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I'm going to upgrade exhaust but want to know the pros and cons on high flow cat and no cat mid pipe. they both cost about the same so thats no big deal. I'm just wondering how high flow a high flow cat is and if a catless mid pipe would make that much of a difference? And does anyone have the new no drone mbrp cat back system on the car? Is it any quietier than thier original cat back system? Thanks for your help in advance.
 

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Well, catless mids are pretty cool at high rpm's on terms of a little power boost kick in the butt and a wicked bad sound. Downfall is drone, overwhelming exhaust smell and sometimes the exhaust flows so freely that it may loose a tad bit of "Get Go" at low rpm's from a small loss in torque on the low end.

I have never used High flow cats myself but what I hear from users is a small power gain that of wich you might compare to an air intake. Depending on what exhaust you have you might get some drone at cruising speeds but on the bright side no crazy exhaust fumes.

Good luck with your decision, friend.
 

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6.1M here and had MBRP's on before hi-flows were added. No additional drone caused (may be impossible to get more) or codes posted but more decibels for sure. No dyno proof but I believe as the engineers do that hi-flows are a worthy power adder and shed a few lbs too. Odor only lasted for first couple heat cycles so must have been left overs from the manufacturing process only.
 

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Curious to know the answer as well.
All things being equal on a boosted 6.1 Hemi with long tube headers, would catless mid pipes make substantially more power than the hi flow cats?

I know about the exhaust fumes without cats and is tolerable if the HP diff is great. Thankfully I live in a non emissions state :) ( but NO racetrack!)

Sound will def be louder. As for the smell you smelled with your new hi flow cats, that is normal. It is your cat "bedding in". The first few hundred miles are critical to not load up your new cats ( in other words no WOT) until that smell goes away.
 

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2009 Challenger R/T
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I have catless mids on my r/t and as you can see from my 60'..there was no loss
In power downlow. I also have the originally mbrp exhaust and it never bugged me with the "drone". I didnt expect a performance exhaust to really be quiet when cruising though lol. And actually after the catless mids, it seems the "drone" has lessened while at cruising speeds. But the car is definitely louder underthrottle
 

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09 RT Challenger auto
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Removing the cats gave me 3 to 4 tents faster in the 1/4 mile. As long as you dont live in california. Loss of low end Tq NO WAY. not in mine. As I have been on the dyno and at the track. A great mod to remove them. High flow cats I cant tell ya. Dunno.
I dont really drone,, mds is off all the time. You will throw a code unless rear o2 sensors are off from a custom cmr tune.
FlatTop
 

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The only problem with removing the cats is if you get caught on the street without them.
Tout
 

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The only problem with removing the cats is if you get caught on the street without them.
Tout
No when you live on a little rock out on the Pacific ocean :thumbsup:
 

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so removing the cats gives you an exhaust smell in the car? Never heard that before
 

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What you will smell is the actual exhaust gases before they are treated/ converted by the cats. So you'll smell some fuel like smells, worse with a lopey cam mostly at stoplights
 

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What you will smell is the actual exhaust gases before they are treated/ converted by the cats. So you'll smell some fuel like smells, worse with a lopey cam mostly at stoplights
My SRT10 Ram is currentl ycat-less and I can attest to the smell, but after a while you don't even notice it..
 
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