Billy Boat muffler

[D-O]

A friend has Billy Boat mufflers on his 930 and his Cayman. They both sound awesome, especially the 930. Anyone have any experience with the Billy Boat muffler for the E46 M3?

Jesse

[Nihilation]

Love mine! On factory headers, there's no drone, nice and deep done. Unfortunately I don't have any video to share but will next week.

[D-O]

Many thanks. My exhaust is stock as well, and drone was my big concern.

Jesse

[Tbonem3]

One of the best, but loud. Tips aren't the best, make sure to get the round ones, not oval which seems most prevalent.

[shibui]

Seems there are two versions of the BB exhaust, an older design with small tips and a newer updated one with larger tips. The older one I’ve heard and it sounded nice and deep.

[ELEM3NT]

Had one on my previous car. Was a tad on the loud side for me. It was paired with headers, OE section 1, and OE section 2.

Ended up throwing the stock box back on and was definitely surprised by noticeable difference in torque. Probably not a huge gain but was definitely noticeable.

[D-O]

Had one on my previous car. Was a tad on the loud side for me. It was paired with headers, OE section 1, and OE section 2.

Ended up throwing the stock box back on and was definitely surprised by noticeable difference in torque. Probably not a huge gain but was definitely noticeable.

Meaning you saw a torque increase by going back to stock?

[ELEM3NT]

Meaning you saw a torque increase by going back to stock?

Correct.

[Icecream]

Meaning you saw a torque increase by going back to stock?

Unless that is substantiated with a Dyno (or if there is data the internal piping diameter is less than OEM) I wouldn’t put much (any) weight into it. If it even made a 5-10lbft difference at the top end, probably couldn’t tell in a blind test.

[TexaZ3]

I have a BB exhaust on my M Coupe, its a nice one.

[Tbonem3]

Unless that is substantiated with a Dyno (or if there is data the internal piping diameter is less than OEM) I wouldn’t put much (any) weight into it. If it even made a 5-10lbft difference at the top end, probably couldn’t tell in a blind test.

It's not the top end, it's the midrange.

And everyone who goes back to the stock muffler says the same thing (even going back a decade on m3f), so I think there's something to it.

[Icecream]

It's not the top end, it's the midrange.

And everyone who goes back to the stock muffler says the same thing (even going back a decade on m3f), so I think there's something to it.

That would be some seriously junk engineering then for a muffler to restrict so much and make it louder at the same time lol. Would still like to see a dyno. I also feel like if it was midrange, then top end would be affected too. I dunno. I jist ise caution on tales from the butt lol
.

[Tbonem3]

I wonder if it's the design of the stock muffler - you read the Arvin white paper? Maybe straight through is better when you have cams or SC/Turbo, but perhaps it's not best for 280-320whp s54s? IDK.

[ELEM3NT]

I wonder if it's the design of the stock muffler - you read the Arvin white paper? Maybe straight through is better when you have cams or SC/Turbo, but perhaps it's not best for 280-320whp s54s? IDK.

It's been a long while back, but the design/engineering of the OE muffler was the gist of the debate on M3F. There was quite a bit of back and forth on the engineering that went into the OE muffler, etc.

I'm not an engineer, not an authority on exhaust set up, and not making any claim there was a "massive" difference by going back to the OE muffler. Dyno aside, the car definitely felt different and that was simply my experience.

GL to the OP with the new setup.

[Tbonem3]

There's a chance of the sound change affecting perception so it's hard to say. Doesn't matter much, we're not talking about any real noticeable amount anyway.