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how often do you try to beat people off the line?

Discussion in 'Gen 3 Prius Main Forum' started by markabele, Jul 31, 2012.

  1. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Before 1990, most cars had carburetors, which used vacuum to (badly) adjust the fuel/air ratio so the gas would ignite. One problem with carburetors is that when you accelerate hard , the F/A goes very lean, increasing combustion temperature and detonation. To 'solve' this most (all?) carbs had Power valves to make sure you were rich during acceleration to keep temps (and detonation) in check. Additionally accelerator pumps poured in pure gas to prevent a 'stumble' when first accelerating. Gentle acceleration did not engage these systems and was wildly more fuel efficient than brisk acceleration.

    No car sold in the US had a carb since 1995, these reasons for gentle acceleration have not existed in 20 years.

    With Fuel Injection we have new concepts: Open Loop and Closed loop

    When the car first starts, before the Catalytic converter warms up, the fuel injection is in an Open Loop, no feed back from the O2 sensors are telling the computers how to fine tune the F/A mixture. The computer uses a map, a table of predetermined and stored values to keep near perfect F/A ratios. Very strong acceleration may also make the ECU choose an open loop mode. Some ECU codes will throw the car in a Open Loop 'limp home' mode.

    Once the Prius is warmed up, the Fuel Injection starts using feedback from the O2 sensors to keep a perfect F/A ratio, always adding the correct amount of gas in a Closed feedback Loop. While your car is in a Closed Loop ideal economy emissions, and efficiency are in constant tune.

    Now if you 'peel rubber' you are still wasting gas, and if you accelerate so hard your computer goes Open Loop, you are wasting gas. (The Scangauge II can tell you when your Prius is open loop or closed loop, but it is dull as it is almost always closed loop) Other than that, getting to a set speed will cost the same amount of energy. (minus efficiency losses)

    Accelerating so hard you suck power out of the battery, then have to recharge the battery, would be an example of one such efficiency loss. Accelerating so soft you are trying to pull air passed an almost closed throttle plate, would be another example of efficiency loss.
     
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  2. Hoosier1

    Hoosier1 Member

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    Going with the flow of traffic is the key to maintaining respect on the road. Most of the Prius encountered during my daily commute actually pass me, and I drive 5-10 MPH over the speed limit. After owning a BMW 335 that would reach 60 MPH in five seconds, I just enjoy the Prius for what it is...a car that gets great fuel mileage. A Prius will put a smile on your face at the fuel pump, but a 335 BMW is the ultimate driving machine. All high quality materials, built like a tank and loads of power and performance but twice the price of a Prius with half the MPG.
     
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  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I messed with the Open Loop/Closed loop on my scangauge in my Prius. I was unable to accelerate hard enough to get out of closed loop, but any time the engine is not producing power it is open loop, which makes sense if you add no gas, you will never have a perfect Fuel/Air ratio. (mind you, 0% fuel/100% air is some other perfect Fuel /Air ratio)
     
  4. priuscritter

    priuscritter I am the Stig.

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    i agree with wfolta, weoh and hoosier. Time and place for everything, and being a prick in traffic does no one any good. nobody likes a prick in traffic no matter what they drive.
     
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  5. NiHaoMike

    NiHaoMike Member

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    There are other good reasons with automatic transmissions and CVTs. Torque converters (when not locked) are very inefficient under heavy load and more gentle acceleration allows the transmission to upshift earlier. (There is a "release and reapply" trick to get the transmission to shift earlier, but it's hard to get it just right.)

    With a manual or automated manual transmission, a common hypermiler's trick is to shift early and keep the engine in the 1000-2000RPM or so range, keeping the throttle open at about the optimum efficiency point. I'm pretty sure the Prius does that automatically.

    I pretty much always stay just below red until I'm up to speed. Where the lights are timed such that accelerating like the average driver makes you miss the next light, slowing down often lets you make the next light, the light after that, and the light after that. In that situation, it's actually faster to slow down a little.
     
  6. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    Everyone has a different definition of what that is so it's kind of a bad argument.
     
  7. priuscritter

    priuscritter I am the Stig.

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    there may be different definitions I suppose, although common sense pretty well dictates what that is.

    My idea of a prick on the road is someone who drives dangerously or makes me change my driving situation. For example, cutting off a person, pulling out in front of someone, driving well below or well above the flow of traffic, not knowing what's in your truck bed until after it flies out and hits another car, that kinda stuff.
     
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  8. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    I would agree with that definition but I would add anyone that is totally oblivious to fuel economy, which is probably 99% of the people on the road (including a lot of Prius drivers).

    Let me put it a different way, people who don't try to improve FE on their given vehicle have zero right to complain about money (or lots of other things).
     
