Polaris VES (Variable Exhaust System) refers to the exhaust power valves used on Polaris 2-stroke snowmobiles. The main idea behind VES valves is to increase engine power and throttle response in low and medium RPM range.
If you want to find out more about this performance feature, you’ve come to the right place.
We at PowerSportsGuide have compiled all you need to know under one roof!
What is a Polaris VES Engine?
Polaris VES engines feature the Polaris-exclusive Variable Exhaust System. As the name suggests, this system utilizes guillotine exhaust valves intended to increase engine power and throttle response. As a rule of thumb, the VES system can increase engine power by about 6-10 HP depending on the size of the engine and its features.
Polaris revealed its innovative VES system in the late ’90s, but VES Polaris snowmobiles became more prevalent in the early 2000s.
It’s safe to say that Polaris’ VES does the same job as Yamaha’s YPVS (Yamaha Power Valve System) and Ski-Doo’s RAVE (Rotax Adjustable Variable Exhaust) systems.
Let’s get down to the nitty-gritty and talk about how the Polaris VES works!
What Does a Polaris Variable Exhaust System (VES) Do?
Non-VES Polaris engines are regular 2-stroke engines in which the exhaust fumes exit the cylinders via regular exhaust ports. These ports can be designed to produce a great performance at either high or low engine RPMs, but not both.
Because of this, the ports on regular non-VES engines have compromised engineering to produce an acceptable performance at all RPM ranges.
This is where the VES system comes into play since this feature is designed to change the size of the exhaust ports at the right time. Therefore, VES engines do a really good job in both low and high RPM ranges.
How does the Polaris VES system work?
In a nutshell, a Polaris Valve Exhaust System (VES) features guillotine slide valves operated with bellows. These valves are mounted on the exhaust ports and opened and closed based on the engine RPM.
On early VES sleds, these valves were controlled by the pressurized exhaust gases, but on later models they are controlled by solenoids.
At low engine RPM, the VES valves stay closed ensuring better combustion and less unburned fuel in the exhaust gases. This increases torque and power in low and mid-RPM ranges.
At higher RPM, the valves start moving and the exhaust ports open up, which creates a high-ported engine characteristic. In other words, the opened exhaust ports allow the engine to breathe easier ensuring higher RPM, more torque, and power.
Therefore, contrary to popular belief, Polaris VES engines generate more peak HP than their non-VES equivalents!
Drawbacks?
One of the main cons of the VES system is that it adds more complexity to the engine. And the more features an engine has the more things there are that can go wrong!
What’s more, VES valves require annual cleaning and inspection, which means more complex maintenance and higher running costs.
It’s also good to know that certain Polaris sleds were released with aluminum valves. These valves are prone to melting during aggressive rides since VES assemblies lack any cooling system.
These aluminum VES valves have to be replaced with more durable ones for higher reliability and durability.
Which Polaris Snowmobiles Feature VES?
The first Polaris snowmobile with a VES engine was the 1997 Polaris XCR 440. Since this machine was a race sled, only a limited number of them were made.
The VES became commercially available in 1998, but they were still only on the 440 twin engine.
In the following years, VES valves found their way to the larger engine categories including 500, 600, 700, and 800cc classes. However, the manufacturer kept many non-VES models in its fleet as well.
As a reference, here’s a list of some popular VES Polaris snowmobiles:
- 1997 Polaris 440 XCR
- 1999 Polaris XCR 700
- 2000 Polaris 500 XC SP
- 2000 Polaris 600 XC
- 2001 Polaris 440 Pro X
- 2002 Polaris 800 Edge X
How do You Identify Polaris VES Engines?
You can identify a Polaris VES model by taking a closer look at the engine. The valves are enclosed in metal nests that are covered by a black plastic cap. These VES valve assemblies are mounted on the side of the cylinders close to the cylinder head.
Here’s a great video on how to locate VES valves on a Polaris sled:
Can You Add VES to a Polaris Snowmobile?
Although you can add VES valves to most non-VES engines, keep in mind that it’s not an easy modification.
Despite that it’s just a bolt-on upgrade, installing VES valves requires you to add and modify a lot of parts and features.
For example, VES engines have slightly different exhaust systems. Also, the ECU has to be reprogrammed or even replaced for a VES engine in order for the valves to operate properly.
Without the ECU upgrade, the engine couldn’t get the most out of the revamped engine characteristics. This also means that you would have to adjust the carbs to match them to the new ECU.
What is a Polaris VES Oil?
VES engines not only require more care and attention, they also need a special full-synthetic oil to run properly. As the name suggests, Polaris VES oils are specifically formulated for VES 2-stroke engines. According to the manufacturer, the key advantages of these lubricants are as follows:
- Maximum engine protection
- Easy starting in extreme cold
- Improved rust and corrosion inhibitor package
- Full synthetic base oil formulation offers excellent load carrying abilities to reduce engine wear
- Provides enhanced valve cleanliness, low smoke & excellent lubricity
- Designed for Variable Exhaust Systems & all other Polaris® 2-cycle engines
What Color is Polaris VES oil?
The color of Polaris VES oil depends on its type and formulation. As an example, Polaris VES Gold oil features a golden color.
Takeaways – What is VES on Polaris?
Simply put, the VES (Variable Exhaust System) is the power valve system of 2-stroke Polaris engines. These valves are intended to change the size of the exhaust ports to get the most out of the engine in each RPM range.
VES valves are nestled on the exhaust ports and open and close based on the engine’s RPM. This causes the engine’s power band to change, which helps increase torque, power, and throttle response.
Thanks to this feature, Polaris VES engines provide better performance and especially in the low and mid-RPM ranges. Also, they offer slightly more top-end power.
The major drawback of VES valves is that they add complexity to the machine and require annual cleaning and inspection.
FAQs About Polaris VES:
What does VES stand for Polaris? Variable Exhaust System
When did Polaris come out with VES? 1997
How do you identify Polaris VES engines? The VES valve assemblies are mounted on the side of the cylinders close to the cylinder head.
References:
