More power?

[Rubirob]

Hey guys, I got my manual 2004 rubicon not to long ago maybe 6 months now. Finally got to take her up to the hills looking at some camping spots with my friends. I am in Sacramento and we went up to ice house/loon lake and stopped at some places along the way. I have mostly only drove my Jeep on surface streets and at the most I get her going 60ish mph..

My question for you guys, is it normal for our Jeeps to be kinda sluggish on the freeway? I mean I could get going to 70-80 but it took some effort, and if I was climbing a hill.. forget about it lol. After the first few hills and fifth losing rpms like crazy I started dropping down to 4th to at least stay at 65ish. I have checked my gearing and I do have the 4.10 that was stock with the rubicon.. or at least my cover says that. I have 265/75r16 tires so I believe those are 30 1/2s

My Jeep is 95 percent stock, other than mud tires it is stock, so the weight wasn’t that much. 4 people and the Jeep. I just wanted to see if I could do anything to improve this.. if it’s the nature of it then so be it, it did fine.. but I am wondering if it can do better..

Also funny part here, so I am used to city driving.. so when going down some of the back roads to a campsite I was riding the brake, I don’t use my transmission to slow me down in the city.. idk I’m weird haha well when I got to the bottom of the hill before a little wood bridge while I was waiting for the first car to cross I noticed my brakes were smoking. I could still brake and the next part was all uphill so they cooled off.. but might need to change them now! [emoji23] anyway it was a lesson to learn.. fun day tho, I love my Jeep!
I included some pictures of my data plate on the rear cover.. kinda hard to read tho. My tire, and a pic of me at “uncle toms cabin” some random bar I found up by loon lake. It was cool tho!

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[Chris]

The TJ is never going to be a good highway vehicle, nor is any Wrangler in general.

The 4.0 engine is is notably better than the 4 cylinder on the highway, but even then, it's never going to be great.

The biggest thing you have going against you is the piss poor aerodynamics of a TJ, which are equivalent to a barn on wheels. Aside from that, when you start adding bigger tires, lifts, and more weight, you really, really need to re-gear it.

Assuming you have the stock 4.10 gears in your Rubicon, with those 31" tires, you ought to re-gear, even more so if yours is an automatic (which really sucks with the stock 4.10 gears).

Re-gearing will make a world of difference on the highway, and you'll honestly be kicking yourself for not having done it sooner. I can't stress that enough either.

It makes a night and day difference.

But even with a re-gear, remember that the Wrangler isn't an autobahn cruiser. Upwards of 80 mph they start to get a bit scary, which is again, the aerodynamics, the amount of air you have rushing under the vehicle (even more if you're lifted), etc.

 

[Rob5589]

Other than making sure it is running as well as possible; no codes, fresh tune up, etc, not much you can do. Learn to anticipate any inclines and downshift prior to them. Last time we were up Uncle Toms was closed for reno. Nice to see it back open. Did you get all the way to Loon Lake?

 

[Rubirob]

The TJ is never going to be a good highway vehicle, nor is any Wrangler in general.

The 4.0 engine is is notably better than the 4 cylinder on the highway, but even then, it's never going to be great.

The biggest thing you have going against you is the piss poor aerodynamics of a TJ, which are equivalent to a barn on wheels. Aside from that, when you start adding bigger tires, lifts, and more weight, you really, really need to re-gear it.

Assuming you have the stock 4.10 gears in your Rubicon, with those 31" tires, you ought to re-gear, even more so if yours is an automatic (which really sucks with the stock 4.10 gears).

Re-gearing will make a world of difference on the highway, and you'll honestly be kicking yourself for not having done it sooner. I can't stress that enough either.

It makes a night and day difference.

But even with a re-gear, remember that the Wrangler isn't an autobahn cruiser. Upwards of 80 mph they start to get a bit scary, which is again, the aerodynamics, the amount of air you have rushing under the vehicle (even more if you're lifted), etc.

Yea I definitely was not wanting to go past 80 with my soft top it sounded like a hurricane besides the way it drove at those speeds. it was more about losing power going up hills.. but I just dropped down to 4th and was holding up better lol.. it’s something I could learn to live with, once you hop off the freeway it is no problem anymore really.

