2.5" cat back or muffler?

[jd31]

Long and short...I have a V6 and am wondering if increasing the exhaust to 2.5" be bad due to back pressure? If I go with a cat back, could I run into emissions problems in Cali?

I've been to two different reputable performance shops in San Diego with polarized views on what exhaust I should get. For some context, I told both I wanted something with more growl but not too loud. Here’s what they suggested.

Shop # 1:
type: cat back
pipes: 2.5”
muffler: magnaflow
cost: $400 installed

Shop #2:
type: muffler upgrade with a straighter pipe to the cat converter
pipe: 2.25”
muffler: flowmaster 60 or incinerator
cost: $200 installed

When I asked shop # 2 about magnaflow, 2.5” pipes, and a cat back, here’s what he said:
• Magnaflow would be loud because it’s a resonator type muffler and would be located under the cab (he said they’re ok for Tacoma’s because the muffler is under the bed)
• I would lose power with 2.5” pipes because of back pressure loss
• Cat back’s are sort of “illegal” in California. I use the term illegal loosely because I don’t recall his exact wording, but he alluded to emissions problems. Don’t recall the specifics.

So what gives? Both shops came highly recommended. Shop # 1 specializes in exhaust systems, shop # 2 does performance/maintenance upgrades for Toyota and Lexus.

 

[azn-sensation]

Check this out if you havent already:
http://www.toyota-4runner.org/class...fore-sale-borla-cat-back-k-n-fipk-intake.html

 

[Elton H]

if your stock exhaust is fine and not falling apart just replace the muffler going to big on a stock 3.4 will have negative effects

 

[the great him]

2.5 isnt too big stock i think its like 2.25 or 2 1/8. A cat back will do nothing as far as emissions is concerned, the pipe and muffler have nothing to do with emissions, they only suppress sound. i run a 18" magnaflow and love the sound. the flowmaster would be loud and raspy and imo not a good sound for a 4runner, too ricey. anyhow the only way you can have an affect with your emissions is to actually change the cat or take it out. as long as you are leaving the cat in then you dont have to worry about emissions. my vote is for a magnaflow over the flowmaster, but there has been some concern over the quality of magnaflow and their customer service in recent past, with sub standard products

 

[jd31]

Thanks for the replies. The pipes are in good condition so the muffler option does make the most sense, especially since the $200 quote included a straight pipe from the cat converter (isn't that technically a cat back?). I just need to do some research on which muffler would be best.

 

[the great him]

Thanks for the replies. The pipes are in good condition so the muffler option does make the most sense, especially since the $200 quote included a straight pipe from the cat converter (isn't that technically a cat back?). I just need to do some research on which muffler would be best.

yeup