415BMW

I've actually thought about doing a setup like yours with an RPI. 1 inlet into RPI and dual out but unsure if the reduction in backflow would cause decreased HP. I imagine it would sound awesome. If you decide to go and do it, i would be willing to contribute some money to test it.

I wonder if the increased size in piping past the large resonator or muffler in this case is the cause of the loss. Would a smaller diameter piping after the muffler help keep performance?

tex_phil

I have 2.5inch piping, I plan on adding dual resonators too before the tips or before the exhaust.

pjinca

My question is:
How come (since the M5 comes with quads) we can't just put a y-pipe somewhere ahead of the resonators and split the exhaust into 2 that way? This method would allow for 2 resonators more like the M's setup and shouldn't result in a loss of power. Any ideas?
Also, I wonder if RPI is even thinking about a quad setup for the I6ers?

tex_phil

I dont think there is enough space. Are you talking about putting a Y off the first Y pipes before the box just in front of the wheels?

So you would have Y off resonator to muffler on the left and then the right side would be off the Y with no muffler?

pjinca

There has got to be enough room for a second muffler under the right side. So a "Y" coming off the resonator and going to a muffler on each side should work. Otherwise what is so different under the M5's rear that allows for full dual exhaust? (besides the fact that it's a friggin M)

tex_phil

The battery compartment is in the way on the non-m for adding a muffler there.

pjinca

Really? Then where's the battery for the M? Maybe there's a way to swap to the M's battery box that sway you can fit it?