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Driving Over 80 MPH Will Cost You

Discussion in 'Prime Fuel Economy & EV Range' started by axle2152, Oct 28, 2018.

  1. axle2152

    axle2152 Active Member

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    Mind you, I'm not talking about getting a ticket. From watching Weber Auto on YouTube I know that the gear ratio on the Prime is slightly different than the regular Prius and I also had a 2016 Prius Two before the Prime. Oh and check out Weber Auto on YouTube, tons of stuff about the Prius, if you're mechanically curious or a techie...or just want to know.

    I will admit, I do have a bad habit driving pretty fast on the highway and South Carolina, for whatever reason seems to always drive faster than the usual traffic.

    I got the worst gas mileage of any of the two other Prii I have owned coming back between Wilmington, NC and Atlanta, GA. 41 MPG... I wasn't hot rodding it but I was at speeds after north of 85 MPH. I've done similar with the other two but always seemed to manage at least 45 MPG. Of course 40...anything is nothing to complain about, especially at those speeds. Sure your Accords and your Civics can achieve 40+ but I really doubt they'll get that driving at those speeds.

    Mind you this was all in HV mode. From what I can tell, there is a very steep bell curve north of 75 MPH, 75 MPG I can get 56-58 MPG..and if I drive 55-60 MPH it's closer to 70 MPG.

    Anyway, I won't discuss speeding, the justification for it. All I can say is drive safely at whatever speeds you drive. I was safe doing it, I don't tailgate or drive like I'm playing GTA. Anyway, somewhere I read the Prime has a top speed of 101 MPH, well I don't know how fast it will go but I did hit 105 at one point.

    Over all the Prime is a better Prius, I think Toyota needs to make a full EV version. I think it was a shame Toyota and Tesla no longer work together. I think both could have benefitted from each other.

    I say that because the Prime, drives fine in EV mode if you're not going over say 60, anything north of that it just lacks power in the acceleration department. It's plenty zippy from a stand still, but the torque/power curve quickly drops off and the gains on the electric motor are reduced. Yeah you can drive 80 MPH but if you go up a hill it won't gain anymore speed. It's almost like a diesel, it won't slow down going up a hill (within reason) but you won't really accelerate. Motor is much more efficient at lower speeds. I think I'm probably restating what's already been said on that but in case you didn't read it in another thread well, here it is again.

    Again, I do not condone nor am I encouraging reckless driving. I mean if you're driving 90 MPH, that's probably what you're going to get slapped with. If you're going to do this stuff, at the very least do it when there is little traffic on the highway, do no tailgate or any of that crazy crap. There's risks involved, tires can blow out, deer and debris on the road and of course other drivers. All that plus your fuel economy is going to suck. If I had just driven 75 MPH probably would have got another 150 miles down the road on the same tank of gas.
     
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  2. bisco

    bisco cookie crumbler

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    makes all the sense in the world. i stay with the speed limit, for several reasons.
     
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  3. padroo

    padroo Senior Member

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    Years ago I was in a 45 mph zone and I had a tailgater on my butt. I was doing the speed limit and in a passing zone but this guy just had to ride me. I noticed something in the road up ahead and it was a big old cardboard box the size of a refrigerator in my lane. I maintained my speed and right before I was going to hit it I made a lane change to go around it. The tailgater ate that big old cardboard box.
    I wonder if he ever figured it out that if he would have maintained a proper following distance he would of had time and went around that big old box like I did. I normally don't have horns on my head. :D
     
  4. axle2152

    axle2152 Active Member

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    As far as driving in general goes. The outliers are the most dangerous... the guy in the Audi driving 100 MPH and weaving in out of lanes and the guy in the rickity pick-up truck going 50 MPH.

    Tailgating, simply following too closely causes wrecks. Simply leaving more space, even if you're driving like a bat out of hell can make all the difference.

    Slower is better for the Prius. Of course it will get better fuel economy compared another car under the same conditions.

    Normal conditions I can get 30 miles EV, and you have to work hard to get worse than 60 MPG around where I live.
     
  5. bisco

    bisco cookie crumbler

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    we get our best mpg's through north and south carolina, even though the limit is 70
     
  6. axle2152

    axle2152 Active Member

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    I always vote for dash cams FYI. I do think there really is a stigma against people who drive a Prius. Probably due to a video with some lady who happens to drive a Prius screaming at a couple of guys who had diesel trucks.

