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    Speedometer calibration

    Has anyone checked the accuracy of the speedometer in a 997? Just trying to find a 1% or so inaccuracy. Curious if this will be a fruitful exercise. Thanks.

    Re: Speedometer calibration

    My 2005 run about 4km/hr too high. If it says 100kph it is actually 96kph. The offset changes slightly with speed, increasing as the speed increases.

    Re: Speedometer calibration

    Since I also live in Virginia, I would get the calibration just to cover my butt if I got ticketed. I once got (not in my 911S) "ticketed" by a state mountie who "clocked" me. I didn't read the ticket properly, but told him that as I had just gotten a new set of tires, I was going to get my speedometer calibrated. I did get the calibration, but the state mountie never filed the ticket, as he had not used radar/lidar on me - he just clocked me in an effort to boost his revenue for the Sunday he was on duty. I should have gone to court and asked him to prove when the last time he calibrated his speedometer. If he hadn't done it recently (close to the date of issuing the citation to me), I probably could have won the case in court, as worn tires on a "mountie-mobile" indicates he was overstating my speed, as he was on that occasion. Foolishly, I paid the fine as I didn't want to waste my time in court, but the citation has never, ever, shown up on my driving record in Virginia. Hence my view that Virginia is out for revenue as much as "enforcing the speed limit."

    Porsche's are rumored to have the speedometer overstate your actual speed. I suspect this is true, but I don't know for sure. Therefore, to cover your butt, get a calibration done soon after getting your Porsche. Then, as it gets older and the tires wear, your stated speed will exceed your actual speed (but probably not by much as the tires on a 911 have a thin tread). If you get ticketed after 5 - 6,000 miles on the odometer, then I would get a calibration to see if you could fight the ticket in court (I once got a reduction in a reckless driving charge to 19 over. In Virginia, unless you are already aware, 20 or more over the limit is considered reckless driving, and it stays on your record for 10 years) by getting my attorney (yes, I paid through the "nose" for an attorney to present my evidence - a legal calibration that showed my speedometer understated my true speed by 3 mph when I was traveling at an actual 74 mph - to the judge before I had to appear in court _ I had a set of Pirelli super touring tires on it at the time).

    In any case, I expect to change my tires soon on my 911S and get a new set (I'll pay for a calibration immediately after I get them put on or ask the dealer to do it, just to cover my butt in case the state mounties nab me).

    Calibration is still likely to be cheap. The last time I got one it cost me under $50, but that was about 7 years ago so I expect it to cost more today.

    If you live in the DC area, there used to be a place not far from Fairfax Circle (I think it was on Campbell road or drive, a street that only abutted route 50 on the north side of it). They did great work for me, and it worked in court. But like I said, I paid through the "nose" for an attorney.

    I think Virginia's traffic laws are designed to: 1) earn revenue for the county and the state;, and, 2) provide income for local attorneys and judges. Given that you live in Virginia, you'll have to judge my opinion for yourself.

    Jim

    Re: Speedometer calibration

    Jim, thanks for the background. I got ticketed in a small town in Virginia for reckless driving due to speed. I live in Northern VA. I had no idea about the consequences of speeding in VA. I want to see if I can show my speedometer was overstating my speed by at least a couple of miles. It won't get me out of a ticket but might help reduce the consequences. Hearing about jail time for speeding makes you consider anything to mitigate what the judge might do. I will try to locate the place in Fairfax. Thanks again.

    Re: Speedometer calibration

    Heard somewhere that ALL speedos are calibrated to show two or three mph _faster_ than actual speed.

    It has been said they do this so the car companies can't get sued.

    Having heard this I checked all my cars (2000-2006 models) with handheld GPS and found they were ALL 2-3 mph off as described!!

    Sooooo, AFAIK, they are very accurately set to be 2-3 mph off.

    Re: Speedometer calibration

    Yeah, that seems right. When passing those speed signs- it indicates about 3-4 mph over the posted speed.

    Re: Speedometer calibration

    Quote:
    MMD said:
    Heard somewhere that ALL speedos are calibrated to show two or three mph _faster_ than actual speed.

    It has been said they do this so the car companies can't get sued.

