Which Jeep Wrangler TJ mods are a waste of money?

Chris

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The purpose of this thread is to inform new Jeep Wrangler TJ owners of the "mods" they should stay away from. These mods may have internet hype behind them, but it's nothing more than that... hype. You won't gain any power with these mods, and if you feel anything at all, I guarantee you it will be the placebo effect. You're better off throwing your money down the drain (seriously) as oppose to buying into the B.S. here.

So, here's the list of mods you should stay away from:

Throttle Body Spacers
(See this thread for more info: Do throttle body spacers work on Jeep Wrangler TJs?.)

4-hole Fuel Injector Upgrades
Sorry boys and girls. This 4.0 engine has more in common with a tractor engine than a Ferrari. I love when people like to throw out that the 4-hole fuel injectors help "atomize" the fuel better. Okay, and that does NOTHING for power on your 4.0.

Cold Air Intakes
(See this thread if you need proof: Cold Air Intake FAQ.)

Superchips or any other PCM / ECU reprogramming advice
(To my knowledge, no one has ever cracked the PCM code on the TJ model Wranglers, and therefore none of these units can actually give you any better performance like they could on other vehicles such as the JKs.)

"Performance" Steering Stabilizers
Or dual steering stabilizers for that matter. They do literally NOTHING for your rig. That's not a statement, it's a fact. Unfortunately the internet has a real hard on for flashy, expensive steering stabilizers. Therefore people assume they must do something.

Low Temperature Thermostats, "Performance" Radiators, and Electric Fan Conversions
Please don't be stupid enough to buy into this total internet hype B.S. Read this thread if you need convincing: The myth: low temp thermostats, electric fan conversions & "performance" radiators

Headers
While controversial for sure, I believe headers to be a huge waste of money for these TJs. For one, they crack in short order (my Banks headers cracked in under a year) as they don't have flex joints like the stock headers. For two, they're all made of cheap metal. For three, unless you can show me a before and after dyno chart that shows more than 2-4 hp of difference (before and after the headers), I still won't believe you, because those numbers amount to nothing more than variables in the dyno charts such as temperature changes, heat soak, outside temp, speed, and dyno variances. If we were talking about some huge, long tube headers like you'd find on an old school V8, then I'd believe there was some serious power to be gained. But since we're talking about a small, tiny portion that is the upper exhaust manifold, I don't buy it one bit. If you want to waste your money on "headers", go for it. I'm just giving you some good, solid advice.


If anyone has anything else to add to the list, please let me know.

Oh, and the disclaimer here is that if you want to prove me wrong on any of this, I implore you to go out and have back-to-back dynos done before-and-after the mod. If you see a few horsepower variance between dynos, that amounts to nothing more than changes in conditions (i.e. engine heat soak, dyno variances, margin of error, etc.).

If you choose to ignore the advice here, it doesn't bother me with one bit. It's your money and you can spend it however you want. Besides... the placebo effect can be quite a powerful thing!
 
Curious if aftermarket headers fall into this category...do they really do anything?

I personally think they do. I had them on my old TJ and they made NO difference whatsoever. People like to claim they picked up a few horsepower from them, but I call complete BS. Show me the before and after dyno charts. A difference of a few horsepower on a dyno chart is nothing more than variances in the dyno and conditions.

Look at the aftermarket headers for these things anyways. They’re anemic at best. They aren’t full headers like you’d find on an old school V8. They just replace the tiny portion of the exhaust manifold before the pre-cats.

Like I said, I didn’t notice an ounce of extra power from the headers on my old TJ. Oh... and within a year they cracked! The aftermarket ones are all made from thin, crappy, Chinese steel... even the Banks ones!
 
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Dual steering stabilizers
Expensive steering stabilizers
Mufflers
185 degree thermostats
Hood vents for the purpose of trying to help engine cooling (not keeping under hood temps down)
 
So maybe I am confused... (most likely as I am new to the jeep world) but why would a good cold air intake (a true cold air) header and stainless exhaust with a high flow cat and muffler not help? All your engine is, is a large air pump and if you can get air in and out more efficiently and cooler why would it not be better? I am not saying huge gains but this SHOULD free up some TRUE numbers. Like I said I am new to the Jeep world but everything else I have done these to it has helped. Please don’t take this as I don’t think you know what you’re talking about just trying to understand
 
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One could argue any mods to a TJR are a waste of money since bone stock it is incredibly capable. And bullet proof until you start mods which always create weaknesses in other stock parts, resulting in more mods..... Want to save $$$$ leave it stock. Maybe the best buys are angry eyes and a farmer jack mount.
 
There are some people who would argue that re-gearing after mounting larger tires is a complete waste of money.

But I don't want to open that can of worms. ;)

(Besides I really like my 5.38 gears with my 35" tires and 42RLE transmission and wish to remain blissfully ignorant of all the time, effort and money I wasted by wanting my engine to operate within its optimal power band.]
 
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There are some people who would argue that re-gearing after mounting larger tires is a complete waste of money.

But I don't want to open that can of worms. ;)

(Besides I really like my 5.38 gears with my 35" tires and 42RLE transmission and wish to remain blissfully ignorant of all the time, effort and money I wasted by wanting my engine to operate within its optimal power band.]

Might as well just open up the OPDA can of worms while you’re at it :p
 
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So maybe I am confused... (most likely as I am new to the jeep world) but why would a good cold air intake (a true cold air) header and stainless exhaust with a high flow cat and muffler not help? All your engine is, is a large air pump and if you can get air in and out more efficiently and cooler why would it not be better? I am not saying huge gains but this SHOULD free up some TRUE numbers. Like I said I am new to the Jeep world but everything else I have done these to it has helped. Please don’t take this as I don’t think you know what you’re talking about just trying to understand

More air doesn’t equal more power, simple as that.

The only way that statement is true, would be if an engine came from the factory with the intake as a weak point. While this is the case with some engines, the 4.0 is not one of them. The Jeep engineers who designed the TJ stated this themselves in so many words (read the CAI link in the original thread).

People have done back-to-back dynos before and after installing an intake and shown no real gains whatsoever.

I realize this isn’t what most people want to hear, but an intake is a giant waste of money on a 4.0. In addition, the filters they use will cause your engine more harm than good. @Jerry Bransford has a story about this.

So while some engines may indeed benefit from a cold air intake, the 4.0 is simply not one of them. A full exhaust might gain you a few hp, but it won’t be anything significantly measurable.

Realize they you’re talking about tuning an engine that has more in common with a tractor than a Ferrari... literally.
 
if you can get air in and out more efficiently and cooler why would it not be better?
Increasing air flow works when increasing rpm. And with a peaky, high rpm engine like the Honda 2000, yes opening up the intake exhaust will improve performance.

Not so when you want torque like the 4.0L engine delivers. In fact high torque, low rpm engines deliver better, more tractable torque with restricted breathing. There is an ideal speed for the air to move. Bigger intake, exhaust runners slow down that air and hurt performance.

If your goal is competing in Jeep Speed Events, yeah open up the breathing.
 
Have to disagree on that one. Mine saved me money on my car insurance and in the end paid for themselves. I use them for daytime running lights, and they are a hell of a lot brighter than stock.

How did they save you on car insurance? That's one discount I haven't heard of.
 
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Have to disagree on that one. Mine saved me money on my car insurance and in the end paid for themselves. I use them for daytime running lights, and they are a hell of a lot brighter than stock.
I didn't know insurance companies offered a discount for day time driving lights.
 
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