4 into 1 or 4 into 2?

[mvalenti]

Thinking of getting an aftermarket exhaust. What are the pros and cons of both of these styles?

[Rob S.]

Thinking of getting an aftermarket exhaust. What are the pros and cons of both of these styles?

Better sound with 4-into-1. Also less rust if you take short trips that don't heat up the tail pipes enough to burn off all the condensation.

More tunable for better performance. Less weight.

[Buffalo Bill]

I dunno about some of what he said.
I don't see any rust on my dual mufflers, one bike is an 82, the other a 90.
As for tuning and sound, they are quieter so that ain't cool? Tuning why not?
Duals cost more because you have to buy 2 mufflers, so oops that will make a few folks jealous you bought them.
You do lose the weight of the 2nd muffler, but maybe you can shed some weight off your gut?
So I'd say it comes down to, noise level, money and the different look.

[tkent02]

There is a difference in how they work. 4-1 can have better scavenging, at certain RPMs a properly designed 4-1 pipe will actually suck some of the exhaust out of the cylinder. Helps to make more power at the top end of the RPM range the engine is designed for. Usually you get less low and midrange power, so it feels even faster when it comes on the pipe. Good for racing, not so good for everything else, but a lot of people like them.

4-2 will generally be better at the low and mid range torque at the expense of a little bit of top end power. Generally will get better fuel economy, because it's tuned better for the lower RPM that most of us cruise at most of the time. Really makes more sense for most riders who aren't winding the crap out of the engine all the time. They can both sound just as good, can both be as loud or as quiet as you want them to be. Both will rust if they are not gotten hot before being parked.

I think the best is a 4-2-1, but they are hard to find.

[mvalenti]

Thanks, seems 4 into 2 is where I should be. AND my apologies for not posting this in the right directory.