Engine and Suspension Performance

[bwaters282]

Many Thanks to the regular contributors on this site - a huge volume of good info and experience here. I have two items I am working on with a 2009 JK: the first is that since I upsized my tires (only 34"), 6th and sometimes even 5th gear become a distant memory. And, I have installed a simple 2" spacer lift kit from SkyJacker, and I am running too close to the stops. My situation is that I live in the northern tip of NY State and store the Jeep in Nevada - I did my build-up before I took it out west and I travel out every chance I can to explore the southwest, until I can eventually relocate there. So, it gets complicated doing mods at the storage site with the limited tools and equip I keep there. So, from what I have read here, I have a few power improvment options. Which are the simplest considering a limited budget and garage facilities? (I already have a K&N filter)
Ridewise, I am only interested in moderate off-roading - no rock-hopping, etc. Do I need stronger springs or should I go with a more substantial lift kit? I spend much of my driving time on the highway getting to parks or BLM lands, so I want to maintain decent highway performance while getting better offroad capability as well. I have seen a number of Pink Jeep Tour vehicles on the trail, and they look like they have got it right. I am hitting my stops and banging along as gently as I can. I'm wide open for suggestions. THANKS

 

[Bounty__Hunter]

Keep the bumpstops as they willl allow your springs to last longer. Too many Jeepers believe max-flex is where it's at but repeated over-compression of springs will substantially shorten their life.

As for power, I recommend regearing the axles to a lower gear ratio. This will bring back the performance on road and allow a lot more control and better ride off road. Post up your current axle ratio and stock tire size and I can recommend a new axle ratio for you.

Regearing the axles is a costly venture, but I believe there's no engine mods short a v-8 swap that will give you what you're looking for.

 

[Utah_jeepster]

The 3.8 is not an engine that likes performance adders. The left bank heads are a known problem prone to cracking. There are limited products on the market I.E. turbochargers and super chargers available for the 3.8. Most go with a better air cleaner and exhaust, and tweeking the motor with a chip. But with the weak heads and lower end bearing separation reported with performance adders your better off re-gearing your axles as Bountyhunter had stated. Depending on your axles a few simple upgrades will be needed. JK axle tubes are prone to bending and the addition of an axle truss would be recommended on any tire upgrade past a 33in. We have been seeing bent axle tubes with 35in tires driven just on the street with normal dirt road use. The JK knuckles are also a known problem area, with larger tires the knuckles need a small gusset welded to support the upper arm of the knuckles. A complete professional axle upgrade along with regearing should be considered.

 

[bwaters282]

The 3.8 is not an engine that likes performance adders. The left bank heads are a known problem prone to cracking. There are limited products on the market I.E. turbochargers and super chargers available for the 3.8. Most go with a better air cleaner and exhaust, and tweeking the motor with a chip. But with the weak heads and lower end bearing separation reported with performance adders your better off re-gearing your axles as Bountyhunter had stated. Depending on your axles a few simple upgrades will be needed. JK axle tubes are prone to bending and the addition of an axle truss would be recommended on any tire upgrade past a 33in. We have been seeing bent axle tubes with 35in tires driven just on the street with normal dirt road use. The JK knuckles are also a known problem area, with larger tires the knuckles need a small gusset welded to support the upper arm of the knuckles. A complete professional axle upgrade along with regearing should be considered.

Thanks for the feedback - I need to check on what axles I am starting with, and then start saving - I am still paying off the simpler mods I did already. Is the tire size the primary performance killer or is weight part of it also? By the time you add some solid bumpers, a few skid plates, a storage rack, and supplies, it adds up. Also, is my currently situation hurting my engine or drivetrain, or just eating gas?

Any ideas on an optimal lift kit for highway and off-road? I figured I didn't need much lift due to my tire choice, but I didn't realize how the spacer-style kit really impacts off-road ability. Thanks !

 

[69jeepcj]

Do you need to add longer shocks with the 2" spacer kit? I ask because im wondering if you are really hitting your bump stops or your shocks are just bottoming out.

 

[bwaters282]

Do you need to add longer shocks with the 2" spacer kit? I ask because im wondering if you are really hitting your bump stops or your shocks are just bottoming out.

I used the 2" Skyjacker with the shocks included - when I look underneath with the Jeep on level ground, I am about 1/2 " above the stops. I am thinking this must be a common problem for owners that add heavier bumpers, winches, etc. with just the spacer kit. The new stops take up some travel and the added weight takes some also. I won't be able to do it for a while (short of hitting the LOTTO), but I am researching now for the best lift kit for my driving - I have 2/3 highway and 1/3 off-road, without anything too agressive. Until I am traveling with a Jeep club I don't go to places where I might get stuck or break something. Thanks

 

[hoobness]

Wow. After reading all that I'm glad I never. "Upgraded lol" to a newer jeep. I remember all the chatter years ago when they were dropping the inline 6 but man I never knew the whole jeep was a weak link. Sounds like he'd be better off selling it and getting a tj, yj or an already built new jeep if that's what he wants. Yikes