6.4L Power Stroke Engine and DrivetrainDiscussion of the 6.4L Power Stroke diesel engine and drivetrain in the 2008 Super-Duty trucks. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 6.4L Power Stroke engine.
17 to 18 in a new 2008 6.4 diesel with 35" all terrains??? I THINK I might be smelling a little bs here?
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Originally Posted by wfodickinson
I think I am smelling the same thing. Someone needs a new calculator.
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Originally Posted by scredfisher
If anyone ever tells you they are getting better than 15MPG w/ this diesel and 3.73 gears under best conditions, blow them off. The earlier post that mileage is in the 11 city - 14 highway range is most accurrate.
I am getting 18 to 23 mpgs avg per tank and thats hand calculated, not just the trucks mpg display. Right now I working on getting 25 mpgs avg per tank, it will be hard to do.
Take it as you will I don't drive with a heavy foot keep, I my boost low. Again just yesterday i drove from the central valley to Morgan HIll and back ave 17.all the way there and back includes going over Pacheo Pass. the truck regens about every other tank full that might be my reason for ok mileage. I have nothing to gain by passing on bogus info. Any way Im off to go fishing..
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Tow Vehicle: 2008 F250 4x4 Crew Cab Manual 4x4 (No Auto 4x4 Here) Lariat Loaded, Leather, DVD player, Audiophile sound system, Memory seats, power extend mirrors, tow command system, tailgate step, bed extender, Rancho 4" lift with BFG 35/12.50 Rancho XL 9000 Shocks.
I am getting 18 to 23 mpgs avg per tank and thats hand calculated, not just the trucks mpg display. Right now I working on getting 25 mpgs avg per tank, it will be hard to do.
You are. It's counter intuitive because larger tires are more heavy; it'll take more effort to make those tires move. You continue to think what you're thinking, the rest of us know you're probably getting half of what you're claiming if you are lucky.
Hand calculation means squat. Unless you've taken into account the DIFFERENCE in size of your stock tires versus your larger tires, you're doing it wrong. Of course, if you've recalibrated your speedometer to EXACTLY account for your new tires size.... then that's different.... but I'm doubtful.
You keep thinking that.
Last edited by RDG : 07-26-2008 at 09:22 AM.
Reason: rules violation
17 to 18 in a new 2008 6.4 diesel with 35" all terrains??? I THINK I might be smelling a little bs here?
I have 35 Terra Grapplers and 15000 miles on my 6.4. I am getting 15.6 mpg around town and to work , and I get 19mpg on the interstate and if I am real careful on flat interstate areas, I can get over 21mpg. It's all in how you drive, and where you get your fuel. ( I don't run the AC )
You are. It's counter intuitive because larger tires are more heavy; it'll take more effort to make those tires move. You continue to think what you're thinking, the rest of us know you're probably getting half of what you're claiming if you are lucky.
Hand calculation means squat. Unless you've taken into account the DIFFERENCE in size of your stock tires versus your larger tires, you're doing it wrong. Of course, if you've recalibrated your speedometer to EXACTLY account for your new tires size.... then that's different.... but I'm doubtful.
You keep thinking that.
If you refigure your mileage with larger tires, you would get better mileage NOT WORSE ! For every 100 miles you drive, your truck thinks your traveling only 90 ( the case with my truck, with 35s ), so it figures your mileage on 90 miles instead of the actual 100 that you traveled. So with larger heavier tires you should be able to offset the heavier tires with the longer traveled distance. With a larger lighter tire , you can pick up some mileage. That's not even figuring in the slightly lower engine speed at the same road speed.
Then I must be full SH!T!!! I am getting 18 to 23 mpgs avg per tank and thats hand calculated, not just the trucks mpg display. Right now I working on getting 25 mpgs avg per tank, it will be hard to do.
I AM NOT SAYING YOU ARE FULL OF it, WHAT I AM SAYING IS THAT YOU DO NOT HAVE A STOCK 6.4L 4X4 W/ 3.73 GEARS. YOU HAVE MADE MODS TO YOUR TRUCK OR DIFFERENT CONFIG MAKING IT DIFFICULT TO COMPARE YOUR NOS. OK?
You are. It's counter intuitive because larger tires are more heavy; it'll take more effort to make those tires move. You continue to think what you're thinking, the rest of us know you're probably getting half of what you're claiming if you are lucky.
Hand calculation means squat. Unless you've taken into account the DIFFERENCE in size of your stock tires versus your larger tires, you're doing it wrong. Of course, if you've recalibrated your speedometer to EXACTLY account for your new tires size.... then that's different.... but I'm doubtful.
