Jeep Cherokee Aeromods

[JeepNmpg2]

Originally Posted by sdconcepts

Has anyone tried a header and a cat back exhaust? i'm curious to see if that will add any efficiency to the 4.0 since the exhaust is pretty restrictive. i have a 99 cherokee with a 4.0 and would like some real world feed back on this mod before i do it.

SD - I have done both stages on my exhaust, first with the high flow cat-back system, which was a huge improvement over stock. I did it at the same time I did the custom air intake, so the combination was very noticable and no torque loss. Some months later, I had the cat switched out for a high flow model from Magnaflow which gives more overall power, but I noticed a tiny bit less in the low-midrange. I had flash new maps to my computer to make up that difference, but if you just want cat-back, it's a great upgrade! Sounds nice too! I recomend Flowmaster 40 series (or 50 series if you like it more stock sounding), which is not very loud, but is noticable. I've gotten a few looks from others thinking I have a V8 under the hood from the lower rumble it makes. Hope this helps you! I noticed a little better mileage when cruising the freeway, maybe 1 or 2 MPG but you have to fight the urge to put your foot in it every once in a while (which defeats the purpose of the economy of the mod)

[winkosmosis]

Those higher flow cats don't catalyze as well. Why bother eco modding and whatnot if you're going to increase your emissions?

[Old Tele man]

...to some people, being GREEN (ecology, not Kermit the frog) and FE (fuel economy) are in totally different camps: GREEN is tree hugging; FE is going further miles for less money.

...others, obviously, see the two as the same...YMMV.

[sdconcepts]

how do you reflash a jeep a computer? i think there is alot of tuning that can be adjusted to get better MPG and overall efficiency. i'm still debating on which header to get, some say the stainless steel is the way to go but me personally i'm thinking the full length pace setter header is the way to go.

[JeepNmpg2]

Originally Posted by sdconcepts

how do you reflash a jeep a computer?

I'm purchasing a UNICHIP setup for my cherokee, and it holds up to five seperate programs (ecu maps, shift points, torque converter lockup, etc). Obviously I'd have one for highway ecomony on 87 octane, one for high horsepower, one for high torque both on 92 octane, one for highway towing, and one bone stock (for emissions purposes).

Originally Posted by sdconcepts

i'm still debating on which header to get, some say the stainless steel is the way to go but me personally i'm thinking the full length pace setter header is the way to go.

I would highly recomend you go with the set by Doug Thorley. They are extremely well tuned and they are coated so that they push A LOT of heat out of the engine compartment instead of letting it build up from/around the exhaust manifold. Cherokees run hot as it is before any aeromodding that might cut off airflow even more, so any help to rid your engine bay of that destructively high heat is good.