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Title / Demonstrate knowledge of exhaust system tuning for performance and noise in competition race vehicles
Level / 5 / Credits / 4
Purpose / This theory-based unit standard is for people who work in a motorsport environment. People credited with this unit standard are able to demonstrate knowledge of performance exhaust system considerations and features, and determine exhaust system tuning requirements for performance and noise to suit particular competition race vehicles.
Classification / Motor Industry > Automotive Fuel Systems and Exhaust
Available grade / Achieved
Guidance Information
1Publications relevant to this unit standard include but are not limited to – MotorSport New Zealand regulations, New Zealand MotorSport Manual No 33.
2The MotorSport New Zealand regulations (motorsport regulations) and the New Zealand MotorSport Manual (motorsport manual) are available from the MotorSport New Zealand website The Motorsport Manual is subject to frequent amendment, and any amendments will take precedence for assessment purposes, pending the review of this unit standard.
3Definitions
Company requirements refer to instructions to staff on policy and procedures which are documented in memo or manual format and are available in the workplace. These requirements include but are not limited to – company specifications and procedures, work instructions, manufacturer specifications, product quality specifications, and legislative requirements.
Service information may include but is not limited to – technical information ofa vehicle, machine, or product detailing operation; installation and servicing procedures; manufacturer instructions and specifications; technical terms and descriptions; and detailed illustrations. This can be accessed in hard copy or electronic format and is normally sourced from the manufacturer.
Header is another name for a manifold, and specifically refers to an enhanced manifold that has been designed for performance.
Crossovers refer to a tangentially Siamese crossover junction to synchronize exhaust pulses on a vee-type engine.
Header-back refers to the portion of the exhaust system from the outlet of the header to the final vent to open air – everything from the header back. Header-back systems are generally produced as aftermarket performance systems for vehicles without turbochargers.
Turbo-back refers to the portion of the exhaust system from the outlet of a turbocharger to the final vent to open air.
Cat-back refers to the portion of the exhaust system from the outlet of the catalytic converter to the final vent to open air. This generally includes the pipe from the converter to the muffler, the muffler itself, and the final length of pipe to open air.
Outcomes and performance criteria
Outcome 1
Demonstrate knowledge of performance exhaust system considerations and features.
Performance criteria
1.1Motorsport requirements relating to the exhaust system of a competition race vehicle are explained in accordance with motorsport regulations.
Rangenoise level, mounting, gas leakage, isolation, outlet position and protrusion.
1.2Performance exhaust system considerations are identified in accordance with company requirements.
Rangeincludes but is not limited to – performance, appearance, sound, durability, economy.
1.3Performance system features are described in accordance with service information.
Rangeincludes but is not limited to – material, exhaust gas flow, diameter, appearance, sound absorption.
1.4Types of exhaust system kits are described in accordance with service information.
Rangeincludes but is not limited to – down-swept and up-swept manifold (header or extractor), pipes, crossovers and balance pipes, mufflers (sound rated), accessories (collection reducers, splitters, downturns, tips);
header-back kit, turbo-back kit, cat-back kit.
1.5The purposes of mandrel bending, slip-fit joints, and flange joints are identified in accordance with service information.
Outcome 2
Determine exhaust system tuning requirements for performance and noise to suit particular competition race vehicles.
Performance criteria
2.1The importance of gas velocity and uninterrupted flow as factors in the tuning of exhausts are explained in accordance with service information.
2.2The requirements of muffler and balance and cross-pipe design to tune sound waves and reduce resonance to meet event requirements are explained in accordance with service information.
2.3How exhaust system tuning affects combustion chamber scavenging, exhaust pressure, and the incoming fuel-air mixture is explained in accordance with service information.
2.4The use of a dynamometer to test engine torque and exhaust noise changes using combinations of components in the exhaust system is explained in accordance with company requirements.
2.5The importance of matching exhaust system specifications to engine requirements is explained in accordance with company requirements.
2.6The use of a flow bench to test muffler flow rates is explained in accordance with company requirements.
This unit standard is expiring. Assessment against the standard must take place by the last date for assessment set out below.
Status information and last date for assessment for superseded versions
Process / Version / Date / Last Date for AssessmentRegistration / 1 / 25 June 2007 / 31 December 2020
Review / 2 / 26 April 2018 / 31 December 2020
Consent and Moderation Requirements (CMR) reference / 0014
This CMR can be accessed at
MITO New Zealand IncorporatedSSB Code 101542 / New Zealand Qualifications Authority 2018