Well I made a trip to Beckley today (about 40 miles) to see my grandkids and go blueberry picking. From where I live in Oceana, WV there are 3 different routes to get to Beckley. The shortest is the worst on fuel mileage because of a rather large mountain to get across. The first part of the trip is about 15 miles steady climb to close to 4000' ASL and at some parts it's a 9% grade. The other 2 routes are a little longer (5 to 8 miles) but no big hills to climb. I've been experimenting lately with the 2 longer routes and found that I can leave home with my MPG showing 14.6 and will end up with that same average when I get home. Now, if I leave home showing 14.6 on the meter and go across the larger mountain (going and coming) when I get home my MPG will read 13.3 or 13.4. Now I said all of that to say this. I had the new flash done this past Thursday and didn't notice anything different. Today I tested the resume on the cruise control on 77-S and it worked really smooth! So no more automatically flooring it when you hit the resume button. Now the good part... I took the shorter fuel sucking route over the big mountain home today and my average MPG is still reading 14.5! I don't know if the new flash has anything at all to do with the MPG's or not but things are looking better. I am anxiously awaiting to see the message thing say "cleaning exhaust filter" because I havn't seen or felt a regen since last winter. One more thing, noticed considerable black smoke today when I got on it a little.
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2008 F250 Crew long bed XLT 6.4 diesel, automatic, White.
Hey stymie, you hit it perfectly that is exactly what mine is doing this time they said the cover was slightly warped but reality i am getting sick and tired of taking it to the shop to repair this problem for the fourth time. sounds like you have the same truck and it is set up the same 6 inch fab tech lift 17x9 rims with 37's what gears are you running? Im thinking i need 4.30 or 4.56 i need it to pull a 40 ft 5th wheel
Hey stymie, that is the exact same problem that my truck is having this one is number 4. I've been reading about people reflashing their computers what is the info on that and what does it do?
adduckhunter,
I have 14k on my truck, It has been in the shop 2-3 times, for the same problem. I had a slight oil leak from a bad seal. First time to the shop they cleaned the engine, and put dye in the oil. 2nd time they looked at the leak with the UV dye and replaced or patched the seal they thought it was (didn't remove cab). The third time, they removed the cab and replaced the seal that it was. I haven't had any other problems.
As for the gas mileage it is still probably better than the gas burners. As for performance it, like most modern diesels has some management built in and some other things to smooth things out and prevent undue stress to components. However, if you want it to accelerate hard, from a stop, it will. With an auto, my truck has outrun a friends car (Mitsu Eclipse) until 60. If you want hard acceleration, hold the brake, apply throttle until boost climbs as high as 20 or so, or the rear tires start to brake free, drop the brakes off an it is gone.
Some of the people here might have got the Gen 1 of this truck, which like most things has more problems than the latter ones. I love my truck, I hate the mileage. That said, I can't think of anything else I would replace it with. In a perfect world, I could drop a 7.3L engine with a manual in my 2008 KR. BTW I wouldn't do this for power, or reliability. I would do it for economy and fuel acceptance.
Oh, and as for the mileage, 12 ish in town, 16 ish interstate (75mph), and 18 hwys (55mph). This truck really is a brick, and regens kill every bit of good mileage you may get. I babied it for a week or so and got about 14 in town, regen kicked in and it dropped to about 13 before the regen stopped. When I drive harder, the regens don't seem to be as bad.
Oh, and a lot of people here claim the computer is way off, the jury is still out for my part. It seems optimistic, but in my experience, it has been very close. If the dash meter said 12 mpg, I was getting 11.7 or so hand calculated. Which probably means my real mpg was between 11.5 and 12. People on here swear their hand calculated mpg is more accurate than the computer. I say unless you pour your diesel in from a graduated cylinder, into something other than the ford stock tank, you have no clue how much fuel is in there when the pump cuts off. The pump could be wrong, the vehicle could be tilted, the pump could have foamed the fuel and cut off early last time, but not this time, ect. There are a great number of factors there, and the error most are talking about are 5% or so. Also, the chances that the pumps are optimistic about how much they pump is greater than the chances they are pessimistic. If I owned the gas station, and there had to be error, I would want it to benefit me. Regardless, I think if you want a new diesel truck, and don't care a bunch about economy, the new SD would be the way to go. Of course I own one, so I could be biased.
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Adam
2008 F250 6.4L 4x4 156" KR CC - "Job 2"
Ordered - 7/26/07, Built - 8/27/07, Purchased - 8/31/07, At Home - 9/5/07
Just my $.02 from my experience with my past trucks. The only TRUE measure of mileage is to keep diligent track of EVERY tank of fuel and EVERY mileage at fill-up. Driving conditions as well as the aforementioned variables affect mileage. Its interesting to see the change in the long term average between each tank. I have snow plowing and hauling stats in my spreadsheet as well as my commuting miles for my 94 6.5 TD GMC Yukon. Its the long tern average as well as the average for each tank that makes the interesting comparison. The long term average is all that REALLY matters. Its also neat to see how you can influence milelage between tanks by changing your driving habits. You might be SUPRISED!
I got a 08 6.4 l with a 8" lift with 37" tires, mbrp 4" exuast and, afe cold air intake and and edge attitude w/ juice. my milage is was 13.5 city and 16 on the freeway and now its droped to 9 city and 12 on the highway. Now my exuast temp is through the roof went from 850 up hills to excess of 1300 on a good hill when towning my 28 ft boat. Also it blows out black smoke and has no balls off the line. i was told i might have a bad dpf pipe which would result in this problem.. Does anyone have any info on this?
(No Auto 4x4 Here) Lariat Loaded, Leather, DVD player, Audiophile sound system, Memory seats, power extend mirrors, tow command system, tailgate step, bed extender, Rancho 4" lift 
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