Perforated vs ACM OEM Exhaust Mod

[Wendall]

I am gonna have the OEM exhaust mod done in about a week. I've read all the threads and watch all the videos. From hearing the different exhausts on videos clips it sounds like the Perforated sounds less bassy and more high pitched/raspy and the ACM sounds more droney/bassy and less raspy.

Those that have heard both, do you think the same? If so, I think the perforated sounds better. They seem equally loud.

I would like to hear your comments.

[anacondatp]

i'd say go ACM route. it's a bit louder and no drone from what ive seen people said so far. also, where are u getting this done at? i am also looking for a place to do this and my shop down here in SD want to charge 300.00 and it's not even stainless steel pipe

[Ohh_5H1T]

I've only heard the perforated fix one in videos... I have the ACM mod and as far as im concerned i sounds more throaty and a bit louder on WOT. I LOVE my ACM mod no regrets. And i speak for all other guys that have it so far. It really depends on the sound you want. I prefer a growl over a high pitch rant and this was perfect for me.

[Wendall]

Originally Posted by Ohh_5H1T

I've only heard the perforated fix one in videos... I have the ACM mod and as far as im concerned i sounds more throaty and a bit louder on WOT. I LOVE my ACM mod no regrets. And i speak for all other guys that have it so far. It really depends on the sound you want. I prefer a growl over a high pitch rant and this was perfect for me.

Drone issues with the ACM?

Im having it done at MRF engineering in Lake Forest, CA.

[Wendall]

Originally Posted by anacondatp

i'd say go ACM route. it's a bit louder and no drone from what ive seen people said so far. also, where are u getting this done at? i am also looking for a place to do this and my shop down here in SD want to charge 300.00 and it's not even stainless steel pipe

I am paying more for it. I also considered just replacing the muffler with glass packs. In fact, It would be lighter, have less bends = better flow, and much cheaper. However, I wanna keep it looking OEM.

Having it done at MRF Engineering.

[Ohh_5H1T]

Originally Posted by biggynuts01

Drone issues with the ACM?

Im having it done at MRF engineering in Lake Forest, CA.

No drone whatsoever. It sounds only a little bit louder than stock from the cabin...

[tom @ eas]

We just installed another one today, no drone at all.

[gatorfast]

I did the perforated method and I love the sound. No drone whatsoever. Haven't heard the ACM method in person though to compare.

[rjd598]

Originally Posted by anacondatp

i'd say go ACM route. it's a bit louder and no drone from what ive seen people said so far. also, where are u getting this done at? i am also looking for a place to do this and my shop down here in SD want to charge 300.00 and it's not even stainless steel pipe

what shop was it? pm me i can recommend a great place for you to get it done at!

[Castr_85M]

ACM exhaust has 0 drone. I'm running AA race xpipe(Full Catless) and its still has VERY little drone inside the car. Basically ACM's method is like an eissenmann race and the perforated pipe method is the sport.

[Wendall]

Originally Posted by alofoque

ACM exhaust has 0 drone. I'm running AA race xpipe(Full Catless) and its still has VERY little drone inside the car. Basically ACM's method is like an eissenmann race and the perforated pipe method is the sport.

Thats great to know. I cant wait to get it done.

[X2Board]

Perforated, unless you like loud all the time. I drove both and the ACM method does drone a bit, so the claim of zero drone is not accurate.

[Denk]

Perforated.

[Khrishna]

+1 Perforated..

If you gonna do ACM, why not just do straight pipes and trim like 50 lbs in the process?

[XR_SIX]

Originally Posted by X2Board

Perforated, unless you like loud all the time. I drove both and the ACM method does drone a bit, so the claim of zero drone is not accurate.

+1
ACM AKA Bypassing the muffler will create a "drone" sound.

[m3an]

Originally Posted by XR_SIX

+1
ACM AKA Bypassing the muffler will create a "drone" sound.

I dunno, I don't think everyone gets the definition of drone as it really doesn't Its def loud but no annoying drone

[m3an]

Originally Posted by Khrishna

+1 Perforated..

If you gonna do ACM, why not just do straight pipes and trim like 50 lbs in the process?

+1; save weight, save your OEM muffler and sounds identical

[anacondatp]

thia has been discussed bf as well. acm is kinda straight pipe but not really. bc they still take advantage if the Hemholt chamber in the stock muffler which some people believe helps eliminate the drone. again, its theory and im speaking from reading. no real experience

[m3an]

Originally Posted by anacondatp

thia has been discussed bf as well. acm is kinda straight pipe but not really. bc they still take advantage if the Hemholt chamber in the stock muffler which some people believe helps eliminate the drone. again, its theory and im speaking from reading. no real experience

Yes but the chambers are now really useless as they aren't long enough for the added volume

[S65NAPWR]

Originally Posted by alofoque

ACM exhaust has 0 drone. I'm running AA race xpipe(Full Catless) and its still has VERY little drone inside the car. Basically ACM's method is like an eissenmann race and the perforated pipe method is the sport.

+1

Both sound good in their own way. Neither have an annoying drone. Question is whether you want a more aggressive sound or not.

[Zaw]

Originally Posted by S65NAPWR

+1

Both sound good in their own way. Neither have an annoying drone. Question is whether you want a more aggressive sound or not.

+1

I have the perforated method done to all 4 pipes. It's very nice, no drone and noticeably louder. Like most people said, stock sound when you want and louder when you get on the gas. Sometimes, I wish it was louder when I am driving with my windows up. Than again, If I had done the ACM method, I know I would wish it was less loud when I am pulling into my work parking garage or when I am out to dinner for work.

So, If you daily drive your M3 than perforated mod will make you wish it was louder sometimes and ACM mod will make you wish it was quieter sometimes.
If you don't daily drive your car, than go for the ACM mod.

If there are guys out there with ACM mod who DD their car and not wish that it was quieter sometimes, please convince me to switch to ACM mod

[BPe90M3]

Originally Posted by Zaw

+1

I have the perforated method done to all 4 pipes. It's very nice, no drone and noticeably louder. Like most people said, stock sound when you want and louder when you get on the gas. Sometimes, I wish it was louder when I am driving with my windows up. Than again, If I had done the ACM method, I know I would wish it was less loud when I am pulling into my work parking garage or when I am out to dinner for work.

So, If you daily drive your M3 than perforated mod will make you wish it was louder sometimes and ACM mod will make you wish it was quieter sometimes.
If you don't daily drive your car, than go for the ACM mod.

If there are guys out there with ACM mod who DD their car and not wish that it was quieter sometimes, please convince me to switch to ACM mod

I had it and actually ended trading for something louder lol