    Having heard this I checked all my cars (2000-2006 models) with handheld GPS and found they were ALL 2-3 mph off as described!!

    Sooooo, AFAIK, they are very accurately set to be 2-3 mph off.



    Thanks for the info. It gives me some extra assurance as I set the warning buzzer on my 911S for 73 mph, and I pay attention to it on the local freeways, especially near speed traps. That way, I probably have 5-6 mph leeway, and as I said about Virginia, they like the revenue, and they will usually let you get away with up to 9 mph over the limit, but hit 10 mph over the limit, and they'll ticket you. The fines are stiffer and the point total rises to 4 from 3. It's a way for the state mounties to cover their butts so they don't lose cases in court and rake in that extra revenue.

    Jim

    Re: Speedometer calibration

    Quote:
    Jim48 said:


    Thanks for the info.



    No problem. I hope it is correct. can't remember if it's actually a _fact_ (that speedos _are_ calibrated like that) of if it was just a discussion/thread/speculation. I _DO_ know mine are all consistently off by 2-3 mph.

    What a drag in VA! Sorry to hear about it; makes me sick.

    They "should" give every driver a reaction time test. like an eye test. Give the "slower" drivers higher insurance rates. Cars with bigger brakes, shorter stopping distances, should be given more leeway.

    So, if you have massive brakes and can score fast reaction times, (and have NO cup holders) you should be allowed to drive faster.

    LOL..., yeah riiiiight!

    What a joke! Again, sorry you are in suuuuch an oppressive state. If I lived there I might just sell all Perf cars and get a sloooooow POS (Hybrid?) and never go faster than 55: just to fk everything up.

    My girlfriend in college had an old Beetle. Was fun to barely get to 55 all the time. 0-60 in 20 seconds. No hope of EVER passing anybody. Was kinda relaxing!

    Re: Speedometer calibration

    It's too bad VA is such a repressive State. Beautiful but repressive. I read about their traffic laws and makes one cringe at driving through that State. And I thought we had it bad in Florida!

    Re: Speedometer calibration

    Quote:
    MMD said:
    Quote:
    Jim48 said:


    Thanks for the info.







    No problem. I hope it is correct. can't remember if it's actually a _fact_ (that speedos _are_ calibrated like that) of if it was just a discussion/thread/speculation. I _DO_ know mine are all consistently off by 2-3 mph.

    What a drag in VA! Sorry to hear about it; makes me sick.

    They "should" give every driver a reaction time test. like an eye test. Give the "slower" drivers higher insurance rates. Cars with bigger brakes, shorter stopping distances, should be given more leeway.

    So, if you have massive brakes and can score fast reaction times, (and have NO cup holders) you should be allowed to drive faster.

    LOL..., yeah riiiiight!

    What a joke! Again, sorry you are in suuuuch an oppressive state. If I lived there I might just sell all Perf cars and get a sloooooow POS (Hybrid?) and never go faster than 55: just to fk everything up.

    My girlfriend in college had an old Beetle. Was fun to barely get to 55 all the time. 0-60 in 20 seconds. No hope of EVER passing anybody. Was kinda relaxing!



    To both MMD and cybergypsy,

    I guess I put up with Virginia because many of the two-lane the roads go through mountains, and the driving is incredible. This is one area where Porsche's truly beat most, if not all, the competition.

    I have spotted most of the speed traps and know where I can take a "chance" with a low likelihood of getting nailed.

    I spotted one place in West Virginia where I could really let the car run, and the traffic was almost non-existent. I hit 151 mph (probably really 148-149 mph and no one was within a mile of me at the time) there a few weeks ago but am not likely to try that again. From now on, it's the local track where it's a lot cheaper and safer.

    Jim

    Re: Speedometer calibration

    Just be careful out there. A speeding ticket on those roads will likely affect your perception of those roads. For me, those roads in VA and WV used to be a lot more fun.

