backpressure/exhaust questions

Im planning out my new exhaust system and im trying to figure out what size pipe i should use. I want a quiet exhaust, i get enough noise from the tranny/t case i dont need more from the motor.

Im using headman fenderwell headers on my v6, right now i just have 3" straight pipes that turn out behind the driver seat. the jeep is extremly loud and im afraid that im gunna burn up valves or somthing because of the short length and lack of back pressure.

im thinking about using a small high flow cat and standuard car muffler then turn right out behind the seat. what diameter pipe should i use? i dont want my exhaust to be too restrictive, but i dont want to loose all power. im tempted to use a smaller pipe so it "shoots" the exhaust out a little better. plus since each side is only exhaling the exhaust from 3cylinders i probably would need somthing no bigger than a stock honda civic correct?

The 3 inch tubes are way to giant,(previous owner's idea)

 

Hey ******* YA, sounds loud!R) If you went with 2" pipes and some turbo tube mufflers that would sound nice, but not to loud. I did the same thing on mine. I had glass packs and swaped them out for turbo tubes. Big improvment! Don't waste the time and $ on a cat. The turbo tubes will be quiet enough. Later.

 

ive always been told that the smaller dia. the more torque, the larger the better horsepower. if it were me id go with a baffle type muffler, meaning the cannister is filled with fiberglass, and noise is adjusted with plates the more the quieter. i dont know who makes this but have seen it on a 2 1/4 system.

the only way your gonna burn a valve is if you have a headder flange leak, you could run just the headders and be ok with no problems.

you might want to look into flowmaster, anything under a delta 40 is quiet and sounds really good

jegs, and summit offer a product brand muffler that sounds ok, or you could just go with a glass pack...

 

If you want a quiet exhaust, are you sure you want headers? Most guys I've talked to said that headers really don't improve performance on the V6 enough to be worth all the headaches they usually cause.
Anyway, I drove a 304 powered CJ awhile back with headers and Dynaflow mufflers that were surprisingly quiet for such a short system. If you must have headers, consider those.

 

my jeep had headers on it when i bought it, i have some manifolds laying around but they wont work with my power steering conversion. i could get some rear dump manifolds off a old buick car but that would be a pain in the butt, and im sure it clearance would still be an issue.

i dont really want to spend a lot of money on exhaust, i dont care for a performance sound or anything, i just want it to be quiet. i was thinking about just buying cheapo car mufflers, there like 20 bucks each,

i think im gunna skip the cat for now, my motor burns so much oil it would clog the cat real fast.

 

2 x 3" HOLY ECHO CHAMBERS BATMAN
One 3" is enough to let a 7.3 NA diesel breath unrestricted, that is WAY to much for a 225. 2" down each side with a turbo knock offs (what ever the local store sells) will knock the noise down and maybe give some torque back. DON'T run glasspacks if you plan on 4wheeling on Forest service land, they are illegal, mufflers need to have a turn for a spark arrestor affect.
Please stay away from cats, they will only add expense and a foot warmer to your Jeep.

 

ok so i think im gunna just run 2" coming out of the header and then a standuard car muffler from the parts store, and turn out with a 2" 90degree angle. ill let you guys know how it comes out.....hopefully quiet

 

2"-2 1/4" through a Turbo any larger is just for noise under 300 cubic inches, now here's the important part, make sure it exits outside not under the body.In front of the wheels behind them or straight out the back(fumes lkely to come back in cab straight out back though) single or dual Sound is much more pleasing/manageable that way without it echoing underneath....

 

Here's a link to a CarCraft test that relates to key4202003's comment regarding smaller tube diameters possibly contributing to better low-end (low RPM) torque, and larger diameter possibly contrubuting to better Hi-end (high RPM) HP. Interesting read.

 

I sure appreciate this thread having been posted, from the standpoint of prompting me to research the multitude of info on the web that qualify and quantitfy the relationships of tube diameters to low-end torque vs. high-end Hp as they relate to the power curves of various engines in varying vehicles and variations of individual component parts of the engines

 

wow just finished the 3rd incarnation of exhaust. went from the hedman :v6: muffler (short but Harley loud), to 25" long glass packs (improved it a bunch), to my current setup, the glasspacks (still the 25") but now i added a 90* turnout. made a BIG difference. The hard top is MUCH quieter.

I will say this though, the hedman muffer's while being loud didn't get as hot as the longer glass pack does.

will take some pics later on today for ya.





why add the cat? never had it stock. unless you NEED to cook eggs on the floorboards, avoid'm.