Re-gearing could be an option. I thought the 4.10s on a manual were pretty good. And that the stock tire for a rubicon was 31s but I could have been miss-informed


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[Rubirob]

Other than making sure it is running as well as possible; no codes, fresh tune up, etc, not much you can do. Learn to anticipate any inclines and downshift prior to them. Last time we were up Uncle Toms was closed for reno. Nice to see it back open. Did you get all the way to Loon Lake?

Yea we did, it was completely vacant. The campground guy “the guy that watches over the campsite” I can’t remember his official name. told us everyone thinks there is still snow up there but there’s normally not around Memorial Day. So the website for loon won’t let you reserve a spot till June 15th but till then it’s first come first serve.. would have been a nice weekend camp. Have the whole place to yourself! Never been to uncle toms cabin.. it was pretty cool. Dollar bills covering everything. So of course we left one too haha


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[Chris]

Yea I definitely was not wanting to go past 80 with my soft top it sounded like a hurricane besides the way it drove at those speeds. it was more about losing power going up hills.. but I just dropped down to 4th and was holding up better lol.. it’s something I could learn to live with, once you hop off the freeway it is no problem anymore really.

Re-gearing could be an option. I thought the 4.10s on a manual were pretty good. And that the stock tire for a rubicon was 31s but I could have been miss-informed


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Oh yes, the soft top is another story. My soft top at 80+ feels dangerous and loud as hell. Once I replaced it with a hard top, that makes all the difference in the world. It's no longer loud and obnoxious at 80+, and it feels much more stable and quiet. It's amazing how much of a difference the hard top makes.

4.10s on the manual transmission aren't that bad (much better than they are on the 42RLE automatic, that's for sure). However, if you plan on keeping 31s, you could re-gear to something like 4.56 and it will make a noticeable difference.

That is the stock tire size for a Rubicon (which is 31"), yes.

My Rubicon is the same way. Up hills on the highway it's just not the best. Drop it down a gear though and it's not too shabby.

My solution was adding a supercharger. That fixed EVERYTHING, haha.

 

[Rubirob]

Oh yes, the soft top is another story. My soft top at 80+ feels dangerous and loud as hell. Once I replaced it with a hard top, that makes all the difference in the world. It's no longer loud and obnoxious at 80+, and it feels much more stable and quiet. It's amazing how much of a difference the hard top makes.

4.10s on the manual transmission aren't that bad (much better than they are on the 42RLE automatic, that's for sure). However, if you plan on keeping 31s, you could re-gear to something like 4.56 and it will make a noticeable difference.

That is the stock tire size for a Rubicon (which is 31"), yes.

My Rubicon is the same way. Up hills on the highway it's just not the best. Drop it down a gear though and it's not too shabby.

My solution was adding a supercharger. That fixed EVERYTHING, haha.

I was thinking about something like that. Do they sell kits for a supercharger? How bad is it on the 4.0? Mine is fairly low miles, and how difficult is it to re-gear to 4.56? Is there any downside? Maybe when your 4x4ing? I just wouldn’t want to turn my 4X4 Jeep away from 4X4ing just to drive freeway a little better.


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[jjvw]

Is yours a manual or automatic?

Mine is the 5 speed, regeared to 4.88 on 33s. While certainly not fast by today's standards, it will get up to 75mph and climb hills just fine.

 

[Rubirob]

Is yours a manual or automatic?

Mine is the 5 speed, regeared to 4.88 on 33s. While certainly not fast by today's standards, it will get up to 75mph and climb hills just fine.

It’s a manual, mine would climb the hills but I would have to drop down to 4th and my speed would drop to 60 instead of 75-80. It could be me getting used to the Jeep. Maybe after a few more trips I can see how consistent my jeeps performance is. Obviously there was people who went around me when I was doing 80 but I don’t wanna go faster than that. The problem was more to do with acceleration I guess, especially when climbing a hill.. also about the brakes, do you guys have a certain performance brake set up that you like? Granted I was harder on them then I should have been, I want to upgrade them if I can. Idk what I got on there atm tho


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[jjvw]

Fwiw, my 75mph is at 3k mph. That's a bit higher than stock and really helps with the mountain highway driving out there.

