FloMaster vs. Magnaflow Mufflers

[Bob B]

Earlier, I posted a thread on muffler cut-outs earlier. Thanks for your feedback. I shopped around locally and none of the speed shops in mid-to northern Maine install cut-outs though they would give it a try. I don't want "try", so I have been looking at mufflers instead.

Local gear-heads have recommended FloMaster and Magnaflow mufflers. Reviews re: their sound seem to net-out to personal taste, but Magnaflow adds additional HP: https://exhaustsystemsguide.com/magnaflow-vs-flowmaster/

Does anyone have any thoughts on these or other mufflers?

 

[Pingu]

Ultimately, the muffler (called a silencer in the UK) has only one purpose. To quieten the exhaust noise. Clever muffler design can change what the sound is, but that is a different (and more complex) discussion.

All the clever internals that create depressions (wrongly called vacuum) is to lessen the effect of the back pressure caused by the obstruction.

When you decide what you want your muffler to do, it will be much easier to make the decision.

BTW, I made a motorway journey last week, and fill-to-fill in an M was 38.9mpg - and it sounds like roaring thunder if I give it the beans.

If you want performance, get rid of the muffler. If you want good performance, tune the exhaust (again a complex topic).

 

[Bob B]

Thanks, but that is not an option in Maine; my roadster would simply not pass inspection. I would just like to have a barely legal muffler with more rumble than the more civil European sound of the BMW stock muffler. I have read that, depending on the design, a performance muffler can add HP as well. What muffler system do you have?

 

[Pingu]

I posted a link to my system on the other thread.

You will increase BHP if you reduce the back pressure compared to stock. This can be done by increasing the bore size, or by removing the obstructions.

There can be increases in BHP by encouraging the wave pulse to bounce back at the correct time. This is done by adding an obstruction. If you have to add an obstruction in order to quieten the exhaust, you might as well add that obstruction in the best place .

I built a flow bench to measure my pressures, but you can do it by ear with a vacuum cleaner.

It's not a very practical thing to consider unless you have the mufflers available to test.

The truth of the matter is that you will be unlikely to tell any difference other than sound unless you change to a straight through. From the two options, the Magnaflow looks the better.



Hint: The car weighs 1600 kg and has 320 bhp. If you can shed 80 kg, it is the equivalent of adding 16 bhp.

 

[Bob B]

Thank you. I went back to the cut-out thread to look at your modifications more closely. Impressive. As for myself, I have no idea how to do such mods. If I still lived in New Jersey, I could probably find a speed shop that could do such things. Here in Maine (not exactly a mecca for speed enthusiasts), about all I can do is to make stock changes that might boost HP, torque, and safety. Clearly, I have a lot to learn. I really appreciate your feedback.