Polaris RZR Exhaust Evaluation

It’s been 3 generations since the RZR first arrived as the sportiest new UTV to hit the market, and we’ve been hearing for a long time that our readers would really like to see a full blown exhaust test. So, after giving each of the manufacturers plenty of time to design, test, re-design, test, and complete their exhausts, it’s time to show you 11 different exhausts from 10 different manufacturers.

But, before we start, we need to tell you exactly how the tests were performed, so there’s no gray area for misinterpretation. First, 19 manufacturers were invited, and 10 ended up participating. For those wondering why some may not be in the test, it’s mostly due to timing for production. But, like the pessimists might assume, I’m sure some didn’t want to stack up against the rest. But, ya know what? It doesn’t matter why some didn’t participate, because we’ll never really know the real reason. What matters is we have 11 different exhausts that we tested more thoroughly than any other magazine or company ever has in the past. Why are so many magazines apprehensive to do it? Well, the fact of the matter is there’s going to be some hurt feelings because of this test. And for some, sales are going to increase. But what it tells me is there’s an exhaust out there for everyone’s needs, whether you want the quietest exhaust, highest peak HP, highest average HP, highest peak torque, highest average torque, or just the one that looks the best. We’re going to provide all the details you could ever want when comparing the exhausts available for your RZR so you can choose exactly which one you want for your type of riding. So, here’s how the tests were actually performed.


As far as dynos go, there are really two types of dynos that are used: a wheel dyno and a crank dyno. There are advantages and disadvantages to both, but we selected a wheel dyno from KMS Performance primarily because Kelly has been known in the racing arena as producing some of the highest power reliable motors around. Not only that, the RZR lends itself way easier to a wheel dyno than a crank dyno because of the location of the motor. In addition, a wheel dyno allows you to get a more real-life dyno result, because the CVT clutch is involved. The ideal process would be to crank dyno a motor, tune the clutch to pull at WOT at the peak power RPM level, then dyno it on a wheel dyno once complete for the optimal results. But, for the purposes of this test, KMS Performance’s 2-wheel dyno was perfect. Last thing to keep in mind about dynoing vehicles is that every dyno is going to produce different results based on how they’re set up. The key is to perform the testing on the same dyno, set up the same way, in as close to same conditions as possible. Keep in mind, as well, that when dynoing on a wheel dyno, the gains are less than what would be produced on a crank dyno. For example, the stock RZR motor produces 52HP at the crank and roughly 35HP at the wheels. So, make sure when you read claims by manufacturers and power production that you ask them if it’s crank or wheel gains they tested with.

We used a bone stock Polaris RZR for our testing with no modifications. Upon doing the initial pulls, we decided the best thing we could do to even the playing field is install some heavier clutch weights in the primary to keep the higher HP/TQ numbers from causing the engine to hit the rev limiter too soon. So, we put some 4 gram heavier weights in the clutch, resulting in 66 grams from 62 grams that come in it stock. This proved to be a wise decision, because even after adjusting the stock fuel curve with the stock exhaust we were pegging the rev limiter off the bottom end, causing the readings to be inaccurate. But, with the 66-gram weights, it was perfect. So, after installing the weights, we did our initial 3 stock pulls after fully warming up the engine. All pulls were recorded, and it was time to see just how much power we could pull from the stock ECU by adjusting it using a Power Commander. The reason we used a Power Commander for our testing is that in most cases, Kelly from KMS Performance said that the RZR is running too rich and benefits from being leaned out a tad to increase power. So, after Kelly adjusted the stock fuel curve to optimal, we made another 3 pulls, and to our surprise, gained some additional power just by adjusting the stock curve. How much did we gain? Well, when looking at just peak horsepower and torque, we added 1.9HP and 1.4 ft. lbs. of torque. But, you’ll quickly find that it’s not about peak HP and TQ, it’s all about usable average HP and TQ gains from zero to top speed. So, after doing both stock and corrected fuel runs, it was time to gather our decibel readings on the stock exhaust.


