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-   -   2013 rubicon questions (http://www.wranglerforum.com/f202/2013-rubicon-questions-559137.html)

jeepwayoflife 02-25-2014 09:06 PM

Hey everyone. I'm a TJ guy but am here to ask a few questions for my friend with a 2013 JK unlimited Rubicon.


We just put on a 4" lift and his tires come soon. He has a Rubicon with automatic transmission. What MPG and power loss can he expect with 35" tires on stock Rubicon gearing? If he regeared, what's best? 4.88?


Thanks!

mattr 02-25-2014 09:15 PM

I lost about 2 mpg going to 35s
4.56 for 35s and 4.88s for 37s seem to be the trend with the 3.6 liter

To be honest with my 35s 6 speed and stock 4.10s I am perfectly content

jeepwayoflife 02-25-2014 10:07 PM

Great, thanks!

RodentSniper 02-25-2014 10:44 PM

I have a JKURX 14 auto with 4.10 gears running 35"s and it does great..

mattr 02-26-2014 08:21 AM

Something else to consider

35s and 37s are very close to the same price depending on the specific tire so with a 4 inch lift 37s would look great especially if he plans to re gear anyways
A lot of people regret not going bigger from the get go
But then again if MPG is a concern 35s would be better, better yet sell the jeep and get a Prius ;)

Joe Dirt 357 02-26-2014 11:46 PM

I just did a 3.5 lift and put on 34" tire on and lost 2 MPG with an Auto tran. As for the power, the JKUR is very sluggish at freeway speeds. I will probably re-gear to 4.88 or 5.13 in a year or so..

I just don't like the power loss at all.

spinlock 02-27-2014 02:30 AM

That much lift will decrease your fuel economy as much as the tires on the highway. 2013 doesn't anything bigger than 4.88 for 35s. You could even use 4.56. Look at the gear chart and pick your preferred cruising engine RPM.

Faith and Trust 02-27-2014 04:15 AM

Quote:

Originally Posted by Joe Dirt 357 (Post 8612033)
I just did a 3.5 lift and put on 34" tire on and lost 2 MPG with an Auto tran. As for the power, the JKUR is very sluggish at freeway speeds. I will probably re-gear to 4.88 or 5.13 in a year or so.. I just don't like the power loss at all.

Need to eliminate 2 inches of lift! 34s need just a little to clear

hooper 02-27-2014 07:42 PM

I have 315-70-17 tires (actual 34.5") with a 2013 JKR and 3.5" lift and lost around 2-3 MPG depending on driving. I do not see a need to regear (have 4:10), cause it drives fine on the hyway. I just recaled my speedo for the tires.

RodentSniper 03-01-2014 07:14 PM

Quote:

Originally Posted by hooper (Post 8634425)
I have 315-70-17 tires (actual 34.5") with a 2013 JKR and 3.5" lift and lost around 2-3 MPG depending on driving. I do not see a need to regear (have 4:10), cause it drives fine on the hyway. I just recaled my speedo for the tires.

I agree 100%

kappaknight 03-03-2014 10:15 AM

I'm on 37's with the stock 4.10 gear and haven't noticed any significant loss in MPG. My stock Rubi tires only gave me 13-14 MPG and now with heavy 37's, I'm still at the same range.

jeepwayoflife 03-03-2014 12:43 PM

Thanks for all the info guys. He got the tires on and said he hardly notices a difference. MPG isn't really a problem but he was just wondering what to expect. Nothing like my tj and its 11-12MPG average :thumb:

Joe Dirt 357 03-03-2014 10:36 PM

Quote:

Originally Posted by Faith and Trust (Post 8613393)
Need to eliminate 2 inches of lift! 34s need just a little to clear

Thanks, I will go out right now and chop 2" off my $1700 lift. What do you suggest I use hacksaw, cutting torch or sprinkle fairy dust on it. Perhaps I'm looking for more clearance you know "break over angle". Thanks for your input on my mall crawler.

TurkTTR 03-04-2014 09:38 AM

When I put the 315/70-17 DuraTracs on my 3" lifted 14 Rubi 6speed, I decreased from about 18mpg to 13.5mpg (mix of mostly city, occasional long highway drives), but once Superchips got the flashpaq updated to work with my Jeep, I recovered back up to about 16.5mpg after I recalibrated for tire size (didn't put in 34.4" like the actual measurement of the tires is- but under vehicle load, the speedometer is accurate with 33.75" actual diameter programmed into the computer).

Maximo 03-04-2014 11:14 AM

Quote:

Originally Posted by TurkTTR (Post 8758433)
When I put the 315/70-17 DuraTracs on my 3" lifted 14 Rubi 6speed, I decreased from about 18mpg to 13.5mpg (mix of mostly city, occasional long highway drives), but once Superchips got the flashpaq updated to work with my Jeep, I recovered back up to about 16.5mpg after I recalibrated for tire size (didn't put in 34.4" like the actual measurement of the tires is- but under vehicle load, the speedometer is accurate with 33.75" actual diameter programmed into the computer).

Interesting. I experienced a similar decrease on my 14 Rubi automatic with 3" lift and 35 duratracs. 18 mpg is what I got with a heavily modified '12 sport. Please tell me more about this flashpaq update and "under load" diameter calibration! Is this mileage per computer or pump calculation? I suspect something like this might help me as current settings seem to make my shifting occur a little later (higher rpm) then necessary.

