2.5 exhaust Questions

So it's finally time to change the exhaust system on my 2001 Jeep Cherokee. It has the CA Emissions pre-cats. Everything on the exhaust is the original stock piping on it and is in bad shape. So I am going to pull the trigger and re-do my entire exhaust. I do have a few questions.

https://www.amazon.com/dp/B000182DMY/ref=cm_sw_r_api_i_CMXB7METK870JG1KW9EZ_0?_encoding=UTF8&psc=1

https://www.amazon.com/dp/B000EQNUES/ref=cm_sw_r_api_i_VA8Z8FQ1QQJN8EG40T66_0?_encoding=UTF8&psc=1

My plan is to replace the muffler with a Flowmaster 40 Delta flow series along with a new high-flow cat. I am going to go with 2.5 piping.


My first question:

1) I am confused with the piping length for the downpipe tailpipe. Most posts and videos I have read had to cut and add piping to their exhaust system. I am looking for piping I can buy that has the direct fit and perfect length. Do they sell any piping kits I could buy that would be a simple plug-and-play for this setup?

I will be putting this all together myself and installing it on my own. This will be my first exhaust swap. I'm not a wealthy man so I am trying to find the easiest and best cost-effective way that I can do as much of this myself without adding labor costs (if possible)

2) I am hoping to increase front-end HP WITHOUT adding any back pressure for the 2.5 piping. My plan is to add a 62mm TB+CIA+Map Adj + 12-hole injectors to compensate. (I watched a video where they did Dyno with 12-hole injectors and it increase the back-end torque)

What do you guys think? Is this plausible?

I any of you guys know what piping would be a direct match LMK, also any advice on the good quality high-flow cat that worked great for you 01' please let me know.

Eventually, I will be upgrading my rear axels to a Dana 44, Chy. 8.25 or Ford 8.8 in the near future.

Thanks guys!

I don't know what you mean by "downpipe tailpipe". The downpipe is the pipe between the exhaust manifold and the catalytic converter. The tailpipe is the pipe from the muffler to the back bumper.

I can't help you with '01 specific issues.

I can tell you that this 2.5 stainless tailpipe works well on my '96: https://www.ebay.com/itm/142544249187?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20220310133107%26meid%3Dae13dedbfcce430fa812782da9c1374f%26pid%3D101196%26rk%3D3%26rkt%3D12%26sd%3D193300063755%26itm%3D142544249187%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv9PairwiseWithPLXWebFitmentFilterConfirmFitSignal%26brand%3DCustom&_trksid=p2047675.c101196.m2219&amdata=cksum%3A142544249187ae13dedbfcce430fa812782da9c1374f%7Cenc%3AAQAHAAABEAzdIKOcP6rVYsexH8mCu6YYN0SdXxqICy66h220Th%252FC6c6aZpFIEmATXPImB6gOXUa%252FXvip3BRuztnBr5L4o8zQdjmher0bCHy2J8hIgiI6LbEA42QGFRBAm0E4qI5bp5ONhP%252FtydSgsETXkNoNvk5gZ97pCdSBxcTJ8d3HyNcRXF28Ku3iyciyOVoyxAp4DEWyiaJrtyfrvxfy8ZuK8mdF6APcj42sQ%252BH%252FHR6TBztLxJhG%252Fy1JZAZ6g%252B7EOahlV1aRUL8RGn%252FYXIr0gwesNnsF1GacvQ6EVdPB%252F54AF3AwPkwIn02WbjR4P5ISaFqrIaAQMidmWSwrfwPCO1FMhaAnCAG8VjRvv%252BONarEXTj4S%7Campid%3APL_CLK%7Cclp%3A2047675

If your trying to keep it CA compliant I would start with a "Bank's Torque Tube" header anything that's done from there in 2-1/2" won't have much of a effect other than sound. With my stroker (2000 XJ) I am running the "Banks Revolver" recommended/tested by Russ with a 2-1/2" stock style cat/muffler made by a muffler shop near me but in a factory configuration and it Dyno at 330HP.

I think banks and borla habe exhaust kits.

I fabbed mine from headed to rear bumper running a spintech muffler along with a flow pro twister all 2.5"

No power difrence from the 3" I had on it with factory down pipe nearly smashed shut.

Id exspect no power increase from any pipe size or amount of money spent.

https://bankspower.com/products/exhaust-system-51360-1987-2001-jeep-cherokee-4-0l-xj

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Buy a 4’ piece of 2.5” exhaust tube, a bends kit from summit, a flex pipe section, and a maybe a couple v band clamps, then build to fit what you want. I recommend a semi rigid mount where it crosses the trans cross member.
The banks header is a nice piece, but make sure your motor mounts are in good shape!

I have 2.5 cat back on a '98 and a 2000. 12 hole injectors, bore TB 60mm presently. 62mm TB on the '98 for a while.
I don't think Borla make the header setup for the XJ anymore. I had a Doug Thorley on the '98. Maybe not as much HP as others, but mine didn't crack. I had DW, so go from there.
I had/have three different 2.5 setups. I ran the KOLAK setup for some years. That also, included the spark plug wires. Magnflow Cat and muffler. The tailpipe wrapped around the axle after some wheeling. My fault and not the kit. I added in couplers. I replaced with the 2.5 pipe from IRO and some cheap muffler. I have a Pace Setter Header on it now. I haven't run it yet. Other projects.
I did get the IRO 2.5 Cat back kit. For some reason the tailpipe didn't quite work with the Ford 8.8 and 2 inch lift on the 2000. ??? It worked on the '98 with 4.5 lift and a Ford 8.8.
I can't say there is a bunch of power improvement. I do note, that I have better driving 'performance' on hills or mountains, than before. I did a JBA header for the 2000. I didn't see much improvement, if any. I think its limited by the exhaust ports. My next 'upgrades' will be a 4.1 mini stroker and the Doug Thorley header. The mini stroker head has 1.94 intake and 1.56 exhaust valves. I am waiting for the block to get done. Then I calculate I need to CC the combustion chambers to 68cc.
I am also looking at the Banks Cat at some point.