Hey guys!
Looking for some friendly recommendations and hopefully some "i run that setup and this is what i think" type of help.
To preface: I see a lot of posters not providing enough information for you gurus to use in order to provide the best help, so figured i'd knock that out up front.

Some quick info
currently running: 08 JKU Sahara w/ 3.73 gears
-Teraflex 1.5" leveling kit
-Duratrac 285/70R17's (right under 32" mounted) on 17x8.5 ATX Crawls
-superchips tuner (tow tune) and AFE drop in performance filter.

I currently average around 17-18mpg with a heavy foot and am perfectly happy with the overall performance, even on highway (mid TN is relatively flat). I do LIGHT trailing once in a blue moon, no heavy wheeling at all.


I finally scraped together the cash to get a 3.25" RC lift and upgrade to the Duratrac 315/70/r17s ("35s" that mount between 33.5-34"/63lbs). Pulling the trigger on everything first week of June. The 35 Duratracs are only 6lbs heavier, ~2" taller, ~1" wider and i will be adding ~2" suspension lift vs my current setup (3.25" total)

Looking for some insight as to what i should expect from a performance perspective when i make the change, keeping in mind my current setup and that i am very satisfied with it (everythign but the looks ).

I really think the new setup will give the jeep a much better look despite it not being a hugely drastic change. i will be recalibrating with my superchips and sticking with the tow tune unless anyone has other suggestions on that. I am fine not having a hot rod but dont want to be hating life and struggling just to drive on the highway to get to work. I realize my MPG will drop a bit, but hoping it wont be too drastic change from current.

Seems like some say 3.73's w/ 35's are fine, others hated it. That being said, most in that situation are running heavier/taller 35's and did not mention re-tuning. Looking on some input based on my particular situation.

Thank you in advance!!

Side note: I realize in a perfect world, another $1200 would be available to regear but i dont have the extra cash and am really not sure if i would need to based on the tons of information i have provided above lol. I also realize that some folks love the RC lifts and others think they are junk. I have done TONS of research and feel confident in my decision there based on my needs, however that is a different discussion.

 

I have a 2008 2 door with auto, 3.73 and a 2.5" lift. I love the Duratracs, my second set. Before the upgrade I went with a MBRP high tuck exhaust and K&N CAI which seemed to help with power on the highway. After putting on the 315/70/17 tires it was a dog until I did the Superchips Flashpack tune. It really woke it up and my MPG went back to the 17-18 range. I can cruise at 80 in overdrive and maintain 2000 RPM plus the shift points are dead on. I am eventually going to do the pro-rock axle swap but until then this is very livable for me.

 

Ah great. Thats exactly what i was hoping to hear. I figured that having the superchips would likely be the "make or break" as to if this setup would be alright. Nice to see you can maintain RPM with OD on as i know i would have a terrible time remembering to turn it off.

What tune are you running? Have you tried multiple ones to compare? I landed on Tow Tune for my first tune after a bunch of reading and never looked back and never tried any of the other tunes.

thanks again for the input! Makes me feel better.

 

goodmorning jeepers!

One and only bump (edited OP to cut it down a bit for easier reading..hopefully)

 

I have a 2007 JK Unlimited Rubicon (4.10 gear ratio, 3.8L engine) with Duractracs 315/70R17 and a manual transmission. I had installed the Superchips Trailjammer (Programmer + aFe CAI) even before I switched from factory tires to the 35" Duratracs.

First off from my personal perspective a gear ratio of 4.10 is the minimum with this setup and that is with a manual transmission. I have tried the 93 octane tune and the major difference was that it seemed to be a little more responsive at low RPMs but not necessarily stronger because the problem remains the same: I have to downshift from 6th to 5th on the highway when driving uphill - in other words when the RPMs drop below 2,500 I have trouble to keep up the speed on almost any incline. I never had that problem with factory tires. With the 93 octane tune I have to keep the ignition turned longer to start a cold engine, the engine also runs a little louder and I get a rough idle when I stop on an incline.

I am now back to the 87 octane tune. With that tune the engine starts, sounds and feels like new and the acceleration feels the same compared to the 93 octane tune - sluggish. Either way the performance of the 3.8L is not sufficient in my book as I would like to be able to cruise at 2,000 RPMs without having to clench my ass cheeks at the sight of the next hill.

My question to you is, what benefits do you get from the tow tune? I have never tried it as I don't tow anything.

 

My 2010 Rubicon on 35's with 4.10's and a manual transmission is geared just fine. I have a Flashpaq and that helped gain a little power and throttle response, but the way I look at it is this: 6th gear should be intended to be a maximum-fuel-economy gear for cruising flat interstates, and with that purpose it does fine. If you're in mountain country and need lower gearing to climb a hill, well you have 5 more lower gears to choose from! Sheesh! If you don't like shifting, you probably ought to have an automatic trans...

 

I am just saying, my 315/75x16 Duratrac's measure 33.75" with 33 psi in them. I run with the OD off at 50mph and below, which in 85% of my driving. Want to regear and 37's someday.

 

I didn't see any mention of which transmission you have, that will make a big difference in how it drives with 35's.

 

I like to be able to interact with the engine, this is why I have a manual transmission. But I don't like the sound of self-decreasing RPMs at full throttle.

I like the sound of the CAI though.

 

I don't have high expectations of the max-fuel-economy overdrive gear. 6th with 4.10's and 35's is perfect for steady-state interstate highway cruising, but once I get into hill country I use 5th.

or 4th

or 3rd

or whatever is the appropriate gear for the conditions.

But if you don't ever want to have to shift out of 6th, you could always install a set of thimble-pinion 5.38's. Or even better, just put the t-case in low range!