TurkTTR 03-04-2014 12:07 PM

Quote:

Originally Posted by Maximo (Post 8760993)
Interesting. I experienced a similar decrease on my 14 Rubi automatic with 3" lift and 35 duratracs. 18 mpg is what I got with a heavily modified '12 sport. Please tell me more about this flashpaq update and "under load" diameter calibration! Is this mileage per computer or pump calculation? I suspect something like this might help me as current settings seem to make my shifting occur a little later (higher rpm) then necessary.

When I got the Flashpaq, I was told that they had 2014 support, but when I first got it set up and plugged it in, it downloaded my stock file and said they would have to get back to me after they coded for my specific transmission/engine combo. I emailed back and forth with a couple guys at Superchips, and they were able to get it working.
Part of the reason I was only showing like 13.5mpg right after adding lift and the 35" DuraTracs was that the tire size threw off the speedometer and odometer (about 6.25% calculated by using a GPS speedometer app on my phone), so I was probably getting actually closer to 14.4 if my calculations were right at the time. When I used the Flashpaq to recalibrate, I put in 34.5" as the tire diameter (specs on the 315/70-17 are 34.4" tall on the DuraTracs) but was still off by a little bit, but in the other direction, so I dropped the diameter in the tuner 33.75 or something and the speedometer reads correctly now, and I'm showing the 16.5mpg now with equal parts conservative highway driving and aggressive city driving.
I drive a manual, but I know that the Flashpaq can reset your shift points in an auto for better power or better mileage.

Maximo 03-04-2014 10:53 PM

Quote:

Originally Posted by TurkTTR (Post 8762641)
When I got the Flashpaq, I was told that they had 2014 support, but when I first got it set up and plugged it in, it downloaded my stock file and said they would have to get back to me after they coded for my specific transmission/engine combo. I emailed back and forth with a couple guys at Superchips, and they were able to get it working. Part of the reason I was only showing like 13.5mpg right after adding lift and the 35" DuraTracs was that the tire size threw off the speedometer and odometer (about 6.25% calculated by using a GPS speedometer app on my phone), so I was probably getting actually closer to 14.4 if my calculations were right at the time. When I used the Flashpaq to recalibrate, I put in 34.5" as the tire diameter (specs on the 315/70-17 are 34.4" tall on the DuraTracs) but was still off by a little bit, but in the other direction, so I dropped the diameter in the tuner 33.75 or something and the speedometer reads correctly now, and I'm showing the 16.5mpg now with equal parts conservative highway driving and aggressive city driving. I drive a manual, but I know that the Flashpaq can reset your shift points in an auto for better power or better mileage.

Turk! Thanks for the explanation. I'm not expecting a miracle of fuel economy but I thought the drop was a little more dramatic than it should have been....plus- I'd like to feel confident that the shifting is where it should be. Sounds like first step is updating software and then a calibration based on actual MPH rather than exact tire diameter. Definitely worth a try. I'll report back with my success and 24MPG fuel efficiency. (Heck- I'll be thrilled with 16, I'll owe you a beer if I see 18 again!)

egb629 03-05-2014 08:48 AM

I have the Flashpaq on a 2014 JK rubicon with bds 2.5 lift, 35" Fierce tires, gas mileage is getting better from first picked up from dealer. The FP will calibrate speedometer but had to use 33.75 instead of 34.5. Mileage about 16 now from 13.5 when just gotten. Performance with FP, Trans shifting, highway accel and all around very very good from stock. Just took about 5-6 weeks for Superchip to get programimg correct

Oh also added 1.5 leveling bushings to front end to get rid of nose down look have gotten quite a few questions regarding the way it sits with 1.5 leveling bushing added

TurkTTR 03-05-2014 08:52 AM

Quote:

Originally Posted by Maximo (Post 8780825)
Turk! Thanks for the explanation. I'm not expecting a miracle of fuel economy but I thought the drop was a little more dramatic than it should have been....plus- I'd like to feel confident that the shifting is where it should be. Sounds like first step is updating software and then a calibration based on actual MPH rather than exact tire diameter. Definitely worth a try. I'll report back with my success and 24MPG fuel efficiency. (Heck- I'll be thrilled with 16, I'll owe you a beer if I see 18 again!)

Glad I could help!

Maximo 03-15-2014 01:16 PM

Favorite propaq tune for JKR auto?

Got a superchips flashpaq! Downloaded the updates then plugged it into my auto '14 rubicon. Went with the 91 octane performance tune, measured actual tire diameter, and ran the drill. Hardest part was downloading the "spark" update at the beginning but that's due to my PC being severely outdated and slow as a Harley. (Note- not saying Harley's are outdated- just slow, and I recognize there are exceptions).

Have only driven it 60 miles now but I can already tell a significant (and positive) difference. The biggest improvement is that the shifts are now smoother and where they should be. Throttle response does seem better but that may just be the shifting I'm noticing. Initial gas mileage seems to be better based on the dash reading but will need to verify after a full tank. I am not using 91 octane (shop recommended trying this tune) so I may experiment with the other tunes once I'm confident in what the changes are. Prior to the calibration my speedo was off approx. 6/7 mph at 65 with actual speed being higher than dash reading. Now it's within 1 or 2 mph with dash reading higher than actual. BTW- tire calibration was completed at the dealer but evidently not very accurately.

Haven't got a lot of miles on, haven't tried it in 4WD, and haven't truly measured fuel consumption but will soon.... This improvement may just be due to the previous poor tire size calibration in which case I should/could have gotten away with just the procal unit. Now that I have it I'm interested in what others have found with the different available tunes as well as using other features (I.e.- tpms adjust, high rev mode, etc.).

Anyone have a favorite superchips procal tune?


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