Custom Exhaust Advice/Opinions

[1slowsilverado]

Ok heres the deal, I am looking to fabricate a undertail exhaust for a 900ie. Im not doing this to for HP/TQ gains OR looking to loose anything at the same time, Just pure eye candy.

I have seen some fine examples from ARC and have done some research, But to be quite honest I dont know crap about exhaust and the R&D that goes into them, What works and what dont. Looking at my stock exhaust just confused me even more, From the little diameter pipe, unequal lenght and the funky crossover setup.

I was thinking about something simple like a 2 into 1, But after some research this is not the best for a duc? I dont have a problem with a 2/2 but selecting the right pipe diameter is a major concern as is, Pipe lenght, and cross over setup (if needed) is hampering my plans.

Has anyone been down this road and care to share setups, Or exhaust experts care to share there thoughts.

Thanks,
Tim

[chaas67]

Not an exhaust expert but this winter I'll be building my own undertail exhaust for my track-only 95 900ss/cr.

My buddy, who is helping me and has quite a bit of knowledge on the 900 motors, tells me that the exhaust system is not the limiting factor on these motors but the heads. Having said that, picking reasonable diameter pipe and running reasonable routes I should not impact the bike in a bad way. (ie reduce HP) Not sure if this holds true for yours. Perhaps someone can speak to the head design being the same/different and what the limiting factor is on the newer 900ie.

Now, I'm sure people will jump all over this but that's fine. I'm not going to market this and it's not going on the dyno. It's going to the track and I'm going to ride it in circles....

hope this helps is some way...

[Exarius]

Hmmm.. tough one... Pipe length is one of the most important things when building exhaust systems, and making sure there arent any sharp bends as the pressure "hits a wall".. once spoke with a german fellow who had converted his tail to a 916 and had actually used those cans, and made his own pipes in stainless.. really good effekt.. he had done this on a 99 900ssie... he said he had lost 2 bhp at the top, but middle range was about the same... this is so little that it hardly matters...

[GregP]

I spoke with a guy who claimed to have gained 10hp with the ARC Fab underatil with an open box and a custom PC3 tune.

Listen to the sound tracks on the site. These systems are for the most part straight pipes (no baffles) so the sound is way obnoxious. Not sure if the folks in the hood will enjoy.

[Cutaway]

+1 For ARC fabrication.... Doug is a FIRST CLASS engine builder & exhaust tuner. The loud ones you refer too are the reverse megaphone... very loud YES, but ver efficient. He just doesnt just do megaphone...shoot him an e-mail... You wont be dissapointed. The stuff he has been doing for my RC is nothing short of spectacular!

Josh

[chris900ssie]

Just to add a bit here, the standard headers are fine for all but the most tuned of bikes, so the 40mm diameter should be fine. as far a the lengths go, a very rough rule of thumb is that longer makes the engine more ... "bottom endy" and shorter moves things to be mor "top endy". 2 into 1 should work, HRC found it to be better for the SP2 in its last season so....
Other than that, copy one that works/is proven if possible. otherwise you could have a gorgeous exhaust system but a motor that is hard to tune or runs like crap. Exhaust tuners/builders are pros. not without good reason. You wouldn't let a gynacologist give you brain surgery would you???



Chris