first MPG test

bwenny247 · Post by **bwenny247** » Mon Apr 18, 2005 2:36 pm

i ended up getting 15.81 MPG out of the first full tank of gas with my lift and tires, i was pretty pleased

this consisted of:
about 45% Freeway (75 MPH)
about 45% Highway (60 MPH)
and 10% city (stop and go traffic)

not bad considering the best i ever got when stock was 19 MPG on all Freeway

jmb222 · Post by **jmb222** » Wed Apr 20, 2005 3:03 pm

I recently got 19.7 without the recently added cap and 21 with the cap installed. They were all highway miles, cruise control set at 75.

wbwillyb · Post by **wbwillyb** » Thu May 12, 2005 3:29 pm

jmb222 wrote:I recently got 19.7 without the recently added cap and 21 with the cap installed. They were all highway miles, cruise control set at 75.

What cap did you replace? I average about 19.6 mpg.

jeff024 · Post by **jeff024** » Thu May 12, 2005 3:55 pm

he means the cap on the bed of the truck a Topper

jmb222 · Post by **jmb222** » Thu May 12, 2005 5:30 pm

Sorry for the confusion. In PA, its called a truck cap. It seems that in other places it is called a truck topper. I'm not sure which is the correct terminology.

realtorjay · Post by **realtorjay** » Fri May 13, 2005 8:43 am

Just thought I would flash my average since it is so low

. I get anywhere from 13-15 but I do mostly in town driving (and have a lead foot) and do tons of it because I use the truck for business. I am going to put a cover on it hoepfully that will reduce drag a little and slightly improve it.

Everyone have a great weekend and Happy Friday the 13th Stay Safe All!

Jay

barch97 · Post by **barch97** » Fri May 13, 2005 9:21 am

In town driving I don't suspect a cap will help you much. In fact it will likely hurt more than help. The reason a cap helps at highway speed is that it decreases wind resistance caused by the truck box and tailgate as well as the general shape of the truck (cab sticking up and dropping off sharply at rear). Around town you'll just be adding weight and using more gas to take off from a stop. A cheaper alternative to test this theory might be to give a soft tonnaue cover a try. Increase areodynamics without adding much weight.

jmb222 · Post by **jmb222** » Fri May 13, 2005 9:31 am

I read a study that a bed cover does not increase the MPG. It was a college study. Then I read another study that said it did and it was another college study.

Rusty · Post by **Rusty** » Fri May 13, 2005 9:52 am

I remember reading about a wind tunnel test where they showed that, contrary to popular opinion, pickup trucks actually get better gas mileage with the tailgate up instead of down. Something to do with the swirling air pattern that forms in the bed of the truck. They even showed pictures of it. Made sense to me after reading it. Just wish I could find the link but it's been several years ago that I saw it.

Of course the beds of our crewcabs are so short, I don't know if it would make that much of a difference. I believe the wind tunnel test were done on full sized trucks if I remember right.

barch97 · Post by **barch97** » Fri May 13, 2005 10:38 am

I have conducted a little study of my own. Maybe not quite as scientifically accurate as these college folks you speak of but a study none the less.

I commute 40 miles each way to work at highway speed mon - fri and then mostly around town stop/go driving on weekends. To compensate for variations in my driving and road conditions I drove five consecutive tanks of fuel in each of three bed configurations. I kept a record of the milage since last fill up and the precise amount of fuel consumed.

I drove five tanks with the bed as it comes from the factory, tailgate up. And then five tanks with the tailgate removed. And I have driven with my soft tonnaue cover on ever since. Fuel efficiency ran about the same (+/- 1/4 mile per gallon) with tailgate up or off. BUT, I gained 1.5 to 2 miles per gallon with the cover on.

What I haven't accounted for in this study is ambient temperature. But, I suspect that will only reinforce my findings. As the typical temperature was between 40 and 50 degrees for the first five tanks and got increasingly warmer as the study progressed. Had I run the first five tanks with the cover on at 45*, I believe the mpg gain would have been substancially larger. Also, over the several weeks and 4,500 miles, my fuel and ignition systems theoretically became less efficient by means of wear and residual build-up.

Had I the resources and funding to run three identical vehicles at exactly the same time and under exactly the same conditions, I estimate the gains would have been in the neighborhood of 2 to 2.5 miles per gallon with the cover in place.

killian96ss · Post by **killian96ss** » Fri May 13, 2005 12:40 pm

I just completed a 300 mile road trip this past weekend and got 17.2 mpg. This trip was 60% steep mountain roads, and 40% freeway driving with the tailgate down. My wife uses the CC for comuting to work and we have done some tailgate tests of our own and have found these results. With the tailgate up she averages 17.8 mpg, and with it down she gets 18.7 mpg. We have tried this at least 10 times with the same results (1 mpg increase with the tailgate down).

Steve

bwenny247 · Post by **bwenny247** » Fri May 13, 2005 1:20 pm

ever since that first test, i've consistanly averaged between 15-16 MPG

i just added a tonneau cover so we'll see if i can add 1 or 2 MPG
time will tell

BobbleSmitty · Post by **BobbleSmitty** » Fri May 13, 2005 2:57 pm

Today, I did the calculation and got 16.38 MPG. That was with 50% highway and 50% stop and go traffic downtown. Normally, I don't travel the freeway to school and I get 13 to 14 MPG. I don't have a tonneau cover.

When I was at the track the other night, I did run faster with the tail gate down though. I'm sure that leaving the bed open with the tail gate up increases the drag on the vehicle to some extent which would cause a loss in gas mileage.

Steve2003 · Post by **Steve2003** » Fri May 13, 2005 6:35 pm

wbwillyb wrote:
jmb222 wrote:I recently got 19.7 without the recently added cap and 21 with the cap installed. They were all highway miles, cruise control set at 75.
What cap did you replace? I average about 19.6 mpg.

welcome to the sight wbwillyb

I don't understand what everyone calls the "toppers" or the "caps", Out here in SoCal we call them camper shells or bed covers. or tonneau covers!
Sometimes I almost fell like I'm from a different country!

Steve

jeff024 · Post by **jeff024** » Fri May 13, 2005 7:21 pm

its ok steve im on the east coast and I call it a camper shell also

F9K9 · Post by **F9K9** » Fri May 13, 2005 7:30 pm

jeff024 wrote:its ok steve im on the east coast and I call it a camper shell also

Hmmmmmmmm..............East = right?

West = Left?

coffeedrnkr · Post by **coffeedrnkr** » Sat May 14, 2005 12:55 pm

I just calcumalated mine yesterday. This tank was ALL city driving, no freeway and I got 14mpg

I thought that was low but after looking at some of your guys' averages I guess it isn't too bad.

S-10CREWCAB.NET

first MPG test

first MPG test

Re: MPG