What this check covers
Selected replacement-engine and performance pathways for supported light passenger and goods vehicles. Electric/hybrid conversions, motorcycles, heavy vehicles and individually constructed vehicles need separate assessment.
The result covers the selected requirements and evidence entered. It does not certify the vehicle or confirm its overall compliance.
What you need
- Vehicle category, GVM, manufacture records and applicable requirements.
- Original and fitted engine identities, including other performance changes.
- Comparable documented manufacturer power figures and the prescribed original reference mass if using the capacity screen.
- Installation, emissions, noise and interacting-system evidence.
Understand the requirements
Identify every engine change
Record original and fitted engine identity separately from ECU, fuel-delivery, internal and forced-induction changes. Same-specification reconditioning and a complete manufacturer optional-engine package have different conditions from a non-original engine installation.
Power and certification pathways
A non-original engine installation needs an LA1/LA2 assessment even where power and mass remain within a 20% increase. Use comparable documented manufacturer standard/optional and replacement figures. Queensland’s selected ECU/fuel-delivery minor pathway also requires continuing emissions compliance; an increase above 20% indicates certification. Other performance changes and forced induction need their applicable LA assessment. A power figure alone cannot establish an exemption.
Capacity is a screening recommendation
Table LA1 uses the prescribed original reference mass, not GVM or the modified vehicle’s current weight. Its factors depend on the mass band and induction type; a rotary’s total swept volume is doubled for the comparison. ADR MC, NA and NB1 are excluded from the table. Being within a recommendation does not establish suitability or permission to fit an engine. A figure above it needs Approved Person/TMR review, with no guarantee of approval.
Emissions and interacting systems
The December 2025 Queensland engine instruction waives NCOP IM240 testing while retaining applicable ADR emissions obligations. Retain the actual emissions-control equipment and supporting compliance basis. Check noise, mounts, clearances, fuel/electrical systems, brake-booster vacuum, driveline and suspension suitability. Structural changes require their additional assessment. Nitrous injection installations, including partial or disconnectable equipment, are not permitted.
This calculator does not verify emissions or noise tests, engineering strength, code eligibility or certificates. Electric/hybrid conversions, motorcycles, trailers, heavy vehicles and individually constructed vehicles need separate assessment.
Worked example
A modest power figure does not decide the pathway
A non-original engine installation still needs its LA1/LA2 assessment even when the documented power and mass changes remain within 20%. Check the actual engine change and all supporting conditions, rather than relying on the percentage alone.
Read this example within the selected scope. The actual installation and supporting evidence determine the finding.
Official sources and review
- Queensland Road Vehicle Modification Handbook
- TMR Minor modifications
- NCOP Section LA — Engine
- TMR Engine modifications — Queensland variation
Sources reviewed 14 October 2026. This check uses the February 2026 Minor modifications guidance and December 2025 engine instruction. Later changes to those instructions have not been confirmed. Confirm current requirements for your vehicle with TMR or an appropriately accredited Approved Person.