FAQ

Q: Does the whoosh of a blow-off valve increase performance? A: No, it just sounds impressive as the unwanted boost is vented to the atmosphere. Releasing the boost pressure is essential, especially when the driver lifts off the accelerator pedal. However, instead of venting this pressure to the atmosphere, it can be recirculated into the induction system (between the air filter and the turbo) using a recirculation valve. Q: Can the engine be damaged by too much turbo boost? A: Yes, excessive boost pressure can risk detonation of the pistons, head gasket failure, damage to the main and big end bearings, and increased wear of the engine’s internals. Using a higher octane fuel and lowering the compression ratio of the engine can help to preserve it, although serious amounts of increased turbo boost may demand a complete engine rebuild with uprated internals. Q: Can I legally fit an EGR blanking valve? A: This is a difficult question to answer. We’ve seen vehicles fitted with aftermarket turbos and EGR blanking valves, which have produced less emissions, so they are capable of passing the MOT. However, we asked the DVSA for their response to fitting an EGR blanking valve and they said: “DVSA’S priority is to help you keep your vehicle safe to drive, ensuring that it meets required roadworthiness and environmental standards. Vehicles may fail the MOT where emissions control equipment has been tampered with but irrespective of the MOT such modification is an offence*. DVSA continues to work with DFT to pursue such offences, including taking disciplinary action against any MOT garages found to be conducting modifications.” * Road vehicles (construction and use) regulations (Regulation 61a(3)). Removal of an EGR valve, diesel particulate filter etc, will almost invariably contravene these requirements, making the vehicle illegal for road use. The potential penalties for failing to comply with Regulation 61a are fines of up to £1000 for a car or £2500 for a light goods vehicle.