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.
Hey guys.. I am new here. Just purchased a new 2008 f450 king ranch with a 4.88 rear. Was wondering if the truck is governed at 81 MPH or is it the 4.88 that keep it from going over 81. Down here in s.fla blue hair grandma's are passing you at 80...Any info would be great...
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2008 F450 Pearl Blue 6.4 w/ 4.88 REARS..
Every option possible.....
Yes it is governed at 81 mph. Really the truck is meant to be run at 60 to 65 mph pulling a 20,000 pound-plus trailer. 81 mph is about 3000 rpm which in my opinion is screaming a diesel. The F450 with the 4.88 gears is also detuned to 325 hp and 600 pounds of torque. I think the reason it is detuned is for durability and heat related issues with pulling so much weight.
Thanks,
Marc
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2008 King Ranch F450 - 4.30 Gears
2008 XT F550 - 4.88 Gears
2006 Caterpillar 420D Backhoe
1957 Wife - Not a diesel burner, but sometimes does a Regen
Cram,
Thanks for the info. That's what I figured. I would have ordered the lower gear ration if I knew that. 81MPH is plenty quick enough in a 14k pound truck, but once in ahwile you need that extra speed for passing...
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2008 F450 Pearl Blue 6.4 w/ 4.88 REARS..
Every option possible.....
Congradulations on the new truck and welcome to the site. There are alot of really helpful people on here. You have bought a great truck and a phenominal towing machine. Some guys are talking about purchasing a gear vendors device that will give you higher gears for when your not towing.
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2008 King Ranch F450 - 4.30 Gears
2008 XT F550 - 4.88 Gears
2006 Caterpillar 420D Backhoe
1957 Wife - Not a diesel burner, but sometimes does a Regen
Yep somewhere around 70 plus miles an hour you can actually see $20 dollar bills shoot out the tail pipe. I have found that about 63 mph gets somewhere around 13.5 mpg running empty. Anything beyond seems to drop fuel economy.
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2008 King Ranch F450 - 4.30 Gears
2008 XT F550 - 4.88 Gears
2006 Caterpillar 420D Backhoe
1957 Wife - Not a diesel burner, but sometimes does a Regen
All F450/F550 trucks are limited to 81mph because they have real truck tires, they are not meant to go 90 or 100 mph. The tires are not high speed rated they are meant for heavy loads. You can remove the speed limiter, but it's your life at stake. My F450 has no longer has a limiter. LS
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2005 F450 XLT Super cab tow truck 6.0, 87K mile, POS Soon to be traded for 09 F550 Lariat Super cab V10
2003 F450 rollback, with V10 power, 141K and still running great.
Mine was removed when I installed a SCT programmer. LS
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2005 F450 XLT Super cab tow truck 6.0, 87K mile, POS Soon to be traded for 09 F550 Lariat Super cab V10
2003 F450 rollback, with V10 power, 141K and still running great.
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Hey guys.. I am new here. Just purchased a new 2008 f450 king ranch with a 4.88 rear. Was wondering if the truck is governed at 81 MPH or is it the 4.88 that keep it from going over 81. Down here in s.fla blue hair grandma's are passing you at 80...Any info would be great...
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As I understand (no comments, please) the 4.88 F450 is limited in top speed and has reduced HP. This truck is designed to WORK, hard and long. I understand your concern on the freeways down there. I hauled four horses and a load of tack to Ocala a couple of years ago and was being passed by semis on a regular basis. I found myself traveling 70 plus MPH in self defense. Not comfortable hauling a live load that fast in heavy traffic. Enjoy your truck and look into an overdrive or gear change if the limit is a hindrance.
I don't let them push me. I run my 5er at 65 and stick that way. The ones that get me are the people who merge on to the highway at 64mph and think I am going to slow down for them. Idiots!
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2008 F-450 Lariat W/ Lots-o-Options - Built on Feb 7 2007, Shipped on Feb 12, 2007, Mine on Feb 22, 2007
Yes the limit is because the 19.5" tires which has been limited in the past to 75 mph from all tire manufacturers for the F-450/550 trucks. On another note the F-350 dually series with 17" tires is computer limited to 96.2 mph. Doubt I will need anything past 95mph.
Enjoy the slow 81mph 450.
I can not even count the number of times I have been traveling at 70 and get passed by a semi with 22.5's running 80+ mph. What are they speed rated for?
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Cram,
Thanks for the info. That's what I figured. I would have ordered the lower gear ration if I knew that. 81MPH is plenty quick enough in a 14k pound truck, but once in ahwile you need that extra speed for passing...
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There's a LOWER ratio than 4.88 available? (I think you meant a HIGHER ratio like 4.10 or 3.73.)
__________________ Stan
2005 F250 4X4 SD R/C Power Stroke / Torqshift
Oxford White, Medium Flint 40/20/40 Vinyl, Prefered Equip. Pkg. 600A , 3.73, Limited Slip, XL Decor Pkg., Jeweled Headlamps, Chrome Rear Step Bumper, 9600# GVWR Pkg., Engine Block Heater, Sliding Rear Window, Speed Control / Tilt Wheel, Camper Pkg., FX4 Pkg., Air Conditioning, Forged Aluminum Wheels-17", Tow Command, Telescoping TT Mirrors. Using this vehicle to produce an ambulance voids Ford warranty. Added: Ford factory upfitter switches, Go Industries Rancher Grill Guard (hammered powdercoat), Hella 4000 Rallye lighting (one Cornering Beam, one Euro Beam), SnugTop Super Sport camper shell.
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