Technical Information: Product Testing
Two tests are specified for assessing the durability of flexes intended for sale in the Global Aftermarket. One is an axial test (i.e. the flex is extended and compressed along its length, the other is a lateral test (where movement is perpendicular to the length).
These tests are based on the expectations of the OE car exhaust manufacturers.
For different flex lengths, the required displacements are different, reflecting the fact that longer, more flexible exhaust flexes can withstand greater displacements.
The apparatus on which the axial test is performed is shown schematically
For different flex lengths, the required parameters of the test are given in the table below. The required number of cycles to pass is 1,000,000.
| Flex Length | Pivot Length | Displacement (mm) | Offset (mm) |
| 4" | 5" | +0.0 -1.4 | 0 |
| 6" | 7" | +3.0 -3.0 | 0 |
| 8" | 8" | +0.0 -6.7 | 8 |
| 9" | 8" | +0.0 -6.7 | 8 |
| 10" | 15.5" | +5.1 -8.9 | 4.7 |
| 11" | 15.5" | +5.1 -8.9 | 4.7 |
The lateral test set-up is shownin this diagram
The displacements are perpendicular to the flex length. The magnitude of these displacements for different flex lengths are given in the table below. The pass criterion for this test is 300,000 cycles.
| Overall Length | 4" | 6" | 8" | 9" | 10" | 11" |
|---|---|---|---|---|---|---|
| Test Lateral Displacements | ± 4mm | ± 6mm | ± 8mm | ± 9mm | ± 10mm | ± 11mm |
Tested flexes meet the specified durability requirements of the axial and lateral displacement tests.
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