924Board.org

[alxch1n15]

so for everyone who lives in wisconsin, paul and flosho...im sure you've heard of the bill that will raise the speed limit on expressways to 75. the state claims that if you go faster, you waste gas. but thats not what i was taught in physics oh so long ago, its how fast you accelerate that burns more gas. once you reach cruising speed, your gas consumption levels out. but the state claims that if you go 75 as opposed to 65 your mpg can go down about 10???! so my camry gets 36 mpg on the freeway going 70, so if i went 75 it would go down to 26mpg? i dont think so! any comments or ideas?
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'81 924 n/a

[Neil924]

ie: If you are moving at city speeds {50 hph} towards your weekend getaway it will take you longer to get there than if you were moving at highway speeds {100 kph}. But you will also save fuel.

If you're going to the cottage moving at 300 kph you will get there quicker but you'll use a lot of fuel.

That's why race cars can use a gallon of fuel on a 2 mile super fast oval track in the sun and if the track is wet {or there is a caution} they don't go as fast, so they save fuel.

And yes your mileage will level out when you get up to highway speed and stop accelerating but it will level out at a higher point than if you were going slower. I can spend 25 cents a km if I want or I can spend 15 cents a km, depending on if I accelerate hard or go very fast.

[Kenodog]

During the fuel crisis of the 70's the then president Carter ? or possibly Ford,can't remember,passed a law stating that all federal highways had a maximum speed limit of 55 mph.This was because that is the speed at which MOST vehicles,on average,get the most miles per gallon.
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1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140

[alxch1n15]

so is the difference between mpg going 60 and going 70 huge? i guess if it isnt, i dont understand why the wisconsin legislature would make a huge fuss about it. the more gas used, the more gas bought! so it help to, i guess, force gas buying, resulting in more revenue.
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'81 924 n/a

[skemcin]

every car is different from the other.

in general, accelerate gently and brake hard, and cruise on the roadways - that will save you the most gas. I've done little experiments with this - and your driving style can save you big money.

i.e. my daily driver is 01 Mitsubishi Montero Sport and my wife has a 02 Subaru Impreza Outback. Our commutes (before she got laid off) where practically identical but I got 18 to 19 mpg to her 15 to 16 mpg - all because she hits the gas when its green and moves in and out, up and back with traffic where I acceletate more gently and maintain a more consistant speed even in rush hour traffic.

Have you ever noticed in rush hour why truckers aren't up on the everyone's butt - its because of three things (a) its a pain to get those things rolliing (b) it actually helps un jam traffic (c) becuase it saves fuel.

Now this next bit, I admit, is a little speculation on my part (please anyone jump in a correct me), but a good guide to run by is what you vehicle is rated for its maximum horsepower at what RPM. Cuz, if you get 125hp at 6000rpm, then running then engine at any higher RPM is a flat out waste. All in all, your RPMs are a good guage for how much fuel you are consuming but it alone doesn't necessarily tell you if you are running as efficient as possible - going 20mph in 5th gear may yeild 1200rpm, but its not ideal.

As I said, I know my experiment is pretty sound, but if I am off on the last bit, i hope someone jumps in to correct me.

All in all you won't find a big difference in most cars betwen 40 and 90 miles per hour - i've made the same trips averagin different speeds and still end up using a tank going there and a take back.
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924.org (no time to complete)
9249206346 - 89k – new shifter bushings, belts, running well.
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[AppleBit]

Any car will have an optimal place to travel at a certain speed because of torque curve, gearing, wind resistance and many other factors.

You will push more air with a truck over your Porsche for example.

It is true that the more speed that you are traveling you have the likely-hood of not having as well of gas mileage but by 10 mpg is not true. From 65 to 75 mph you might see a 5% average drop in mileage but for some cars going from 65 to 75 mph will make no difference since either the engine is too small to make a difference or the gearing is better in that rpm range.

I watch my gas mileage EVERYWHERE I go and know that traveling in any of my vehicles and putting the pedal down further will result in a little less mileage but not significant. My Saturn mileage in the summer time is around 32-33 mpg at 65 mph. At 75 mph it can vary from 31-32 mpg. For the travel time dropping significantly I feel this is totally worth it. Cars back in the 70's had carbs and were not as good at optimizing fuel and so when you travelled 10 mph faster you would see significant drop in mileage, but that all varied.
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[alxch1n15]

i wish i could send this to the wisconsin legislature....

everyone wants it, but there is no one in the legislature to voice that opinion. i dont see how these people are elected to their offices....
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'81 924 n/a

[stexch]

Another factor to consider is the benefit to the economy that an increase in speed limit would bring by reducing the amount of time employees and contractors spend on the road. By increasing speed by 15% (65 mph to 75 mph), you cut the time that all the people on-the-clock spend on the road by 15%. When you factor in the real cost of labor (including both wages and benefits), I would speculate that the value of man-hours saved exceeds any additional fuel expense. This applies whether the workers are state employees or private sector employees.

Manufacturers can make overdrive high gear as tall as they want, thereby reducing rpm to the optimal level for mpg.

[Neil924]

Speed also kills.

[alxch1n15]

there was some study that was done on some expressways in wisconsin and i guess they found that if we increased the speed limit there would be less accidents. something about something and something....ill look it up after work. but i think that if you're going faster than 50, hitting anything will do a lot of damage.
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'81 924 n/a

[teo]

[AppleBit]

[stexch]

Here are the top causes of fatal accidents:

1. Driving while intoxicated or improperly medicated (including alcohol, legal&illegal drugs, & those who need to be medicated but aren't);

2. Inattentive driving (including putting on make-up, talking on cell, falling asleep, changing CD's);

3. Unfit drivers: While many of the oldest and youngest drivers do just fine, there is a segment of this group that poses a danger. This also includes those with anger control problems. If you have such poor anger control that you use your car as a weapon, you shouldn't be driving.

4. Driving at a spend that is at great variance with the prevailing traffic. If you charted speeds, you would find a bell curve around the speed limit. It's those that are on the far left and far right that are involved in the accidents (accounting for the other factors mentioned above). Thus it is a waste of resources ticketing those that are within 10mph of the posted limit, as they pose a minimal risk.

While the best law enforcers use profiling to pick out who to stop (often using a minor speed violation as a justification), there are those who lose sight of the big picture, and write tickets just for the sake of writing tickets. I hated being profiled when my daily driver was a Camero, but now that I primarily drive a plain white pickup I enjoy being practically invisible.

[D Hook]

Back in the 70's I remember when they passed the 55mph max on all interstates and highways, the truckers were very upset. They said their rigs were more efficient at higher speeds and at lower speeds they would use more fuel.

A few years ago, when they lifted the 55 and let states set their own limits, the truckers were very upset. They said their rigs were more efficient at the lower speeds and at higher speeds would use more fuel.

These were both newspaper articles I recall reading.

I still haven't figure that one out.
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'80 924 n/a SOLD

[Neil924]

"Speed kills" means, the faster you go, the less reaction time you have and if you hit somthing you will hit it with more force {energy} and do more damage. I'm not for lowering the speed limits but they should be too fast for everyday driving.