    Re: Speedometer calibration

    A year and a half ago I visited VA. I went to Williamsburg, Yorktown and Alexandria and really loved the place. Nevertheless, if I am to live somewhere, I cannot do it in a place that will, with 100% certainty, land me in jail some day for something that will only get me a speeding ticket in FL. Here one has to go over 30 mph over any established limit in order for it to be considered an "arrestable offense". Mind how I wrote "arrestable" since it is up to the officer to decide that. At least that is what I got talking with some Deputies around my area. I am planning on visiting it again soon but will have to refrain from having fun once I cross the VA border. When I visited, I got a $94 ticket for having a radar detector even though it was turned off at the time. How many States have laws against radar detectors, for crying out loud!

    Re: Speedometer calibration

    Everytime I see one of those "cute" GEICO commercials I think about them giving lots of free laser guns to state cops.

    This is true, right?

    What a great alliance: States get more money from fines, Insurance get more money from raising rates. Public gets squeezed and overly fearful of "dangerous 10mph-over speeders."

    Why not just house the insurance company offices in the state capital buildings?

    Really makes me sick because I remember mention of a study done somewhere that concluded MOST drivers WILL vary speeds on roads and conditions _but_ will mostly travel at a _SAFE_ speed given those roads and conditions.

    BTW, would be interesting to find out how many drivers with speed violations get dropped by insurance carriers nowadays. My guess is they will never be dropped unless they can't pay their ever-increasing premiums. get it? It means thet they are not really "dangerous!" (of course if they have huge points or an arrest for 100mph+ THAT's another story).

    sorry, rant over.

    Re: Speedometer calibration

    Up to about 70 mph my GT3 is off by about 5 mph. At 185 mph it is off by 12 mph. Both according to my DriftBox GPS. Good luck with the ticket - get an attorney and have your spedo calibrated.

    Re: Speedometer calibration

    Quote:
    cibergypsy said:
    A year and a half ago I visited VA. I went to Williamsburg, Yorktown and Alexandria and really loved the place. Nevertheless, if I am to live somewhere, I cannot do it in a place that will, with 100% certainty, land me in jail some day for something that will only get me a speeding ticket in FL. Here one has to go over 30 mph over any established limit in order for it to be considered an "arrestable offense". Mind how I wrote "arrestable" since it is up to the officer to decide that. At least that is what I got talking with some Deputies around my area. I am planning on visiting it again soon but will have to refrain from having fun once I cross the VA border. When I visited, I got a $94 ticket for having a radar detector even though it was turned off at the time. How many States have laws against radar detectors, for crying out loud!



    I think Connecticut is the only other state that outlaws radar detectors.

    By the way, even if you have the radar detector "turned off," as long as it is plugged in, there is some minor power drain, which is detectable by the radar detector detectors the state mounties have.

    Jim

    Re: Speedometer calibration

    Quote:
    MMD said:
    Everytime I see one of those "cute" GEICO commercials I think about them giving lots of free laser guns to state cops.

    This is true, right?

    What a great alliance: States get more money from fines, Insurance get more money from raising rates. Public gets squeezed and overly fearful of "dangerous 10mph-over speeders."

    Why not just house the insurance company offices in the state capital buildings?

    Really makes me sick because I remember mention of a study done somewhere that concluded MOST drivers WILL vary speeds on roads and conditions _but_ will mostly travel at a _SAFE_ speed given those roads and conditions.

    BTW, would be interesting to find out how many drivers with speed violations get dropped by insurance carriers nowadays. My guess is they will never be dropped unless they can't pay their ever-increasing premiums. get it? It means thet they are not really "dangerous!" (of course if they have huge points or an arrest for 100mph+ THAT's another story).

    sorry, rant over.



    MMD,

    You are right on all counts.

    GEICO is based in Virginia, near Fredericksburg. They bought the first set of radar units (probably radar detectors, too) for the state mounties once the state of Virginia passed a law banning the use of radar detectors.

    You're right again about safe driving. Most drivers drive according to conditions. If it's a safe road, they travel a bit faster. If a dangerous road, they travel a bit slower. Simple as that. Human judgment trumps, and is normally superior to, stupid laws.

