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Discussion Starter #1
I'm looking to ad some performance to my stock JK engine. as far as im aware of with my extremly limited knowledge of wranglers. the only three ways to increase horsepower is to add
1. programmer/chip
2.exhaust
3. air intake.

my question is what makes and models of each of those 3 and you all like. and how much HP am i realistically going to add to my engine?
 

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MBRP exhaust has a documented 9hp increase.

I would NOT do a CAI if your going to wheel it. Get a drop in airfilter replacement, you will get more power and better MPG

A chip or programmer is the way to add power. Even on the regular gas settings.
(Either superchip or hypertech) AEV is only for tires/ gears and NOT for power.
 

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Why not do the CAI? There are a few good looking sealed ones like the Volant and the S&B. I understand the issues with swamping to engine, and if you plan to wheel in water, the get a snorkel. Some of us live where there just is not any water we can legally drive through and dust is the main concern.
The stock air box has a smaller hole than a stock 700cc V-twin. Yes, more availible air will do nothing with out more fuel, but with a CAI and the right mapping in the chip, you will get more power.
 

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get the ripp supercharger
 

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all those are pretty much a waste. Any gains seen in most of these are above the 4k RPMs mark so unless you plan drive around at 4-5,000 RPMs spend your money on the gears for those 37's :beer:


O and don't get suckered into the "when I installed X exhaust I could feel the difference." Yeah when I was in highschool I swore my car was faster after an oil change and car wash too :laughing:
 

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all those are pretty much a waste. Any gains seen in most of these are above the 4k RPMs mark so unless you plan drive around at 4-5,000 RPMs spend your money on the gears for those 37's :beer:


O and don't get suckered into the "when I installed X exhaust I could feel the difference." Yeah when I was in highschool I swore my car was faster after an oil change and car wash too :laughing:
Bingo...
 

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Why not do the CAI? There are a few good looking sealed ones like the Volant and the S&B. I understand the issues with swamping to engine, and if you plan to wheel in water, the get a snorkel. Some of us live where there just is not any water we can legally drive through and dust is the main concern.
The stock air box has a smaller hole than a stock 700cc V-twin. Yes, more availible air will do nothing with out more fuel, but with a CAI and the right mapping in the chip, you will get more power.
You are right, I thought I clarified wheeling in water... but alas..I didn't.

I live in Florida so everything is mud and water to me....LOL

The MBRP exhaust does document an increase in overall HP from 1800 RPM as I recall.

And I agree with gears being the first thing.. I missed that, even though I did this when I put my 37's on.
 

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From what i hear, the 3.8 is pretty much at its peak performance right now, so most mods dont make much of an improvement save for a supercharger. Whereas if you could afford to swap a hemi into it, you're starting with a base to build on. Also, you can make your own CAI for your JK for about 70 bucks.
 

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Freeing up the intake and exhaust does help,but not major HP gains.Definately helps with the mpg,at least in my case.You don't need to spend stupid money on exhaust mods either.A simple glass pak,flowmaster 40,magnaflow etc will do the same job as the arm and a leg mbrp system.It's just a catback,it ain't tuned like headers.If your really looking to run 37's,then you really need gears first. :beer::beer:
 

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Discussion Starter #14
sounds good i think i'll go with the consensus and buy gears so i can run 35"s or 37"s. and then maybe in the long run i'll screw around with engine preformance.
 

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Well when I put my River Raider Snorkel on My GPM went up.. Plus I have a few other mods that gave me more on top of that. See my Sig


GPM? You mean you're using Gallons Per Mile? It's not a Hummer! :D

From what I can tell you, MOST of the catbacks will give you a few horsepower UP TOP, and maybe a couple in the midrange. But this isn't a Honda, where revs=go. This is a JEEP, where torque is king. Backpressure (up to a point) shifts the power band to lower RPM's, adding torque. Our cars have fairly minimal backpressure (for an OEM setup), and reducing what little is to be had with larger diameter exhaust will kill what little backpressure is to be had, thus why the 3.8 with the bigger exhausts sounds like a Honda with a 5" fart can out the back- there's no backpressure!
This is why most people go with just a Flowmaster or other muffler- they reduce backpressure a MINIMAL amount, get rid of that monster OEM muffler, and add a deep sound because you still have backpressure.
Having built race and high-performance engines for years now, I can tell you- virgins brag about horsepower- pros brag about torque :) Unless you're turning your JK into a NASCAR "stocker," brag about how you improved your torque curve via engine tuning.

