luisdesab

So guys I was checking that there is a huge difference between 2.5 and 3 inches exhaust systems you can check it in the video. Since the comparison is with a 454 chevy, you think this would be any difference on a 4.0 XJ?

SatiricalHen

3" is overkill. Stock is 2.25 so going up to 2.5 is enough in my opinion.

kyle96xj

The peak hp in that is at 6k rpms, my Jeep rarely gets above 3k I'd say not worth it you might even have to adjust fuel pressure with that kind of extreme size difference from stock unless you drag race

luisdesab

Roger on the diameter, now that we got that out of the question... straight pipeline or do we put a Magnaflow there? some people claim more power without Mufflers

SatiricalHen

personally, it's really annoyingly loud and ricey straight piped to me, didn't tell a difference between when I had my muffler on and after I had ripped it off.

luisdesab

Copy that, case closed, may go for a magnaflow ill just see wich one.

SatiricalHen

I personally like my flowmaster super 44 but I also got it for free so that's how I made my decision. My friends liked it so much they all got them too.

austinjoe13

The 454 has over 200 cubes on the 4.0... 2.5" is to the 4.0 what 3" is to the 454.

Check out the thrush welded if you are looking at flowmaster. They're basically the same but half the cost.



Otherwise this is similar to a magnaflow. Made out of stainless and everything.

kyle96xj

Technically the MagnaFlow straight through will flow better than a straight pipe at WOT due to the perforated inside tube of the muffler having less surface area and the exhaust gasses getting trapped in the muffleing part allowing the rest to just flow through with less friction than a straight pipe

Basslicks

It's probably negligible because if you think about it, they were running 8 cylinders through 2 3" systems (4 cyls per side, essentially)... So you're looking at 227 c.i. going into 3" exhaust on each side vs. 242 c.i. going through 3" total.... now, granted, the CFM is going to be different because you're talking about a high compression motor vs. a low compression motor, but you can probably expect similar results.

HOWEVER, their motor is running higher RPMs constant. Whereas, you're more than likely staying around the 2000-3500 rpm operating range WHICH, if you remember in the video, is where power LOSS is seen. If you want to keep your low-end torque in the range that your engine operates at, you're going to want some restriction in your exhaust.


Magnaflow is pretty good. I prefer the sound of a flowmaster myself, but the FLOW of the two is pretty comparable.

As far as your question about straight pipe, if you upgrade all the piping to 2.5" and run nothing but the cat... it will sound similar to this:

austinjoe13

I had my old jeep straight piped with a cat, tip, and header. It sounded like a small V8 while I drove, and a cummins at idle

Gunmetal Pearl XJ

My old exhaust was kinda rusty so I threw together a rag tag set up together at my shop and it sounds horrible. I thinking of putting a new exhaust system and header on it, is there any good combinations for this?
I'm thinking of this header http://www.summitracing.com/parts/ps...model/cherokee
and this exhaust system http://www.summitracing.com/parts/fl...model/cherokee
I would like it to have a nice deep sound to it but not have it be annoying while driving, any help is appreciated!

kyle96xj

Ive heard those pacesetters need a bit of modification to work, I saw a YouTube video by martinbuilt (I think that's the channel) where he installs one and had to cut and weld in an extension to fit the 02 sensor

austinjoe13

I didn't have any trouble fitting the header, but the down pipe is bent to the wrong angles. Also, the O2 sensor gets moved to a goofy spot.

Gunmetal Pearl XJ

Was it a hard installation and how does it sound?