135i muffler on 125i - no change in volume?

[GUM911]

So I bought a 135i backbox a while back after reading that it would slightly increase the volume of my exhaust note on my 2008 E82 125i due to being less restrictive and slightly larger diameter tips.

I finally got around to installing it yesterday and couldn't really notice any difference in sound or volume. Has anyone else done this mod and noted an increase?

Interestingly though, I did notice an increase in throttle response and initial pick up (EvolveR tuned) which I'm not really able to explain.

[sprp85]

Since your car is a 125i, I assume you are in somewhere outside the states?

Anyhow, 135i muffler is a quite popular mod, along with 2ndary cat delete (If your car has them) and resonator delete. It should give you volume+some rasp+lots of popping without drone.

I have done Supersprint 2ndary delete + Supersprint res delete + 135i muffler and it by far the most satisfying noise Ive gotten out of this car (128i), without headers.

Reminds me of my friends e36 m3 with supersprint setup.

[STR8-6IX]

delete your secondary cats

[asbrr]

So in general the volume inside the car is not changed much. From outside the car its deeper than the stock muffler.

Not sure if you have disabled the vacuum actuated valve, that will deepen it in the low range (3000 rpm and under) and give you some pops/burbles on overrun.

Overall for me it strikes a good balance of not sounding obnoxious and still a nice deep tone.

[GUM911]

Thanks guys.

Originally Posted by asbrr

So in general the volume inside the car is not changed much. From outside the car its deeper than the stock muffler.

Not sure if you have disabled the vacuum actuated valve, that will deepen it in the low range (3000 rpm and under) and give you some pops/burbles on overrun.

Overall for me it strikes a good balance of not sounding obnoxious and still a nice deep tone.

You're speaking from experience? Did you find it took a week or so to settle in and become louder? That's the feedback I got from one my mates who did a similar thing with his 335i.

I have gold ball tee'd it prior to installing, so yep disabled; I only rarely get pops and burbles though =/

[asbrr]

Originally Posted by GUM911

Thanks guys.



You're speaking from experience? Did you find it took a week or so to settle in and become louder? That's the feedback I got from one my mates who did a similar thing with his 335i.

I have gold ball tee'd it prior to installing, so yep disabled; I only rarely get pops and burbles though =/

Yep. I have a 135i back box which I had an exhaust shop weld directly to the back of my resonator. Headers, secondary cats, and resonator are all stock. I have a the golf tee mod done.

It's a subtle difference, as I said not much difference inside the cabin. Outside it's different than just the stock muffler with a golf tee mod. Pops/burbles on overrun happen in the lower RPM range, so like 2500 and under. Noticeable in an underground garage for example.

I guess it's all relative, for me the change in sound is fine...for others it may be too subtle....