Best results I've seen from the 3.8 in terms of a solid on/off roader are from a Mopar/K&N drop-in, a muffler, and a Superchips/Hypertech programmer. Other than that, bump for a Hemi- Mark W.
 

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GPM? You mean you're using Gallons Per Mile? It's not a Hummer! :D

From what I can tell you, MOST of the catbacks will give you a few horsepower UP TOP, and maybe a couple in the midrange. But this isn't a Honda, where revs=go. This is a JEEP, where torque is king. Backpressure (up to a point) shifts the power band to lower RPM's, adding torque. Our cars have fairly minimal backpressure (for an OEM setup), and reducing what little is to be had with larger diameter exhaust will kill what little backpressure is to be had, thus why the 3.8 with the bigger exhausts sounds like a Honda with a 5" fart can out the back- there's no backpressure!
This is why most people go with just a Flowmaster or other muffler- they reduce backpressure a MINIMAL amount, get rid of that monster OEM muffler, and add a deep sound because you still have backpressure.
Having built race and high-performance engines for years now, I can tell you- virgins brag about horsepower- pros brag about torque :) Unless you're turning your JK into a NASCAR "stocker," brag about how you improved your torque curve via engine tuning.

Best results I've seen from the 3.8 in terms of a solid on/off roader are from a Mopar/K&N drop-in, a muffler, and a Superchips/Hypertech programmer. Other than that, bump for a Hemi- Mark W.
I totally agree,especially about the exhaust hype.The outfits trying to sell you 4 or 500 dollar exhaust systems for "big hp gains are full of crap.Even if they dyno proved it,it's done at top rpms,which you'll never see.Keep It Simple and enjoy ;)
 

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^ I'm not sold on the blower for a couple reasons.
1. Is heat. The JK underhood area gets pretty darn toasty as it is due to a relatively lean-burning enine. While the chip included with the kit would remedy some of the lean-burn issues, the blower itself creates a lot of heat, as does the increased boosted compression (not to be confused with compression ratio- this is that, plus the pressure of the forced air).
2. Is cost. For not much more (relatively), you get a garuanteed, known entity. The 5.7 Hemi is dead-reliable, stock (assuming you leave it that way), and thus built in a way that Chrysler is comfortable giving it a LIFETIME warranty. The supercharger's warranty only covers the kit itself, and says nothing about how well the engine itself will hold up. While Chrysler obviously won't warranty the Hemi you put in your JK, it is garuanteed to last for years as long as you don't mess with it too much.
3. A report I read from Mopar a few years ago about their efforts to make a turbo 3.3/3.8 setup. I remember distinctly the phrase "came apart under even mild boost." Now, the newer 3.8 is somewhat stouter than the 3.3, BUT it is still the same basic architecture. I know that to an engine builder/engineer, "mild" boost is under 14.7 PSI of boost. I can't remember seeing what the blower kit pushes, but it is likely 5-9 PSI on most setups. I know that supercharger boost is quite different from turbo boost, but the problem lay in the rods, which take up a lot of the pressure of combustion, which is increased massively under ANY kind of boost.
While this is not THAT much, it is enough for me to question longevity. I simply won't be able to reccommend something as (relatively) untested as the supercharger kits until I see 100k mile+ individual vehicles with no major problems becoming the norm.

I am in NO way associated with RIPP, and have nothing but the utmost respect for anyone who brings a new and (by what I've seen and heard) high-quality product to the market. As a professional, I simply tend to stick to known quantities on street vehicles. On race cars, I run prototype and one-off pieces all the time, but for a daily driver, I just can't reccommend aftermarket super- or turbocharger kits, especially relatively new ones.
No hard feelings fellas- there's always beer in my garage for you guys at RIPP :) Mark W.
 
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