Our test vehicle is a 2008 Polaris RZR with 416 miles

We borrowed a sound meter from the folks at Worcs Racing, so we knew we were getting a well-used and accurate tester for our testing purposes. The only challenge with this is that it’s not an exact science at all. In fact, in our opinion, the standard method for testing decibels is bogus, because it’s tested at idle and an RPM between 2500-3000 RPM. Well, it was quickly realized that getting these readings was harder than expected. So, we placed the tester at the appropriate location, turned the vehicle on and let it idle to record the stock exhaust’s idle reading of 86db. From here, we raised the RPMs as steadily as possible and recorded the test level decibels of 88db. We also had plans to test it at wide open throttle, but we realized that this wasn’t going to be accurate at all, given the hard concrete floors and difficultly to precisely read the meter at a specific RPM for all exhausts. So, although we have readings for every exhaust at idle and the test RPM, I’d take it with a grain of salt, honestly, because the reality is they may be quiet at low RPMs, but most of them became totally different animals when running wide open. The true test of decibels at wide open throttle (WOT) would be to record max decibels as you drive by under WOT. But for this test, we couldn’t do that. So, once the sound testing was complete, it was time to install our first exhaust. But, before we jump into each exhaust’s results, here are the items we’re going to be testing:

1.    Horsepower, Torque, Air Fuel Ratio Curves 2.    Retail Price of Exhaust 3.    Dollar Invested/HP Gained 4.    Dollar Invested/TQ Gained 5.    Decibels at idle 6.    Decibels at test RPM 7.    Three runs per exhaust – best run will be used 8.    Quality 9.    Ease of Installation

Most of the results are pretty easy to quantify, but the two items that are not are quality and ease of installation. In regards to quality, we took into account the actual quality of construction, such as welds, fitment, and appearance. But, we also took into account the actual design and attachment points for longevity purposes. The hardest thing is having an exhaust that allows enough flex to allow the rubber-mounted motor to move freely and not break welds and cause leaks at all the various connection points. Ease of installation was pretty much how long it took to install. So, to begin our testing, we chose the slip-on exhausts first. Here are the results for:

Two Brothers M-7 V.A.L.E. Slip-On


Decibel Readings: Idle – 85.5 • Test – 93.5

Retail Price: $399.98 Part Number: 005-1850406V

Dollar Invested Per-
  • Peak HP: $99.50
  • Avg. HP: $152.08
  • Peak TQ: $144.92
  • Avg. TQ: $189.56


two-brothers-2 twobros-bar-chart  

SuperTrapp Mudslinger


Decibel Readings: Idle – 82.0  • Test – 88.2

Retail Price: $339.00 Part Number: 136-1804

Dollar Invested Per-

  • Peak HP : $72.59
  • Avg. HP : $115.70
  • Peak TQ : $102.42
  • Avg. TQ : $142.44
ST-V-CORR st-ex-install-rzr supertrap-bar-chart

Gibson RZR 800 Exhaust


Decibel Readings: Idle – 84.5 • Test – 90.00

Retail Price: $532.00 Part Number: 98001

Dollar Invested Per-

  • Peak HP: $150.71
  • Avg. HP: $271.43
  • Peak TQ: $195.59
  • Avg. TQ: $287.57
GIB-V-CORR Gibson-rzr-exhaust-installed Gibson-Bar-Chart

Hot Seat Performance


Decibel Readings: Idle – 83.3 •  Test – 89.7

Retail Price: $749.00 Part Number: N/A

Dollar Invested Per-

  • Peak HP: $161.08
  • Avg. HP: $197.63
  • Peak TQ: $209.80
  • Avg. TQ: $224.92
HOT-V-CORR hotsperf-rzr-exhaust-installed Speedwerx-bar-chart

Ron Wood Race Exhaust w/ SuperTrapp


Decibel Readings: Idle – 85.6 • Test – 96.5

Retail Price: $729.00

Dollar Invested Per-

  • Peak HP: $192.35
  • Avg. HP: $282.56
  • Peak TQ: $276.14
  • Avg. TQ: $305.02
RW-V-CORR Ron-woods-rzr-exhaust-installed Ron-Wood-Bar-chart

