totally redoing my exaust have some questions on backpreasure?

I have a 96 2dr with a 4.0 and ax15 Im planning on doing a header probably borla but open for suggestions custom downpipe w/o the kink. then i was going to do a flex pipe to stop the header from cracking and a high flow cat with a dynomax or borla muff. What should i do about the tail pipe what size or have it costom bent (i have a 5.5" lift so i dont need all those bends) what do you guys think about those things and any suggestions on brands are welcome. i want to spend as little as possible. also how much is too little back preassure? thanks guys

As long as you have a gradual decrease in pipe size you wil be fine. Usually 2.5 to 2.0 ( at the exit) works nicely on the 4.0L.

i just redid mine from the cat flange back. I found the most amazing thing! Checker auto parts sells the bent tailpipe from the muffler back for 16 bucks!!!
can you believe that? mine is a 89, but i think it'd be the same kind of price. of course, it's no mandrel bent job. you can see the deflection of the tubing on the bends.. .but mine runs way better with this one than the prior. not the best quality, but with labor selling for 50/hr at my local shop, i prefer the 16 bucks for a china pipe to the 150 i'd get stuck for getting someone to throw welds i can do myself.
So, for my money? checker.
On back pressure: i ran for a week and a half with nothing after the cat flange. it sounded awesome from the perspective of my inner redneck. but the power is better with a cheepo muffler and pipe from checker. way better.
i thought about just a 60 degree bend after the muffler and an exit in front of the passenger rear tire. could be cheeper, but not much.
enjoy.

If you want cheap, don't even bother looking at Borla. My brother put the Dynomax cat back system on his 93xj with my 2-yr old magnaflow cat and it sounds good(but not as good as my Borla setup). He still needs to change out the pos crushed and small diameter downpipe, which we might be able to get if the freaking JY will stop getting crazy with the torch when they cut off the cats(basically they end up cutting in front of the crossmember mount.

22 in glasspack and mandrel bend 2.25 in pipe $125, 2 years ago.

broqenjeep said:

22 in glasspack and mandrel bend 2.25 in pipe $125, 2 years ago.

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x2. As long as you're using the right diameter pipe, the least amount of backpressure you can get the better. And glasspacks do that very well, especially for their price.
As far as headers go, I think Clifford makes stuff you won't have to worry about crackin. I opted for the dual outlet header w/dual exhaust and it cost me about $350 for parts and installation not including the header. That's for two glasspacks and a dual in/out muffler that's also an x-pipe. And it's suprisingly not very loud at all.

That "kink" in the downpipe is there to allow the front driveshaft to clear the pipe at full stuff (at stock height) - if you don't have it, your driveshaft will "self clearance" on the pipe and you'll probably end up with a hole. I'd not bother with a custom pipe, unless you had at least 3" of lift (or so) and you'd extended your front bumpstops.

A flex joint might not be a bad idea, but cracked header collectors are typically accompanied by failed engine mount cushions - how are yours?

Oh - and there are loads of discussions already on "backpressure" - that should help you sort through them. Computers are very literal, and I've not heard of many cut-down search algorithms that use "fuzzy logic" to check for things close to what you've spelled, so you may want to check to make sure you're spelling a word properly if you're not sure yourself. A dictionary is a handy reference to any home office (I use one myself from time to time - the brain is far better at fuzzy logic than computers...)

Not trying to cut you down - I'm honestly trying to help you:wave1: