[den525]

I'm looking into getting an exhaust, but I'm getting to a stage where I want good exhaust sound, but don't want any drone at all.

Is it from the catless DP? removing mid resonators? rear resonators?

Which combination have you guys done which has experienced drone, and which combination don't.

[YYZF22N55]

Originally Posted by den525

I'm looking into getting an exhaust, but I'm getting to a stage where I want good exhaust sound, but don't want any drone at all.

Is it from the catless DP? removing mid resonators? rear resonators?

Which combination have you guys done which has experienced drone, and which combination don't.

I have ER catless DP installed. Not much drone over stock at highway speeds but you can definitely hear the difference when you WoT.

[e46m3to335i]

Originally Posted by YYZF22N55

I have ER catless DP installed. Not much drone over stock at highway speeds but you can definitely hear the difference when you WoT.

Is this with the stock rear muffler?

[kd0t]

I have ER catless dp with resonator deleted. No drone, sounds good on the outside

[YYZF22N55]

Originally Posted by e46m3to335i

Is this with the stock rear muffler?

Yeah, stock muffler.

[Milkee_0923]

Originally Posted by kd0t

I have ER catless dp with resonator deleted. No drone, sounds good on the outside

Do you have a video of that setup? I may go the same route or m performance exhaust.

[kd0t]

Originally Posted by Milkee_0923

Do you have a video of that setup? I may go the same route or m performance exhaust.

I don't, unfortunately. But there's a thread on the F30 forums with videos of N55 w/ er catless dp and resonator delete. Check it out

[mike@x-ph.com]

Originally Posted by den525

I'm looking into getting an exhaust, but I'm getting to a stage where I want good exhaust sound, but don't want any drone at all.

Is it from the catless DP? removing mid resonators? rear resonators?

Which combination have you guys done which has experienced drone, and which combination don't.

Good catless DP like the Evolution Racewerks will not add any significant drone. Same for the exhaust. Get a highly reviewed exhaust and you will not have any problems with droning ( Remus , GTHaus).

[den525]

So which part of the exhaust most commonly create drone within the cabin?

[Josh/AWE]

No drone? Have you heard our Touring Edition Exhaust System? It's easy to make a free flowing exhaust system, but it takes a lot of work to encourage power while controlling the tone. Our 180 Technology™ equipped resonators are designed to eliminate drone while achieving maximum power gains and an overall sophisticated sound. It's a science to eliminate drone without neutering the pleasing spectrum of an exhaust roar. How do we do it?

We document the sound and exhaust temperature of the vehicle.
We do a detailed spectrum analysis to identify undesirable frequencies.
We run that data through our proprietary differential calculus equations to determine the volume and shapes of our 180 Technology resonator internals.
By this point we have laser scanned the underneath of the vehicle so we can CAD model the resonator package to fit on the vehicle.
We optimize the routing for our .065" thick 304 stainless steel exhaust, maximize the power output while ensuring the sound quality remains intact, dial in the tip aesthetics, and hone in on crafting an exotic and exciting tone at full throttle while combating all signs of droning.
After plenty of dyno and street testing, we are confident to release a system we can stand behind.

Adding a catless downpipe will increase overall volume as you are removing a great restriction in the system. Starting with an axleback designed to eliminate drone is your best bet to end up with an overall tone you can live with.

Shoot me a PM if you have any questions!

[The Nerd]

Originally Posted by den525

So which part of the exhaust most commonly create drone within the cabin?

To answer your question....I believe it's lack of a resonator that causes the most drone.

But obviously removal of other components can add to the issue as well.

[den525]

This might be a very noob question... so from the "cat back" there's a mid pipe, from what I've heard the N55 is a straight pipe... So from my understanding that's not "too important"... and from my understanding the resonator for the m235i is in the connecting pipe between the mid pipe and the muffler, and the other resonator is in the muffler of course.

So at the moment I've ruled out doing the DP and tune for now...

Basically what I want from now is a slight increase in exhaust noise, love a bit of the growling and crackle and pop, but no drone on long journey.

Now the question is difference between cat-back and axel back... From the milltek website, it says the stock pipes are 80mm, which is 3.14inches in diameter which should be very "free flowing" already (most of my previous cars' aftermarket exhausts were 3" in diameter).

So is it necessary to change the midpipes to a sportier midpipe/connecting resonator? For what I want to achieve? As I don't really want a midpipe resonator delete.

[M2-BM35i]

Originally Posted by den525

This might be a very noob question... so from the "cat back" there's a mid pipe, from what I've heard the N55 is a straight pipe... So from my understanding that's not "too important"... and from my understanding the resonator for the m235i is in the connecting pipe between the mid pipe and the muffler, and the other resonator is in the muffler of course.

So at the moment I've ruled out doing the DP and tune for now...

Basically what I want from now is a slight increase in exhaust noise, love a bit of the growling and crackle and pop, but no drone on long journey.

Now the question is difference between cat-back and axel back... From the milltek website, it says the stock pipes are 80mm, which is 3.14inches in diameter which should be very "free flowing" already (most of my previous cars' aftermarket exhausts were 3" in diameter).

So is it necessary to change the midpipes to a sportier midpipe/connecting resonator? For what I want to achieve? As I don't really want a midpipe resonator delete.

If you are looking for just a mild increase in sound then best is go for MPerf exhaust... nothing better

[M2-BM35i]

Anyone here know how the 'blurt flapping sound ' between changing gears exactly works?

Is it a valve opening and closing on gear change due to pressure changed or has it for more to do with excess feul being dumped being the cause ?

And does DP make it much louder with a more cracking sound...(like the M4?)