Engine modifications are the single most important category to get right when declaring car changes to your insurer. They are the most common category of undisclosed modification, and the most common reason specialist claims are disputed. The right approach — full, documented disclosure — costs slightly more upfront but eliminates the risk of a six-figure claim being rejected over an undisclosed camshaft.

What Counts as an Engine Modification?

Any change to the engine from factory specification is an engine modification. This is broader than many owners realise:

• Performance air intake or induction kit (including drop-in panel filter upgrades)
• Performance exhaust (headers, cat-back, downpipe, race pipe)
• ECU tune or remap
• Camshaft changes (bigger cams, different timing)
• Cylinder head work (ported and polished, bigger valves)
• Forced induction (turbocharger or supercharger — factory or aftermarket)
• Larger injectors or fuel pump
• Upgraded intercooler or charge cooler
• Nitrous oxide system
• Short-runner intake manifold or plenum swap

How to Document Engine Modifications

The more documentation you provide, the stronger your position at claim time:

1. Photographs: engine bay before and after each modification; label each component in photos
2. Receipts: parts receipts and installation invoices for all modifications
3. Dyno sheet: before/after power and torque figures with the dyno operator’s details
4. Build sheet: a written summary of all modifications with dates, part numbers, and installer details

How to Tell Your Insurer

Contact your insurer (or broker) directly — don’t wait for renewal. Provide the modification list in writing. Most specialist insurers can process a mid-term endorsement within 48 hours. You may pay an additional premium; you may also need to provide photos or a dyno sheet.

What Happens If You Don’t Declare?

At claim time, an assessor will inspect the car. Engine modifications are visible and impossible to hide. If undisclosed mods are found:

• The insurer can void the policy from its inception date
• You receive no payout
• Any third-party liability costs may be pursued against you personally
• The insurer may report the non-disclosure to CIBIL/CUE (the claims database), affecting future insurance ability