    I have also found this to be true with my 2016 Prius and my 2018 Prime, GPS reports my speeds being between 2-3 MPH slower than the speedometer. So if the speedometer says I'm driving 55 MPH, GPS shows I'm going 52... That being said, I can't say what other cars do, but if this is true this might explain some of the tailgating. I'm a stickler for slow pokes. If the conditions do not call for someone driving under the limit I get quite annoyed, or I used to...learning to be more patient.

    My opinion if you're going the speed limit that should be good enough. That being said, if you're in a 45 zone and the traffic is whizzing by you like you're sitting still then you really should be going faster. The outliers cause wrecks in my opinion, the people driving the fastest and the slowest. Not saying that either driver is the cause but could be setting the stage for something bad to happen. I'll give you an example. Columbia, SC. Interstate 20, 3 lanes. Speed limit is 55. No one is going 55. People are driving in excess of 80 in the left lanes and in the right lane around 70. If I were to be driving 55, or even 65, I could cause the conditions that could cause a wreck. An impatient driver swerves in the left lane to pass me causing someone behind them in the left lane to slam on their brakes, swerve and could cause a wreck right there involving several vehicles simply because I was just driving the speed limit. Plenty of dash cam videos out there to show a scenario like this. No, usually doesn't explicitly involve a driver going much slower than traffic in the videos I've seen but I've encountered people driving unexpectedly slow that someone in front of me swerves into the next lane to avoid them leaving me to slam on the brakes and try to merge.

    Not trying to knock anyone for hypermiling or driving the speed limit. However, I think going with the flow is the best rule and probably the safest.
     
  7. bisco

    bisco cookie crumbler

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    i have to disagree. a law abiding citizen may be an outlier, but never the cause of an accident.
     
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  8. Diemaster

    Diemaster Active Member

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    you got worse MPG b/c at 84MPH the EV motor dosent have enough torque left and is maxed out. at 85+ MPH, the ICE kicks in (even in EV mode) to accelerate the car faster. this is why the sudden MPG drop. the Prime can go max 110MPH i think. my old civic was 113 but that was on speed appropriate rated tires. Stock Prius tires shouldn't go faster than about 80-85 per the speed rating.

    here in CA i get dirty looks just for not keeping up with the speed limit + 20MPH flow of traffic. i love i have the carpool stickers. most of the time i go the speed limit in the carpool lane. i want to get a dash cam so i can get a part time job and review the footage, write down the licence plates of the cars that cut me off that dont qualify to be in the carpool lane. then send that to my local sherrif office. who knows maybe if i did that it would give me a venerable "get out a ticket free card" LOL.
     
    #8 Diemaster, Oct 28, 2018
    Last edited: Oct 28, 2018
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  9. sam spade 2

    sam spade 2 Senior Member

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    This is not news and should not surprise anybody.
    It applies to ALL vehicles. It is just more dramatic in some.
    Most of your fuel is used in bucking wind resistance......which goes up exponentially as your speed increases.
     
  10. axle2152

    axle2152 Active Member

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    I would have to agree in most cases, where traffic is going considerably faster than the posted speed limit, yes a wreck resulting in a driver swerving around a slow driver who is going the speed limit wouldn't be legally at fault. Someone has to be tailgating at some point or not paying attention. Perhaps another thread in one of the other forums we can get into the whole butterfly effect of things. Sometimes it's not the citizens, but lousy laws and lack enforcement. Clearly, the stretch of I-20 needs much more law enforcement, problem solved. There's too much traffic going way too fast with all the interchanges. West Texas would be a different story.

    Haven't had the pleasure of driving in CA, but if traffic is going 20 MPH faster than the limit and you're driving the speed limit in the carpool lane yeah you're likely ticking off people. Not that I care, you do you. I won't get on my soap box and my philosophy of driving.

    I use a Thinkware F550, it is a 2 channel dash cam, both 1080p. Has park mode and isn't too crazy expensive. There are some newer models the F770 and F900 which are little more expensive. There are some that have a 4k up front and 1080p rear but I haven't personally used the brand but looks like they're comparable to the Thinkware cameras.

    As far as reporting people. My opinion is to only report people who are being reckless, if they're running you or someone off the road, brake checking and on that sort of thing then yeah I would report them. Likewise the whole point of the dash cam is to prevent insurance fraud. It can also tell on you too...
     
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  11. axle2152

    axle2152 Active Member

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    I guess I didn't do a good job explaining what I'm getting at. I had a 2016 Prius, it would be a little less of a drop in MPG under those conditions and I think it has to do with the gear ratio (on final drive? I'll have to go back and lookup what the differences are in the transaxle) between the regular Prius and the Prius Prime.

    Yes wind, engine RPM's and motor torque are all factors. I don't think a 300 lb battery should be enough to make a significant difference. I've never noticed a difference unless I had 4 people in the car.
     