HMF Swamp XL


Decibel Readings w/ Quiet Core: Idle – 81 • Test – 85.8

Retail Price: $739.95 + $25.00 Quiet Core Part Number: PRZRXSSR

Dollar Invested Per-

  • Peak HP: $196.14
  • Avg. HP: $429.75
  • Peak TQ: $261.08
  • Avg. TQ: $413.39
HMF-V-CORR HMF-rzr-exhaust-installed HMF-w-core-bar-chart

HMF w/o Quiet Core


Decibel Readings w/o Quiet Core: Idle – 88 • Test – 91.5

Retail Price: $739.95 Part Number: PRZRXSSR

Dollar Invested Per-

  • Peak HP: $153.84
  • Avg. HP: $225.59
  • Peak TQ: $212.63
  • Avg. TQ: $261.47
HMF-NO-CORE-V-CORR HMF-xl-rzr-exhaust-installed hmf-xl-bar-chart

Trinity Stage IV Exhaust


Decibel Readings: Idle – 87 • Test – 93

Retail Price: $599.99

Dollar Invested Per-

  • Peak HP: $122.45
  • Avg. HP: $157.48
  • Peak TQ: $168.06
  • Avg. TQ: $190.47
TRIN-V-CORR trinty-rzr-exhaust-installed Trinty-bar-chart

Bikeman Performance Full Velocity Exhaust


Decibel Readings: Idle – 83.2 • Test – 88.6

Retail Price: $569.00

Dollar Invested Per-

  • Peak HP: $116.84
  • Avg. HP: $143.32
  • Peak TQ: $171.90
  • Avg. TQ: $159.38
BMP-V-CORR bikeman-rzr-exhaust-installed Bikeman-bar-chart

Alba Action


Decibel Readings: Idle – 89.9 • Test – 93.2

Retail Price: $649.99

Dollar Invested Per-

  • Peak HP: $151.51
  • Avg. HP: $208.33
  • Peak TQ: $191.17
  • Avg. TQ: $231.31
ALBA-V-CORR ALBA-rzr-exhaust-installed alba-bar-chart

Dragon Fire Racing True Dual

Decibel Readings: Idle – 85 • Test – 92.2

Retail Price: $899.00

Dollar Invested Per-

  • Peak HP: $174.56
  • Avg. HP: $264.41
  • Peak TQ: $250.42
  • Avg. TQ: $335.45
DF-V-CORR DFR-RZR-dual-exhaust-installed Dragonfire-bar-chart


Overall, our first exhaust evaluation was a huge success. Hopefully, based on the results, you can now choose exactly which exhaust best suits your needs and riding style. We broke it down by peak power gains, average (usable) power gains, cost effectiveness, quality, ease of installation, and decibels. Our goal was to do the same type of test on the Kawasaki Teryx, but our next step is actually going to be one more thing for the RZR. Can you think of what it might be? Well, till next time, and we’ll give you what you need to gain upwards of 8+ HP in the next issue when combined with your favorite exhaust.


Also, for all those wanting the optimal fuel curves or at least a great baseline to start from, we will have all Power Commander maps available for download on our website for each of the above pipes. Keep in mind, these are set for 1000 of altitude on a stock RZR, but once next issue is done, you’ll not only have the correct maps for the exhausts, you’ll also have it for the combination of parts, as well.


About KMS Performance

Helping us Dyno the 10 different pipes was the crew from KMS Performance.  At the master control panel was Kelly McLean.  Not only is Kelly very knowledgeable on a Dyno, he knows his way around a motor.  He builds everything from quad motors to Rhino motors, as well as building custom exhausts for sand drag bikes. And he knows how to clutch a variety of vehicles to get the best performance, as well. While we were swapping out exhausts in between Dyno pulls, he was rebuilding a transmission and started tearing apart a RZR motor that should have some sick power gains.  KMS Performance is big in the Rhino market, but they have a few trick RZR mods that no one else has, including a stiffer throttle spring and an intake for the RZR that gains around 4 hp. This is just the start of what new products KMS Performance will have for the RZR.  With constant testing and refinement, they will not release anything until it has been proven by Kelly and has a significant performance gain with a fair price.

If you are looking for performance for your Rhino, RZR, quad, or bike, whether it is for play or race applications, KMS Performance knows their stuff. From service and repair, routine maintenance, Dynotuning, OEM and aftermarket parts to performance modifications, they have you covered.

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