MPG, How do you do it?

[Mark Ventry]

Took a trip from Atlanta to Indianapolis and back on Friday. Set the cruise control at 75 the whole way. I was surprised that I averaged the same MPG, 18ish, on the trip (all highway miles) as I do during the week which is a mixture of highway and side streets. How do those of you average 20-21+ on the highway?



On a side note, my next purchase will definitely be new shocks. I've got an 05 with 10K miles and I never really noticed the bounce until this recent trip. I felt like a basketball by the time I made to back home.

 

[Andy G]

Well...dunno......



My average is 18.5. No matter what the city/hwy mix was. Some tanks are as high as 19.5, some as low as 17.



I have done some performance changes (Underdrive pulley and Electric fan) and am compiling a new MPG log, which I hope to post in the next couple of weeks. It looks to have bumped my high to about 20, maybe 21, but I will know more after a few more tanks.



Mine is a 2001 Job 1 4x4. Stock tire size, and the only modification I have had up to this point was the Mac intake. That took me from about 17.6 to my current 18.5.



You may have been closer to 20 if you had set the cruise at 65. Dunno for sure though, mine doesn't seem to care. The only time I see the MPG really drop is when I keep it to the floor all the time in the city, and a recent trip to Vegas with the cruise at 85 dropped me to about 17.



As far as shocks go, anything is better than the factory shocks, but I swear by the Monroe reflex series. You can usually dig a up a pretty good deal on those too.



cheers,

Andy

 

[Kevin Palmer]

I always got 21-22 hwy. The trick, keep your foot out of it. If I went over 70, I lost my MPG pretty fast. For some reason, my Trac got the same mileage around town the momment I went 70 MPH or faster..

 

[Mike Dziubina]

i took my '01 on a trip from here in CT to myrtle beach and averaged about 18-22 mpg. when on the highway keep the S/T at aroudn 65 and u wil have better gas mileage! i had jsut a k&n intake at the time...since then i put a dynomax exhaust kit on and bumped my mileage up a little better...



i have Rancho RSX5000 shocks....not as good as the 9000's but better than stock! i suggest new shocks for everyone...good luck

 

[Mark Ventry]

I just thought for sure that I would get at least 2+ more MPG on the highway especially since I recently installed an ASpec Air intake system. Will replacing the stock exhause help any?

 

[Ben Poche]

20 to 22 high way i do not use cruse if i want good gas milage

 

[Mark Ventry]

bpoche - I noticed you have the Xcal2. Do you think that is the difference?

 

[Michael Cacioppo]

bigdawgfan, the coefficient of drag goes up with the square of velocity, so the faster you go the more HP has to be expended to maintain that speed. On the other hand, the engine efficiency based on torque and HP curve has an optimum around say 2400 RPM (just guessing where it is on a trac.) so by raising the rpm nearer to the optimum efficiency of the engine, you are at the same time requiring more HP and Torque because of the increase air resistance. Somewhere in there is the optimum for the Trac. Depending on the rear end ratio this is going to be a different speed that is optimal for the 4.10 and 3.73 equipped vehicles.



I had a 1984 F150 with a straigt six. A lot of torque but low on HP. No matter what speed I went I got about 12-13 MPG. At Highway speeds the engine was in a more optimal rpm range but the F150 cut through the wind like a brick wall would.

 

[Rich Stern]

Speed kills...gas mileage.



As MikeC wrote, when you move the ST along the highway at a quick pace, the engine has a lot of work to do to overcome the air resistance.



Try a trip at 65. You'll be shocked at the difference.

 

[Mark Ventry]

Rich, not sure my ST is capable of going that slow, at least not on the highway.

 

[Ben Poche]

yes it made a difference but i also drive very light footed i will cruse @70 but i take off and slow down easy as for cruse when it accelerates up a incline it does it so harsh as if i accelerate lightly. i travel 30 miles each way to work and go over 14 over passes if i uses cruse my mpg suck

 

[Greg Grimes01]

I AVERAGED ABOUT 22.4 ON MY TRIP TODAY. 2001 JOB 2 THROTTLE BODY SPACER, OPEN ELEMENT BREATHER. AND A NEW SCAN GUAGE. NOTICED THAT BEST MILAGE WAS ABOUT 67-69 MPH. THE SCAN GUAGE REALLY HELPED ME CHECK MY MPG.:wub:

 

[Gerald Pierce]

65-68mph and no cruise if it gets hilly.



I get 19-21. Over 70, it drops like a brick.



My 95 E150 would got 17 towing a UHaul trailer loaded with tools (3k lbs) at 60 mph, it normally got 13 at 70+. Slowing down makes a big difference.....