The fact of the matter is that we all dump some kind of money into our Jeeps to make them go faster at some point. Whether it is a simple air intake kit, or a full on engine swap, enough is just never enough.
The sad fact that goes hand in hand with that is those pesky money trees. We still haven't found any and doubt that you have either. It doesn't matter if you are arguing with your mother, wife, husband, dad, girlfriend, or dog, at some point someone will get agitated with spending so much money on the Jeep.
We've been there, done that. With those two facts of life in mind, we thought it'd be a great idea to do a story on which power modifications give the best bang for a certain number of bucks.
$0.00
There are a few easy things you can do so that the ol' seat-of-the-pants dyno feels more power out of your Jeep. Get rid of the air horn on the stock Jeep airbox; it's as easy as a quarter turn and yank.
Lose weight. If you carry around tons of extra weight needlessly, losing it will make you feel like you've got more power. Rather than raising the power side of the power-to-weight ratio, you've lowered the weight side for the same end effect. If you look around and think about it, you can easily gain perceived or actual power for no money.
$250
This is, by far, the easiest one to get away with. If this is all you can squeeze out of the family's purse strings, switch to ramen noodles or mac and cheese. We'd suggest going with an after-cat kit for the sound you want and to reduce backpressure for later modifications. Besides, your muffler is about ready to go anyway, isn't it?
$500
For most of us, this is all that is needed: an after-cat and an air intake system. Sure, at the $250 level, you're talking about an aluminized after-cat system, but get the best cold-air intake you can. And if you wheel your Jeep, make sure to get a kit that includes a good filtering element (see "Air Filter Blowout," November '06).
$750
If this is your budget, go with a header, high-flow catalytic converter, and a cold-air intake system. Replacing the cracked stock manifold and adding a high-flow cat while you are in there opens up the exhaust while helping clean it better in many cases. Forget after-cat for this budget level-you can always get it as a birthday present down the road.
$1,000
Now we are at the top of the bolt-on pile. Almost all of us have been here at some point. We usually get here piecemeal: first an intake, then an after-cat, then a header, then-after we've failed emissions-a new catalytic converter. Get them all at once, and flex the significant other's plastic buying power.
$1,500
To take it one step further you could get everything from the last step, then add the Edge Products Trail Jammer Throttle Body and Module to the mix. The company claims a 20 percent boost in power, and with the downstream modifications to the exhaust, it's possible to realize even more.
$2,000
At this point, you might be able to squeak an engine swap through, but don't hold your breath. There are many variables, but if everything went right, then you might be able to swing it. You'd be rebuilding a junkyard engine and transmission or just stabbing them in and hoping for the best. Barring that, for two grand, we'd go with everything we added for the last step with the addition of a camshaft and larger injectors.
$3,000
You would think that $3,000 would be a good amount to fund an engine swap. Well, it could be. But you aren't going to get a new engine and transmission for that. And if you wanted to stay emissions-legal in any Jeep from the last 25 years, you are talking about a fuel-injected engine, which means computers, wiring harnesses, and so on. So grab a long-block from GM performance parts (PN 12499529 for the 290hp 350 V-8), snag a transmission from a junkyard (or an adapter for your trans), intake, wiring, and sensors from the appropriate year donor truck. This will get you 290 hp at the crank, but check in your area for emissions compliance before jumping on the bandwagon.
The other option is to grab the aluminum HESCO head for your 4.0 six-cylinder, toss a cam in the block, and add higher-flow injectors, an intake, larger throttle body, and header. That will get you up around 275 hp and still pass a sniffer test, even in California.
$4,000
Aside from more V-8 swaps opening up at this level, there are two big inline options, both of which will net about the same power and bolt up to your stock transmission. Granted, at 300 hp your transmission's days are numbered. But that's for another story. Take it easy on the skinny pedal to save the transmission, that's what we'd do if we just put an additional 100-plus horsepower in our Jeep. Really, it is.
Build a 4.6L inline-six for around $3,500 with a custom-ground cam and bigger injectors, then add the stuff from the $1,500 option, as your budget allows. You get a stroker motor that passes visual inspection, and you'll be right around 300 hp and 345 lb-ft of torque.
The alternative is to take your stock short-block, add the HESCO aluminum head, all the stuff from the $1,500 option, plus cam and injectors to get right around 300 hp and 345 lb-ft. If you've got a healthy engine with less than 100,000 miles, this is likely the way to go.