Exhaust System Resonator Specification Example for City Buses: Vented Design
Exhaust System Resonator Specification Example for City Buses: Vented Design
This is a worked specification for exhaust system resonator in a vented design programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The vented design version exists because the duty cycle on city buses is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually packing that arrived crushed at the port.
Example specification
| Item | Exhaust System Resonator |
|---|---|
| Application | City Buses |
| Version | Vented Design |
| Base material | Forged Aluminium |
| Controlled dimensions | 4 key dimensions, recorded per lot |
| Tolerance band | ±0.05 mm |
| Finish | zinc plated |
| MOQ | 1,000 pieces per specification |
| Sampling | 10 working days, 3 days per revision |
| Compliance | REACH |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Forged Aluminium, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.
Processes involved
- anodising
- powder coating
- cold forging
- rubber vulcanisation
- die casting
- heat treatment
Where this example applies
Programmes that run vented design most often specify this build for city buses. Related applications include export programmes, three-wheelers, passenger cars, racing teams, off-road bikes.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 4.0 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
Can the specification be held on file?
Yes. Once approved, the specification is recorded against your part number so a reorder reproduces the REACH-compliant build instead of a fresh interpretation.
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
Can you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
How long does sampling take?
Samples leave the factory in 10 working days, and each revision round adds about 3 days once you have seen the first piece.
Send the specification you are working to and we will confirm what we can match, what we would change and why.
