How to Understand Official Polaris Kawasaki Horsepower Tests

275 HP vs. 250 HP: Why the RZR and TERYX Numbers Aren’t Yet Comparable

Twenty-five horsepower sounds like enough to settle a Facebook argument. Polaris advertises 275 hp for the 2027 RZR Pro R Boost, Kawasaki claims 250 hp for the 2027 TERYX H2, and subtraction appears to do the rest.

The footnotes make that math far less conclusive.

Kawasaki says its TERYX H2 figure was measured under ISO 4106 and warns that the result may be higher than a measurement made under an SAE standard. Polaris’s public Boost product page and August 3, 2026, launch release identify 275 hp at 7,000 rpm, but neither public source reviewed by SXS Nation names SAE J1349, ISO 4106, or another test code.

The honest statement is therefore simple: Polaris publishes a number that is 25 hp higher. That is not the same as independently proving the Polaris engine makes exactly 25 more horsepower under identical conditions.

What Polaris and Kawasaki Actually Publish

The current manufacturer disclosures do not provide a controlled comparison.

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That table does not mean the 275-hp claim is wrong. It means Polaris has not given buyers enough public information to determine whether its number and Kawasaki’s number were produced under matching rules.

It also means this should not be framed as a confirmed “SAE Polaris versus ISO Kawasaki” contest. Kawasaki brings SAE into the discussion through its disclaimer, but Polaris has not publicly said the Boost figure was measured under SAE J1349.

ISO 4106 Is Net Engine Power, Not Wheel Horsepower

ISO 4106 is an engine test code written for motorcycles. The standard defines net power as output measured on a test bed at the end of the crankshaft, or its equivalent, with specified equipment and auxiliaries installed. It is a full-load engine-dynamometer procedure, not a chassis-dyno pull through the complete TERYX driveline.

That distinction matters. The TERYX H2’s CVT, belt, transmission, final drive, axles, wheel bearings, and tires are downstream of the measurement. Whatever power those components consume is not subtracted from the published ISO crankshaft figure.

The 2012 edition of ISO 4106, which was replaced by a 2026 revision in March, called for production-type intake, exhaust, cooling, electrical, supercharger, and emissions equipment under defined conditions. It also corrected measured output to reference climatic conditions of 100 kPa, 25 degrees Celsius, and 30% relative humidity.

That is not an old-style “gross horsepower” test with the intake, exhaust, and every power-consuming accessory removed. Describing the Kawasaki figure as gross horsepower would be inaccurate.

There is still an unresolved detail: Kawasaki’s footnote says “ISO 4106” without naming an edition. Because the TERYX H2’s 250-hp figure predates the March 2026 revision, SXS Nation will not assume whether Kawasaki used ISO 4106:2012 or ISO 4106:2026 without confirmation.

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SAE J1349 Is Also an Engine-Power Standard

The current SAE J1349 standard is titled “Engine Power Test Code — Spark Ignition and Compression Ignition — As Installed Net Power and Torque Rating.” SAE says the method is intended to produce repeatable measurements that reflect typical in-service engine functioning and specifically warns against optimizing an engine only for the test.

SAE J1349 is also not wheel horsepower. It is an as-installed net engine rating with its own setup, reference conditions, corrections, and reporting rules.

There is another distinction buyers rarely see in launch coverage: an engine can be rated using an SAE procedure without the number necessarily being SAE Certified Power. SAE certification involves a separate witnessed verification process under SAE J2723. Neither Polaris nor Kawasaki publicly describes these two UTV ratings as SAE-certified.

Kawasaki’s disclaimer tells riders the ISO number may be higher than an SAE measurement. It does not supply an SAE-equivalent TERYX rating, a percentage adjustment, or a conversion formula.

There is no defensible rule that says “subtract 3%,” “subtract 5%,” or use any other internet correction to turn the TERYX’s 250 into an SAE number. The same physical engine would need to be tested or recalculated with the required data under the other standard.

The Word “May” Does a Lot of Work

Kawasaki does not say ISO 4106 always produces a higher number. It says the measurement may be higher than an SAE result.

That leaves several possibilities. The standards could produce only a small difference on this particular engine. The difference could consume a meaningful portion of the 25-hp published gap. It could also leave Polaris with a clear advantage. The information released so far cannot establish which outcome is correct.

The two claims may differ because of reference conditions, correction formulas, equipment load, cooling configuration, fuel and calibration requirements, or another test detail. They also may remain 25 hp apart when properly standardized. Declaring either result before equivalent data exists would replace testing with speculation.

Polaris could clear up much of the confusion by publishing four things:

• The exact standard and edition used for the 275-hp figure
• Whether 275 hp is a corrected net crankshaft rating
• The complete horsepower and torque curves
• Whether the result received independent certification or verification

Kawasaki could do the same by identifying the ISO edition and publishing an equivalent SAE result.

