I also got my y pipe from Mike at 5 Star. Installed yesterday and i haven't heard Any Flutter

 

The flutter sound, IMHO, is caused by the crazy y-pipe design. It can really be heard when you don't have a CAT. The CAT does a lot more muffling than the muffler does.

Again, I believe the flutter sound is the exhaust gasses from each bank ramming into each-other through the stock y-pipe and forcing their way downstream from there.

Every engine will have a certain resonance with certain pipe diameters. With the V10 there are more pistons, the firing order is balanced and the frequency of the resonance is a bit higher than a V8. A V8 will generally produce a hum/drone in the 1,800-2,000 RPM area. What I have noticed about the V10 is that it sounds really angry from 2,200-2,400 RPM. If you have it straight-piped or lightly muffled with the stock y-pipe going into the stock 3" then you can hear the flutter like crazy. It is like a chewbacca gasoline hurricane as the exhaust gasses fight their way out. My dual 2.5" exhaust really smooths that all out. It revs right through that RPM range with ease now an my fuel economy has increased. I do get some drone cruising on the interstate, but that is from the mufflers. The mufflers I have are designed to change/lower the tone of the exhaust. I am going to get some Magnaflow ovals and add an x-pipe to tame it down a little bit.

Anyway. It is my understanding that the y-pipes from 5 Star or Banks are quite well tuned to prevent the exhaust gasses from fighting each-other and they promote scavenging instead.

I would highly recommend a y-pipe or any other mod that increases flow. When I chopped of my muffler, economy went up. Chopped off the CAT economy went up. Put dual pipes from the down tubes all the way back, economy went up.

The V10 likes to rev high into it's power band. The less restriction the better it will rev, simple as that. Use the power to turn the wheels not fight to push the exhaust out.