K24-Powered Acura RSX Exhaust Swap Discussion
Acura RSX owner is hesitant to change to a smaller exhaust system, but he only loses 1 horsepower.
A big aftermarket exhaust can help your Acura or Honda breathe a little easier, which often leads to more power, but it also often leads to more sound. Some people want as much sound as possible, but others prefer a system with a more subdued tone. “JRCivic1” recently posted in the Acura RSX DC5 & Honda Civic EP3 section, voicing his displeasure with his current exhaust system and looking for advice on a new system. His car is K24-swapped and built, so the big exhaust system makes sense, but he wants something quieter.
Acura RSX Exhaust Complaint Introduction
When the OP first posted his question about quieter exhaust on his K24-swapped Acura RSX, he shared the following information.
I am currently driving my K24 swapped RSX as a daily driver… and I like everything about it except that the cat-back exhaust is soooooo loud. I mean loud like it is “Open Header” loud. I have the PLM/K-Tuned 3″ oval mid-pipe cat-back. I hate to pull it off and buy something quiet (I might lose some power, but I could sell this then to someone who likes loud exhaust)… then again, having a muffler shop replace the tail end with a quieter muffler just means dumping more cash into this system… so, does anyone have the same system on their car, and if so, do you hate it as much as me and what did you do to make it better??? I am soliciting suggestions… hopefully inexpensive ones since driving this car is temporary. Motorvations is about to start on my K-Swap EM1 which is what I really want to drive, so this RSX only has to tie me over for a few more months before I put her up for sale.
Chime in gang and tell me your thoughts.
While removing exhaust sound from a built Acura RSX might sound crazy to some people, not everyone wants their car to be as loud as possible and the community has advice.
The Community Responds
The first person to reply was “Caoboy”, who recommends stock exhaust.
Solution would be to put on a stock exhaust system, from the header back.
That idea makes sense in terms of the sound, but the OP is also concerned about losing power.
Thank you for your input Caoboy. That would make it quiet for sure… but how much power would I have to give up for maximum sound reduction ??? I fear that it would cut quite a bit, so I am thinking more of somewhere in the middle. Slightly louder than stock, but not as loud as I have now. When I bought the car, it had a 5Zigen cat-back and it was really loud too… but I kind of figured that maybe it was simply worn out and much of the packing inside the muffler was collapsed or gone because of it’s age. A replacement was necessary… and I got talked into going big. Shame on me.
I don’t have a stock cat-back to try. I would have to find a used one at an affordable price. I am also cognizant of the fact that other younger Import owners like cars this loud… and I have to consider the long-term effects of my decision here. Less power affects the value of the car when I go to sell it.
In my mind, I guess I am willing to lose 5-10 HP to make it quieter… but I am afraid I will lose 20-25 HP putting a stock cat-back on it.
After a bit of back-and-forth about the possible power losses, “stin1” shared some insight on a similar exhaust system of his own.
My suggestion is a stock exhaust. I can say going from a world sport to a stock ek9 exhaust my but dyno didn’t really notice any loss in power. I also went from a mellow greddy on a em1 and didn’t notice switching to a modified dc2r exhaust any loss of power. It did free me of having every minivan and SUV flooring it every light. Lol . My will to live greatly improved by removing whatever aftermarket engine mounts were in the car. It really played a part in the cabin noise, not so much outside of the car. May want to look into that as well.
No Real Power Loss
After weighing the options presented by members of the forum, the OP shared an update on his Acura RSX exhaust dilemma.
The 3″ cat-back was unbearable… I couldn’t take it one second longer. So I ponied up the cash and purchased the Apexi WS2 60mm cat-back and prayed that I wouldn’t lose too much power. Installing it was a bolt-on affair. No real hiccups except to get the 3″ cat-back off. I had to drop the rear sway bar and the right rear lower control arm to remove the axle-back portion of the exhaust. Once the Apexi WS2 was all snugged up, I drove it around for about 20 minutes to blow out the residual packing and get a feel for the sound. It is WAAAYY better. Very quiet at idle and light throttle and a sporty tone at full throttle. I then talked Motorvations into strapping the car to the dyno just to see the difference between the 3″ system and the new smaller 60mm system. No tuning changes… just a pull to compare it with the fully tuned 3″ system from before. Much to my surprise, I only lost 1 HORSEPOWER at peak !!! There is a weird transition at the VTEC crossover that the Tuner says can be eliminated with some VTC tuning, but otherwise, it appears that there is no significant power loss between the two cat-back systems. Below is a photo of the Dyno Graph so you can see for yourselves. The Blue lines are the 3″ cat-back and the Red lines are the 60mm WS2 cat-back.
So with all of the Internet push suggesting that “K” series engines make way more power with large exhaust systems, why doesn’t this hold true on this car ???
As you can see in the dyno sheet shared here, the change to the smaller exhaust system led to a drop of less than one horsepower, but it also picked up almost a pound-foot of torque.
Click here to head into the forum to share your insight on the exhaust change, or to ask questions about making a change of your own.
Photos: Honda
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