The 223 lb-ft vs. 146.3 lb-ft comparison needs its own footnote.

The torque numbers look even more dramatic than the horsepower labels, but the public disclosures are uneven.

Kawasaki lists 146.3 lb-ft at 8,800 rpm as peak torque. Polaris’s consumer page lists 215 lb-ft at 4,000 rpm but does not call it the peak. Reporting from Polaris’s technical briefing places the Boost near 223 lb-ft at 6,000 rpm, with roughly 97% of that output available at 4,000 rpm. That 223-lb-ft value is credible briefing coverage, but it is not currently presented as the official peak-torque specification on the consumer page reviewed by SXS Nation.

RPM cannot be separated from the comparison. Horsepower is a function of torque and engine speed:

Horsepower = torque × rpm ÷ 5,252

Using that relationship, Kawasaki’s published 146.3 lb-ft at 8,800 rpm represents roughly 245 hp at that point on the curve. That fits with a 250-hp peak arriving slightly later at 9,000 rpm.

Polaris’s published 215 lb-ft at 4,000 rpm represents about 164 hp at that lower engine speed. That is not a contradiction; it shows that the Polaris is already producing substantial torque well before its 275-hp peak at 7,000 rpm.

The practical difference is engine character. Kawasaki’s strongest published numbers arrive close to its 9,500-rpm redline. Polaris is describing a wider, lower-rpm torque curve. A continuously variable transmission can hold either engine near the part of its powerband selected by the clutch calibration, so the full curves and the CVT behavior matter more than comparing two isolated torque peaks.

Drivers do not feel crankshaft torque by itself. They feel torque after the CVT ratio, final-drive reduction, traction controls, tires, and available grip have changed it at the ground.

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A Chassis Dyno Would Answer a Different, Better Rider Question

An independent chassis or hub dyno would not directly certify either advertised crankshaft number. It would answer the question owners care about more: how much corrected power reaches the drive wheels or hubs through the production vehicle.

That result would include losses and behavior through the clutch, CVT belt, transmission, and final drive. It would also reveal how well each system keeps the engine near peak output, whether the ECU closes the throttle or reduces boost, and how output changes as the CVT and engine heat-soak.

One dyno sheet would not settle the comparison unless the procedure is controlled. Dyno software can display the same run with SAE, DIN, EEC, JIS, STD, or uncorrected correction settings. Tire pressure, tire temperature, tie-down load, fuel, drive mode, warm-up procedure, and dyno type can all change the result.

There is also no trustworthy fixed “drivetrain loss percentage” that can turn wheel horsepower back into crank horsepower. A belt CVT does not lose the same percentage at every speed, ratio, load, and temperature.

The Fair Test Is More Than One Peak Number

A useful RZR Pro R Boost-versus-TERYX H2 test should publish the procedure before publishing the winner.

• Test stock two-seat machines with documented break-in and maintenance status.
• Use the manufacturer-required fuel from the same source, matching stock tire sizes and published tire pressures.
• Weigh both machines in their test configuration instead of relying only on advertised dry weight.
• Use the same dyno, operator, tie-down method, drive configuration, correction setting, and warm-up procedure.
• Publish corrected and uncorrected wheel-power curves, not only the highest number from the best run.
• Record engine rpm, wheel speed, boost or supercharger data, intake temperature, coolant temperature, and CVT or belt temperature when available.
• Repeat pulls from a consistent starting temperature, then repeat them after heat soak to identify power reduction or belt-temperature effects.
• Follow the dyno work with controlled acceleration, roll-on, and grade tests using the same driver, vehicle load, surface, and weather conditions.

Peak wheel horsepower would be useful, but repeatability may matter more. A machine that produces one large number and then pulls power as temperatures climb may feel very different during a long dune run than one that repeats nearly the same result.

What Buyers Can Say Without Overreaching

Four statements are supported today:

• Polaris advertises 275 hp for the RZR Pro R Boost at 7,000 rpm.
• Kawasaki advertises 250 hp for the TERYX H2 at 9,000 rpm under ISO 4106.
• Polaris’s published number is 25 hp higher, but its public materials reviewed by SXS Nation do not identify a directly comparable test standard.
• No independent same-standard engine test or controlled same-dyno wheel-horsepower comparison has established the real gap.

That does not take anything away from the Boost. Polaris has paired its higher published output with lower-rpm torque, major cooling changes, and a reinforced driveline. It also does not make Kawasaki’s 250-hp figure fake. ISO 4106 is a legitimate net engine-power standard, and Kawasaki deserves credit for placing the qualification where buyers can see it.

