Am I the only one who very much does not like dual exhausts on inline engines?
Dual exhausts were originally created for V shaped engines, as they had two exhaust manifolds and could therefore benefit from two mostly separate exhaust pipes. Over time, the dual exhaust became a fashion piece on cars. Some vehicles that had a V shaped engine were single exhaust up until the end of the system, where it branched into two separate tips. This is what is known as “fake duals”. Recently, inline engines have been leaving the factory with the fake dual exhausts. Is it for performance, or just looks?
An excellent example of a fake dual exhaust on a stock vehicle is the Subaru WRX and STI. The dual portion of the exhaust starts right as the passenger compartment of the vehicle is ending. Does it matter if it’s a fake dual exhaust, though? Will it still give a performance increase?
The simple answer is no: A fake dual exhaust on an inline engine will not give a proper performance benefit. The reason for this is that, although it may breathe more freely than the stock one outlet exhaust, a single larger diameter exhaust would be more efficient. An exhaust system with two pipes effectively doubles the weight of itself for as long as it has the second pipe. This adds weight that is unnecessary, which we all know ruins performance. A dual exhaust also splits the exhaust flow in separate directions, which impedes the straight flow that would be ideal and easily done with a single pipe.
In conclusion, a larger diameter single exhaust is better for all aspects of performance on inline engines than a dual exhaust system. Is it still worth it for you guys to have the looks of a dual exhaust, even while compromising performance? Let me know why in the comments below.
Comments
I’ve noticed many tuners do a single exhaust conversion on the fake dual systems.
Yes, just for the better performance. Those are normally the performance focused cars.
Ahem….. E92 335i.
Sure, BMW in general is a good point of reference.
Straight pipes sound bad
Straight pipes on what?
I hate dual exhaust on inline cars but now manufacturers cut bumpers to fit them perfectly and when you convert it to a single it looks stupid with a huge gaping hole.
I am planning to get a Evo X next year and I’ll keep dual exhausts only because it would look stupid with a single.
True, the cutouts make it hard to work around. The bumper either needs to be molded and repainted, or an aftermarket with a single slot. Neither of which are easy tasks for most cars.