7.3 Powerstroke7.3 Power Stroke

The "Good"

6.0 Powerstroke6.0 Power Stroke

The "Bad"

6.4 Powerstroke

6.4 Power Stroke

The "Ugly"

The 6.4 PowerStroke

The 6.4 L Power Stroke, used in 2008 model year Ford Super Duty trucks, is a V8 turbodiesel engine. The engine has a sequential twin-turbo intercooled forced induction system. The engine also uses a high pressure common rail fuel injection system. It produces 350 hp (260 kW) at 3000 rpm and 650 ft·lbf (880 N·m) of torque at 2000 rpm.

Technical Specifications:

  • Power: 350 hp (260 kW) @ 3000 rpm
  • Torque: 650 ft·lbf (880 N·m) @ 2000 rpm
  • Induction: Sequential twin-turbo intercooled forced induction
  • Fuel System: High pressure common rail fuel injection

This engine will also be used in International trucks and buses under the name MaxxForce 7. However, the MaxxForce 7 will not have the sequential turbocharger system; rather, it will use a single stage variable vane turbocharger. Displacement and injector systems are the same. In MaxxForce 7 guise, the engine will produce between 200-230 hp and 580–620 ft·lbf of torque.

For the 2010 model year, Navistar has upgraded the MaxxForce 7 with dual sequential turbochargers, giving it a new power range (220-300 hp @ 2600 rpm and 520–660 ft·lbf of torque @ 1600-2200 rpm).

The Biggest Complaint: Poor Fuel Economy

The biggest complaint we have heard from our customers is poor fuel economy. Read below - these posts are taken from internet blogs:

I bought my 08 F350 Super Cab FX4 in Dec 07 for a couple of reasons. I had on 04 F350 with the 6.0 it was fast, MPG was about 13 but man you could hear me coming from a mile away. The new 6.4 was quiet, dealer told me to expect 15 to 18 MPG and it was faster than my 04, with still all of the towing capacity. FAST FORWARD to the real world.

Reality Check:

  • Expected: 15-18 MPG
  • Actual: 9.5 MPG average
  • Towing: 7 MPG
  • Miles: 3,700

I baby this truck, I have 3700 miles on her and I am getting on average 9.5 MPG, when I am hauling my trailer I am getting 7 MPG. And it isn't faster than my 04 F350.

I love the truck, it is tough looking, very quiet and it does have good towing capacity, but the mileage is killing me. I am even considering a different truck because the mileage is so poor. For all of you out there who claim 15 MPG and more, please tell me how you are getting it.

Comparing 7.3 vs 6.4:

Love the 7.3. Gave my son my old 1997 F-250 2wd 5-speed 4.10 gears 7.3 (8,800 GVWR) back when it had 220,000 miles on it. 244,000 now. Gets 15 around town carrying 1,000 lbs of pool chemicals. Gets 20 on the interstate @ about 75mph.

7.3L Performance (1997 F-250):

  • Around town: 15 MPG (with 1,000 lbs load)
  • Interstate @ 75mph: 20 MPG
  • Mileage: 244,000 miles

I bought a 08 6.4 F-250 4 door 2wd automatic 3.73 gears (9,800 GVWR). I initially got 9.5 to 11.5 mpg around town. At just over 6,000 miles it bumped up to 12.5 to 13.3 mpg around town. At that time it got 16mpg @ 70mph on the interstate highway only. I made one trip at 66 mph on cruise and the mileage kept climbing until 21.2 mpg. If I pulled off the interstate further than I could throw a rock the mileage drops like a rock.

6.4L Performance (2008 F-250):

  • Initial around town: 9.5-11.5 MPG
  • After 6,000 miles: 12.5-13.3 MPG around town
  • Interstate @ 70mph: 16 MPG
  • Interstate @ 66mph (cruise): 21.2 MPG
  • Warning: Mileage drops dramatically off interstate

I love the truck. I buy one...pay for 5 years and drive it for 10. I average 22,000 miles per year. That should easily be within the life of my truck. Do I wish the mileage was better? You bet! Would I buy a Dodge or Chevy? Nope... Drove both...not bad trucks ... just not what I liked. Dodge has a great motor but the body feels, sounds, looks and is flimsy in comparison. I still like the truck but didn't like the feel. The Chevy just didn't have enough room. Stopped right there with it. I even drove the Toyota gas motor full size. Tons of power but had a cheap look on the inside of the truck. It was a very nice truck but I wanted the longevity of a diesel.

I have about 17,000 miles on my 6.4. At 36,000 it will probably lose its dpf and get a 5" exhaust. Will check mileage figures then.

Had a 7.3 got a 6.4 wish I had a 7.3 again!

Read more: http://forums.dieselpowermag.com

Expert 6.4L Powerstroke Service

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