I have an 06 883 with SE slip ons. How does the crossover effect the way the bike runs. I've gutted the SEs and put torque cones at the top of the exhaust and am really satisfied with the results. Just wondering if the crossover is really needful. Have any of you taken them off and with what kind of results? Thanks !!!

 

The history of that pipe goes back to the 60s, IIRC, when BSA or Triumph fitted one to one of their parallel twins. It gave a significant improvement in low/mid range torque, so they installed them across the range. Other brands who made twins quickly copied them, including Harley. You will probably not find a twin today that does not have them!

So they give improved performance and are well worth keeping. On later bikes they have been moved out of sight, whereas on earlier bikes they were very visible.

 

Like grbrown said, it's for exhaust scavenging. It adds a good part of the low/midrange torque. Taking it out can mean a 3-5 ft-lbs of torque loss, which on an 883 is a pretty hefty chunk.

 

The crossover is there to allow the exhaust from each cylinder to exit both mufflers. This allows the mufflers to be smaller (for looks) while not choking the engine too much to meet the noise regulations. When you put low-restriction mufflers on the stock headers, the effect of the crossover is greatly diminished, as there's very little restriction through the mufflers.

 

Correct

Correct

About as wrong as you can get.

 

Yep, but I needed a good laugh this morning.

.

 

So,...why don't you educate me?

 

Wait so all exhausts have x-overs? I remember when I got my bike my buddy's told me to take out the baffles and cut of the x-over. I never did because it didn't sound very smart. I've never really looked hard for them, but on dual looking exhausts how do they hide them?

 

Dont need to................the first two guys did.

 

Not ALL exhausts have them. The stock ones on Sportsters will, and many other bikes for the reasons stated above. The newer Sporty's have them hidden directly behind the mufflers so they cannot be seen easily looking at the bike. Nearly all multi-bank car engines use an x-pipe or other sort of crossover for the same reason.

Some exhausts are true duals that do not have a crossover. These are usually tuned in length/shape/diameter to have the same effect as a crossover. Other types are just "drag pipes", whose main purpose is to prevent restriction for high rpm horsepower and performance at the cost of low/mid-range performance.

There is a lot of testing, math, and tuning/computer simulation that goes into the design of exhaust geometry from the factory. I know first hand from engineers whose job it is to do just that, 40+ hrs a week, year round. To simply hack away at a stock pipe offers no benefit, especially if you don't know what it is doing in the first place.