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Benefits of dumping exhaust after muffler??

C

Cherokeekid88

NAXJA Forum User
Location
North Carolina
Like the title says. Any benefit from dumping exhaust after muffler and adding a turn down? Any increase in sound? any better?? any worse?? Currently running FM 40 with stock cat.
 
so your saying just leave the pipe off the exhaust outlet on the muffler? I don't see what would be wrong with that... you see brand new cars everyday with 3 inch tail pipes after the mufflers from the factory with no turndown... Mines like that... just keep the cat on there.
 
Benefits? Little to none.

Change in sound? Little to none.

You're still going to have a muffler in place. If you want to change the sound of your rig, think about going to a less restrictive muffler instead. Keep the cat - and, if it wants replacing, I usually end up using a "universal fit" V8 cat. If you have OBD-II with the HEGO sensor after the cat, you can either get a universal OBD-II cat or have a sensor bung (they're all the same thread - M18-1.5) welded into the extension pipe you're probably going to need.
 
You also want to watch the laws in your state. Most states will not pass inspection with turn downs or cut off exhaust unless you have a P/U and the pipe is cut after the cab. They say the Carbon Monoxide fumes will get in. yeah, I know.....
 
My ext was cut right before the rear end(do to ext. rott)
but i didn't like the idea of the ext going straight at my fuel tank.
so i put a down pipe on. it got rid of a lot of resonating in side the jeep.

Flash.
 
i have a turn down just after the muffler on mine, behind a dynomax muffler, and i get alot of exhaust noise inside the jeep. plus its louder standing around it, and it kicks up alot of dust off the ground when i start it in the dirt. i like it tho, i would say my exhaust is around 20% louder than my buddies with the same muffler and a rear exit. if you do the turndown expect to hear your exhaust more, inside the truck. other than that i dont think there would be any performance gains or losses.
 
Think i might end up doing it, just to see, if i dont like it or doesnt do right, i can just get it welded back up. But im not looking at my jeep and its too cold to go back out, but if i end the exhaust with a turndown after the muffler, do i need to install a hanger or anything?? will it stay up?
 
You'll probably need a hanger - as I recall, there's the "slip" hanger bracket right near the transmission mount (forward of the cat) and the hanger for the arch over the rear axle, with nothing in between.

I'm fairly sure you'll want something right after the muffler, if you put in a turn-down. Otherwise, there will be a lot of leverage on the forward hanger and the welds to the cat.
 
Mine is currently cut right after the hanger after the muffler until I can get it fixed. There is no performance gain and very little sound gain. Be careful that it doesn't dump the exhaust straight onto the axle or the brake lines. You don't want to boil the brake fluid and lose your brakes.
 
I doubt you'll get much gain unless your old exhaust pipe was narrower than stock. I've seen some aftermarket systems with a slightly smaller diameter at the outlet end, and when I replaced the one on my 87 with a correct one, I thought I detected a tiny bit of gain.

Having run various XJ's with rotten and partial exhausts, I think you'll find it is a good bit louder with a stub.

If you're going to go with a stub, you really need to make sure that there are not little rust holes. XJ's do tend to rust right above the exhaust, so it's not an idle concern.
 
Mine is cut off about 3" past the muffler and it seems louder in the cab but no different outside. Kinda can get fummy if you sit at idle and there is no wind, but I have no cat and its a carbed model.
 
IMG_1089.jpg


no gains....just doesent coast farther....atleast thats how isee it...and accelerating takes a little longer...

thats just me though heh

i had to do it because of the tnt boomarang shakles
 
on my friends YJ he dumped it off behind a flowmaster - 4.0 - and it made it much louder - kinda annoying but again it is a smaller vehicle

i am going to do it so i have less exhaust tubing to dent or mess up - it might get fumey and a bit noisier but thats cool cuz my jeep is trail oriented now - like previously said i will dump it off with a turndown pointed away from gastank and rear axle - kinda out the side of the jeep but still pointed towards the ground
 
i have a turndown right at the muffler. kinda loud in the cab but a 5.00$ turndown was way cheaper than a new tailpipe, plus it was chrome so that adds at least 20 hp. i added a universal hanger between the cat and muffler to hold it up. it sounds decent with an apn and magnaflow.
 
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