[QUOTE=whunter;1729932]Now the question is???

I have a 1985 300SD getting 28 MPG at 65 MPH.

What MPG would I get at 115 MPH???


Claim whatever you wish, since the car won't go that fast.

The mileage will be as believable as the speed!

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Actual mileage can only accurately be determined over several full tank comparisons.

If you think you are getting better fuel economy at 75 than 65 your calculations are erronious....sorry.

I suppose it might be theoretically possible in some vehicle, but I have owned about 100 and it has been untrue with any of them.

I cannot imagine the circumstances in which it might be true.

Tom W

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

65mph uphill and 75mph downhill.

Brian Carlton, thanks for taking the time to work the math. That is why I love math, it never lies.
My question is if we are all so concerned about fuel prices, why are so many people wanting to increase speed limits. I try to drive 65MPH when on the Highway but I'm finding it unsafe to drive this speed. I never drive above 70MPH.
Mike

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1999 E300 Turbodiesel
179,000 Miles

For the same reason they abolished the 55 MPH nationwide speed limit, because to some people their time is worth more than the fuel they saved and that way they can have the choice to drive slower and save some gas or drive faster and save some time. You just can't do both, despite the theories of some people.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I love this thread. I can't believe it actually took a math equation from 5th grade to prove to the "non-book-believing" members that 65mph (versus 75mph) results in better fuel economy. Smashing good fun.

I did enjoy the 240TD pics though.

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1981 240d - 135k - Arlene

Unfortunately, the 5th grade math equations didn't convince certain people of anything..........

My 300TD appears to be getting about 26 or 27 MPG so far, after three tankfuls. That seems pretty good to me.

I was reading the MPG findings on new cars in the last Car and Driver magazne and was surprised at how low it was for a lot of the very small "economy" cars. Is it my imagination, or do cars today get comparatively worse fuel economy than similarly-sized cars from 15-20 years ago?

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" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

It was because 55mph is stupidly slow on a multi-state highway system. 80mph is currently the highest speed limit, I think 95 should be the limit.

.......another factually incorrect statement.

Haha, sorry, I just wanted to say that. I giggled everytime I read a falsehood and then quickly scrolled down to see your reply.

Seriously though.....it doesn't get much simpler than the miles/mpg breakdown.

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1981 240d - 135k - Arlene

A national speed limit of 55 mph was established back in the 70s as the Carter administration's way of dealing with its energy/oil crisis. It was done to save fuel -- because all cars get better fuel economy at 55 mph than 75, which, prior to the enactment of the 55 mph speed limit, was the then-highest allowable speed. Some engineers concluded -- like we just did -- that you get better fuel economy at lower speeds, so one day the President said "we're all going to go slower now to reduce our dependency on foreign oil". It actually worked to some extent, but of course not everyone follows the law either. In the early 90s after a recession hit, fuel prices started to drop because of reduced global demand and by 1997 or so, fuel was really really cheap. I remember getting gas for my Festiva in NJ for $0.79/gallon in some places. It cost me around $5 to fill my 7 gallon tank. If you don't believe me, look really carefully at the opening credits of the Sopranos. Toward the end, you see a drive-by seen of a Sunoco station and you can see the cost of fuel was less than $1. It was filmed in the late 90s.

In any event, the battle to raise speed limits took root in the mid 90s since some lawmakers in Montana and elsewhere -- where some highways go straight for hundreds of miles -- though he could get some more voters behind him by proposing to raise speed limits. Fuel was so cheap it didn't matter. It worked, and that's where we are today.

They say everything is cyclical and it wouldn't surprise me if speed limits drop again.

-a traffic engineer (honestly)

Swift limits their truck's top speed to 63mph (Recently lowered from 64mph) in the interest of fleet fuel economy.

The problem is that they firmly believe those are the results they are getting. If you were repeatedly taking measurements and getting those results yourself, how could you not stand by what you saw yourself with your own measurements?

I would tend to think their measurements are off in some way or there are some other factors involved, but you can't blame them for believing what they are seeing with their own eyes rather than what someone else tells them, "has to be true." Both of you see the other as an idiot because of what you "know" is true. There is no point to arguing either way or putting people down over it.

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FYI, It didn't take BC's math to convince me, I was just thanking him for taking the time.

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1999 E300 Turbodiesel
179,000 Miles

I think that making diesel fuel $3.60 a gallon is a pretty effective way to get people to try harder to conserve fuel. It works for me. I don't LIKE it, but it IS effective.

__________________
" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles