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Catless with muffler. Suggestions? 2005 3.8

  #1  
Old 06-15-2017, 11:56 PM
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Default Catless with muffler. Suggestions? 2005 3.8

Me again. After watching some videos and looking at reveiws ive decided what im going to do is go catless and no resonator but put some sort of flowmaster or magnaflow muffler on. Any suggestions for the muffler would be greatly apreiciated. I was thinking super 10 flowmasters but I want some other opinions on the matter.
 
  #2  
Old 07-13-2017, 04:02 PM
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Location: Centralia, IL
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I wouldn't go catless, first its illegal to remove smog controls devices even in states with no emmissions testing, second your car need a certain amount of "backpressure" to run right (o2 sensors, cylinder scavaging). Spend the money for high flow cats and account for backpressue when building that "loud" exhaust.


your motor and gas milage will thank you for it
 
  #3  
Old 07-13-2017, 04:46 PM
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Originally Posted by Steelbizkit View Post
I wouldn't go catless, first its illegal to remove smog controls devices even in states with no emmissions testing, second your car need a certain amount of "backpressure" to run right (o2 sensors, cylinder scavaging). Spend the money for high flow cats and account for backpressue when building that "loud" exhaust.


your motor and gas milage will thank you for it
Let me correct this.. These cars(05 SS is s/c) do better with as much free flowing exhaust as you can get.. He will have enough back pressure from the stock manifolds.. Even upgrading those would be beneficial however..

Res and cat delete are an AWESOME upgrade and is usually recommended from most of us.. Although some like to keep some sort of resonator, I do not..

I suggest whatever muffler you choose, go with anything other than a thrush welded.. I tell people to get something with the perforated tubing inside the muffler.. The "walled" inside mufflers can get quite raspy..

You wont get much better sound than with a thrush turbo muffler, they can be had for 30 dollars each with shipping..

BUT BUT BUT... Flowmaster does know how to make a really great "walled" muffler.. They are the only ones I would suggest with that type of interior design..

For the money tho, i dont know.. Its just not that much of a sound improvement to justify that much more money..

EDIT: I thought I saw you had the s/c 3.8 however, everything I said still stands..
 
  #4  
Old 07-14-2017, 02:31 PM
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I agree with the above. You're not going to run into back pressure issues just by removing the cat and resonator especially since you're still running it through 10+ feet of pipe and mufflers.
 
  #5  
Old 07-14-2017, 03:58 PM
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E.P.A. guidelines state that replacement converters may be installed only in the following situations:

1. The vehicle is missing a converter
2. A state or local inspection program has determined that the existing converter needs replacement
3. Vehicles manufactured prior to 1996 must have more than 50,000 miles, and a legitimate need for replacement must be established and documented
4. In cases of OBD Il-equipped vehicles (1996 and later), the O.E. manufacturer's 8-year/80,000-mile warranty must have expired and a legitimate need for replacement must be established and documented.
Please note that Federal law prohibits removal or replacement of a properly functioning O.E. converter.
from Catalytic Converter Laws

Yet still illegal by Federal Law
 
  #6  
Old 07-14-2017, 07:52 PM
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I don't think anyone was arguing against that point. It certainly is illegal as are many of the mods people do on here.

Certainly one big downside to not having a cat is that many exhaust places won't touch the exhaust after that's been done. The reputable shops won't want anything to do with the car as the fines are pretty steep for them.
 
  #7  
Old 07-14-2017, 08:49 PM
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Do what ya will then, just saying.

Do know from my dirt track car (350sbc 0.030 over 327 heads 11.0:1 compression) we pick up 50HP and 75ft/lbs and move the curve lower in the rpm range (to match our gears) by going from open 3.0" hpipes to 2.75" hpipes with a dynomax muffler.

627HP start, 677after. And no I don't have dyno sheets as this was 10 years ago.


But your car, just my 2 cents.
 
  #8  
Old 07-16-2017, 06:07 PM
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Originally Posted by Steelbizkit View Post
Do know from my dirt track car (350sbc 0.030 over 327 heads 11.0:1 compression) we pick up 50HP and 75ft/lbs and move the curve lower in the rpm range (to match our gears) by going from open 3.0" hpipes to 2.75" hpipes with a dynomax muffler.

627HP start, 677after. And no I don't have dyno sheets as this was 10 years ago.
IMO, that's apples to oranges with what the OP is trying to do. It's hard to draw a comparison between a race motor with dumped exhaust and a stock engine trying to change up a couple components but is generally leaving the rest of the stock system intact.
 

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