socale39

I know everyone here states that quad setups will lose horsepower and based on common knowledge of exhaust system backpressure, I can understand how you'd lose low-end power, which everyone talks about, however how about the top-end? In theory wouldn't the quad setup provide better top-end performance than a more restrictive single-sided exhaust system with higher backpressure? Does anyone have empirical data to support that a quad setup would indeed impair performance throughout the entire power band?

Also, couldn't one achieve the same or close to stock backpressure by using different exhaust tube diameters and lengths to create the backpressure needed to retain low-end performance? It just seems that it is quite a bold statement to say that with any quad setup, you'll lose power. Personally it sounds like there just hasn't been a quad setup that has been developed correctly, unless of course we have data to support these claims.

Anyone?

I am looking to do a quad setup soon so I'd really like to hear what efforts have been made to prove that a quad setup will indeed impair performance. And please don't post "Butt Dyno" results, as there are so many various conditions that can play a role in how your engine performs between not having quads and having quads.

Looking forward to hearing from the crowd!

jasperxli

good topic! i wanna know too. i dont know shat aboout exhaust so i would love to learn if its possible to not lose power at all by going with quads.

danzanchy

isnt the loss like 5-10 hp with a buttdyno? if you like the way it looks/sounds, go for it. you're most likely not gonna notice the loss in power.

socale39

Like I stated earlier, the "butt dyno" is completely inaccurate and in my belief, psychological. So how it "feels" doesn't cut it for me.

FRONJONI

I dont know about performance, but the quad setups I have seen are y-pipes with a muffler in the middle splitting out to two pipes that exit the rear.
I dont know the engine specifics, but I am going to try putting two mufflers after the pipes are split in the rear. I dont know if its because of the higher cost of mufflers or what, but I just havent seen this setup, and i think it would sound a lot better than just one muffler.

socale39

^^^ I was planning on using all the stock components except for the muffler. So I was going to use the stock resonator and then y-pipe out to two mufflers than tips. Sounds very similar to what you are going to do. This would seem to best simulate the stock setup and I'd imagine power loss would be minimal if any.

FRONJONI

honestly, im not too concerned about power loss...
im more concerned with improper cabin noise when sticking the muffler under the driver seat and achieving the deepest most luxurious sound.

socale39

I guess no one has proof? Dyno charts?

Gene

http://forums.5serie...__1#entry849818

http://forums.5serie..._maganflow+quad (be sure to get to post #50)

socale39

One dyno and a bunch of talk about magnaflow. Not convinced yet. Maybe members with quad exhausts can chime in and let us know piping diameter used and more specific information with their setups.

Also, how about getting a dyno from an individual, not a competing exhaust manufacturer.