Porsche 356b super 90 vs Porsche 911: reliability comparison
MOT pass rates, common faults and mileage compared from real UK MOT data.
Porsche 356b super 90
82%
MOT pass rate · 1 vehicles
Porsche 911
85%
MOT pass rate · 74,656 vehicles
Verdict: On MOT pass rate the Porsche 356b super 90 (82%) and Porsche 911 (85%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.
Head to head
| Measure | Porsche 356b super 90 | Porsche 911 |
|---|---|---|
| MOT pass rate | 82% | 85% ✓ |
| MOT failure rate | 18% | 15% ✓ |
| Faults & advisories per test | 0.5 ✓ | 1.1 |
| Dangerous-fault share | 0% ✓ | 1% |
| Average mileage | 10,740 mi | 70,982 mi |
| Sample size (vehicles) | 1 | 74,656 |
Most common faults
Porsche 356b super 90
- Offside Stop lamp not working (1.2.1b)
- Nearside Direction indicators not working (1.4.A.2c)
- Nearside Stop lamp not working (1.2.1b)
- Offside Direction indicators not working (1.4.A.2c)
- Offside Steering system has a road wheel fouling a part of the vehicle (2.2.D.2a)
- Nearside Registration plate lamp not working (1.1.C.1d)
Porsche 911
- Nearside Rear Tyre worn close to the legal limit (4.1.E.1)
- Offside Rear Tyre worn close to the legal limit (4.1.E.1)
- Under-trays fitted obscuring some underside components
- Nearside Front Tyre worn close to the legal limit (4.1.E.1)
- Offside Front Tyre worn close to the legal limit (4.1.E.1)
- Oil leak, but not excessive (8.4.1 (a) (i))
Reliability FAQ
On MOT pass rate the Porsche 356b super 90 (82%) and Porsche 911 (85%) are very close — weigh the individual measures below, and remember condition depends on age, mileage and upkeep.
Full Porsche 356b super 90 report Full Porsche 911 report Most reliable cars
Pass rates are computed over completed (pass/fail) MOT tests. Reliability also depends on age, mileage and upkeep — see each model's page for the full picture.