3" Exhaust on Gen3 rx

[Shrab Kebab]

Hey guys, so a friend of mine is offering to sell me his old xforce exhaust from his forester for a good price and I was considering buying it, to my knowledge, the exhaust is a 3" catback and has been modified to a 2.5" inlet, I was thinking about taking it to an exhaust shop and getting it cut to suit my gen3 my00 RX liberty but have heard that 3" might be overkill for an NA and I would potentially lose backpressure so I just wanted to get some thoughts or advice on anyone who's a bit more educated on the topic.
Thanks in advance guys

[RX25SE]

3" is too large for a 2.5lit engine.
I would imagine by the time you pay for the 3" system, pay an exhaust shop to cut it apart to fit it to the RX you could have paid for a new custom exhaust that suits the car.

[Shrab Kebab]

hes offering me the 3" system for $150 and from places near me the general quote for a 2.25-2.5" catback system is around $500-$600,
Do you say 3" is too wide of a diameter for a 2.5L because of backpressure loss?

[Yowie]

"Engines need exhaust backpressure" is a horseshit myth from which we can move on.

If you want to mess around with a 3" exhaust picked up for a good price then go for it.

[millcon]

Any update, OP? I'm curious about the sound of a 3" exhaust.

[bigBADbenny]

Since its a cat back, and the cats are usually the biggest restriction in any stock exhaust system, the cat back diameter shouldn’t matter, or affect the tune.

This changes when you’re tuned for high flow cats, in that case changing your cat back to more or less restrictive does change how the tune behaves, in my experience.

Either way, checking your tune, eg afr’s or long term fuel trims etc: before and after the mods, is the only way to be sure.