JK Poor Performance
06-03-2008, 02:06 AM
#21
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Unfortunately they don't sell horsepower in a bottle, so pretty much anything you do for the JK (bolt-ons or a hemi swap) is going to be cost prohibative compared to the gains. For about $1000 you do a CAI, exhaust, and programmer. THis combo would yield decent results, but only you can decide if the 20 or so HP is worth the money.
06-03-2008, 02:08 AM
#22
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I've had my fair share of quick cars too (as far as Chrysler products go my quickest was a 67 Plymounth GTX with a Hemi). I almost didn't buy a JK because of the engine but we rented one in Ouray, CO and had it up to 13,000 and always had planty of power.
So we bought an Unlimited Rubicon with auto. At 2400 miles it is quicker than my 98 TJ auto. And at 6000 plus feet the TJ falls on its face whereas the JK just scoots along. My wife recently made a 1800 mile trip from the Western Slope of Colorado to NE Nebraska which included a 12000 ft pass with no complaints about power and got 18.2 MPG for the trip. The TJ, going slower, would have done 13.
All the above was done before the RE 3.5 SF lift and 35" KM2's. But stock it did 75 MPH (by GPS) at 2250 RPM. It's getting 5.13's next week which should bring the RPM at 75 MPH to 2550. I understand that 2400 to 2700 is the sweet spot for power and milage and the 5.13's will put me right in the middle of it. Stock it came out of OD too easy on the freeway. I know for sure in a few weeks but my guess is that the best money spent on a JK power wise is going to be gears.
As far as off-road goes I've bent my share of axles doing stupid stuff (usually means going too fast and too heavy on the load pedal) in the past and the JK has enough power to do what needs to be done. But then I'm a bit older now too.....
So we bought an Unlimited Rubicon with auto. At 2400 miles it is quicker than my 98 TJ auto. And at 6000 plus feet the TJ falls on its face whereas the JK just scoots along. My wife recently made a 1800 mile trip from the Western Slope of Colorado to NE Nebraska which included a 12000 ft pass with no complaints about power and got 18.2 MPG for the trip. The TJ, going slower, would have done 13.
All the above was done before the RE 3.5 SF lift and 35" KM2's. But stock it did 75 MPH (by GPS) at 2250 RPM. It's getting 5.13's next week which should bring the RPM at 75 MPH to 2550. I understand that 2400 to 2700 is the sweet spot for power and milage and the 5.13's will put me right in the middle of it. Stock it came out of OD too easy on the freeway. I know for sure in a few weeks but my guess is that the best money spent on a JK power wise is going to be gears.
As far as off-road goes I've bent my share of axles doing stupid stuff (usually means going too fast and too heavy on the load pedal) in the past and the JK has enough power to do what needs to be done. But then I'm a bit older now too.....
I agree with on the higher elevations, my JK did much better in the mountains than my 4.0L TJ did.
06-03-2008, 02:11 AM
#23
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WHile it's true that adding larger tires will dog performance, if he re-geared he could remedy that, maybe even make his acceleraion a little better than stock if that's what he's after.
06-03-2008, 03:59 AM
#24
Eternal ***erator
For GOD'S SAKE!!!!!
Why on EARTH would you recommend a Throttle Body Spacer on a Sequential Multiport Fuel Injected Engine?
There is no possible why for it to help, period. (Unless a potential whistling noise is desirable)
Don't people TEST DRIVE things anymore before spending their money?
Why on EARTH would you recommend a Throttle Body Spacer on a Sequential Multiport Fuel Injected Engine?
There is no possible why for it to help, period. (Unless a potential whistling noise is desirable)
Don't people TEST DRIVE things anymore before spending their money?
I got one free with my CAI.
I put on the CAI and tried to drive exactly the same as i always do for a fair test. Moderate gain in milage, but only about 1-2 at best.
Threw on the spacer with the CAI and did the same. Net result, not a damn thing (which is pretty much what i expected)
IMHO an exhaust, and CAI, possibly a chip is about all your going to do. However for the gains you would get, spending the money elsewhere as mentioned above would probably serve you better.
I'll get around to the exhaust eventually, but for now my engine mods are done, except for pulling off the spacer one of these days when i get bored. I really dont have a problem with this engine, Just learn to keep it in its happy spot for RPM's and it has all the grunt I need.
