Do Quiet Baffles Affect Performance?

Let me guess, you just installed a sick new exhaust. Looks great, revs great but it’s too loud! Your neighbors don’t like it, your girlfriend doesn’t like it and now you need to quiet the bad boy down. 

Did I get it right? I would be surprised if you are riding on a stock exhaust and you want to quiet it down. 

Either way, let’s talk all about quiet baffles in this article. How they work, how they impact performance and if you could even do it yourself (D.I.Y)

For a quick answer – quiet baffles will not impact performance (horsepower or torque) as much. You could lose a small amount of high end power but nothing significant. You might see it at a dyno but will not feel it.  

Now that’s out of the way, let’s go into the details. Read on if you wanna understand all about quiet baffles.

Baffles are a relatively small device – located at the end part of an exhaust. Replacing or removing them will not impact the air-fuel ratio on your motorcycle as much.

Which means, you won’t really feel much difference in terms of horsepower or torque. Let me explain. 

(Recap) How Do Motorcycles Generate Power?

Motorcycle engines are combustion engines – they use a mixture of air and fuel to create combustion and generate power (as well as exhaust gases). 

To get more horsepower, you need bigger combustions. Which means, you need more air and fuel in the combustion chamber. Injecting more fuel into the combustion chamber is relatively easy – this requires a tune. 

Getting in more air is the trickier part. Most performance mods work to achieve this. For example, a performance exhaust has wider piping and less restrictive CATs and mufflers. 

This allows exhaust gases to flow out quickly and provide more space for air to enter – resulting in a bigger combustion and more horsepower! 

Remember, to get more horsepower, you always want your engine parts to be less restrictive – meaning, they allow exhaust gases to flow easily. I will talk more about this later in the quiet baffles section.

(Recap) What Are Baffles?

Baffles are a small device located inside the muffler. Their job is to quiet down sound waves coming from a motorcycle’s combustion engine. Some baffles are quiet while some are geared for performance and are very loud. 

Baffles silence sound waves by having uniquely shaped walls that are designed to bounce sound waves into each other and cancel out. 

Image of baffle. Their walls cause sound waves to bounce into each other and cancel out.

There are also other baffles that use fiberglass packing to absorb sound waves. These are usually quieter but more restrictive – they make it hard for exhaust gases to flow and could cause a slight reduction in performance.

Quiet baffles wrapped in fiber glass

How Do Quiet Baffles Work?

Quiet baffles are usually wrapped with fiberglass packing or steel wool. This way, sound waves are absorbed as they pass through the baffles – reducing the amount of sound waves that actually escape to the outside.

You could purchase quiet baffles that already come pre-wrapped with fiberglass or you could just wrap it yourselves. I will talk more about this later on.

How Do Quiet Baffles Impact Performance Really?

In the section above, I explained to you how a more restrictive exhaust can decrease performance. To get the highest performance (horsepower and torque), you always want to reduce the amount of back pressure from your exhaust. 

Quiet baffles wrapped with fiberglass packings are unfortunately more restrictive. They increase the back pressure from your exhaust and restrict the flow of exhaust gases.

Theoretically, this reduces the amount of room available in the combustion chamber for air – which results in a smaller combustion. Thus, reduction in power. 

However, the change from quiet baffles is insignificant. You will definitely increase back pressure from quiet baffles – which then results in lesser air in the combustion chamber. 

But while riding in real life, you will likely not notice this change. Dynos would tell you a reduction in 1-3 horsepower. However, I don’t think you should worry about it. Unless, you bring your bikes to race or tracking.

And specifically speaking, you would lose a small amount of torque in the high-end. But this is insignificant and the change in high-end torque won’t make your bike feel slow or less aggressive.

The case of gas mileage and quiet baffles are the same as performance. 

In theory, gas mileage should reduce. However, the change is so small that it won’t have any noticeable change in real life. Let me explain. 

We have established that quiet baffles are more restrictive – causing it to increase back pressure in the exhaust. With this increased pressure, exhaust gases from the combustion chamber cannot leave quick enough and remain inside. 

With the combustion chamber occupied, not much additional air can enter – causing the next combustion cycle to not have enough air and become small. 

And if you still remember, to have more power, you want bigger combustion – which in turn requires more air and fuel.

After the installation of quiet baffles, your combustion chamber will have reduced air but the same amount of fuel (provided that you don’t tune). This means, not all of the injected fuel will be used (there’s not enough air!). 

Causing them to escape into the exhaust system and out of the bike. In theory, some unburned fuel will escape from the bike and result in a reduced gas mileage. 

But again, these are all in theory. In real life, the impact of installing quiet baffles would be so small that you won’t notice it. I suggest you don’t worry about this. 

If you have been reading since the beginning, then you should have seen the trend by now. In theory – yes but in real life not really! The same goes for tuning.

The change in air / fuel ratio that’s caused by quiet baffles are not significant enough to the point that it needs to be corrected through tuning. 

There are usually two scenarios on when you should tune your motorcycle. 

1. When you just modified your motorcycle, the air/fuel ratio is skewed and you need tuning to correct it (or improve it). 
2. You just want a better performance and aggressive feel to your motorcycle. So you custom tune it to meet your needs. 

When installing quiet baffles, you are likely in the first category. And if you are, then you don’t need to tune! Your air / fuel ratio should not be impacted much. Don’t worry about it.

If instead, you are installing an aftermarket performance exhaust, then yes – you should probably look into tuning. 

I have an article here, where I discuss tuning and aftermarket exhausts. Check it out. Do You Have To Tune Your Motorcycle After Installing Exhaust? 

Typically, quiet baffles cost about $40 to $60 – they are more expensive than regular baffles because of the additional fiberglass wrapping that’s included.

This does not include the installation cost. I am not sure how much the installation cost would be. It’s actually quite common to install baffles yourselves – they are easy and can be done quickly.

However, if you still prefer to have someone else install it for you, I wouldn’t pay more than $50 for the installation. 

Before you decide though, read the next section where I talk about baffles installation. They are really easy and you should do it yourselves!

These are the steps to install baffles

• Unscrew the bolt that’s holding the baffle in your exhaust
• Slide the existing baffles out
• Slide your new baffles into the exhaust
• Tighten the screws that hold the baffles in place

It’s that easy! All you need is a screwdriver. Here’s a YouTube video that shows you how to install baffles. You could skip directly to 0:45

You could make a D.I.Y (do it yourself) quiet baffle for sure. It’s just a matter of buying fiberglass packing and wrapping it around your baffle. 

It’s not hard and you could find many tutorials online. Just make sure you wear gloves when you wrap your own baffle. Fiberglass can get on your skin and make you itch for a long time – especially if you are allergic to it. 

Here’s a great YouTube video showing you exactly how to do this. 

If your exhaust is too loud, installing a new quiet baffle is definitely a good idea. As we have already discussed, quiet baffles will not impact performance and gas mileage in any significant way.

To completely cut cost, you could even wrap your existing baffles yourself and also install it yourself – cutting the cost down to just a couple of dollars.