I was wondering what everyone is seeing for Fuel mileage/ what accompanying mods have attributed to the increase/decrease?

Heres mine:

05 F350 no mods, and I see on average around 15.5mpg.

 

Guess no ones drives a power stroke.....

 

I drive a powerstroke. Truck came with a K&N. After the egr cracked, I completely removed and bypassed the EGR cooler and replaced head gaskets and installed head studs for future mods. I also cleaned the VGT turbo vanes and ring, removed the muffler and cat. I am running a towing program which adds 40hp and I forget how much torque. Empty I am getting 15-17 depending on my foot. Fully loaded with my boat which is somewhere in the 9,000lb range(gotta get it weighed) I am getting 12-13.

 

I have a 96 f250 powerstroke superchips programmer on h.p. mode, 400 hp injectors, full exhaust, cold air intake,lifted 6" on 36" tires. I was getting 21 on the road with my foot out of it. However, I have had a lot of issues with my front end. I just bought another 96 f350 for the dana 60 solid axle swap and 3.55 gears hoping my mileage will go up. I also plan to do a 2" body lift so I can install a bigger turbo and fit the 5" downpipe and also plan to add a fmic. Even with the cold weather I had the truck up to around 110 mph and I was seeing an egt reading under 900* The bigger injectors are not even being pushed yet. I also plan to do a hi pressure oil pump to knock down some of the rattle and give the big injectors a kick in the pants, Also I plan to add the TS performance potentiometer tuner again to help push it a liittle more. My mileage has dropped down to around 16 I would say but it is winter time and with all the additives and crap in the fuel it usually happens not to mention the p.o.s. front end but it runs like a striped ass ape.
brandon

 

Forgot to add that I am driving an 03 F-350 crewcab DRW LWB 4x4 with the 6.0 and auto trans.

 

I get 14-15.5 MPG in town and 17-20 MPG on the freeway unloaded in my FX4 07 6.0L with a catback 4" and a SCT flash tuner on the 60 hp tow mode. Everything else is stock. I want to get the Accufab intake elbow and the S&B airfilter kit. I would expect to get another 1-2 mpg better on the highway with that.

 

How much of an increase was the exhaust/ tuner?

 

The best I ever got out of my PSD was 22. That was with just a cold air, straight pipe, and a superchips programmer. That was rolling on 35's with full replacement bumpers, 3.73 gears, 6spd 4x4, and the wind going with me. BTW going to cummins now

 

I get 13-15 hot rodding around town and about 19 on the highway with a hypertech programmer on tow perf mode and i have 35 inch tires.

my truck is a 01 f350 drw CC LWB 7.3 L

 

Driving how fast on the freeway? Also are you using the trucks computer for those figures or calculating it on your own? And did you drive it stone stock for long enough to get mpg comparisons for before/after mods?

I get 15-17mpg(closer to 15 lately due to speeding more) with mixed driving but that mix is more towards freeway than city. I tend to drive 75-85mph on the freeway. When I kept it closer to 70-75mph I would routinely get 20mpg. The one time I did 55mpg through 50% or so of my tank, I got like 24mpg. I always calculate my mileage by hand since I like a computer in the truck to tell me. I always fill my truck up to the point where I can see the diesel towards the top of the fill neck and it is not going down any, meaning I spend a few minutes getting that last 4-5 gallons of fuel into the truck after the pump first automatically shots off. Truck is a stone stock(unless you consider Amsoil motor oil a mod) 2003 6.0L with 3.73 gears and an automatic. I have always wondered if doing mods actually helped mpg, the ads claim that they do but not met many people who actually saw an increase in economy and always say things like "anything they gained in economy, they lost to their right foot"

 

Where do you get 400 HP injectors?

 

I just took my '01 F350 CC 4X4 LWB AUTO to Florida last weekend and got 22mpg with the cruise set at 76 the whole way . I run the Diablo Predator on the 60hp setting with a K&N filter and 5" exhaust . The truck also just turned 101000 miles .

 

My 06 FX4 CC gets 17mpg around home and 19mpg on the hwy. I have gotten 20mpg before. It has MBRP 4" exhaust(no cat), SCT tuner with custom tunes, and Air Raid filter. Towing my 24' enclosed trailer it'll get 11-12 depending on how fast I need to get there!

 

Been averaging 16.5mpg in my '01 7.3 2WD PSD. Mix of city/highway. Going up/down the hill (Sierra Nevada mountains) I get Terrible milage on the way up, but coming down more than averages it out....I get 17.5mpg.

Mods:
5" exhaust
Edge tuner on level 5
SCT handheld (no extra power, just shift modifications)
K&N filter
Stock size tires (32")
3.73's

I'll shortly be swapping in a set of 3.08's with programming modifications (for proper gear transitions). I currently drive ~70mph on the local highways which nets 2100RPM. Driving at 55 seems to be the 'sweet spot' at 1650RPM. The gear swap will drop RPM's 400 in top gear. This *should* net a gain in fuel economy. We shall see....

