991 Fuel Consumption
#31
Burning Brakes
Join Date: Mar 2004
Location: Calif
Posts: 1,151
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
re 1/X - I guess I find it obvious that a constant value improvement in MPG is a decreasing percentage improvement - it is clear from the math - what is not at all clear is why that makes MPG a bad metric. by the same argument, going from an average speed of 10 mph to 20 mph gets you to your destination in 1/2 the time. going from 100 mph to 110 mph only gets you there 10% sooner. Does that make MPH (or KPH) a bad metric? we should use seconds per foot as our metric of speed? (or if you prefer, microseconds per milimeter)??? We use units of measure that we are all comfortable with and which are convenient for their intended purpose. We could infact measure distance traveled in steradians, but it wouldn't be very helpful, miles (or km) is much more useful.
#32
Platinum Dealership
Rennlist
Site Sponsor
Rennlist
Site Sponsor
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
for me the price of bad mpg is more about having to spend additional time at the pump, not so much the financial cost of the car...I just hate having range anxiety. I hate having to get gas every other day- I drive a lot, and have a few different cars, and don't have lots of spare time built into my day. I really don't like the "who cares about mileage" thing because everyone buys cars for different reasons and uses.
these are relatively expensive cars but when you can get that one extra leg of your commute without having to pull over at a non-familiar gas station it adds to the peace of mind. all things being equal a 25mpg car saves you that little bit of cumulative time vs a 15mpg car.
with cars that are part time use like typical italian stuff or a CGT (<3k miles per year) then obviously you don't really care about mpg or gpm because driving the car is such a special occasion...but these 911s/991s are sold as EVERYDAY cars...sure they are special but their flexibility and usability is the real reason why we like them more than cars that are outright faster (zo6, viper, etc) for this purpose.
at least porsche makes durable, easy to use clutches in their 911s.
these are relatively expensive cars but when you can get that one extra leg of your commute without having to pull over at a non-familiar gas station it adds to the peace of mind. all things being equal a 25mpg car saves you that little bit of cumulative time vs a 15mpg car.
with cars that are part time use like typical italian stuff or a CGT (<3k miles per year) then obviously you don't really care about mpg or gpm because driving the car is such a special occasion...but these 911s/991s are sold as EVERYDAY cars...sure they are special but their flexibility and usability is the real reason why we like them more than cars that are outright faster (zo6, viper, etc) for this purpose.
at least porsche makes durable, easy to use clutches in their 911s.
#33
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
re 1/X - I guess I find it obvious that a constant value improvement in MPG is a decreasing percentage improvement - it is clear from the math - what is not at all clear is why that makes MPG a bad metric. by the same argument, going from an average speed of 10 mph to 20 mph gets you to your destination in 1/2 the time. going from 100 mph to 110 mph only gets you there 10% sooner. Does that make MPH (or KPH) a bad metric? we should use seconds per foot as our metric of speed? (or if you prefer, microseconds per milimeter)??? We use units of measure that we are all comfortable with and which are convenient for their intended purpose. We could infact measure distance traveled in steradians, but it wouldn't be very helpful, miles (or km) is much more useful.
But, 1/x metrics are BAD metrics. You buy insulation by R-value, not thickness. R-value is proportional to 1/thickness, and directly proportional to heat loss/gain. The 1/x thing is the reason the high-math-skill countries (the rest of the world) use liters/100 kilometers (or liters/100 miles) to measure fuel use, and they don't think about fuel economy (1/fuel use). It's the same reason the EPA does geometric averaging (GPM) when calculating CAFE.
Actually 110 MPH only gets you there 9.09% sooner than 100 MPH. By screwing up that simple calculation, you just proved my point that 1/x metrics are bad metrics.
![ooops](https://rennlist.com/forums/graemlins/icon501.gif)
#34
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Just by coincidence, I rented a Prius V today. I'd reserved it last week, before this crazy thread started. It was brand new when my wife picked it up. So far, 50.6 MPG even with the AC blasting. Gaming the MPG meter makes you drive like an old person though.
Final update (I promise): The right off the truck Prius V ended up with 51.0 MPG when I turned it back in. As I pulled into the Toyota dealership's parking lot it was at 50.9 MPG. But, my batteries were at a high level of charge, so I drove around the dealership's parking lot until it clicked up to 51.0 MPG.
MPG the first 300 miles on a new car is horrible. I wonder what a broken-in Prius V would get.
Final update (I promise): The right off the truck Prius V ended up with 51.0 MPG when I turned it back in. As I pulled into the Toyota dealership's parking lot it was at 50.9 MPG. But, my batteries were at a high level of charge, so I drove around the dealership's parking lot until it clicked up to 51.0 MPG.
MPG the first 300 miles on a new car is horrible. I wonder what a broken-in Prius V would get.
Last edited by goatboy; 10-03-2012 at 11:07 AM.
#35
Burning Brakes
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
33.6 mpg today at 75mph from State College Pennsylvania to near Philadelphia. The car is fully broken in. Oil and filter changed at 2000 and 6000 miles.
This car is amazing
This car is amazing
#37
Drifting
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Ya'll are doing this wrong. The harder you drive the car, the worse the mileage you should get. It's like you're bragging about being the slowest kid on the track team.
So... what's the worst mileage you've gotten?
So... what's the worst mileage you've gotten?