speed limiter

I have a 99 F-250 SD with the 5.4l and was running down the highway with my buddy in his F-250 SD with the 6.0l. he had the jump on me so I slammed it to the floor and was catching quickly only to find my truck seemed to shut down at 85mph.

Are the 5.4 limited? I know, I know I shouldn't be doing 85mph but the thought of being out run by a diesel has me bummed..

thank Jim (the speed demon)

Reply to
James Gillespie
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Reason 412 to by a diesel. Clearly, it's the cheaper alternative to chipping your gasser. ;-P

Reply to
RLB

Reply to
Michelle P

Reply to
pete

You are incorrect! NEITHER of you should be doing 85!

Reply to
Rob Munach

With the exception of some high performance vehicles, almost all are limited with respect to both road speed and engine RPM. Road speed is generally limited to the rating of the tires installed by the manufacturer or powertain components such as the drive shaft. Engine RPM is limited to the max safe for the engine or torque converter.

Reply to
lugnut

I use the Hypertech Stage III tuner with my '99 F350 SD PSD, there is no longer any limit on top speed or rpm. You have to be careful, but that's what we were before we had computers to "keep us under control".

Spdloader

Reply to
Spdloader

As a professional 'emergency operations' driver. I can attest to the fact of how unstable SUV's and pickups get at high speeds. The rear end on a pickup will not have any 'drag' and will actually float up around 85 to 90. I have proven this. The bed acts as a sail and will lift the rear end up and thus no traction. SUV's area bit different, but the same principle works. They are not made to be aerodynamic at all (think brick with wheels) the drag behind them at a high speed will cause the rearend to sway and slide. I do indeed drive a 2001 F250 extcab SB with the 5.4 motor. Under controlled and professional conditions, I found my cutoff the be 91mph. With more testing, i discovered that ther was only a 25 to 30% traction efficiency at the rear tires. Not enough if I had to do any kind of maneuver. Stick to cars that are made to go fast if you want to actually go fast.

Reply to
My Own Little Universe

I've had my '03 Supercrew well over 100 using a Superchips Microtuner to raise/remove the limiter.

SMC

Reply to
MOTO

I would like to thank all for the responses.

to RLB and his reason 412 - still not enough for me to spend an additional $5000 on the diesel. My 5.4 has 240,000 miles, gets 14.5mpg and would take that 6.0l off the line day in and day out.

to the rest - I just wanted to know if there was a limiter or not? I know I shouldn't be doing 85 that wasn't the point. My buddy has had his diesel up over a 100, again not the brightest move, but he didn't hit an limiter?

again thanks for the responses

Jim

Reply to
James Gillespie

||As a professional 'emergency operations' driver. I can attest to the fact of ||how unstable SUV's and pickups get at high speeds. The rear end on a pickup ||will not have any 'drag' and will actually float up around 85 to 90. I have ||proven this. The bed acts as a sail and will lift the rear end up and thus ||no traction. SUV's area bit different, but the same principle works. They ||are not made to be aerodynamic at all (think brick with wheels) the drag ||behind them at a high speed will cause the rearend to sway and slide. ||I do indeed drive a 2001 F250 extcab SB with the 5.4 motor. Under controlled ||and professional conditions, I found my cutoff the be 91mph. With more ||testing, i discovered that ther was only a 25 to 30% traction efficiency at ||the rear tires. Not enough if I had to do any kind of maneuver. Stick to ||cars that are made to go fast if you want to actually go fast.

James A few years ago GM built a S-15 Bonnevile record truck. It was an extended cab longbed. They found that the best aero package for the bed consisted of a hard tonneau cover from about 2 feet behind the cab extending to the tailgate. A verticle panel blocked the front of the covered space. This negated most of the lift and drag. Texas Parts Guy

Reply to
Rex B

Guys, my experience is with an 01 F150 SuperCab XLT with 5.4L and i hit 110 on a straight run and did not expereince any problems with handling or speed limiting of the truck. i did it alone at dusk with no other vehicles around me. i just wanted to see how fast she could go, i beleive she could have gone faster as i was at about 3700 RPMs. As an FYI my 04 F150 SuperCrew runs

2k RPM at 75 mph which is the avaerage commute speed to keep up with everyone else here so im believing she may have a higher top end.

Reply to
Joe Sumbody

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