 

How much is it going to cost to go to a 3.08 gear?

 

Depends on how you do it.

The 10.5" rear end in my truck uses the Long spline pinion gear. Ford (Motive Gear) only made these as low as 3.55's in mass production....however, there are a few long spline 3.08's floating around. If you can find a set of these, the swap is just as cheap as a set of 3.55's & an easy install.

The Short spline 3.08's are more readily available (although still hard to find). You can do one of 2 things to make these work...
1. buy a Yoke from Ford ($85) that fits the short spline pinion. The problem is the yoke only works with 1350 U-joints. My SuperDuty has 1410's. The local driveshaft shop will cut/modify my driveshaft for $125 to use the 1350 & fit the new Yoke. Although the 1350's aren't as beefy as the 1410's....I don't really think I'll have a problem.....I'm not doing tractor pulls or anything like that.

2. Not 100% sure this will work, but I was told by DTS that all that would be required to use the stock 1410 yoke is to put it on a lathe & cut it down 1/4" where the pinion bolt flange is. The local rear-end shop I'll be having do the swap can do this....& if it is possible, this is the route I'll be going. If not, I have the new 1350 Ford Yoke just in case.

Along with the swap I'll be getting new bearings & having the trac-loc beefed up with extra clutches.

BTW, 3.08 (short) gears retail anywhere from $225 to $749 depending on brand!

I figure if I gain 2mpg it'll take 2 years to pay off on the swap at the current cost of diesel. But.....I'll have this truck longer than that & I'll feel much better going an extra 50+miles between fillups.

 

Well apparently I got lied to or i was mislead. I was told 400 hp injectors but maybe they meant my injectors would support 400hp.??? I don't know I can't get a straight answer from them. A local diesel performance shop sold them to me and said they would support anything I wanted to do to the truck. This shop builds injector pumps and injectors and has an on site flow bench... I don't have any idea wtf I got. I have often contemplated recently, pulling them out the truck to get a part number and find out what they will support. I vaguely remember him saying they were RC? brand injectors back when I bought them. Which was way before I even cared about having a fast diesel. I just wanted a truck that ran like it should to pull my mustang to the track. Now I want to know what's in my truck.

 

I just picked up an 02 with the 7.3 in it. Truck has 103k on it, CC SRW Short bed 4x4, drove it from Ky to NW IN and averaged 19.1 crusie set at 64mph. Only mod is a 4in turbo back straight pipe.

Now where to start with the mods?

 

Update on the 3.08 mod:

Total cost was $525
$200 for the gears
$300 for labor/bearings/fluids
$25 to modify the 1410 Yoke to fit the short spline 3.08's

Looks like a conservative 2mpg gain on the highway cruising at 65-75mph (1500-1700RPM) with some stop & go traffic & some street driving.

This was with computer correction for the 3.08 gears (Speedo calibrated). No other tune changes were needed since the computer uses RPM & MPH to shift, it did all the calculations & I actually don't even notice a difference in the way the truck drives. Although it is definately slower on an incline. Seems to be bogged down compared to the 3.73's.

I'm not expecting any gains in town under 50MPH. The truck stays in 3rd (w/locked converter) till 55mph where it'll shift into OD.

As we all know, it's very hard to accurately gauge fuel economy with a diesel since it's hard to get an accurate 'fill' on the fuel tank. I'll be logging milage & fuel used over the next few thousand miles to get a more accurate measurement of fuel economy from the swap.

 

I have a 2003 F350 4x4 CC FX4 7.3l auto with 4.10:1 and I wish I had the mileage some of you are posting. I get 12-13 driving 75-80 on the highway. I have changed the xfer case and rearends to synthetic and did the wix filter mod. When I bought it I got around 18 at those speeds. Here is a couple of observations from over the years.

When I added a canopy I lost 1 mpg.

When I added 305/70-16 MT tires I lost 1-1.5 mpg.

I get 16-17 mpg in Colorado and 12.8 in Louisiana at the same temp...?..WTF

A lot of diesel sites say the factory mileage calculator is garbage but everytime I check it with my own calculations it is spot on and I check it regularly.

They also say that changing gears does not require a reflash of the ecm, just when you change tires as the speed is calculated by the wheel sensors. If this is the case then it is impossible to hand calculate the correct mileage as your speedometer/odometer will be off by X amount of error therefore your calculations will have the same error in it.

The most interesting is that after up sizing my tires 2 sizes my speedo is acutally spot on with 2 different gps systems as well as those radar signs you see on the highway. This makes me wonder how far off it was in stock condition.