swaangin

I was thinking about getting a muffler delete but then I didn't. I have a 2015 IS 250. I saw one post specifically about someone who lost a noticeable amount of low end torque after his/her muffler delete because there was a decrease in 'back pressure'. The IS 250 already has low torque so I don't want to install it and have to deal with this. The mechanic said that it strictly effects sound only. My friend also said that there are so many restrictions in the exhaust already (primary cats > secondary cats > resonators> mufflers) so there would instead have a no effect to a slight increase in performance. Can someone shed some light on this please?

(inb4: you have a slow car why modify it like this -- to me IS 250 is plenty fast, I just want it to sound slightly better!!)

JoelsLexIS

Try removing your resonators first... it won't make a crazy difference but you might be happy with the change of sound and you won't have to worry about losing any back pressure. I know a lot of people talk about getting a "drone" when you remove the resonators but I removed both sets of resonators from my IS 200t about 2 months ago and I have not had any issues.

abenjack

I did my mufflers first cause a resonator won't do to much and I haven't lost any performance. The car still has the resonators and 4 cats so you'll be fine with a muffler delete. I'm working on getting two of my cats out

HOMER350

Good info. I came across this video in an article by Road and Track. Basically, the less back pressure the better. However, the backpressure or "scavenging" that takes place up front in the headers is what matters. Unclear if a muffler (or lack of) makes much difference on "scavenging".

I have no interest in doing a muffler delete but I was curious. I did do it when I was younger though.

My personal experience is that I found significant increase in acceleration when I put a after market chamber muffler back onto my car from having a straight pipe exhaust. Did it as a teenager BUT with a different car (SC300 - 3.0 6 cyl)

IMO... dont do it if you dont know what you're getting yourself into. It lasted 6mo before I couldn't stand the sound anymore ( but yes, it was a different car). Consider swapping mufflers if you're only going for increased sound...and keep the old ones if you go through with the delete!

Thesickest