Cutting the cat

[ramthis9501]

Are there any cons to cutting the cat off besides having a code thrown and having it smell a little weird? Those I don't mind.

And there's no restrictions or inspections here.

 

[HemiBabe]

I think it might cause a loss of backpressure and make it run funky... not 100% sure tho

[ tapatalkin ]

 

[wermbang]

yeah I am not sure either. maybe run the magnaflow one?

 

[Hotroder383]

Now I have personally tested this on a 355 in a chevy Elky so keep that in mind not a dodge but princple is the same.
I built a 355 for drag race 1/4 mile and tuned it down just enough to run on street, I ran full length cermic coat headers through 3" pipe and cheap pair of turbo mufflers. No codes to worry about but No performace gain either. The engine dyno'd with in 10 hp and 20 ftT with and with out cats no other change. Now I did use the good high flow Magnaflow cats, but the little change I seen could be do to me running tests back to back also.
my 2cents says leave the cats on and dont worry about engine codes, if you replace then deff go with a good high flow cat.

 

[ramthis9501]

I thought less back pressure on the engine was a good thing.

 

[rambob]

you should leave it on if you do not plan to modify fuel delivery.
back pressure is good for low end torque. which is ideal for a truck.

 

[Okiespaniel]

you should leave it on if you do not plan to modify fuel delivery.
back pressure is good for low end torque. which is ideal for a truck.

Yes...that is what we were discussing the other day on the other forum.

Exhaust length and diameter affects the power range of the motor. On a stock engine, large short pipes benefit top end power while killing off low end. BTW top end power is somewhere around where your stock cam and intake system run out of steam.

Colton, I have to admit I'm a bit blunt on this. It isn't my first rodeo with exhausts. On my old roadunner I used to add a piece of straight pipe behind the headers. By using heat crayons, I could determine the exact length of pipe to give me up to a .1 reduction in 60 ft times without affecting mph on the high end.

I also found that a 2.5 inch lead pipes run to two hemi turbos gave me another .03 on the 60 ft witout losing more than a couple mph through the traps...making worth while to run a rather quiet exhaust that I didn't need to remove to race.

 

[HemiBabe]

you should leave it on if you do not plan to modify fuel delivery.
back pressure is good for low end torque. which is ideal for a truck.

mmmm hmmmm