Best CAI,& Aftermarket Headers. Brands and Suggestions

Once I get my issues on my '94 4.0 AW4 situated, I am starting to tweak it for more mpgs. My last '94 got a consistent 18mpgs with 30" BFG AT's, no lift and an AirRaid Throttle body spacer. While the spacer was to help pickup some power and mpg, it did the power not mpg. My first mod this time is gonna be a CAI, and I was wondering on brands and results here. I guess I am looking for you all with a slightly similar setup, what brands you all like and what kind of mpg increase or decrease you got with yours, as well as performance. Im not building a race car here, but I think I can get some low to mid 20's out of this with a little work. The exhaust already has to be upgraded as well, and I am looking into the headers, so some thoughts here would also be appreciated. I plan to keep modifying it till I hit the 20's and then see where I go from there. Post up what you got and how well you like or dislike it, as well as your thoughts on its performance upgrading.

Jeff

Whatever CAI you go for make sure you get a "dry flow" airfilter for it., I have an APN header on my XJ and when I was doing the header I also upgraded the intake manifold to the 99+ style with larger equal runners and did a Firepower complete ignition upgrade(coil cap,rotor& wires) , new plugs and a new fuel filter as well as a catback(I chose borla).

JP Magazine did a story on high flow exhaust, and it included part on high flow Catalytic Convertors. They didn't list any part numbers or brands. Without that now I also need to get some help on the Cats too. Mine is shot, and since I am going to do a complete upgrade, I am considering all of this at the same time. I know that if I did the exhaust and intake modifications, this should yield me the mpg's that I need. Plus the performance benefits will also be right where I need them. Thank you, and keep the suggestions coming.

Jeff

I have a borla hi-flow cat on a magnaflow cat back and i got noticable power and a little better mpg's, not to mention it sounds great. I took out the regular filter and put in a K&N replacement. As for the header ive heard good things about APN and Banks.

I like the Magnaflow high flow cats. Not expensive either. Their exhausts also come highly recommended.

What ever cai you go with make sure it has some kind of shield to block the hot engine air. Don't get an S&B though as they fit like crap.

I am having a hard time trying to locate any of the cats in "high flow". Do I need them to have a larger inlets and outlets than 2.25? I'd go 2.5, but I need to make sure that the header to cat pipe is either the same, or I'd have to enlarge the pipe to make it fit. I would think just a slightly larger pipe size would be able to help evacuate the exhaust better. Thoughts, as well as part numbers of some of the items available?

Jeff

TB spacers don't do anything on a MPFI engine
What gears are you running?
Pull the roof rack, and check tire pressure

For cat, I believe they are 2.5 in 2.25 out stock, IIRC. performance-curve.com has universal high-flow cats, 2.25, 2.5 etc. IF you have decent lift, a custom mandrel bent down pipe to 2.5 cat and either straight pipe all the way back or muffler of your choice.

I was also considering a high flow, or performance muffler here as well. My mods on exhaust will work together, and other than the header, will all be likely done at the same time. Its lining up the $$ to get all the parts at once. Thanks and keep the suggestions coming.

Jeff

You didn't mention what type of driving you are doing, that you expect to get 20+ MPG. Stop 'n go gets me 18+, but the freeway gets 23+ on my '94 with the 5-speed and 225/75R15 tires. Mixed driving gets me 20+.

I have an AirAid CAI, with the sheet metal air dam. Putting that kit in also eliminates the restriction in the OEM intake pipe, which allows a little whistle at high throttle but that doesn't bother me a bit. My wife doesn't even notice, and she's picky about that kind of thing. I'd recommend that, or a similar homebrew. I've been considering putting in a cowl snorkle, which should get you the same benefits.

Driving style is going to be slightly mixed. It will see a bunch of highway driving, but i have a 7 mile commute to work, and once I get my diesel Scout here and swapped, that will end up being my DD, as it gets mid to upper 20's. My last '94 I used the tachometer to drive by. I kept mine at around 60mph on the highway, unless conditions dictated differently. Goal is to improve mileage, and some performance as needed. I am also considering upgrading the intake since I will be replacing the exhaust manifold, and system from the block back. I am doing my research and stuff now, so that once I get it running, I can get started on the mods to increase some efficiency and performance at the same time. I am just wanting to improve some things, so that it can be a tad better than my last '94 in the mileage category.

Jeff

I have an Airaid intake. Its nice. comes with a heat shield and seems to work well. whatever purpose it serves

I think I have settled on the K&N unit for the CAI. I already have to replace the entire intake, and I was considering upgrading the intake to the new style, but after doing some reading, it doesn't seem that that modification will make a real difference in my mpgs, but it would in my torque and throttle response. I think at this stage, I will just do this upgrade, as well as the exhaust pipe from the header back. I am still looking into the cats and mufflers right now to see what the best alternatives are for what I am doing. I will post up my findings after I get the fuel issue situated and then can get started on some modifications. Keep your suggestions coming as well.

Jeff

Anything that helps your engine breathe better with less work is going to net better mpg's. The newer style intake is DEFINITELY something id look into. I've got a magma flow high flow cat, and their muffler as well. I'm satisfied with it. Cheap, sounds decent (not too loud or droney), and it's stainless so they'll both last forever. I bought everything from Performance Curve, including their tailpipe. Welded it into one piece, then chopped it into 3
Sections and welded in turbo v-band clamps for easy removal and installation.

What is the best range of rpm's to optimize mpg?