No, I'm not planning on changing anything on my Fit but just had a question regarding dual exhaust set ups vs a single. Does one pose and advantage over the other?

 

less back pressure in high rpms but maybe not enough in low rpms

 

The concept of a dual exhaust is actually quite confusing!

Take a car like the V6 Honda Accord, or even a stock Nissan 350Z for example. Even though you can see two exhaust pipes from the rear of the car, that isn't a true dual exhaust setup...it's just two pipes coming from the same single exhaust setup. This is done basically just for show.

A proper dual exhaust setup has not only two pipes, but also two cats and two paths through the muffler to be a "true" dual exhaust. Two pipes isn't even really a requirement...the cats, etc could concievably file through a single pipe at the rear of the car...when I was doing research I found out that some BMWs are actually set up like this.

I believe that the main advantage of a true dual exhaust setup is a reduction in back pressure in the engine, because exhaust gases can be expelled more quickly and efficiently. From a performance standpoint, this increases hp and mpg. It also reduces engine operating temperature and sounds nice

 

That's sort of what I was thinking. The only things I could come up with was it would get more money for the dealership (because it looks cool) and it would cost you more in the end for exhaust work.

Thanks for the explanation.

 

If anything, running dual pipes through a single exhaust setups would probably very slightly reduce performance if anything, due to the additional weight of the second set of piping.

 

So if I remove my exhaust entirely I'll increase the performance of my Fit! Thanks!! J/K

 

Yes, it probably would, until the ECU kicked into limp mode.

 

This one is a straight pipe, no muffler:

YouTube - Honda Fit Exhaust w/ K&N CAI but no muffler

Sounds great!

 

^ This.

Like someone else said, in most cases, it's just for show. A lot of cars that don't have true dual exhausts but are being modded for legitimate performance reasons (i.e. S2000, 350Z, etc.) end up switching to a single exhaust anyway, especially since it's mostly aesthetic, compared to larger engines not just with separate cylinder banks but separate catalytic converters that do benefit from it.

Did the current Evo and STI really need to switch from the single exhaust setup? No. But it looks cooler, plus the aftermarket manufacturers will be able to charge more for it too when manufacturing dual exhaust setups to be used as OEM replacements.

 

Not necessarily, if you look up most aftermarket exhaust (even comparing stock single, dual pipe) they always weigh less because of the material they're made of. In the case of a 350z its the same weight and a major gain in hp

 

Hmmmm. Keen observation; didn't consider this. I will research further. I was comparing single exhaust/dual pipe to single exhaust/single pipe here; I thought that more piping = more weight = decreased performance.

 

But the weight doesn't exactly decrease the performance in terms of it affecting the engine output, if that's what you thought. More piping = more restriction.