nando52

[QUOTE=Woods;380570]If you are looking for mileage and power, then you don't want to go with a system that does NOT have true mandrel bent tubing. Mandrel bending is much more expensive, but is the best way to do it. Also keep in mind that the factory exhaust is Stainless Steel. You may as well match it, if you want it to last the longest. I've had a couple of guys tell me that they are seeing mileage improvements, after installing my kit.

I posted the following on some other threads, and though it made sense here also. My kit is $315 plus shipping. If interested, please PM or email me.
This kit works on a 2 door, if you relocate the Evap Canister.

We have tested 5 different mufflers. I've got video and sound for four of them. I'll post up video links as soon as I can.

We tested:
- Magnaflow 14377 14" X 4" X 9" Same side offset
- Magnaflow 10436 22" X 4" round Center in/out
- Magnaflow 11226 14" X 4" X 9" Center in/out and offset in/out
- Borla 40653 13.125" X 4" X 9.5" Center in/out and offset in/out
- Flowmaster 50 series 942554 17" X " X 9.75" Oval Same Side Offset

The following are our observations.

Both Magnaflow ovals, and the Borla sounded the same. I do not recall any difference at all. They all represent the most mellow deepest sound that I have heard on a JK.

The Flowmaster and Magnaflow round 4" both sounded very similar. Louder and and more ricey/tinnie/sharp sounding.

The Flowmaster is a very large muffler. The goal here was to see if a larger size created a deeper tone. Just the opposite turned out to be true... This muffler may be a good fit, if you wanted a louder muffler, and did not worry about clearance, or wanted to install in the stock location.

The Magnaflow and Borla with the Offset In, and Center Out would not fit in the location that I wanted to install the muffler. Both would be a good solution if you wanted to install the muffler in front of the Evap Can, on a 4 door.

Hands down the best muffler for the location where I wanted to install (just behind where the Evap Can was previously located) was the Magnaflow 14377. It has the best clearance, is well protected by the rear lower control arms and has as good a tone as any muffler that I've heard.

Picks of Magnaflow install





[URL=http://imageshack.us][IMG]http://img123.imageshack.us/img123/

Woods

Stock piping is 2.5" O.D.

You can weld stainless with a mig welder. You need Stainless Steel wire and to be running gas shielding.

The concern that I would have with not having a tail pipe, is heat. I've heard of parts melting under the back of the JK. Sorry, I don't remember which parts



The only feedback that I have, is from two customers. They have indicated an improvement in MPG. The most unbiased example, as it was explained to me is; customer told me that he had not reset his average MPG on the computer for several thousand miles. It had leveled off (about 13MPG, as I recall). As soon as he installed the muffler kit, it started to creep up. Last I heard about 1.5 MPG, with a thought that it may get to 2 MPG.

robboyadjian

The reason I was asking is because I have a Magnaflow catback system from my brother's ex-Mach1, it's been sitting in my shed for 2 years now and he's pretty much abandonned it. It's 2.5" ss, Magnapack muffler, so it's center in center out rocket shape muffler, not oval shaped like traditional mufflers. Just debating if it's worth it or not.

brestman

I just had a stainless steel oval cat-back free-flow muffler(15x10x5) with a 2.5 inch in and out...great mellow sound..couldn't even hear it inside the cab...I suppose the reason that there is a drop in MPG with some members after cat-back installation is the heavy-foot!..some are eager to hear the nice sound and to feel the increase in responsiveness so they revv-up more!I admit to this especially after making new mods to any vehicle

Woods

Chances are, that it's 2.5" ID, so the stock piping will slide inside the muffler. If not, you can always use a butt joint band clamp. No need to weld.

Pic:

Woods

Did you install a kit?

I think 15 city with 35's is good. Before the muffler, you got 17MPG? Was this on the computer? I think the computer is only good for relative results. I do not think it's truly accurate. Thus your mileage change would be relevant, but I'd be surprised if you actually got a true 17MPG city.

I went and dug up an old note that I got from Dayton1999. Here's what he wrote:

My mileage numbers for the last 6 tanks of gas:

PreMuffler Kit
1. 10.85 MPG
2. 11.75 MPG
3. 10.26 MPG (Top off the Jeep)

Average: 10.96 MPG

PostMuffler Kit
1. 12.93 MPG
2. 11.93 MPG
3. 11.29 MPG (Top off the Jeep)

Average: 12.05 MPG

So, I'm seeing a 1.09 MPG increase right now. I will continue to track it as I think the increase is closer to 1.5 MPG.

Jeff

These calculations are based on his standard drive to work, the odometer readings and actual gas used. No computer data.

Woods

BTW, how do you get into the Polish JK owner's club? (now that's a classic Polish question) Is there a thread about this somewhere?

Woods

I doubt that you'll see any performance increase by going to a flowmaster. Did a muffler shop do the install? If so, my guess would be that the piping has been reduced in diameter, where they bent the pipe. This would restrict the flow. You may actually see an increase in torque at lower RPM's though. Do you feel any difference when starting out?
If a muffler shop re-used the pipoing over the axle (like they did on mine), it may be fairly easy to cut the back piping off, and test it that way for a couple tanks. I wouldn't run in traffic or crawling around on the rocks like that though. I've heard of heat issues from the pipe not being run all the way out.

Do you have to be pure Polish? I'm only 3/8's. And would my wife count if she has a little Polish in her, every once in a while?

TINMAN_2469

I have put on a banks exhaust after about four tanks of gas. I have now gone used another four tanks and my numbers seem to be showing 1 to 1.4 mpg increase. This is based on the computer.
I feel it is save to say we atleast gain 1 mpg.

RedneckJeep

How does the Banks stuff sound? Can you tell any power difference? Banks is usually top notch.