hardtop to soft top gas milage - JeepForum.com
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post #1 of 35 Old 11-13-2008, 09:36 AM Thread Starter
jimaug87
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hardtop to soft top gas milage

I get better milage with my soft top on and that surprises me. I was regularly getting 16-17mpg with the hardtop on for the past 3 months. I sold my hardtop last week (to fund the lift I'm instaling this weekend ) and I'm back to my summer 19-21 mpg. I drive no different with the different tops, I always like to drive quick and inefficient.

Why is my soft top doing better than the hardtop? The I can see more friction with the soft top but more weight with the hardtop. Does the added weight put more stress on the engine than the friction from the soft top does?


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post #2 of 35 Old 11-13-2008, 01:27 PM
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Must be a weight thing

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post #3 of 35 Old 11-13-2008, 01:38 PM
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I don't believe it is the weight. Adding an extra 150lbs shouldn't cut 3-4 of your mpg.
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post #4 of 35 Old 11-13-2008, 01:40 PM
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post #5 of 35 Old 11-14-2008, 11:55 AM
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Added weight will most certainly have an effect on mpg. Keep adding weight, winch, high-lift straps, coolers, a fat friend and all his chow, damn, extra gas cans......
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post #6 of 35 Old 11-14-2008, 01:24 PM
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I have a noticable difference with MPG in the summer when I have the hard top off so I would also state that the hard top weight is a factor in it. Keep in mind the hard top and hard doors is pushing 250lbs.


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post #7 of 35 Old 11-14-2008, 03:51 PM
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Originally Posted by OhGee View Post
Added weight will most certainly have an effect on mpg. Keep adding weight, winch, high-lift straps, coolers, a fat friend and all his chow, damn, extra gas cans......
Yeah, but not just 150lbs. 150lbs ain't gonna cut your mileage as much as his dropped.
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post #8 of 35 Old 11-14-2008, 05:59 PM
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i've noticed i get noticeably better gas mileage and performance with my softtop on versus no top???
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post #9 of 35 Old 11-14-2008, 06:04 PM Thread Starter
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i've noticed i get noticeably better gas mileage and performance with my softtop on versus no top???
I've noticed that too. I'm assuming the wind gets 'trapped' in with the seats and such topless.

The hard doors didn't make a noticeable difference. They were off for months at a time in the summer, and I was still high teens pushing 20mpg. I didn't see anything over 17.xx with the hardtop/doors. Hardtop on, window open, doors off had me 16/17ish as well.

A bunch of us should pitch this to mythbusters. We might get a Jeep episode.

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post #10 of 35 Old 11-14-2008, 06:32 PM
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wow how are yall getting these gas mileages? i get about 15 to 17. i mean i do drive my jeep, but still im not jimmy johnson with it.
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post #11 of 35 Old 11-15-2008, 06:42 AM
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My question is how come you aren't out wheeling instead of debating marginal differences in fuel economy in a vehicle notorious for poor fuel economy?

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post #12 of 35 Old 11-15-2008, 07:19 AM
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Originally Posted by jimaug87 View Post
I've noticed that too. I'm assuming the wind gets 'trapped' in with the seats and such topless.

The hard doors didn't make a noticeable difference. They were off for months at a time in the summer, and I was still high teens pushing 20mpg. I didn't see anything over 17.xx with the hardtop/doors. Hardtop on, window open, doors off had me 16/17ish as well.

A bunch of us should pitch this to mythbusters. We might get a Jeep episode.
Actually it's a long known fact that generic convertibles have a higher top speed with the top up, and usually, if the car is available in an identical hardtop, the hardtop is slightly faster at top end.

Individual situations can vary, however, because aerodynamics is far from intuitive. (i.e. many pickups do better with the tailgate in place than removed)
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post #13 of 35 Old 01-19-2009, 09:53 AM Thread Starter
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My question is how come you aren't out wheeling instead of debating marginal differences in fuel economy in a vehicle notorious for poor fuel economy?
Because I drive my Jeep on the road more than in the dirt. My question to you is how come you bother posting if it's not going to be helpful?

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post #14 of 35 Old 04-01-2014, 12:47 AM
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How much of a difference does it make when you drive with out the top altogether? I drive an 87 YJ with an AMC 258 I6. 3in. body lift and 35in tires. I have been doing work on it all winter so not much wheeling. Drove it right at 200 miles last weekend with a bikini top and no doors, got roughly 21 MPG. (Most of the 200 miles was on the interstate) Yesterday drove 146 miles with the full soft top on and only got 12MPG. Turned around to go home took the windows off and the upper doors off and it jumped up to 18 MPG. I would have never imagined the top causing enough drag to drink that much gas.
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post #15 of 35 Old 04-01-2014, 05:56 AM
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I noticed a very slight (maybe .3-.5 MPG) increase when I sold my Hard top and went with a soft top. I think I get slightly worse MPG with the top off then with it on, but I don't really care. I routinely get somewhere between 16.5 and 18.5 on my weekly trips to / from work. Yeah. It's that much different and it's mostly due to wind.
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