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6.7L Driveability Characteristics

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I probably picked-up on this long ago but I recently installed an engine in an F550 and as usual I was overly critical of how it ran when I was done. I noticed that a 550 has a little bit of a lag off of the line then it snaps to life. They seem a little doggy when compared to the pick-up models. If course we know the turbos are different...

 

Anyone else notice this difference in driveability?

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Big time difference. Early on in the 6.7 days, I chased my tail on a few chassis cabs thinking they were lagging... But quickly found out it's normal when compared to other chassis cabs.

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Perfectly normal.

 

Our fleet is mostly 550s with one or two pickups thrown in. the pickups have alot more power and very little hesitation off the line compared to a cab and chassis truck.

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The first cab and chassis I drove when the 6.7 hit the streets, I thought it was broken right off the truck it seemed so lazy.

 

Comparison to a like unit showed the same characteristics.

 

I'm not all that overjoyed with the pickup leaving a stoplight, either. First gear feels like 4-Low, then someone clicks it back into 2WD and the power comes on.

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Many complaints of this at first. The first reprogram recall did in with most of them. A big loaded up 550 is a toad off the line, borderline unsafe pulling out into traffic. It's like a 6.0 with a stuck turbo.

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  • 3 weeks later...

What's really funny is the chipped and deleted trucks that use calibrations based on very early factory cals.

 

I did a turbo on a truck that had no dpf or egr on it, and an H&S tuner, from what I could tell by the firmware date, was a very early tuner. (Early tuners display "RACE" options, late tuners display "HIGH SULFUR" options)

 

I pulled that bitch out into traffic and thought the driveshaft fell out of it, it was so lazy. It rolled ahead, plunked into second gear, and took off like someone had run into the back of it.

 

The only way it was driveable was when it was set on "kill" on the tuner. I wound up driving it on "no power, delete only" tuning because it was kind of dirty on the high power tunes. But holy christ was it ever a dog.

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  • 2 weeks later...

Aug 02 2013 6419 -2011-2014 F-Super Duty - 6.7L Diesel - Turbo Performance Characteristic Differences Between F250/F350 and F450/F550 Vehicles

Some customers with multiple 2011-2014 F-Super Duty vehicles may report the 6.7L diesel equipped F450/F550 chassis cabs may exhibit a characteristic turbo lag when accelerating from a stop compared to a 6.7L diesel equipped F250/F350 pickup truck. This is primarily due to the design differences of the turbocharger and air intake systems. Chassis cab vehicles use standard Variable geometry turbocharger while pickup trucks use a duel boost turbocharger and have different HP and torque curves. Refer to the F-Series Super Duty 6.7L Power Stroke Diesel "Coffee Table Book" located on the PTS website under the service tips tab for additional engine specific information.
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I did one as a barn job and I don't even work at the dealer anymore.

 

I will upload some pics tomorrow if I remember. I'm sure it's nothing you guys haven't seen before though.

 

5000km after the truck got a replacement longblock, the turbo went for a dump and it was out of warranty.

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