Last edited by HappyCurmudgeon; 06-03-2008 at 04:01 AM.
06-03-2008, 04:00 AM
#25
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I got one free with my CAI.
I put on the CAI and tried to drive exactly the same as i always do for a fair test. Moderate gain in milage, but only about 1-2 at best.
Threw on the spacer with the CAI and did the same. Net result, not a damn thing (which is pretty much what i expected)
IMHO an exhaust, and CAI, possibly a chip is about all your going to do. However for the gains you would get, spending the money elsewhere as mentioned above would probably serve you better.
I'll get around to the exhaust eventually, but for now my engine mods are done, except for pulling off the spacer one of these days when i get bored.
I put on the CAI and tried to drive exactly the same as i always do for a fair test. Moderate gain in milage, but only about 1-2 at best.
Threw on the spacer with the CAI and did the same. Net result, not a damn thing (which is pretty much what i expected)
IMHO an exhaust, and CAI, possibly a chip is about all your going to do. However for the gains you would get, spending the money elsewhere as mentioned above would probably serve you better.
I'll get around to the exhaust eventually, but for now my engine mods are done, except for pulling off the spacer one of these days when i get bored.
06-03-2008, 04:03 AM
#26
Unfortunately they don't sell horsepower in a bottle, so pretty much anything you do for the JK (bolt-ons or a hemi swap) is going to be cost prohibative compared to the gains. For about $1000 you do a CAI, exhaust, and programmer. THis combo would yield decent results, but only you can decide if the 20 or so HP is worth the money.
06-03-2008, 05:17 AM
#27
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There is a article in the July Issue of the Four Wheeler Magazine on this subject. If anybody has been keeping up with Project Con Artist they have a four door Jeep Wangler Unlimited that they have been trying different things or changing things that needed improvement. Any how this months article is called Power Play. In the first series of articles they mention how the new Wrangler and especially the Unlimited did not have the power it needed and once they started adding all their stuff the Unlimited it was struggling to keep up with highway speed. Pick up a copy of this magazine because it to long for me to write and to go into details but it is worth the reading. They did mention once they added AEMS Brute force Dryflow and added a JBA Stainless Steel Exhaust system. As quoted by them " The gains were more then expected"
06-03-2008, 06:00 AM
#28
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This is the first new car I've ever owned and the first one that was worth adding mods too. So I gave into the hype and went and got a CAI for my JK. It does absolutely nothing for the power. At first I thought it did but I think it was more my imagination and the new sound of the engine that made me feel that way. However, what it did do was give me a 1-2 mpg boost. I figure that I will drive about 20,000 miles a year and the way gas prices are going that 1-2 mpg will pay for the CAI and start saving me money in about 2 years or so which is a relatively quick payback. So from that standpoint I would recommend it to someone. Anything that boosts mpg is OK with me.
06-03-2008, 07:03 AM
#29
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Unichip
A local shop is really pushing the Unichip. They swear they've installed 5 or 6 and all have had good gains.
Does anybody have any experience with this? At 600 bucks it would be an expensive mod.
I may suggest to them that if it's so damn good they should buy one and use it as a demo. Since it is a piggy back unit and installs quickly let me run it for a week or so (t least one gas tank) and make up my own mind. If it REALLY worked I'd spend the money. We have a dragstrip here too. I could make a few runs without the Unichip (average them) install it and make a few more runs. Lacking a dyno there would be solid evidence that it did or did not improve performance.
Does anybody have any experience with this? At 600 bucks it would be an expensive mod.
I may suggest to them that if it's so damn good they should buy one and use it as a demo. Since it is a piggy back unit and installs quickly let me run it for a week or so (t least one gas tank) and make up my own mind. If it REALLY worked I'd spend the money. We have a dragstrip here too. I could make a few runs without the Unichip (average them) install it and make a few more runs. Lacking a dyno there would be solid evidence that it did or did not improve performance.
06-03-2008, 07:41 AM
#30
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is it the Unlimited owners with the biggest complaints about power issues? I have the 2dr, and no its not a beast but it does pretty much what I tell it to. I have the 6spd with 4:10's. Stock wheels right now but it won't change that much when I go up to 32"s. I have the drop in K&N...but thats not really a noteworthy powermod. Just helps a little and worth the $40 IMO. Granted this JK is not as stout as my 79 CJ7 with 304/TH400 was...but it gets a hella better gas mileage!