Hey guys

So, my cat is an old rusty piece of garbage. Pretty sure its getting plugged, not sure if it's ever been replaced. I replaced my old muffler with a flowmaster 40 and love the sound. After a year of the flowmaster being on, its not loud enough anymore. I don't want it to sound like it has straight pipes, but I need a slight volume boost. Originally I was going to cut the cat out, replace it with a pipe and an O2 plug to stop it from throwing codes. Now I'm considering putting a hi-flow cat in from magnaflow. So, what would you guys advise? (ignoring legal issues). Does anyone have any videos of a high-flow cat with a flowmaster 40 series? or flowmaster 40 with no cat? Just looking for some +/-s for each option, thanks guys

 

Cats rarely go bad by themselves, something else usually causes it, on the Magnum engines it's likely a leaky plenum.

Without a cat your truck will stink and even if you don't have emissions it's still a federal crime to remove it (EDIT: No idea about Canada).

Consider a different muffler too, I replaced my 40 series with an Aero Turbine 3030, along with being louder under WOT and quieter when cruising than the 40 series, it sounded better too, I also gained a little power as well.

 

I loved my magnaflow duals but I then took that off and im now just running my stock cat and it sounds sweet. Im not going to be putting my duals back on.

 

I am running a hi flow cat, 3" in and out with a 3" Flowmaster exhaust and muffler. It sounds really nice, I picked up some power and a little mileage, plus the truck is legal since the parts all have carb #s.

 

The aeroturbine sounds like a quiet straight pipe and imho, its one of the best sounding mufflers out there for a dak!

 

Yeah I have emissions here too..has to be done every 2 years, last time it passed with flying colours. I just want a little bit more volume, I like the grumble of the flowmaster, dumped out behind the rear wheel. Sounds good when I boot it and it doesn't resonate in the cab on the highway/city driving. I just wanted a little bit more volume. I think I'll go with the magnaflow high flow cat (mainly because it's the only brand of high-flow cat I really know..) to keep it legal...if not I'll shorten the pipe between the cat + muffler & dump the exhaust out infront of the rear wheel. just talking about all this makes me want to get headers, a turbo, a lift, new headlights, brush guard..etc etc etc lol

 

Yeah well when I took my exhaust off and the cat it right there under the passenger seat it was pretty loud so I got a piece of tubing and ended it right at the start of the bed and its much better now not that loud in the cab.

 

Unless of course the cat was subject to a recall...as ours were...

Magnaflow makes EXCELLENT products. I would not hesitate to use anything they produce...

Now, as for making your exhaust louder...

Purely on a volume basis, a 40 series is honestly as loud as any other muffler you are likely to encounter. The TONE is not the same however. Some folks equate "raspy" with "loud". If you want "rapsy" (I have also heard it described as "nasty" or "mean") you can switch to a different style of muffler. An example is a Magnapack. They are the ones that just look like a tube with the inlet and outlet in line with each other.

 

i have a before and after of a magnaflow cat install but its with a hooker aerochamber muffler not a 40 series...their on youtube just search aerochamber and look for my truck i think its in the description...the best one is the video with the red dak because the camera didnt shut off like the other one i have up on their with the magnaflow cat haha it def opened up the sound after 2500 before it would just not increase in volume it just seemed to stay the same

 

I have a FM Super 50 (SUV) muffler and Magnaflow high flow cat on my Dakota, and it sounds pretty good (not awesome). the MF cat did make the exhaust louder and deeper in tone. I spent $50-$60 for the cat, and about $90 for the muffler and installed them myself. I believe I had to add about a 1 foot length of pipe to make it all fit.

I have a AeroTurbine 3030 on my Hemi Ram, and I think it would sound better on the Dak than the Flowmaster currently does.