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.
A friend Test drove a 2008 3/4 Ton 3.73 rear end computer read 24 miles to gallon. ordered a 1 Ton 4.10 rear end computer reads 12 miles to gallon. the mileage should be lower but not cut in half. what happened.
I'd have a hard time believing even 20mpg with an 08'. No question they are thirsty.
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2003 350 Lariat FX4 Short Box 6.0L *SOLD*
2008 FX4 F350 6.4L Dually Long Box, Black on Black PICTURES
2007 Keystone Raptor 3712TS PICTURES
The other one broke down and was towed in... [img]/ubbthreads/images/graemlins/wink.gif[/img]
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88 F 250 7.3 Super Cab XLT Lariat4X4...Cream Puff
81 Corvette...Pampered
Harley Shovel 88" Show Stoper...WOW
BBC 468 Jet Boat...Gotta get Wet!
It's the Women that cost me the $$$$
You can get the computer to show a really high average mpg by driving at about 50-55 on a long slow downhill grade or flat ground with a tail wind. If it's long enough, the average won't change by much during a short test drive. I took mine on a 330 mile round trip from Yorktown, VA to Charlottesville, VA today. Not much of an elevation change (about 600 feet) but on the way there I averaged around 75 miles an hour and that was the uphill direction with a headwind. Average mpg was about 15. On the way back, I kept it at 65, especially for the first 50 or so miles where most of the elevation change occurs and had a tail wind. I got 19 mpg. I'll bet if I'd done 55 I would have exceeded 22 mpg. That's not very realistic but my point is that from that point on, the displayed average mpg didn't change very fast. This is all computer vs hand calculated but I meant to illustrate that a crafty salesman can get that display looking pretty good.
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Jeff
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2008 F-350 Lariat, CC, Short Bed, 6.4PSD
Gold on top, black on the bottom, camel on the inside
Go Hokies!
Sorry guys, but I'm going to need some help here. I've had mine since early March and have just over 4,000 miles on it. Changed the oil at 3,000 miles and have yet to tow anything. Just returned from a trip (virtually all highway miles) of 686.9 miles and burned 46.8 gallons. Squeezed every last ounce possible into the tank immediately before and after getting on and off the highway. Set the cruise on 75 and left it there. Where I went to school that works out to 14.677 mpg. Since this is my first post on this site, I certainly don't want to be confrontational, but anyone posting here saying they are getting 22, 20 or even 16 - 18 mpg on the highway I must question. Either there are some tall stories being told here or something is wrong with my truck. I truly would like to know which it is. Please enlighten me.
I just started on my second tank of fuel and got 10.2 a U.S. gallon on the first tank.All city driving.
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2008 F350 SRW CC Lariat,6.4,20 inch wheels, Spray in Boxliner,Retrax Roll top cover, Bluetooth, Warn Transformer with M12000 winch and SST Cover,HID Lights, Dual 150 watt Daylighters.5 inch Magnaflow exhaust. etc.
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Sorry guys, but I'm going to need some help here. I've had mine since early March and have just over 4,000 miles on it. Changed the oil at 3,000 miles and have yet to tow anything. Just returned from a trip (virtually all highway miles) of 686.9 miles and burned 46.8 gallons. Squeezed every last ounce possible into the tank immediately before and after getting on and off the highway. Set the cruise on 75 and left it there. Where I went to school that works out to 14.677 mpg. Since this is my first post on this site, I certainly don't want to be confrontational, but anyone posting here saying they are getting 22, 20 or even 16 - 18 mpg on the highway I must question. Either there are some tall stories being told here or something is wrong with my truck. I truly would like to know which it is. Please enlighten me.
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The front ends of our 2008's are a bigger, bolder, and blockier then just about about any year or make of pickup truck made in the last 10 years. Personally I'm willing to trade 1 mpg for that look. The Coefficient of drag is high and up until a point the slower you go the better your MPG. If you're getting 14.67 mpg at 75, you'll get about 16.5 mpg at 65, and 18 mpg at 55 mph.
Try it on level ground. Reset your computer and drive 55. Reset and drive 65, reset and drive then 75 etc,.. You can map out all of 40-80 in 5-10 miles of level ground.
Mapping out your most efficient speed can be very handy when you're low on fuel. If you missed a diesel stop and you have 3 gallons in the tank and 50 miles to go. It sure would be nice to know that sweet spot that will get you to the next filling station. It might be 40 mph or it might be 60mph. Each truck is different and speed will change if you tow.
Boat magazines always chart out the best speed for mph or "gallons per mile" for larger boats. This sweet spot is the speed where many boaters cruise to save gas. The savings can be $100's a day. But more importantly this can be a life saver if your out at sea and your know your low on fuel and the only way you'll make it back is to cruise at the most fuel efficient speed.
I have a trick or two to increase your mpg 30-60%. But first understand these are not exactly the best things for your transmission or tires and are only to be used in a emergency situation where running out of gas is not an option.
<font color="red"> WARNING: In some states this is not even legal to do and it could damage your transmission if done improperly. Also some transmissions may actually overheat when coasting in neutral</font>
1st is the neutral trick. Slowly accelerate to about 70mph. Carefully put the truck in neutral and coast to about 50mph. While your coasting down to 50mph your engine is idling. Now repeat by Slowly accelerating back to 70mph and drop it into neutral, coast to 50mph and repeat. By doing this your 6.4L is Idling 50-66% of the time and your average RPM's are so low it's like your 6.4L is a 2 or 3 liter multi displacement engine. You'll be shocked at how many mpg's you'll get doing this. I wouldn't try this if your pulling a trailer. Vehicles with big displacement engines, high gear ratio's and the lowest coefficient of drag seem to get the best mileage increases. You can actually double mpg in some vehicles.
Two other simple tricks. Fold in your giant electric Dumbo the Elephant towing mirrors to cut down on wind resistance. Also not that practical but if you have a compressor you could fill your tires to the max rating to help lower rolling resistance to make it to your next fuel stop.
<font color="red"> WARNING: The tips in this post are only intended for use when you're going to run out of fuel before you reach your next fuel stop and the risks are so great(Like running out of fuel in 115 degree desert heat on a deserted road) that you are willing to risk damaging your transmission or worse.</font>
BTW: On my SRT-8 the transmission neutral trick raises my mpg from about 20mpg to well over 30mpg. [img]/ubbthreads/images/graemlins/smile.gif[/img]
Technologist: What do you have an SRT-8 In? Charger/300C? just wondering. [img]/ubbthreads/images/graemlins/smokin.gif[/img]
__________________ 2005 F250 XLT wedgewood blue 4x4 C/C SWB,6.0L PSD, Auto.(Member of 05 STC Failure Club ) 2006 Expedition Eddie Bauer,5.4L (Wife's) NRA Life Member. TSRA Life member.
2005 F250 XLT wedgewood blue 4x4 C/C SWB,6.0L PSD, Auto.(Member of 05 STC Failure Club 
) 2006 Expedition Eddie Bauer,5.4L (Wife's) NRA Life Member. TSRA Life member.
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