE the savings This ScanGuage is seriously one cool toy
Ed