Thinking of doing some performance upgrades...Cold air intake, throttle body spacer and
catback exhaust, maybe a programmer. Will this help or hurt my fuel economy? Any thoughts on this?

 

Not sure how much more a programmer would help but this is a pretty decent dyno before and after.

http://www.youtube.com/watch?v=ho9Ux...eature=related

I would definitely look into changing ALL fluids into synthetics, you may gain a couple horsepower there too.

 

I don't know what foxbody is talking about? I have flowmaster super 44 in the stock location and a custom cold air intake and I can say they do make a difference, in the dirt and on the street, can't notice the exhaust but the intake is awsome! Rpm moves alot faster up and down, and can notice more torque at a lower rpm

 

There are a few decent headers out there now for the JK. The best is RIPs header kit but expensive. The other brands are much cheaper

 

Cold air intake, yes
throttle body spacer, no
catback exhaust, yes simple low restriction rancho or straight pipe type configuration
maybe a programmer, yes superchips

milage depends on how you drive it. everything helps increase HP which makes you want to get on it more which hurts MPG, but if you drive conservatively you will do better than stock. I average about 17mpg with 37s, but i have a lot of freeway to balance out the fact that i decided not to re-gear. (keeps my rpm low while traveling at fway speeds)

 

For those of you running 33s, an intake, exhaust, and probably a programmer will definitely help the jeep get going. 35s should get the same result. The real power issue is the highway which is where the 3.8 falls flat. If you want real power, get a blower or a engine swap.

I run 33s on stock 3.21 gears with mbrp catback and an aem cai. The jeep is faster than stock to 60, but can't hold highway speeds as well as stock. I am faster than my dads rubi unlimited with 4.10s, Gibson exhaust, airraid intake. I am also slightly quicker than my girlfriends 2010 sahara with the auto and 3.73 and a drop in filter. They can hold highway speeds better though.

 

I have CAI, SPACER, MAGNAFLOW and it definetely makes a difference in performance. The Superchips or Bully Dog would probably be the best upgade for performance, which I have yet to do till I regear.

A lot of opinions on this so read some of the other threads and good luck.

 

I have the Superchips FlashPaq, Spinteck muffler and CAI and it made a big boost in power. Thats with stock 3.73 and 35s!

I have 4.88 on there way but haven't installed them yet.

 

In theory, a less restrictive intake and exhaust will improve pumping efficiency of the engine (its basically a positive displacement pump) and in turn, positively affect fuel economy. But...they also add noise and some people like hearing it...so they stand on the accelerator and then complain about loss of mileage.

Like others have said, it all depends on how you drive it. I easily exceed EPA estimates on all my vehicles just by driving like a granny. Its a Jeep, not a sports car. I plan on RIPP headers, CAI, Dynomax VT muffler with custom piping, and a custom tune when Diablo gets there 2011 base tune out. I am positive that this will net me power gains and mileage gains for when I drive like a granny.

But...its just my opinion from past experience and basic engineering principles. And opinions are like buttholes...everyone has one.

 

I have a CAI, TB spacer and exhaust... Don't bother with the spacer, all I found was that it made things less responsive. I will be taking mine off shortly. You will definitely notice a change with a CAI/exhaust, if not at the pump, than at least in the bottom end torque.

Either way, that's part of the fun... there is always craigslist for mods you don't like.