  12. sam spade 2

    sam spade 2 Senior Member

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    Forgetting the hybrid factors, partly because they come into play less and less the faster you go...............
    In general, a smaller engine will suffer more as the speed goes up because it is designed so that there isn't much excess power available.
    A large truck with a 350 HP engine that might get 15 MPH at 60 MPH, might still get 13 at 80.
    A tiny little economy car with an 80 HP engine that gets 50 MPG at 60 MPH, might go down to 30 or less at 80.
    The engine is straining more to keep up and the rev's need to be higher to produce the necessary horsepower.
     
  13. Mendel Leisk

    Mendel Leisk Senior Member

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    Let me get this straight: the speed limit is the minimum you should be going. Huh, didn't know that.
     
  14. Salamander_King

    Salamander_King Senior Member

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    75 mph is probably my max on any interstate driving. Now if you do the cost and time saving comparison say for a 300 miles drive at constant speed using your figures.

    85 MPH 41 MPG you save 88 min but use 3.03 gal more for gas compared to 60MPH
    75 MPH 57 MPG you save 60 min but use 0.98 gal more for gas compared to 60MPH
    60 MPH 70 MPG takes 300 min and use 4.29 gal

    If you assume gas cost is $2.50, the extra cost would be $7.58 for 85mph and $2.44 for 75mph compared to 60mph. I guess, there may be a time when saving 88 min is worth more than $7.58, that's if you don't get caught speeding or do not get into an accident by speeding.
     
    #14 Salamander_King, Oct 29, 2018
    Last edited: Oct 29, 2018
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  15. Salamander_King

    Salamander_King Senior Member

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    Are you asking about minimum speed posted on interstate? They are quite popular on many interstate highway in the US.
    Speed_limit_85.jpg
     
  16. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah, don't see that much up here, not a bad idea.

    I'm pretty sure @axle2152 was referring to the speed limit, in the post I took a partial quote from.
     
  17. axle2152

    axle2152 Active Member

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    @Mendel Leisk Yes, I understand that a speed limit is the speed that you're not to exceed. Some states are different in interpreting the speed limit or what they will consider speeding. North Carolina for instance 56 in a 55 is speeding, will you get a ticket for doing 56 in a 55 no, of course not.

    Now why would they have a minimum speed on an interstate? Hmmm...

    The point I'm making, legal or not, if the limit is 55 (88 km/h) and the 4 lanes of traffic are all going 70+ (112 km/h), that's a fair bit slower than the rest of the traffic. If you ask me those who do drive like that are increasing the risk of an accident, like it or not, legally responsible for such an accident or not. Mind you I'm not talking about driving in the middle or town or around a residential area where there might be people or kids out playing, I'm speaking of highways and interstates.

    Even insurance companies have a few things to add...

    Slow Ride: the Dangers of Driving at Low Speeds | Esurance

    Here's a good example of what I'm talking about.
     
  18. CraigM

    CraigM Active Member

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    I wonder how some folks coped in the mid 1970s with the 55mph national speed limit?
     
  19. The Electric Me

    The Electric Me Go Speed Go!

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    The way the world has evolved....
    IMO doesn't matter what you are driving, the environment usually doesn't allow for really great speed.
    Just the other day, I was caught in a traffic jam on the highway, behind a really beautiful Porshe.

    Not sure of the model, but wide tires, huge spoiler and a real "super car" look. I'm sure it was capable of amazing acceleration, given the pavement to facilitate it. It really was a beautiful vehicle.

    But for the majority of our shared highway experience, I matched the Porshe's driving experience....with my Honda Fit. At considerable less fuel expenditure I'm sure.

    My point is?
    The older I get, and the more congested highways and freeways seem to become?
    The more I realize that a vehicle with simple average speed and acceleration capabilities is fine with me.

    I seldom find the NEED or the OPPORTUNITY to accelerate from 0-60 in less than 6 seconds.
    So if I'm driving something that demands a few seconds more?
    I don't really care.

    My 4 cylinder Honda Fit, IS capable of legal highway speeds. It can reach those speeds safely.
    Those are the acceleration standards I now embrace.
     
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  20. sam spade 2

    sam spade 2 Senior Member

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    Yep. Totally predictable.

    No more inter-city train service.
    Lack of infrastructure funding......as politicians ALL concentrate on things they shouldn't even be involved in.

    Those who forget the failures of history are doomed to repeat them.
    And those without foresight are doomed to fail.

    Environmental awareness is one example.
    Crumbling infrastructure is another.