While the exhaust pipe on your motorcycle might seem pretty simple on the outside, the engineering that goes into designing one is quite amazing. Designing an exhaust pipe requires tons of calculations and even a slight tweak could result in meaningful changes in both performance and sound.
Luckily, choosing a new motorcycle exhaust is pretty easy, as you really have only two options to choose from: short and long exhausts. But which is the right one for you?
In this article, we’ll break down the pros and cons of both and hopefully make it easier for you to choose between the two.
Performance: More Torque At High RPMs vs Low RPMs
Let’s start with performance first.
Now, before we talk about the performance side of short vs long exhaust, we first need to get the technicalities out of the way. I promise I’ll make them as brief as possible.
Backpressure and Velocity
Think of your motorcycle’s engine as a big air pump (which is essentially what it is). A four-cylinder, four-stroke engine will produce four exhaust pulses per cycle. Any resistance to these pulses is considered backpressure.
Now, I’m sure you’ve read somewhere that engines need backpressure – this statement is plain false. Engines need exhaust velocity, not backpressure. In fact, engines need as little backpressure as possible and as much exhaust velocity as they can get.
Engineers achieve that by using exhaust pipes that are narrow (and long) enough to achieve high exhaust velocity, yet wide (and short) enough to maintain close to zero backpressure.
Differences In Performance
To put it as simple as possible, by swapping between short and long exhausts you can move the torque curve to higher or lower RPMs.
Generally, a long exhaust will slightly increase low RPM (bottom end) torque, while a short exhaust will slightly increase high RPM (high end) torque.
These changes in torque are quite small, but definitely noticeable if you get your engine tuned for the new exhaust. Tuning the engine after replacing your exhaust with a shorter or longer one is extremely important. If you’re not going to tune it, then you will likely lose power.
Last but not least – weight. Short exhausts obviously use less material and are therefore lighter. Every ounce makes a difference when it comes to motorcycles.
Sound: Tame & Subtle vs Loud & Sporty
Sound is another big factor when it comes to choosing long vs short exhausts.
Long exhausts are obviously quieter, and that’s the no. 1 reason why they are still the go-to in most applications. They extend to the very back of the motorcycle and direct the sound away from your ears.
They also shape the exhaust note to a deeper, more rumbly kind of sound, which is always nice.
On the other side of the spectrum, short exhausts are loud. Some of them, especially the high-performance ones, are so loud that they can only be used on race tracks, and are illegal on the streets. They have a higher-pitched sound than long exhaust, but the road that you get with them is incredible. Although, it does get old fast if you’re on a long trip.
Choosing between the two comes down to personal preference, however, longer exhausts are probably the best choice if you’re unsure.
Looks: Short & Sporty vs Long & Traditional
Last but not least – aesthetics. Again, this one comes down to personal preference and I’m sure that you’ve already made up your mind on which one is better for you, but I’ll list the pros and cons of both just in case.
Short exhausts are becoming more and more popular lately and it’s easy to see why – they look stealthy and modern.
Long exhausts, on the other hand, are a classic. They stick out visually (and literally) because of their size and length, and look great in chrome. But if chrome is not your thing, long exhausts can be painted matte black for a more modern and stealthy look.
As a good rule of thumb, long exhausts look best on cruisers and short exhausts look best on sportbikes.
Conclusion
While long and short exhausts look very different visually, they’re not that different when it comes to performance.
By switching to a short or a long exhaust, you can move the torque curve around a bit, but the engine needs to be tuned for the exhaust, otherwise, you will lose power or even make the engine run lean.
So choose according to your own preferences and don’t forget to tune your motorcycle afterward. There really is no downside to choosing one over the other as far as performance goes.
Jake is the site’s primary contributor.
Motorcycles and automotive repair have been a big part of his family for generations, therefore it’s only natural that he decided to become a heavy-duty diesel tech.
Outside of work, you’ll find Jake restoring and riding rare street bikes and ATVs.