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Old 09-08-2013, 03:35 PM   #1
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horsepower

I have a 2004, 2.4 , 4 cylinder wrangler that is very sluggish on hills and on the highway. What's the best way to increase rpms?

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Old 09-08-2013, 03:39 PM   #2
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What gears do you have in it ?

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Old 09-08-2013, 03:50 PM   #3
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I mean horsepower. What are the best after market modifications, like air intake, muffler, etc.
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Old 09-08-2013, 03:52 PM   #4
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Do a search on here. You wont find many in agreement that you will get much out of aftermarket parts.
Banks, magnaflow, k & n, search...
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Old 09-08-2013, 04:06 PM   #5
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I have been driving 4 banger wranglers for years, the dealer made me leave a large deposit when I ordered my 04 with one. Other than replacing the engine you either learn to enjoy it or sell it.
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Old 09-08-2013, 08:58 PM   #6
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Originally Posted by davidwith1i View Post
I mean horsepower. What are the best after market modifications, like air intake, muffler, etc.
Intake, exhaust etc. for our 4 bangers are not gonna do much for all that money except change the noise of it haha , but dropping lower gears can give you some lost power back
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Old 09-08-2013, 09:05 PM   #7
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Downshift baby.
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Old 09-08-2013, 09:08 PM   #8
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Originally Posted by davidwith1i View Post
I have a 2004, 2.4 , 4 cylinder wrangler that is very sluggish on hills and on the highway. What's the best way to increase rpms?
have you tried down shifting?
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Old 09-08-2013, 09:12 PM   #9
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Mechanical advantage. Gears
The option is a new motor.
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2010 JK added 17" rims and 32 inch At tires, hitch, Ace rock sliders, Barricade bumper,
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Old 09-08-2013, 09:25 PM   #10
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have you tried down shifting?
Literally made me lol!
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Old 09-08-2013, 10:24 PM   #11
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Gears will be the only thing you can do

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Old 09-08-2013, 10:45 PM   #12
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4.88 gears is the largest you can fit in your dana 35 rear,, works well with 33" tires
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Old 09-08-2013, 10:50 PM   #13
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This is what I did !
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Old 09-08-2013, 10:56 PM   #14
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This is what I did !
Do you still have the shoe horn that you used to get that in there laying around? NICE!
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Old 09-08-2013, 11:18 PM   #15
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Despite what every one says. The 2.4 is not a typical jeep motor. It is a car motor same as the neon and pt cruiser. It does respond quite well to an air intake and cat back exhaust. But it really only creates power in higher rpms... Around 3200 to 4000... Gears will help out also but it also depends on the tire size your running. Any bigger than 30's you'll need a regear no matter what. I've been looking into puting together a turbo setup... not sure how I want to go about it yet.... But good luck and keep your rpms up and the 2.4 will respond well for you
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Old 09-09-2013, 01:58 AM   #16
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Despite what every one says. The 2.4 is not a typical jeep motor. It is a car motor same as the neon and pt cruiser. It does respond quite well to an air intake and cat back exhaust. But it really only creates power in higher rpms... Around 3200 to 4000... Gears will help out also but it also depends on the tire size your running. Any bigger than 30's you'll need a regear no matter what. I've been looking into puting together a turbo setup... not sure how I want to go about it yet.... But good luck and keep your rpms up and the 2.4 will respond well for you
These are AMC engines.

New exhaust and CAI will not help you much if any unless you are at wide open throttle at redline RPMs. Better to swap in a bigger engine than to get a turbo in there.
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Old 09-09-2013, 05:04 AM   #17
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These are AMC engines.

