The Best Gas Guzzlage

me27821 · Nov 3, 2007

You know the scam the government gives us? Driving the speed limit gives you the best gas milage? Well, it seems for my 04 stick shift GT, it gives me the best gas guzzlage. The speed limit on a road I drive every day, is 55mph. It seems that I either have to be in 4th gear at about 2500rpm, it 5th gear at about 1400 rpm. If I understand right, you dont wanna be driving around at a low rpm, especially when there's hills. That means I have to drive at a gas guzzling 2500 rpm for a half hour, or do 65-70. Now I know every type of engine is different. So, what's the low rpm limit for the 4.6? What is a safe level, before you risk doing damage to your engine. Also (and I know this is something everyone would love to know), what rpm range gives the BEST gas milage?

04DarkShadowGT · Nov 3, 2007

When I had my 5spd car anything above about 50mph I used 5th and got very good mileage. I got over 25mpg on my 04 GT 5 speed.

DBMSTNG · Nov 3, 2007

you could drive at 500rpm as long as the car made enough power to move it efficiently. hell, i drive my focus at 2000rpm at 55mph and it's got less than half the displacement and torque of the 4.6L. 5th gear at 1400rpm is fine on a V8.

CobraRed_96_GT · Nov 3, 2007

52-55 is perfect for my auto w/ 3.73's. anything around and over 70 really is bad for gas milage.

Stangsgrl · Nov 3, 2007

they mainly say 'drive the speed limit for good gas mileage' because the faster you go the higher your drag so lower gas mileage....

i just try to keep my rpm's around 2k though. when i'm on a road that's 55mph...i try to stay around 60 so i can be in 5th. i don't like being in 4th at 55mph either. I know how you feel lol..

SaleenGT2001 · Nov 3, 2007

get a 6 speed. i am turning 1900 rpm's in 6th at 80MPH with 3.90's

i got 23 MPG on the interstate with a S/C car running 60# injectors!

StangYellow · Nov 3, 2007

If you are getting more than 200 miles on a full tank, you are driving your Mustang like a Betty.

Scorcher2005 · Nov 4, 2007

I get 15mpg in mine. I use 5th all the time once ive hit my desired speed.

Mustang5L5 · Nov 4, 2007

me27821 said:
You know the scam the government gives us? Driving the speed limit gives you the best gas milage? Well, it seems for my 04 stick shift GT, it gives me the best gas guzzlage. The speed limit on a road I drive every day, is 55mph. It seems that I either have to be in 4th gear at about 2500rpm, it 5th gear at about 1400 rpm. If I understand right, you dont wanna be driving around at a low rpm, especially when there's hills. That means I have to drive at a gas guzzling 2500 rpm for a half hour, or do 65-70. Now I know every type of engine is different. So, what's the low rpm limit for the 4.6? What is a safe level, before you risk doing damage to your engine. Also (and I know this is something everyone would love to know), what rpm range gives the BEST gas milage?

I get the best gas milage in 5th gear under 2000RPM. I usually go around 1500-1700RPM and get 26-27MPG. Using the cruise control helps out even more.

I drive 50 miles highway each day to work, so i've had plenty of time to sit there and calculate gas milage figures. I've gotten 325 miles to a tank before (my personal best)

It's not a scam. The faster you go, the more air resistance and your fuel ecomony drops exponentially. At 75MPH you burn almost 20% more fuel than you do at 55MPH. At 100% it's probably amost 2X as much fuel at 55.

streethorse · Nov 4, 2007

The best mpg I have got has been at 85mph on the highway.
04 automatic. I have done multiple tests doing 200 mile runs to Oklahoma
and I get 23 mpg consistantly. When I try the stay below 2500 rpms test
around town I only get 18 mpg.

eliteJAE · Nov 4, 2007

like i posted in another thread, i just can't grasp how some of you guys get more than 200 miles to a tank or more than about 15 mpg. I'm not calling anybody a liar, i just guess my car must be THAT jacked up to consume so much gas at near-stock configuration highway miles seem to kill me the most

Mustang5L5 · Nov 4, 2007

eliteJAE said:
like i posted in another thread, i just can't grasp how some of you guys get more than 200 miles to a tank or more than about 15 mpg. I'm not calling anybody a liar, i just guess my car must be THAT jacked up to consume so much gas at near-stock configuration highway miles seem to kill me the most

I agree with you. WHen i drive around the city, it's VERY hard to get better than 200 miles to a tank. Usually i get around 150 miles to a tank with all city driving. This has to go with my driving style pretty much. I wind each gear ouyt to 3K, roll on the throttle from time to time and basically don't care.

However, during the work week, i try to squeeze every MPG i can from my car. Like i said in my previous post. I drive 50 miles each day (actyally 57.8 miles) driving to a from work. I'll fill my tank sunday night and hit the trip reset and won't reset it until i fill again. I get right up to 5th gear and pop the cruise control on.

With 5th gear (0.63 ratio in 2003+ GT's) and 3.27's i can do 300 miles on a tank as long as it's done in 5th gear. The minute i go to side roads and start banging gears it drops right down.

eliteJAE · Nov 4, 2007

i dont take too many long hauls on the mustang because of the gas, but i guess is should try it out to see how much it would REALLY use on freeway miles alone

the silver lining to all this: at least ill be used to the mileage when i decide to go blown or buy cobra

MadMikeyL · Nov 4, 2007

It is not true that driving the speed limit will get you better gas mileage. Any internal combustion engine is most efficient at whatever rpms it makes peak torque. As you get closer to that rpm, the engine is more efficient, and as you get farther from it, it gets less efficient. Air resistance does increase as you speed up, but with a car that has a low coefficient of drag, the the increased air resistance from speeding up may be less than the increased efficiency from the engine running at a higher rpm. I did many tests on drives up and down I-95, and in my 94 cougar with a 4.6V8, I got the best gas mileage of 29mpg at right around 80mph. Dropping to 75 got me 26. Dropping to 70 got me 23. Going up to 85 got me 21. The same test in my 89 cougar with the supercharged 3.8 found a best of 26mpg at 75, 24 at 80, 20 at 85, and 22 at 70. As you can see, up to a point the increased speed netted better gas mileage, and once you got past a certain point the air resistance was too much and the mileage dropped, but up till then, it was better to be going faster.

StangYellow · Nov 5, 2007

MadMikeyL said:
Any internal combustion engine is most efficient at whatever rpms it makes peak torque. As you get closer to that rpm, the engine is more efficient, and as you get farther from it, it gets less efficient.

Drive your Mustang at 3800rpm on the highway and let us know if you drove more than 150 miles without running out of gas.

Mossberg · Nov 5, 2007

True!

The Best Gas Guzzlage

me27821

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04DarkShadowGT

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DBMSTNG

I fantasize about it being BIG!

CobraRed_96_GT

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Stangsgrl

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SaleenGT2001

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StangYellow

Scorcher2005

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Mustang5L5

That is…until I whipped out my Bissell

streethorse

eliteJAE

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Mustang5L5

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eliteJAE

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MadMikeyL

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StangYellow

Mossberg

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