Black Magic brake pads are a very good upgrade. After that, you are looking at the Vanco Big Brake kit.

 

[Chris]

I was thinking about something like that. Do they sell kits for a supercharger? How bad is it on the 4.0? Mine is fairly low miles, and how difficult is it to re-gear to 4.56? Is there any downside? Maybe when your 4x4ing? I just wouldn’t want to turn my 4X4 Jeep away from 4X4ing just to drive freeway a little better.


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Yes, I got my supercharger for my last TJ Rubicon from http://boostedtech.com

$2500, bolts-on in under 4 hours the first time (I could do it in 2 hours or less the second time), and comes with everything you need to get it up and running that day. You'll get around 220hp at the wheels, and it will blow your socks off how much of a difference it makes. Literally, it feels like you have two 4.0 engines under the hood, and going up hills will be effortless.

At only 7 psi, you won't have to worry about any major stress on your engine. The only downside is that you'll be forced to run premium gasoline.

No downsides whatsoever... none. It will benefit you both on-road and off-road.

 

[Rubirob]

Yes, I got my supercharger for my last TJ Rubicon from http://boostedtech.com

$2500, bolts-on in under 4 hours the first time (I could do it in 2 hours or less the second time), and comes with everything you need to get it up and running that day. You'll get around 220hp at the wheels, and it will blow your socks off how much of a difference it makes. Literally, it feels like you have two 4.0 engines under the hood, and going up hills will be effortless.

At only 7 psi, you won't have to worry about any major stress on your engine. The only downside is that you'll be forced to run premium gasoline.

No downsides whatsoever... none. It will benefit you both on-road and off-road.

I think this is something I will seriously look into, I would have to save up some cash for it but maybe one day. What about re-gearing to 4.56? Would that change performance in any negative way?


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[Rubirob]

I think this is something I will seriously look into, I would have to save up some cash for it but maybe one day. What about re-gearing to 4.56? Would that change performance in any negative way?


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Looks like it is 3500$ with a ecm switch. But still pretty cool. Something I would like to do one day!


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[jjvw]

.. What about re-gearing to 4.56? Would that change performance in any negative way?


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Negative? None at all. Your tires are one size larger than stock. While it shouldn't make a huge difference, it isn't helping anything either. 33s are where most start to feel the need to regear.

 

[jjvw]

How many miles?

One thing that could be slowing you down are the cats and o2 sensors. They only last about 90-100k miles.

 

[Rubirob]

Negative? None at all. Your tires are one size larger than stock. While it shouldn't make a huge difference, it isn't helping anything either. 33s are where most start to feel the need to regear.

Right on, how challenging is the job? I have never done any gear work on vehicles


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[jjvw]

Right on, how challenging is the job? I have never done any gear work on vehicles


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Most have the work done professionally for good reason.

It's excruciatingly slow, tedious, repetitive and precise work. I "helped" a friend regear mine. Mostly, I watched. Having been through the process, I could probably do it over a long weekend.

 

[Chris]

I think this is something I will seriously look into, I would have to save up some cash for it but maybe one day. What about re-gearing to 4.56? Would that change performance in any negative way?


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I re-geared mine to 4.88 (mine is an automatic with 33" tires) and put on the supercharger. The combination of the re-gearing and the supercharger made it very, very quick. People would get in it and assume it had a V8 under the hood. Doing 4.56 gears wouldn't have any negative effect either. Of anything they'd only help!

 

[Rob5589]

A re-gear is best left to a pro unless you have a good amount of mechanical ability and experience. 4.56 would definitely help but you shouldn't be that bad at 4.10 and 31's. I have 4.88 and 31's but that is with the 2.4. Again, I would make sure it is running as good as possible before anything else.

As far as the SC, we are in CA so it may or may not be legal.

 

[Rubirob]

I think this is something I will seriously look into, I would have to save up some cash for it but maybe one day. What about re-gearing to 4.56? Would that change performance in any negative way?


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Freaking California laws lol, yea I’m thinking about taking it to a pro if I decide to do it. Anyone got an idea of around what the cost is to upgrade to 4.56 at a shop?


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