Exhaust Back Pressure?

[blue_kjR417]

I unbolted my muffler the other day.... I loved the sound! I remember reading a while back that TJKJ said the 3.7 was built to run with some back pressure. I did enjoy the sound of no muffler, but I wouldn't want it like that all the time because some times when I take my rig hunting I don't want that obnoxious sound. So I was thinking about having a cut out welded in behind the y pipe infront of the muffler with an electric flap. This way I could open the cut out and hear that massive 226 cubic inch motor lol and still have some backpressure from the excess still exiting the muffler or just close the flap and it'd be stock again. Would this be enough back pressure to prevent the bending of rods, etc?

 

[LibertyOrDeath]

What, like this.

 

[kb0nly]

I used to have a cutout like that on an old Chevy Scottsdale with a 350, used two of them and a y-cable for the throttle on an old dual carb snowmobile to control both at once so i could have each side dumping out before the Y-Pipe.

Worked great but i don't know how it would work on a modern vehicle with the computerized emissions stuff we have to deal with these days.

It was fun though... One day leaving town i opened her up before leaving the city limits and a cop came flying out of some side street, when i saw his lights go on i closed up the exhaust and she got nice and quiet, he pulled me over and i left it idling, just as quiet as an old lady at church. He walks up with a puzzled look on his face, listens for a second, and then says i'm free to go as he made a mistake....

Guess he thought he got the wrong vehicle! LMAO

 

[Powerslave]

You can buy mufflers now, that have an electronically controlled valve, by YOU, to direct exhaust through the muffler baffles, or straight through. I saw them on Muscle Car a few months back, they ARE pretty cool. That way, it's somewhat legal, as those "Y" pipes are not. I knew someone who put a freeking steam TRAIN whistle on the other side of that "Y"? That was funny as hell! Got busted though...

Back pressure, yes, that's for the low end torque. If you lighten up on back pressure, the torque curve also changes, to a higher RPM. Back pressure and valve-overlap essentially do have the same results... You can use valve over-lap with an open exhaust to give the lower RPM range torque back... You can look all that up.

Still, that muffer I saw, I want one, and are currently looking for one, because I will use it. They are used for pro-street, so you can open it up dragging, or leave it normal for everyday use. The muffler has all the components in it to route the exhaust.

 

[blue_kjR417]

yes midnight like that but with an electronically controlled valve no cables

kb my brother has a 2001 camaro and he has them on his right after the down tube from the headers and hes never had any computer problems

ps i'm not lookin for a new muffler i'm stickin with the stock just a cheap loudness lol

 

[kb0nly]

yes midnight like that but with an electronically controlled valve no cables

kb my brother has a 2001 camaro and he has them on his right after the down tube from the headers and hes never had any computer problems

ps i'm not lookin for a new muffler i'm stickin with the stock just a cheap loudness lol

The Camaro might not mind it, but your going to pop o2 sensor codes on the KJ if you put them there, i guarantee it! But before the muffler, as long as your after the CAT's and the sensors, you won't have any computer problems on the KJ.

 

[JeepJeepster]

http://www.jegs.com/p/JEGS/JEGS-Electric-Exhaust-Cutouts/1231909/10002/-1

Seems ya gotta get their cut out too.

We took the exhaust off the hemi once and it was the loudest thing Id ever heard. You couldnt talk to the person beside of you when that thing was WOT. It was great!

 

[blue_kjR417]

yeah kb thats what i had planned after the y pipe right before the muffler that way the cats weren't a problem

yeah jeepster that was i was lookin at somethin like that