New exhaust and CAI will not help you much if any unless you are at wide open throttle at redline RPMs. Better to swap in a bigger engine than to get a turbo in there.
The 2.4, which superseded the 2.5, is of Chrysler design, starting life in the Neon/Stratus/Caravan class about 20 years ago. They were the second-generation Chrysler small car engine, iron block SOHC/DOHC (Liberty and Wrangler were DOHC).
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Old 09-09-2013, 05:13 AM   #18
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Despite what every one says. The 2.4 is not a typical jeep motor. It is a car motor same as the neon and pt cruiser. It does respond quite well to an air intake and cat back exhaust. But it really only creates power in higher rpms... Around 3200 to 4000... Gears will help out also but it also depends on the tire size your running. Any bigger than 30's you'll need a regear no matter what. I've been looking into puting together a turbo setup... not sure how I want to go about it yet.... But good luck and keep your rpms up and the 2.4 will respond well for you
You're right, and it's true that the 2.4 was the most advanced engine design the TJ class ever saw. I also believe it is a sleeper that will eventually find a performance following since it had homogenous SRT exposure.
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Old 09-09-2013, 05:13 AM   #19
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The 2.5 is actually a GM engine. It was referred to as the "Iron Duke" 4cyl. It was used in just about everything from the small FWD cars like the Citation to S series trucks, Astro vans and there was also a marine version of it.
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Old 09-09-2013, 05:41 AM   #20
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The 2.5 is actually a GM engine. It was referred to as the "Iron Duke" 4cyl. It was used in just about everything from the small FWD cars like the Citation to S series trucks, Astro vans and there was also a marine version of it.
The 2.5 you speak if was originally a Pontiac design, and subsequently part of Powertrain. It was dropped from Jeep service in 1983 with the introduction of the homogenous AMC 2.5.
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Old 09-09-2013, 12:55 PM   #21
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Yes I down shift. A friend of mine suggested air intake and performance exhaust to increase hp. Just wanted to know what the forum thought.
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Old 09-09-2013, 12:57 PM   #22
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Yes I down shift. A friend of mine suggested air intake and performance exhaust to increase hp. Just wanted to know what the forum thought.
ok good, so now, what size tires are you running, and what's the gear ratio you have in your axles? do you have a manual or auto?
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Old 09-09-2013, 01:14 PM   #23
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Originally Posted by Slater451 View Post
Despite what every one says. The 2.4 is not a typical jeep motor. It is a car motor same as the neon and pt cruiser. It does respond quite well to an air intake and cat back exhaust. But it really only creates power in higher rpms... Around 3200 to 4000... Gears will help out also but it also depends on the tire size your running. Any bigger than 30's you'll need a regear no matter what. I've been looking into puting together a turbo setup... not sure how I want to go about it yet.... But good luck and keep your rpms up and the 2.4 will respond well for you
Considering a CAI doesn't even help my 5.9 Cummins untill I get into the 600 HP range, nor do they help the 4.0 (both proven on dynos) I don't see it helping this little 4 cyl.
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Yes I down shift. A friend of mine suggested air intake and performance exhaust to increase hp. Just wanted to know what the forum thought.
I had a 4 cyl, I did a CAI and TB spacer. I got some cool noise untill I yanked them and added 2 more cylinders.
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Old 09-09-2013, 02:19 PM   #24
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i had a 4banger great solid engine, but its very slow.
the mods i did
CAI
hi performance cat back,
8mm spark plug cables,
TB spacer
all the mods aren't worth it. truth is that i only gained like 10 hp with all but i wasn't noticeable i did felt a bit more efficient but when i sold that 4 banger the guy told me it did feel slow but with a lot of torque.
now i have the 4.0L on my 06 ruby trust me what a difference it made!!
if you dont like the 4 banger get the 6 cil its alot better the only downside mpg went 1-2 miles down xD anyway i still love my 6 angry squirrels
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Old 09-09-2013, 02:25 PM   #25
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Originally Posted by jeepstertj View Post
i had a 4banger great solid engine, but its very slow.
the mods i did
CAI
hi performance cat back,
8mm spark plug cables,
TB spacer
all the mods aren't worth it. truth is that i only gained like 10 hp with all but i wasn't noticeable i did felt a bit more efficient but when i sold that 4 banger the guy told me it did feel slow but with a lot of torque.
now i have the 4.0L on my 06 ruby trust me what a difference it made!!
if you dont like the 4 banger get the 6 cil its alot better the only downside mpg went 1-2 miles down xD anyway i still love my 6 angry squirrels
Then you have something set up wrong my 4 cyl got worse MPG than my current 6 cyl or any of my buddies 6 cyls with same tires. The 4.0 doesn't have to work as hard to keep up.
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Old 09-09-2013, 04:28 PM   #26
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The tires are 31x 10.5. In the winter I run a snow tire 225/70r. Manual transmission. How do I find the gear ratio?
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Old 09-09-2013, 10:26 PM   #27
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If its a 5 speed the ratio is 4.10 if it's a 6 speed it's 3.73
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Old 09-09-2013, 11:04 PM   #28
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I dont know... I personally like the 2.4L it gets great mileage 18-20 all day. As long as I keep the rpms up it climbs hills just fine. And with over 96000 on it I've had zero engine trouble. Just had trouble with the garbage 6 speed tranny... So I swaped with the 5 speed and I think the mateing of the 5 speed and the 3.73's make mine a bit different than others set ups.... But not sure.
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Old 09-10-2013, 08:11 AM   #29
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The tires are 31x 10.5. In the winter I run a snow tire 225/70r. Manual transmission. How do I find the gear ratio?
there is a tag on the front and rear diffs. it's off to one side, attached to two of the bolts. you'll probably need a rag and maybe a wire brush to clean it off.

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Old 09-10-2013, 08:45 AM   #30
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Yes I down shift. A friend of mine suggested air intake and performance exhaust to increase hp. Just wanted to know what the forum thought.
It's hard to resist this advice, but do it anyway. The air intake and exhaust modifications do nothing for motors that are already breathing fine (like ours). People THINK they feel a difference because they want to feel a difference and it's louder. (Do a search and you'll find the research and real numbers.) Heck, even the BS manufacturer marketing hype tends to show gains on the order of only 3% or 4%... you can see that much change on a dyno from changing tire inflation LOL. These mods don't make sense on a six either. When you're talking about bumping horsepower even 5% on a motor that only makes 140 horsepower, it's a whopping 7 horses...

A turbo makes even less financial sense than putting a $4,500 supercharger on a JK.

If you're prepared to spend go s of money buy a new motor. Otherwise change the gearing as others have suggested.

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