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.

 

Solution would be to put on a stock exhaust system, from the header back.

 

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.

 

In my mind is 30hp really gonna break your daily driver ?

 

Not for me... but it is only going to be my driver for another 90-120 days. Then it will be someone else's car... and they may not feel the same as you and I. My previous daily driver, an 8G Si sedan, had a lightly modded TSX ('07 K24A2 w/ 50' VTC, Si Intake cam, RBC Intake mani, and Alpha header) engine with stock cat-back exhaust and it made 217 HP/177 TQ tuned.

I dunno man... 260 HP down to 230 HP is a BIG jump... a strong price to pay for quiet. Maybe I should check with Steve at HMO and see if he has a DC5-R cat-back for cheap.

 

Include both exhausts in the sale to the next person...

 

That's not very cost effective for me Caoboy... are you angling for a deal on a nice RSX-S ???

 

No, I'm just saying it's a selling point that with the big aftermarket exhaust you gain xx amount of hp!

 

Sort of a matter opinion. Aftermarket parts are a deterrent when I am shopping for a vehicle. Especially a loud exhaust.

 

This one wouldn't be the car for you then stin1... it is FULL of aftermarket parts. With the exception of the fore mentioned cat-back exhaust... this car is better than a stock one in EVERY way without sacrificing the ride quality. Tasteful aesthetic mods and high quality performance mods with a full interior swap and a double din navigation unit.
I do agree with you that some people think that modded cars are less desirable... because they may have been abused since they have high performance parts or the non oem parts detract from it's value as a collector car. This car's history is different than that... I am an old guy who doesn't do burn outs, street race or otherwise act in an abusive manner to any street-driven car that I own. When it is time to sell, I am sure someone will buy this car and appreciate it for what it is.

So does this mean you were suggesting a stock cat-back ???

 

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.

 

Ok HT fans... UPDATE !!!

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 ???

 

Well...60mm is about 2.5"

a 1/4" less radius is not much, and in fact, with the increase in back pressure, you gained more midrange HP/TQ while 'sacrificing' your top-end.

If you were to drop to a 2" system (or stock) you'd see more of a decrease. Maybe, for your mods and tuning, 2.5" is a better daily system. is the WS2 chambered or a straight through muffler?

 

I am not sure to be honest... I think it is chambered, but all I know is it was expensive and it is super quiet. The quiet part makes me VERY happy. Now I gotta save up and get that power dip tuned out.

 

Thank you HT Admin for putting my post on the front page... I feel like a Celebrity now !!! I hope this post helps others with their exhaust decisions and dispels some of the "misinformation" with respect to NEEDING large exhaust to make maximum power in moderately built K-Series engines. I will update this post when the car is tuned to make a full and fair comparison.

 

Pretty cool it made the front page. I really like the links to the relevant tech articles instead of the curated content of the past on the home page.

 

what have you done to the engine for more HP and they make a pipe you can add to race that bypasses the cat like open headers that you can open and close manually if you race, in terms of mufflers just cause its quiet your not going to lose much and you can add a computer to adjust the car for race and normal driving to keep your computer from frying or sensors failing, they can program your computer for the changes with the backpressure to make it run better with whatever exhaust you got. (if you put a lot into the car don't give it up cause it means you got to start from nothing)