Hey bro just go straight pipe off of your 4 cats that is probably the loudest you r gona get without spending a lot and its not even that loud. You won't make it louder by adding a muffler just change the sound a bit. Only downfall to this is that you may lose a little bottom end, but will gain on the top. These trucks like back pressure.

 

It made mine louder and deeper.

I had a shop cut mine off and weld in a pipe.

I can't tell a difference, and I haul crap every day!

Mil eliminators are a few bucks off ebay and they take about 20 min. to install. They are not necessary, but I got tired of looking at the check engine light. (buy the 2 wire mils)


I gained 2-3 mpg.

It doesn't hurt your truck. Your truck has O2 sensors that monitor the cat's performance. The MIL eliminators trick it into thinking that the cats are still there. They don't contribute to A/F ratios at all. So, If you don't care about the check engine light, you really don't have to do any modifications.



Sorry Guys. You might not like it, but it's the truth. Now as for emissions testing, you might have trouble passing if you cut them off. Also, if you think you're gonna get a lot of hp gains, you're fooling yourself. I probably wouldn't have gained much mpg's but my truck gets sucky gas mileage anyway. It couldn't hurt!!

Oh, and If it hurts torque, hp, gas mileage etc. to remove them, then why does everyone have "hi flo" cats? Nuff said.

 

in a word.......thorough......thanks for the info, still trying to decide....

 

You're an idiot So if my truck didn't get louder when I removed the factory muffler and added a Flowmater 40 series, then what did it do? Is the increased sound just a figment of my imagination?

 

Hello Zaairman you are so cool. I meant that the easiest way to get buddies truck louder was to add a straight pipe off the cats. That will be louder than what you got. So you putting in a flowmaster isn't gona make it louder than somebody with no muffler. Pretty common sense. You have a 40 series muffler. Wow you must really be old. A lot of technology in flowmasters. Ya right.

 

"Straight pipes from the cat back will be loud, think racecar loud, not so much at idle, but under load. Without the muffler backpressure, low end torque will drop"


I can vouch for this whole statement. My 98 4.6 has straight duals off of the stock cats...2.0" pipes...it's loud. When the motor is warm but the pipes are cold (like shutting it off for 30 mins or so), cranking it and getting on it is insanely loud. Sounds extremely rappy, like glasspacks on an older V-8, only my 4.6 is louder! Also lost some low end grunt, but it will get it pretty good from about 70-85 or so. But it sure does have a good grumble... blub blub blub

 

i put on a 40series si/so what most people don't know about the 40 series it that technically its an amplifier not a muffler test pipes or straight pipes will give you a good backfire pop on decel but not worth it because you'll need earmufs on long trips to deal with the canstant DRONE
my buddy put basically test pipes on (hes got true duals with a pair of mufflers that just reduce the pipe size by about a 1/4inch for a foot) drones pretty bad but sounds bvery cool

i like my flowmasters sound but i need a tail pipe and to take off my cats
i think mine was louder with the 40 than without

 

My buddy was in getting something like brakes done and the guy said to him that to cut the old muffler off and weld in a straight pipe was no big deal, Rick said go for it. Might as well with it bieng in the air already. I think the guy charged him 50 bucks. I'm not sure what he did, haven't looked at it yet but boom! straight pipe.

This thing is loud and it was dirt cheap- winner: straight pipe.

 

If that is what you originally meant then SAY SO! And I'm 18. I'm very happy with my Flowmaster, but I still want it louder. So guess what I'm doing? Straight pipes.

 

go whith a dynomax bullet series round muffler i think the part no is 17220 it has a 3" in and out and is straight through have it put on with no tailpipe but with a turn down, sounds awesome