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  9. Brett.

    Brett. Junior Member

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    In reply to the original topic: Anybody who rides my rear bumper (As I'm doing the speed limit) relentlessly on multi lane highways with the potential to pass, but for one reason or another never does, then finally as a light turns red they pull up next to me. Those are the people I waste a few mpg on.
     
  10. sdtundra

    sdtundra Senior Member

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    I drag raced my friend in his Civic Hatch....single cam, non v-tec 2400lbs, 106hp stock, his is probably around 130 but with the added 15x8 wheels and a sound system with 2 12 inch subs adds weight...needless to say he was disappointed at the loss to a "girls car".
     
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  11. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    As a male, it is embarrassing that all cars designed for adults are called Chick Cars.
     
  12. Brian T

    Brian T Junior Member

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    I agree Jimbo, the other guys at work quite often take the "mickey" out of me for having a Prius. At the end of one of these conversations, I threw in "well I get 600 miles for £50 worth of fuel" and the smile suddenly went off their faces and one (the FD) said really... I left it at that, feeling smug! £50 in the UK gets you about 9 uk gallons at the moment (10ish) US gallons. Even more reason in the UK to have a Prius!
     
  13. priuscritter

    priuscritter I am the Stig.

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    i have had two experience that some would refer to as emasculating. I traded my full size pick up for a nissan altima, and i traded a mustang gt for the prius. the thing is, i like all of those vehicles. i felt bad getting rid of the truck and the mustang. but i liked the two cars also. it's very confusing.
     
  14. ftl

    ftl Explicator

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    Richard Feynman was one of the great geniuses of the 2oth century, and I always remember the title of one of his books: "What Do You Care What Other People Think?"

    This comes from was when he was a senior in high school in Far Rockaway (not far from me here on Long Island) back in the mid-1930s. He relates how his girlfriend (later his wife) was very sensitive to other people's feelings. His view was as follows:

    "I thought one should have the attitude of 'What do you care what other people think?' I said, 'We should listen to other people's opinions and take them into account. Then, if they don't make sense and we think they're wrong, then that's that!'"
     
  15. brucepmiller

    brucepmiller Member

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    Meh. Have noticed recently that some days everyone drives slow and some days everyone drives fast. Phases of the moon?
     
  16. car compulsive

    car compulsive Active Member

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    My Prius is faster 0-60 than the car it replaced, an 07 Subaru Ouback 2.5 auto.

    This afternoon, I pulled up to turn onto a 55 MPH road and my GF said to turn into a traffic opening right after a Mustang passed. I agreed, made the left turn, and got up to speed with no problem. Just about then she asked if we were riding in my GS or the Prius. (She's vehicularly challenged - and it doesn't help that both vehicles are pearl white.) She said that if she realized we were in the Prius, she'd have told me to wait.

    Later I pulled away from a light and the guy in a new Focus in the left lane didn't turn left. About 200 feet up the road, it narrowed to one lane and I got there first. When I looked in the mirror, they were laughing that they were just beat by a Prius.
     
  17. lovemypriustoo

    lovemypriustoo Junior Member

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    I must confess I often accelerate briskly off the line ... I like to see cars who have been tailgating me to a red light and then when the light turns green I accelerate quickly and they are 3 - 4 car lengths behind me thus making them trying to catch up to me again at which point they back off from tailgating me and drive with the flow of traffic as they should. I too prefer to accelerate briskly and then pulse and glide when possible for mpg's. With that said, I am very happy to be averaging 50+ mpg's driving in rush hour traffic with a/c during this extremely hot summer we have been having!
     
  18. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    Tailgaters are like children. If a child is throwing a tantrum is it best parenting practice to give into their desire? Most people would say no. Tailgaters are the same. If you leave them in the dust you are doing what they want. If there is very little traffic around with more than one lane I will continue to slow down if someone is tailgating me. Maybe they might think twice about tailgating someone again...probably not, but maybe.
     
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  19. xs650

    xs650 Senior Member

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    Rolling roadblockers are like children. If a child is throwing a tantrum is it best parenting practice to give into their desire? Most people would say no. Rolling roadblockers are the same. If you adjust to their speed you are doing what they want. If there is very little traffic around with more than one lane I will continue to pass if someone is a Rolling roadblock. Maybe they might think twice about Rolling Roadblocking someone again...probably not, but maybe.

    Rolling Roadblocks and tailgaters are opposite sides of the same coin, both are self centered twits that mess up the flow of traffic. A pox on both of them.
     
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  20. brucepmiller

    brucepmiller Member

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    My coupe rode so badly on run-flats that it drained all joy and fun from what I was used to in a BMW.