I own a 2005 4.7l QC ram and I forget where my speed is limited If its at 108 or 110 (never pushed it past that speed cus i dont want my engine to shut off) but my question is.. why? I know all vehicles are limited but is it for safety purposes or is it because the stock tires would blow up at those kinds of speeds. I still have stock tires on mine and if that is the case then I will need new tires before I buy a chip that will let my truck go past the limit.

 

Do you really need to go 100+ in a 5000 lbs+ vehicle?
I think its a little of both tires and safety.
Dont get me wrong......Everyone should feel the top end at least once[sm=badbadbad.gif]

 

It is actually for neither. It is to keep idiots that can't handle speed from killing themselves, and thus getting lawsuits for excessive speed. The insurance companies kind of forced their hands on that. The Superchip will raise that dramatically. I have had mine to 125 with no vibration or sway at all, and it still had more. Mine is extremely stable at that speed.

 

It is kind of good, I was out trying to see how the top end was and I got a ticket, if the speed limiter was not there I would have gotten a ticket for doing more than 104 which was a bad enough ticket.

 

Now that's funny.

 

Yeah, ha ha ha....

 

Can be for more than one reason.
My old '97 T-bird was limited to 114 before I added a chip. Ford did this because the tires it came with were only rated for that speed, and I read on some T-bird forums that the drive shaft could set up some nasty harmonic vibration above 120 that potentially could blow the U-joints, so I never took it over 125 with Z rated rubber. The solution for that car was to replace the shaft with the stiffer aluminum unit used on the Lincoln (same chassis).
My Cobra is electronically limited to 155 without a chip. Believe this was also due to the speed rating of the factory tires, and agreements with the Insurance Industry. I know people who have taken their supercharged Cobra's over 165 on a chassis dyno, but I've kept mine just shy of 140 on the hiway. The thought of blowing a tire at 150 doesn't make for a pretty picture in my mind...
I wouldn't take any truck over 120 unless it was built like an SRT-10 Ram.

 

So let me get this straight JRH, you have A dodge, and TWO fords??

 

My Ram cut out @ 105 MPH. I also was surprised it kicked in that low, my Saturn kicks in @ 110. No real need to go that fast but I was curious what it will do.

I actually posted this on an ATV forum and had a guy go ballistic on me, wished me death or paralaysis<sp?> for driving that fast. Nice guy, hope he doesn't teach that kind of hate to his kids.

 

i believe the 4.7s cut out at 106. i had mine at 105 and it wouldnt go any faster and i thought i had the pedal on the ground but then i pressed more and found that i had a considerable amount of pedal room left. i floored it and it hit 106 and stayed there apparently the engine doesnt shut off the computer just keeps it from going over that speed. now if superchips would just make one for the 4.7 i might buy it. im trying to save up as much as i can cuz i wanted to buy a 1 or 2 yr old powerwagon when i was between 22 and 24 that would put my truck between 8 and 10 yrs old so i had decided not to mod anymore and just save money but a superchip might be pretty tempting.