Engine family SHSNX.454USV

What this record says

Sold in the US by

Hisun Motors Corp., U.S.A.

Engine built by

Chongqing Huansong

Vehicle category

ATVB & UTV - EPA only

Certificate numbers

SHSNX.454USV-003

What the number itself says

Reading SHSNX.454USV left to right: S is the model-year letter for 2025, HSN is the three-character code the EPA assigned to Hisun Motors Corp., U.S.A. as certificate holder, X marks an off-road certification, .454 is the displacement in litres, so 454cc and USV is Hisun Motors Corp., U.S.A.'s own sequence for that year. Nothing in the number names the factory — that comes from the certificate itself.

The engine, as described on the certificate

The test vehicle Hisun Motors Corp., U.S.A. submitted for this family (model HS450UTV) carried engine code HS183MZ. In the Chinese engine-model convention that reads as one cylinder with a nominal 83 mm bore, MZ series.

The certificate describes a four-stroke, single-cylinder engine with 2 valves per cylinder fed by sequential multi-port fuel injection, with an oxygen sensor for closed-loop fuelling, run by an engine control module (ECM). There is a catalytic converter in the exhaust, recorded as "Three Way Catalyst (TWC), single-bed, closed-loop warm up".

Rated power on the record is 17.2 kW (about 23 hp) at 5,500 rpm, driving through a CVT (belt and variator).

Engine code on test vehicle

HS183MZ

Nominal bore (from the code)

83 mm

Cylinders / valves

1 · 2 per cylinder

Cycle

four-stroke

Fuel delivery

sequential multi-port fuel injection

Oxygen sensor

yes (closed loop)

Engine control

ECM

Catalytic converter

Three Way Catalyst (TWC), single-bed, closed-loop warm up

Rated power

17.2 kW (≈23 hp)

Rated speed

5,500 rpm

Transmission

CVT (belt and variator)

Sales area

50S+49S

Vehicle built by

Chongqing Huansong Science and Technology Industrial Co., Ltd.; Vietnam New Century Industrial Company Limited

Test vehicle model

HS450UTV

Filing history and where it was sold

Hisun Motors Corp., U.S.A. filed one certificate under this family, for model year 2025, sold as both a 50-state and a 49-state version.

The vehicle itself is recorded as built by Chongqing Huansong Science and Technology Industrial Co., Ltd. and Vietnam New Century Industrial Company Limited in China and Vietnam, while the engine came from Chongqing Huansong. Chassis parts and engine parts therefore have different origins.

Certified emission levels: CO 3.3, HC+NOx 0.6 g/km.

Other records carrying the same engine code

Hisun Motors Corp., U.S.A. certified an engine with this code under 15 other family numbers — the same engine filed again in another year, or in an off-road and a street version:

• KHSNX.454ATT (2019)
• KHSNX.454UTV (2019)
• LHSNX.454ATT (2020)
• LHSNX.454UTV (2020)
• MHSNX.454ATT (2021)
• MHSNX.454UTV (2021)
• NHSNX.454ASV (2022)
• NHSNX.454USV (2022)
• PHSNX.454ASV (2023)
• PHSNX.454USV (2023)
• RHSNX.454ASV (2024)
• RHSNX.454USV (2024)
• SHSNX.454ASV (2025)
• THSNX.454ASV (2026)
• THSNX.454USV (2026)

A shared code from the same factory is a strong search lead. From a different factory it is as often a naming coincidence. Either way it narrows the search; it does not settle it — measure before you buy.

Models certified under SHSNX.454USV

Every model designation the importer listed on this certificate. If your machine's model name appears here, this is the right record — even if the name on the bodywork is slightly different.

Axis 400 · Axis 450 · Back40 400 · Back40 450 · Bad Boy 450 · HS400UTV-2 · HS400UTV-3 · HS400UTV-4 · HS400UTV-5 · HS450UTV · RK Performance 400 · RK Performance 450 · Sector 450 · Vector 400 · Vector 450 · Viper 400 · Viper 450

Other American badges on engines from the same factory

• Chongqing Huansong · 250cc4 American brands · 2010–2015
• Chongqing Huansong · 500cc and above4 American brands · 2012–2027
• Chongqing Huansong · 200cc4 American brands · 2009–2026
• Chongqing Huansong · 450cc3 American brands · 2012–2026