The problem is not that either number has been disproved. The problem is that the industry is asking riders to rank two machines without giving them the same ruler.

Until equivalent test data arrives, treat 275 and 250 as manufacturer claims produced with incompletely disclosed methods. For a deposit, a race build, or simple bragging rights, the better questions are how much power reaches the ground, where it appears in the rpm range, how consistently the machine repeats it under heat, and what the chassis does with it.

Sources

1. Kawasaki Motors Corp., U.S.A. — “2027 TERYX H2” product page — update date not stated; accessed August 11, 2026 — Direct URL — Confirmed the 250-hp claim, ISO 4106 disclaimer, model identity and starting MSRP.
2. Kawasaki Motors Corp., U.S.A. — “2027 TERYX H2 Specifications” — model year 2027; accessed August 11, 2026 — Specification sheet — Confirmed 250 hp at 9,000 rpm, 146.3 lb-ft at 8,800 rpm, the 999cc supercharged inline-four and 9,500-rpm redline.
3. Polaris — “Polaris Introduces Breakthrough Power, Innovation and Value across 2027 Off-Road Lineup” — August 3, 2026 — Launch release — Confirmed the official 275-hp claim, 2.0-liter turbo engine, drivetrain changes, $49,999 starting MSRP and November 2026 dealer-shipment timing; no horsepower test standard is identified in the release.
4. Polaris — “2027 RZR Pro R Boost” — update date not stated; accessed August 11, 2026 — Product page — Confirmed 275 hp at 7,000 rpm and 215 lb-ft at 4,000 rpm; no SAE, ISO or other horsepower test code is identified on the reviewed page.
5. International Organization for Standardization — “ISO 4106:2012, Motorcycles — Engine test code — Net power” — June 2012; withdrawn March 12, 2026 — ISO standard record — Confirmed the standard’s purpose, scope, net-power focus and replacement by the 2026 edition.
6. ISO 4106:2012 standard preview — “Motorcycles — Engine test code — Net power” — June 1, 2012 — Public preview PDF — Confirmed crankshaft/equivalent measurement location, reference atmospheric conditions, listed auxiliaries, full-load test setup and treatment of intake, exhaust, cooling, generator and charge-air equipment.
7. International Organization for Standardization — “ISO 4106:2026, Motorcycles — Engine test code — Net power” — March 12, 2026 — Current ISO standard record — Confirmed publication of Edition 5 and withdrawal/replacement of ISO 4106:2012.
8. SAE International — “SAE J1349_202511, Engine Power Test Code — Spark Ignition and Compression Ignition — As Installed Net Power and Torque Rating” — November 19, 2025 — SAE standard record — Confirmed the current standard title, revision date, net-rating purpose and stated focus on repeatable, typical in-service engine performance.
9. Vehicle Certification Agency — “SAE J1349 Certified Power” — update date not stated; accessed August 11, 2026 — VCA explainer — Confirmed the distinction between an SAE J1349 net rating and witnessed SAE power certification under J2723.
10. Dynojet Research — “Enhanced Dynojet RunViewer User Guide” — August 29, 2003 — User guide PDF — Confirmed that dyno results can be displayed with SAE, DIN, EEC, JIS, STD or uncorrected correction settings, supporting the need to publish the correction method.
11. UTV Guide — Jon Crowley, “2027 Polaris RZR Pro R Boost First Look: Polaris Raises the Horsepower Bar” — August 3, 2026 — Article — Reported the Polaris technical-briefing figure of 223 lb-ft at 6,000 rpm and approximately 215 lb-ft at 4,000 rpm.
12. Car and Driver — David Beard, “The 2027 Polaris RZR Pro R Boost Is the Most Powerful Side-by-Side” — August 3, 2026 — Article — Independently reported the same 223-lb-ft-at-6,000-rpm briefing figure and lower-rpm torque context.
13. SXS Nation — “275 HP Isn’t an Automatic Win in the New Sport UTV Battle” — August 7, 2026 — Article — Confirmed existing comparison coverage, overlap risk and the opportunity for a narrower measurement-standards investigation.
14. SXS Nation — “7 Secrets Of The Polaris RZR Pro R Boost” — August 4, 2026 — Article — Confirmed existing Boost specifications, sourcing and internal-link context.
15. SXS Nation — “New Kawasaki 250 HP 200 Pound Lighter Two Seater” — August 7, 2026 — Article — Confirmed existing two-seat TERYX H2 coverage, ISO disclosure language and internal-link context.
16. SXS Nation — “Supercharged, Turbo, or Big NA? 2026’s SxS Power War” — publication date not displayed; accessed August 11, 2026 — Article — Confirmed that SXS Nation had previously introduced the ISO-versus-SAE issue but had not performed the detailed standards audit in this article.