I have a 2dr X with 33's and 3.73 gearing and a bunch of aftermarket stuff. If you followed my other threads I recently road tripped to LA a couple weekends ago. Anyway...

- When going to LA I drove with the Bestop Bikini Top on. I mostly maintained a 75mph speed at about 1800rpm, and was getting 19.8mpg.

- For the 4th of July I went to visit some friends in Tucson and drove with the factory soft top on (I hate how loud that thing is) and mostly maintaining a 75mph speed at about 2100rpm, and was getting 16.5mpg.

NOTE: I live in Scottsdale, AZ. To Tucson or to L.A. I take the I-10 which is flat and on open desert land. Thus, nothing in the terrain or the flow of traffic I was in changed throughout both road trips. The weather also was hot and sunny with a slight breeze.

CONCLUSION: My ride with the bikini top was quieter as my music volume was at 16/17 and I was getting much better MPG. Whereas the factory soft top was abnoxiously loud, having my music volume at 20 and my MPG were suffering.

QUESTION: Why is this?

Thank you for reading my observation.

 

i'm wondering why the difference in rpm's if your going the same speed?

 

x2

 

x3

 

I don't understand how your factory soft top is so loud....mine is very quiet, i keep my volume around 15-17 unless I'm jammin'!

 

You and me both. I was pondering this as well while driving on the I-10. That's why there has to be some logical answer in aerodynamics and engineering that explains this -- as far as I'm concerned, bikini top vs. soft top, I'd rather drive with the bikini top on during big trips.

 

just drive no top no doors, drive 1200mi round trip and who cares what the mpg were, I just did it this weekend. It was awesome

IMO mpg can vary so much from so many different factors that is why I never bother to try and figure out mpg and never trust that computer either

 

When I ditched the factory hard top for the soft top I was expecting an increase in noise. And I have been surprised by the fact that there isn't any!

Down here in Georgia (CSRA Region) the winters don't get bad enough to need the hard top, so I don't see any reason to ever put it back on.
All of th aftermarket soft tops I have seen can't hold a candle to the factory Sunrider soft top I go from a forum member here. It is from a 2009 so maybe it has "improvements" over the earlier ones.
When you can pick up one for $500 new, tinted windows, all hardware, why would you get anything else?

 

If anyone who cares about their mpg, then why did you buy a Jeep?? You should have bought a hybrid or electric car...

I hate reading about everyone complaining about their sucky gas mileage and blah blah blah.... Get over it!! and "It's a Jeep thing, you wouldn't understand"

 

I'm a manual guy but maybe the increase in rpm's comes from some sort of OD Off button on the automatic. Either that or one night on your trip some one came and stole your jeep, installed 4.88's then returned it without you knowing. Not sure what my MPG is (jeep owner) but I'm guessing it's not 20mpg. 2 inch lift, 33's, aftermarlet front and rear bumpers, automatic and you're pulling 19.8? That's awesome man. I want your motor.