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Why exactly do cars have speed limiters?

Discussion in 'Non-Mopar Tech Support' started by adrienne224, Oct 18, 2017.

  1. Dave Z

    Dave Z It's me, Dave
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    Generally, Chrysler has speed limiters that match the OEM tires — and this has been the case since at least the 1990s. Not sure about before that.

    valiant67 pretty much said this. I've seen it with the same model having different speed limiters for trim levels with different tires... and that's the extent of their liability for the most part.

    The only other reason for speed limiters that I know of, in cars, is if a component other than tires is not able to handle the speed — e.g. it redlines the engine (not likely! but in the Ford Thunderbird SC I drove, not owned, if you went over around 130 mph on the speedometer — not sure if that was accurate! — it would downshift and go over redline, which is just about the same problem).

    Aerodynamic lift is another possibility though I don't know of any examples there.

    The video of crashes at the Ring shows that at very high speeds, tiny mistakes yield huge problems very very quickly. I have exceeded 100 mph many times and now I am thinking that was a huge mistake... but I'm still here, no thanks to Young Me’s lack of wisdom.

    On trucks, sometimes they set relatively low top speeds to match the desires of fleet buyers. They might do that on cars, too, I don’t know.

    If it was a matter of liability, SRT cars would be top speed limited.
     
  2. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    In Sept 1985 just before I traded in my 72 Dodge Dart Custom for my first new Daytona, I decided to take it up on the highway and see what it could still do at 174K miles and 13 years.
    The slant-6 and Torqueflite got to 94 mph, then I could feel the transmission starting to slip, but worse than that was the fact that the front end started to lift noticeably. Steering control was compromised, and if I had blown a tire I would have been dead.
     
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  3. GaryS

    GaryS Well-Known Member

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    Don't know about more recent governors, but in WWII era military Power Wagon-based utility vehicles that the Air Force governed at 35 mph, removing them was as simple as finding a steep hill, accelerating to the maximum speed, and then depressing the clutch. When gravity raised the speed to 40, you would pop the clutch and discover the governor no longer functioned. Don't ask me how it worked...or how I know.
     
  4. wolfsblood07

    wolfsblood07 Active Member

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    Where is the dislike button? These ideas are horrible. Let's just hand all of our freedoms away to the powers that be and be like sheep. Let's let computers do everything, they are so great.
     
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  5. 85lebaront2

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    Dave, read back to what I wrote earlier in the thread, my 1966 Shelby GT350 would get light in the front around 137 mph due to aerodynamic lift. Shelby fitted the R models (R or S in the VIN number denoted Race or Street) with chin spoilers to solve the problem. Mine had enough rpm left at 137 to easily hit 150 at the redline of 7500.
     
  6. 85lebaront2

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    Gee, our M37B1s in the Marine Corps would do 62 mph on the governor, don't think I would want to much faster than that in one, between the drifty steering and marginal 1930s vintage brakes they were a handful on the highway.
     
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  7. GaryS

    GaryS Well-Known Member

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    I don’t know which model, or which year it was, but it was open-sided with a canvas top. One day In the summer of 1960, we drove 200 miles from Holloman AFB, NM to El Paso, TX and back in a weapons carrier version. It was over 100*F, so we cranked the windshield open and found a big rock to place on the accelerator so we could take our boots off and put our feet on the dash to let the wind cool them. Hottest, slowest, and most unforgettable highway trip I ever took.

    We didn’t have unit-owned utility vehicles, so I don’t know if the motor pool vehicles we checked-out were governed at the same speed, but on that trip, a roadrunner paced us in the ditch for a short distance, and he was nearly as fast as us! Similar vehicles we occasionally had to check out in Germany were just as slow. That's where the governor-destruct technique was demonstrated to me.
     
  8. sickboy

    sickboy Well-Known Member

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    I spend quite a bit of time in cabs that deadhead across state(s). Morning noon night, sun rain and snow. There Was one driver who insisted at driving 15+mph over the traffic. It was terrifying. He did end up rear ending stopped traffic which resulted in a coworkers broken neck.everytime I’m driven anywhere, (whether there is a human driver or not) I’d rather it be at legal or at least reasonable speeds.(keeping up with the flow)

    side question: when you’re driving and someone screams past you at whatever speed, is he your hero? I’m not trying to insult you or anybody, I’m asking. if someone’s “right to speed” (you don’t have the right to go above the speed limit, it is illegal, ask me how I know) infringes on everyone else safety?
     
  9. wolfsblood07

    wolfsblood07 Active Member

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    Aggressive drivers who speed and cut in and out of lanes like maniacs are a danger. Strict enforcement of traffic laws is a must. Texting while driving should be a crime imo. My rant was more about self driving cars, remote tracking and engine shutoff and things of that nature. I'm not a big fan of speed cameras either, I don't think they make us safer. Speed limiters are fine. They are simply part of the car and you can buy cars capable of going over 150 mph if you want. Freedom to choose!
     
    #29 wolfsblood07, Oct 31, 2017
    Last edited: Oct 31, 2017
  10. AHBGuru

    AHBGuru Active Member

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    Ford really has some problems with that. The Panthers had the same issue - the Crown Vic's had a 119 limit with the 3.55, and 129 mph limit with the 3.27. There are always a bunch of clowns bragging about how their Clown Dic smoked a Hemi Pursuit, but it's all BS. The fastest P71 was actually the '96, which ran out of steam at 135 mph, which is 6 mph slower than the 141 mph limit of the V6 Pursuit.
     
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  11. AHBGuru

    AHBGuru Active Member

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    I must agree. It's a tires/brakes/suspension thing. The cars they have set up to handle the speeds get to go faster - the Squads, the Scat Packs, and the SRT's. All of those cars come well-tuned for the higher speeds and their performance abilities.
     
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  12. Doug D

    Doug D Virginia Gentleman

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    A much older friend of mine had a late 60's Stingray (I forget which year) that at high speeds (100+ mph) barely had the front wheels touching the pavement. One time as he finished passing an 18 wheeler, it drifted into the lane in front of the truck due to the air flow despite him holding the steering wheel straight. The front aerodynamics for that year Stingray did not do a good job holding the front end down at all - had a tendency to lift.
     
  13. Dave Z

    Dave Z It's me, Dave
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    That would be a good example if they had a speed governor ;)
     
  14. Muther

    Muther Well-Known Member

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    Yeah, gen 2 Vettes (64-67) were infamously, very infamously, light on the front end at speed. An old friend of mine talked about coming oflver the hill on the front straight in one, and the front wheels just lifted and wouldn’t come down, so he had to brake in the middle of the straight. That is why they were so short lived. GM didn’t want the liability. That is also one reason why the Stingrays we’re designed like they were.
     

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