    Regarding rates, you're right again (and you're not ranting, you're just being honest about what is a real racket). Here's a good one, again based on my experience. I was insured with GEICO for 25 years. In the early 1990's, after getting four speeding tickets (the last one for doing more than 20 over the limit, doing 81 mph in a 55 mph zone), I had to go to court. Fortunately (for the attorney that is, whom I paid $600 - that was in late 1994), because my speedometer understated my actual speed by 3 mph at 75 mph, I was able to get the reckless driving charge reduced to 19 mph over, and the fine fell to only $83. I had to go through some driver counseling session. Virginia can arbitrarily yank your license pretty easily, all the the whim of some bureaucrat, especially if he doesn't like your attitude. Anyway, to the point of all this. I was worried about getting cancelled by GEICO so I called them to talk it over. Recognizing my long time with them (nearly 20 years at the time), they said the reason they would not drop me was that I never collected from them on accidents. That's all they really care about. Did they have to pay out money in claims? Thus, it's only indirectly that insurers give a hoot about safety. Hell, if driving fast, and presumably unsafely, didn't lead to claims, they wouldn't care one bit!

    Jim

    Re: Speedometer calibration

    Quote:
    SurferDude said:
    Just be careful out there. A speeding ticket on those roads will likely affect your perception of those roads. For me, those roads in VA and WV used to be a lot more fun.



    Yes, I will be more careful. I'll get my butt out to Summit Point, just over the West Virginia line. It's a first class facility, and they have track time on Fridays, both for novices and for those who have gone through their training. It's a winding circuit, lots of fun for going fast with good handling. I haven't tried it yet but have seen it. I saw someone with a Carrera GT out there in May of 2006 and some Lotus Elises along with loads of Porsches.

    Summit Point is near Winchester, Virginia and you can find them on the web with all the details. I think they are all booked up for this year. You either bring your own helmet or they can provide you with a loaner.

    Jim

    Re: Speedometer calibration

    Wow. Jim. They got detectors banned too! Holy s.! Interesting story too; very sorry you got nailed by them. Every fellow Porschephile I know only "speeds" when it's safe. We have the equipment (brakes) and an acute interest in driving and we're not teenagers. If this witch hunt thing spreads to all states I'm getting rid of my fast cars and get a friggin' hybrid and do 55 mph and never more. I will stay in right lane and get out of way (pull off road etc) ONLY for Porsches.

    Re: Speedometer calibration

    Quote:
    MMD said:
    Wow. Jim. They got detectors banned too! Holy s.! Interesting story too; very sorry you got nailed by them. Every fellow Porschephile I know only "speeds" when it's safe. We have the equipment (brakes) and an acute interest in driving and we're not teenagers. If this witch hunt thing spreads to all states I'm getting rid of my fast cars and get a friggin' hybrid and do 55 mph and never more. I will stay in right lane and get out of way (pull off road etc) ONLY for Porsches.



    I just lost a bunch of weight so I'll ride a bicycle for short trips to keep the fat off and get a Smart car with a diesel for everything else. Maybe I can "blow some smoke" their way as an act of defiance!! But I'll keep the Porsche for the track, even though it won't be often.

    Since the "law" is driving us off the roads, the private sector is beginning to offer alternatives. In addition to the relatively inexpensive track about 40 miles from my home (it costs about $200-225 per visit to the track), there is at least one private club starting up northeast of here, in the Pocono mountains in Pennsylvania, that is going to have a race track for its members. You must put up a real chunk of change to get in, but your are guaranteed a certain number of track dates per year. It's sort of like a country club. There are annual dues, too, so it's not cheap. Don't know if any are being started up out west, where there should be plenty of room for such a facility and lots of potential members.

    Jim

    Re: Speedometer calibration

    Quote:
    SVNSVN said:
    Yeah, that seems right. When passing those speed signs- it indicates about 3-4 mph over the posted speed.



    Oddly, when I pass those speed signs in my 06 Club Coupe, the speedo is identical to the posted speed--first one out of the 6 different Porsches I've owned that didn't have a speedo that read 3-4 mph over actual speed. My Audi A6 is off by about 2 mph, btw.

    Perhaps Porsche took extra special care to get the X51's calibrated closely? (Not true, I know; I've read/heard others who have said unlike earlier models, their 997's are very close to "dead balls on accurate").

     
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