Bigger Tires & Lift for the 2.0T 4-Cyl

deejorama

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The 8 speed is magic! You will lose some MPG but it still drives great and plenty of passing power when the turbo kicks in. AEV Dual Sport spring lift, 315/70-17 on stock 3.45 gears, dealer programmed tire size correction.

New JL wheels tires.jpg
Struggling right now with the rear track bar tower install. Could you share a photo of the installed part?
 

Msilvs777

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We bought our sport and immediately put 35s on it for a long trip. Drove great, not as peppy but still plenty of pep and far better than any of our JKs, TJs or YJs with same tire size. We have since lifted (3.5"), moved to 37s and calibrated the speedo to be correct. I was sure after the lift and 37s I would be itching to regear and am glad we waited. We have added bumpers and armor and still have no lack of giddy-up from the 4-banger with etorque. 8th gear is there on the highway if I am not driving like I usually do. This is the best motor/trans combo Jeep has put together in a LONG time. Baby step your upgrades if you are nervous, you don't need to over-spend out of the gate. Also, everyone's tolerance for how a Jeep "should" drive, feel, accelerate is different.

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Whiskey 13

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The key for success when changing to larger tires without a doubt is reprogramming to match new tire size. Computer controlled shift points only work with proper input (old saying: Garbage in, Garbage out)
The reprogramming should also be as accurate as possible, if you install 37" tires don't tell the computer 37 inches. Get the tires mounted on your rims then install them on the rig and under full weight measure the height of your tires. The measurement will be less than 37 inches, probably 35.5 to 36 inches and that is what the computer gets told to provide the best overall performance.
 
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Obi.Wan.Shawnobi

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I live at sea level. I use the Tazer and some performance mods. Its almost likes to be at 75 versus 70 to sit in 8th gear (but will still be in 8th the majority of the time) . I'm also running on 37's with 4.10's.

I went on a 9 day trip back east to Colorado and hit up some high elevation passes. Never really felt any sort of performance loss.
 

DEdney1775

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You would get a great deal of the pep back, by correcting the programmed tire size. Right now, your shift points are all over the place because your transmission is confused.
I'm new to the JL world. How do we program it? I just purchased a set of 35's for my 20 JL Sport.
 

MadDog27

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I'm new to the JL world. How do we program it? I just purchased a set of 35's for my 20 JL Sport.
2 of the most common methods is with the Tazer by Z automotive or the flashcal/flashpaq by superchips. Each offers their own features depending on your needs.


Superchips link

Tazer Link
 

Headbarcode

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I'm new to the JL world. How do we program it? I just purchased a set of 35's for my 20 JL Sport.
As MadDog said, get one of the programmers mentioned, or pay a dealer to flash the Jeep. In my opinion, its money better spent getting your own programmer. I got a Tazer Mini that changes tire size, tpms adjustment, puts a memory on the auto stop/start being turned on or off, and a slew of other features.

There's also the Tazer lite, which has fewer features for a lower cost. And I believe the superchips unit is most cost efficient for even fewer features.

Its not just a simple issue of an inaccurate speedo due to larger tires. The ZF 8-speed is an adaptive unit that learns your driving style and adjusts the shift points, on the fly, to be able to perform optimally. It can't accomplish that unless its fed accurate info.

And welcome to the community, Daniel!
 

WhyUMad

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I recently just did a regear on my 2019 JLU Rubicon (4.10's) that had a 2.5" lift & 37's on it for about 15,000 miles. The 4.10's did great with this, it just took about a month for the TCU to relearn how to go into the 8th gear on the highway. I didn't notice much issue, but wanted to gain some of the low-end grunt back & that's why I put 5.13's in it. I'd also recommend the Tazer JL mini to correct tire sizes & regears, as well as to do a plethora of other things. It's very handy & works great.

I'm not sure what the gearing is for your particular Jeep, but I'd check to see what rpm you'd be at with that tire size at whatever speeds you anticipate to be at on the highway. 8th gear would eventually hit at 65 mph on the highway, but realistically you'd have to be over 1800 rpm to really hold 8th gear without juggling between 7th & 8th. I'd make sure you'll be over 1800 rpm at your highway cruising speed to ensure that you'd remain in 8th once the TCU learns the new tires.
 

Storm chaser

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Hello! Newbie here,
I just purchased a 2.0T 4-Cyl a couple weeks ago and I am looking to install some 35 inch tires, 18 inch wheels, and a 2.5” lift soon. Wanting to know if the stock gears and other components would be able to handle this upgrade or if it is a bad idea without regearing first.

also I am not sure what the stock gear ratio is on mine, it’s a 2018 unlimited sport.

thanks!

AE430EEB-9888-45F1-9986-0B652A0B8AED.jpeg
I have a 2018 jl 2.0t with 2.5 teraflex 17x9 with 35x13.50 nitto trail grapplers and it runs fine cant tell the difference
 

Chupacabra

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Weird. You have stock 3.45 gears yet go into 8th like normal? I never adjusted the speedometer for 35s. Maybe that's why. Didnt think it would make a difference.
Earlier you said your mileage went down too. If you didn't adjust for the bigger tires then your speedometer/odometer is going to read low and your displayed and hand calculated MPG is going to be lower regardless of impact of the bigger/heavier tires.
 

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