Possible Elimination of Exhaust Drone

[cobrafast1]

Elimination of Exhaust Drone

I, as well as many of us, have been suffering from the exhaust drone from MagnaFlow and FlowMaster exhaust systems as we've modded our cars. I've been doing a lot of reading on this and the drone comes from the "pulses' produced by the engine as the cylinders fire. It's a frequecy thing.

Some have tried many solutions and even gone to other mufflers and systems to eliminate the drone in their cars.

Has anyone installed a 2 or 3 disk "CC Insert" in their exhaust pipes after the catalytic converters to eliminate drone? I'd like to hear actual reports on this product (not what you think might be, but actual usage reports).

Check out this website:

http://www.carchemistry.com/techinfo...stallation.php

Thanks

 

[stkjock]

sorry I can't read that font, can you make it bigger please.....

Also not tech... thread moved

 

[ChiDiddy]

so many exhaust note topics hear lately....

 

[tjm73]

You need resonators. They cancel drone almost completely. Lots of cars come from the factory with them.

 

[TenSpeed]

so many exhaust note topics hear lately....

To me, the note is important. You gotta have it sounding right.

 

[tripwyr71]

Its called Corsa's

 

[loots06]

What about staggering the resonators or midpipe set up. This could help reduce the amount of drone.

 

[Memphis 05]

mine are installed right before the turn at the rear axle.... the other straight area at the front has the exhaust cut outs.... those are more important. When the resonators were installed the drone went away completley!

 

[weather man]

Staggering is a good idea. It will get the frequency out of phase.

 

[Department Of Boost]

What about staggering the resonators or midpipe set up. This could help reduce the amount of drone.

Bingo!

 

[Sky Render]

I am unable to read posts made in Comic Sans MS. I'm sorry.

 

[HellsBells]

Its called Corsa's

This, exactly.

Another surefire way is dead-end pipes, like these:

 

[Sky Render]

This, exactly.

Another surefire way is dead-end pipes, like these:

A clever use of Helmholtz resonance. The pipe's diameter and length must be tuned for the specific frequency of drone, however.

I am curious: are those pipes for a Mustang or a different car?

 

[HellsBells]

A clever use of Helmholtz resonance. The pipe's diameter and length must be tuned for the specific frequency of drone, however.

I am curious: are those pipes for a Mustang or a different car?

Yeah I didn't bother elaborating on the frequency and the fact that you may have to cut the pipes a few times and test them--mainly because most people will not bother going this route.

Those I believe are for a 2V Mustang. The best systems I've seen them on are for BMW's aftermarket exhausts, where the entire system has the dead end pipe already built by the manufacturer. Then again, those catback systems cost $1500-$3000.

 

[Sky Render]

Yeah I didn't bother elaborating on the frequency and the fact that you may have to cut the pipes a few times and test them--mainly because most people will not bother going this route.

Those I believe are for a 2V Mustang. The best systems I've seen them on are for BMW's aftermarket exhausts, where the entire system has the dead end pipe already built by the manufacturer. Then again, those catback systems cost $1500-$3000.

You know, I'd be interested in experimenting with my Magnaflow Competition mufflers using Helmholtz chambers to get rid of the TERRIBLE highway exhaust drone. But the system also fits like total shit, so I don't think it's worth my time. I'm planning on replacing them with Corsas.

 

[HellsBells]

You know, I'd be interested in experimenting with my Magnaflow Competition mufflers using Helmholtz chambers to get rid of the TERRIBLE highway exhaust drone. But the system also fits like total shit, so I don't think it's worth my time. I'm planning on replacing them with Corsas.

I have a ton of experience with exhaust drone, not on the Mustang, but on previous cars. I tried them all, Borla, Magnaflow, Flowmaster, etc...you name it, I tried it. When I got the Mustang, I was skeptical of Corsa's claims but went ahead and pulled the trigger. I figure for the price, it's either totally worth it or the world's biggest scam. I don't think I'd put anything but Corsa's on now.

But here's a caveat. The Corsa systems are designed around stock cars, that is, 3.55 gears and a completely factory motor. I was going to switch to 4.10s and asked Corsa how that would affect it. They basically said that they wouldn't know and did not do any testing on modified cars. They design the systems and tune them around the characteristics of a stock motor. With that said, they referred me to Rick at Livernois and Rick told me I would likely see more drone. Needless to say, I didn't go with the gears.

I had no drone with an off-road H or X pipe, no resonators, just the pipes and Corsas.

Now, when I installed my hot rod cams, that's when it got interesting. I got a slight slight drone at freeway cruise speeds. I mean, it was a really quiet hum. If you rode in my car before and after, you would not notice unless you had ridden in it a lot of times (or driven it a lot like me). It's one of those things only the owner would really notice.

Then I threw on a blower and I have more drone now at freeway cruise when I accelerate. It is really dependent on throttle input. For example, between 70-80mph, there is no noticeable drone at cruise. But if I'm climbing a hill and maintaining speed, or accelerating, there is a bit of drone.

Anyway, this is a longwinded way to say that if you do extensively modify the motor in a way that affects its harmonic properties (for me, cams and supercharger), you may get more drone but nowhere near what you get with magnaflows, borlas, etc. Another cool trick I know (which is also based on Helmholtz frequencies) is to nudge the exhaust tips a little past the bumper. Basically, you can adjust your midpipe and axlebacks forward/backwards as long as the pipe couplings allow for it, and effectively get rid of some drone at certain frequencies. I believe this is one reason why the Corsa tips tend to stick out of the bumper rather than be flush with it.

 

[908ssp]

Dual exhaust systems drone when the sound from each pipe reenforces the sound at a specific frequency. Staggering can alter the tone from side to side eliminating much of the drone. If you want to try the Helmholtz you can probably get away with putting it on one side only.

 

[Sky Render]

It's nice to know Corsa actually puts some development into their products.

The droning of my Magnaflows is so bad and the fitment so atrocious, I have to wonder if a ball-less monkey designed the system.

 

[HellsBells]

It's nice to know Corsa actually puts some development into their products.

The droning of my Magnaflows is so bad and the fitment so atrocious, I have to wonder if a ball-less monkey designed the system.

The way Magnaflow and most other companies do it is they just have a bunch of mufflers of different size. They make piping to fit certain cars, throw on whatever mufflers fit (or a variety so they can have multiple kinds of systems), and sell it.

The way I understand Corsa's development, is each muffler is designed for each vehicle along with the piping. How much of that is true, I'm not sure. But I asked about buying their mufflers alone to fit onto a car that they did not make a system for, they told me that's pointless and it will most likely drone anyway.

 

[stkjock]

I had Corsas on my blown 06 with 4.10s, never droned, the only thing gears will do, IMHO, is change the speed one may hear drone.