Question about california cats and exhaust sound/restriction

Im looking to buy a muffler to replace my stock one thats been on the jeep since 94. Im repiping with 2.5 all the way. Apn header to be installed at the same time. Ive looked at numerous vids and read thread after thread on different sites.

I cannot find the exact info.So I gotta ask.

I live in a semi quiet residential neighborhood in CA. I leave for work at 4am. I am looking to buy a muffler flowmaster 50 or 70. I like the quiet of 70 but would prefer the more free flow of the 50. Being I live in the nazi smog state a high flow cat is not an option.

Would the california cat affect the loudness or tone of a muffler? If I were to get the 50 would a cali cat quiet it down some ?

Thank you.

I run a 50 series with a Walker high flow cat - you know when I crank up for sure. Driving and pulling away are not as loud, just a smooth, deep purr.

Magnaflow makes a very nice flowing cat for the early XJs, and it is CARB approved as well. It's very similar in size and design to the Walker that I have on mine.

From my experience building engines/exhaust, when I finally install the converter it makes the tone of the exhaust deeper, and takes a few decibels off. I had to run a Ranger 5.0L with just a Thursh welded for a while, and once I got the cats on it really made it deep and took a drone away from it.

The presence of a cat definitely quiets things down. I can hear the difference between an exhaust system with or without cats. We have a lot of out of state military folks around here and some of them are running modifications that they can only get away with by having their vehicles registered in their home state (and more power to them). I can't tell how many times I have heard an exhaust system and wondered "How on earth does he get away without having cats?" and then noted the out of state plates. Take away restrictions and the system gets louder. And vice-versa.

FWIW, I was running an OBDII cat and a Flowmaster (probably 50 series) and it was just too loud for my taste. Courtesy of the state of Kalifornia I had to re-do my entire exhaust system. Now I am running a Borla header, Magnaflow cat, Dynomax Ultraflow muffler and a mandrel bent 2.5" tailpipe (all in stainless) and it is a much more tolerable exhaust note. Still might wake someone right next door when I start it, but should not wake the whole neighborhood as I drive through. If I had to worry about the time of day you are considering I would probably go with a turbo style muffler.

I really would want the 50 series but dont want the key job my jeep would get around here. I saw a vid on youtube made by summit on the 3 different types of mufflers they had the flowmaster the turbo and glasspack. I like how sturdy the flowmaster looked. The turbo has some type of stuffing that seems to me would burn or deteriorate with time and maybe?? Changing its characteristics??

Im thinking of just getting the 70 series with the magnaflow cat mentioned above. A muffler wont mean much in terms of crazy hp/torque gains anyway right?

If you wind the engine out every time you drive it, you'd maybe notice the power gained from a bigger exhaust. Driving like an ordinary citizen, no, the muffler won't do anything special for you.
I drove with a 40 series on my cherokee and it annoyed the piss out of me. Doing it again, I'd stay stock replacement parts.

Forget the Flowblocker and go with a Magnaflow. If you do a FM, you will see zero performance difference between the 50 and 70. You will however see better performance with a Magnaflow (I have EFI logging data that proves it).

Magnaflow you say? Any type that is similar to the 70 series in tone?

DieselSJ said:

Forget the Flowblocker and go with a Magnaflow. If you do a FM, you will see zero performance difference between the 50 and 70. You will however see better performance with a Magnaflow (I have EFI logging data that proves it).

Click to expand...

I agree. I took the FM off my new rig and put and 18" oval magnaflow. It sounds great and not nearly as loud. Not loud at all really.

You have a part number on that muffler? Maybe I can check out a vid to hear it.

https://youtu.be/LvHZdy0re0s Im loving the 70 series sound.

I was searching just now but I am seeing flowmaster does not carry the 70 series in stainless only in aluminized

Is that right?

This will give you an idea of sound. I can't access all my vids at work...I'll try to get find a better one.

https://youtu.be/MmfD3pfH4f0

All stainless 2.5" everything, Walker cat, Flow 50, and pipe routed exactly like original

Don't waste your time with failmaster. I had a 14" 4x9 oval magnaflow on my XJ with a turn down. Now I have a Spintec muffler on it. It's louder but still has nice tone to it.
I was going to put a spintec on my MJ, but my exhaust guy does not have any the correct size. So, I will most likely be going with a magnaflow Oval, maybe round pending price. Unless I happen to find a Spintec or Dynomax Ultraflo for less.

Quiet-ish, magnaflow-wise you will want an 18 or larger. Amazon seems to be the cheapest place, unless you find a local shop that has a good deal. Also, do not remember what the PN is, but magnaflow makes an XJ specific 2.5 CA cat.

the dynomax is mellow, and appeared to be what the dealer installed mopar high performance exhaust used.

no difference noticed between the fancy mopar one and the dynomax.

edit:
Happened upon this at the rockauto site today as well
http://www.dynomax.com/downloads/promotions/dynomax_fall2015_promo_us_websecure.pdf

$25 rebate on the dynomax.

http://www.walkerexhaust.com/assets/downloads/promotions/Walker_FCP_Converter_Days_RPad_US.pdf
$50 on walker cats.