So I asked this on another forum and apparently, the consensus opinion over there is that anyone who tries to do anything engine/performance related with their JK is mentally retarded. The whole attitude really rubs me the wrong way, but after reading all of the positive feedback about the Superchips here on this forum, I'm thinking I might get some more constructive and objective advice this time around.

I know that my 3.8 is never going to be fast. I'm not planning on drag racing Civics, but if stuff like that Flashpaq can make getting on the freeway a little less sketchy and help with shifting on steep hills, not to mention a little better mileage, then I'm all for it. I know an exhaust isn't going to make a huge difference, but I'll admit I like the sound of aftermarket exhausts, so I'm not going into this expecting huge performance gains.

My specific questions are:

Cat-back vs. muffler only. Personally, I don't think there's much difference from a performance standpoint, one just costs more and is easier to install yourself. Any differing opinions on that?

Do any of you have good or bad experiences with specific brands and models? I'd like to get something with a nice tone, but I don't want it super loud. Tone is much more important than volume to me.

If you have installed an aftermarket muffler, did you notice any performance changes?

Thanks in advance for any input.

 

There's not a thing wrong with trying to get a little more from the 3.8.......as long as you realize that's probably all you're gonna get. A little more. I had great success with a custom cat back I had done by a local friend who owns a muffler shop. He relocated a Magnaflow straight through muffler along side the evap canister on the driver side and ran it out the driver side to the rear. It really made a very noticable difference right where the flat spot used to be. It decreased alot of the gear hunting it used to going up hills, because of the added torque. I was really surprised. My other surprises came in the form of a drop in aFe air filter element and E3 spark plugs. I did them seperately, and I cannot lie. I felt a small increase with each mod. I do not have a tuner as of yet. Hell, I don't even have my Jeep right now. It's been at the dealer several weeks getting a new engine. Had some internal noise so they decided to put one in it. Don't let anybodt tell you that you can't get more power.......you just won't get THAT much more. Maybe with a tuner and all the mods I mentioned above, it could be pretty decent. I'm sure the tuner would work better with a good intake and exhaust at the very least.

 

I concur with what Redneck stated. I think you can get a moderate amount of power from an exhaust, but don't expect much.

Replacing the can is the way to go and skip the expense of a catback kit. Your call as to how you want to do it, with a relocation kit or at the local muffler shop. You'll be able to get the can out of the way with a relocation kit so it serves more purpose than whatever performance you get. I'd stay away from the chambered mufflers and run with a pass through design. The Magnaflow stuff works as well as anything, they are inexpensive and people are happy with them.

As for a programmer, I do believe it ties after market intake and exhausts together better than the stock PCM. I don't have a way to quantify that as I did a lot of the upgrades in a short window and added the programmer(s) later. First one I bought didn't do much to tie things together and the Flashpaq was what really breathed some life and power into my JK.

 

Never satisfied with anything factory Is part of owning a Jeep IMO just look at all the options we have for mods I added a TB spacer, K&N filter, Max energy , and Gibson single outlet all the same day. I can say there is a difference ( some ) even with larger tires. IMO based on past mods the muffler change will give you the sound and a little feel without too much $$$$.

Have fun

Chad

 

I went with the Borla cat back, one of the on-line stores was running a sale on this system, so I saved a few $$ over the Magnaflow.. I can't see where there would be a difference in brands...
as far as added performance, maybe a little, it does sound a little better but is still very quiet. overall I'm happy with it, and it was very easy to install by myself....

 

Yes, their is. Changing the muffler only, will just change the exhaust note. Their are more restrictions and issues before the muffler that need to be dealt with. I don't understand how you think their isn't much difference between a full cat back system and just swapping out the muffler.

Look at it like this: If flow velocity increases right after the cat, it will have increased 9 ft before the exit. If flow velocity increases right before the muffler it will have increased right before the last 18 inches. Which do you think would be more efficient?

Obviously the most efficient system would include headers, test-pipe, and straight pipe. However, their only seems to be one company who offers headers AND a test pipe and that's borla.

check it out here: http://www.borla.com/products/product_detail.aspx?prod_sku=17251

The price seems high, but is definitely worth it. It is a full system WITH test pipe. It deletes the cats, which may not be allowed in some states, but it is a well thought out system, in that even includes the TEST PIPE. Other manufacturers who have made headers retain the stock test pipe which I could go on all day about it's inefficiencies.

If you were to go to a muffler shop and have them fab something up like the MBRP relocated exhaust, it wouldn't take long, and would be your best bet. A flowmaster 40 would do you good.

 

By test pipe are you referring to the stock Y pipe?

If so, I agree the thing sucks and is the constant bottleneck in increasing performance. The stock Y pipe has been something I would love to get some sort of heat barrier coat on but when I looked at it I certainly didn't want to throw any money at the thing. It holds a ton of heat, has the cats integrated into it and pretty much just leaves you shaking your head.

I'd love to do something like the Borla long tubes, but that means in a state with bi-annual inspections I would need to figure something out as far as getting cat(s) installed and also pray that the PCM (with Superchips) could resolve it. That's an experiment that is going to be real pricey and after some stuff that happened with my previous programmer I'm unsure if I could ever get it resolved.

 

Yes

It needs to be trashed, not coated.

You could always weld in performance cats. OR just 1 performance cat could be slip fitted where the cat-back system normally starts. Most state inspection shops won't know how many cats are supposed to be on a vehicle. Some state inspections (like VA) just make sure you have a cat in place.

We need a tuner with actual TUNING capabilities (I want to be able to manipulate ignition timing and fuel values). With that, I could make ANY 3.8 pass an emissions test, with ANY modifications. It would also help in extracting more power out of the mods we do. We only get half of the actual power when bolting on performance parts. The other half is tuning. Many people don't understand this. I used to do product development and tuning for high end European cars. This stuff is simple.

 

Yep, I agree and that is why the stock Y pipe remains uncoated, although I'd love to further reduce my under hood heat.

As for the after market cats, I looked at, perhaps it was really just dreaming of what ifs and I don't think they would be that hard to make fit and weld in. The bigger problem is no tuners for the platform, probably won't ever be and your maxed out with what can be delivered with a programmer. Additionally with the tuners that are on other chrysler platforms none of them seem to have the chrysler PCM dialed in as well as superchips. While they can be helpful when people really push the limits of their engines on these other vehicles, I continue to see lots of comments from users of Diablo or SCT make mention of "when they get XXXXX figured out like Superchips".

Anyway, you're way more savvy on the tuner stuff than myself and the long tubes with cats aren't something that I plan on being the guinea pig for.

 

No, not a flowmaster 40 if you don't want it loud. Chambered mufflers are loud and they drone. Stick with a straight thru design, like the magnaflows or several others. And I'm pretty sure deleting the cats is illegal everywhere in the US.