oneal916

so i was wondering if i went and step up my muffler that it would help out but i think i went to big . and i want some input on it. to see what i could do to ether fix it or go back to stock . i have a little bit loss of power and some idle issues with it all i did was have Bucky's put on a flow through muffler and side pipe it . i think my muffler is a 2.5 " ill take some pics later and post . any feed back would help

CRoading

I also had some loss of power when I replaced my muffler from stock that is why I decided to put it all back...

CAEMI

This exhaust size issue has come up before. Just my opinion, but messing around with aftermarket whoopi parts like K&N filters and large exit tubes always results in disappointment and sometimes ruined engines (like with K&N). There are a lot of people out there making money by dreaming up fairy tales about "performance" gains from one part or another. The mantra is always the same: "those OEM guys are idiots and do what they do to appease the EPA and lawyers" blah blah blah. They are wrong...but they've already got your money when you figure it out.

There is a reason all of the guys with Phd's in mechanical engineer at Jeep chose the setup they chose. Contrary to the aftermarket hype, nobody understands these engines even remotely as well as the OEM. The R&D budget at Jeep is ten times the size of K&N's entire company. This ain't David & Goliath...it is Albert Einstein and Alfred E. Nueman.

dbcox

You need back pressure, to big of an exhaust and you lose back pressure and power. Keep your pipes close to stock and you should be ok, an aftermarket muffler will flow better than stock but keep stock size pipes.

THENNING

X2 with backpressure....i ran 2.5 inch from the cat back and wasnt impressed at all...shoulda went with the 2.25 flowmaster just my .02

jmm0122

I run 2.5" pipes from the header all the way back and I havn't noticed any power loss or any power gain. In my opinion it sounds better than my 95 that just had a flowmaster muffer on it.

Metlic53

i run with same setup +++ a magnaflow high flow cat. no loss of power, felt a little gain but i put a APN header, 63mm T-body as well.

LizardRunner

As with most vehicles, stock diameters are designed to have the correct back pressure at the exaust valves so the engine doesn't pull spent gasses back into the cylinder as the piston heads back down after the exaust stroke. Larger diameters mean better scavaging of exaust gasses for a fuller new charge of the cylinder. Many High performance exaust systems will have larger diameter pipe but will use a muffler that keeps the back pressure high enough for proper function of the intake. If you have done a lot of engine mods, then you are going to see more benifit with the larger, free flow exausts system than if everything but the exaust is stock. It is also possible to take away enough of the back pressure to induce a stutter in the engine. All that in mind, If you increase the tube size of the pipes, keep the stock type muffler or use the stock tube size pipes and use a free flow muffler. Even most of the nascar vehicles use large pipes with a "rebound" muffler inline to get the proper backpressure for their engine setup. This is so they get a smoother powerband. Fully open exausts will increase the top end hp but at the sacrifice of the low end torque, so it just depends on how you want your power band to work for you.

djb383

How can u tell u have loss of power from installing a bigger muff? Also, wouldn't idle issues possibly mean there are other issues effecting performance?

http://www.uucmotorwerks.com/html_pr...torquemyth.htm

http://start.toshiba.com/search/inde...+back+pressure

oneal916

i can tell loss of power by the way i give it throttle . it lags more than what it did when i had stock muffler. going up a hill i have to give it more gas than usually. almost stuffing it to the floor , taking a corner and letting off the gas my rpm's will die to 0. on the freeway i have to shift into 3rd gear to get it to go . and sometimes i have to floor it to get it to go from a dead stop, its almost as if the computer puts to much fuel in at once

i think i possible have other issues but the muffler is like a cherry bomb but has a tornado type of flow . ive had it on for a couple of months its nice on the freeway, but when i get into town and drive city i have to sit on the brakes and the gas to get it idling. if i unplug the two sensors on the throttle body sometimes it fixes the problem also at a stop light in drive it will idle between 950 and 600 and sometimes will die for no apparent reason. i also just recently fixed my intake and gasket manifold too.

tandersen45

That definately sounds like a lack of backpressure. Are you running any sort of cat????

djb383

Any links/info out there saying exhaust back pressure is a good thing?

http://www.uucmotorwerks.com/html_pr...torquemyth.htm

http://start.toshiba.com/search/inde...+back+pressure

98jeepsrt6

For those that are not impressed with there slightly larger exhaust setup, have you considered resetting the Ecu to relearn your new system.. The o2 sensor will provide the ECU correct A/f reading from the new system and reprogram itself to add more fuel = to the amount of air flowing through the system.. That would be the purpose of the all the sensors in the vehicle each playing its part to learn what the engine is doing and how to make it run/perform most efficiently.

Most people dont realize that when you add mods to a vehicle that drectly interfier with OEM specs, it will show poor results. Becuase your vehicle is comparing readings from previous start up to a new different spec. Resulting in poor performance..

so my point today is reset ur ecu and the come down to a final conclusion..

Treemagnet

When I had to change the pipes from the manifold to the catalytic converter, I bot the original from my local Cdn Tire Store (probably the same as walmart in the us) but for a muffler I put on a Cherry Bomb (red) its just a small straight you can see right thu the muffler and the catalytic went back on and pipes stock size and never had any problems. Great sound too

Ogre in KS

Just my opinion, but I think it sounds like you've got more problems than just lack of back pressure/ too big of exhaust. When I redid my exhaust, I used a 2.5 in. Flowmaster 40 with 2.5 in. exhaust pipe starting before my tranny crossmember to the cat then to the muffler and about 18-24"s of straight pipe after the muffler and I never noticed any difference in power, the only difference I noticed was the sound, which I'm not a big fan of, Flowmasters sound GREAT on v6 and v8's, but on an inline 6 they don't sound right, just my opinion,lol.