when I hear tuning I think of the chips and crap people use to tune diesels and stuff and those don't work on 4.0s much, bolt on parts are another story. Also, that's a lot of money for not a lot of gain in my opinion, all of those parts aren't cheap.

 

exactly. no chips, just good technology


Thank you

 

That is a great link.
now I believe I can get where I need to.
the only thing missing is possibly a snorkel.
but the exhaust will work out great


Thanks again

 

Tuning is any modification to a vehicle's engine to up its performance... be it internal engine, external engine, exhaust, ignition, etc. etc... installing a "chip" is just an extension of that and adjusts settings in the ECU to increase performance by itself or in conjunction with other mods.

 

A couple weeks ago I posted in this thread asking about headers, and after some research and finding that just about every header and oem replacement has had plenty of people complain about breaking I made a most likely stupid decision and bought some Chinese banks style knockoff header, like the APN, graywerks, Amazon no name etc, I will disclose the company name in a couple days after talking to some customer service, it seems to be a fairly well made piece, T-304 stainless, tig welded, cnc machined flange and all for the price tag of $88.98. Well one thing that I have concerns about is that the flange where the header meets up to the engine head is warped across the header at some points about 1/16" I highly doubt this is okay but I thought I'd check in with you guys to see if it is within spec or if any of you have any experience with such a situation. (edit: I accidentally double posted a couple of pics and one uploaded sideways, I'm still figuring out picture posting)

 

Quite common. Tighten from the center bolt out and it will flatten out.

 

I hope you're right, I'm still gonna contact customer service and see what they say. I'll make sure to keep you all updated on this.

 

So I've been trying to understand the emissions setup on the Jeep and comparing it to what others have stated prior. So the "Pre-cat" is the two-cat section after the exhaust manifold that has ports for the O2 sensors. I assume this is the "don't talk about removing this crap or be banned" section of the exhaust. next comes the line to the "main cat" whom someone had said that it was a resonator and not a cat, which kinda threw me through a loop and made me curious about which section everyone was actually talking to when referring to the "cat." lastly there's the obvious muffler to tip section. Now being a college student with my jeep being my (hopefully) long-term car to get me through the New England weathers with all my dorm-room crap to lug around, I wanted to put together an exhaust setup that's legal and still gives a bit of "performance" which I would assume is most likely only a reduction in backpressure (to which I'm uncertain of any mpg gains or not). I'm rather certain my "main cat"/resonator needs replaced as a while back it was rattling at idle and low rev (internally) so i assume whatever filter was in there was seperated, eventually it stopped rattling which has me more worried. I know that i want to get a dynomax muffler, one of the cats from the performance-curve link many have shared so far, but as for legality and such i'm more unsure as I near the engine.
If anyone could help clear my confusion that would be a lot of help, thank you.

 

Just got mine back from the shop. Custom 2.5" setup with magnaflow hi-flow cat and magnaflow muffler. I had him tuck it high

 

I put an eastern cat and dynomax super turbo on my now 5.9 jeep, also the dynomax tail pipe. Sounds pretty good and still pretty quiet. Seems to have good throttle response, supposed to flow pretty good. It is louder than OEM, but not much. I guess it will get louder as time goes on, I mostly wanted to better flow they advertise. Oh I had to rob an 02 sensor from a 99 4.0 jeep I had as a spair, it works fine if anyone was wondering. Them pesky O2 sensors lol

 

I am jealous

 

Nice. 2.5" is the way to go

 

I need to do the same thing to mine.
Could you please take a pic where the exhaust goes around the front of the trans.
Mine is rubbing against the bell housing.

 

Looking at Exhaust manifolds, since I plan on keeping it road legal with replacement precats and a high-flow 2nd cat, are my choices limited to any manifold models that are two-piece due to the split pre-cat? or are there OE-replacement single-pipe pre-cats for such setups?

 

Yep, ill get one tomorrow