Upping Performance and Reliability
Trevor Cuthbert treats his Td5 engine to a hybrid turbocharger and a warp-resistant exhaust manifold system TIME 4 HOURS COST £1470
Trevor Cuthbert treats his Td5 to a hybrid turbo and warp-resistant exhaust manifold
The work that I have been carrying out on my 15-yearold Discovery 2 Td5 has all been geared towards preserving and protecting the truck from corrosion, making it competent for 21st century motoring and for longterm reliability.
The repair and galvanising of the chassis, and other steel components, will minimise rust attack – thus addressing the corrosion issue head on. This month’s work will bring performance up to modern standards and further increase reliability.
The new turbocharger that I will be fitting is certainly going to improve reliability and also increase the performance of the Discovery on the road. Likewise the replacement exhaust manifold will primarily help reliability by dealing with a common fault that can develop. But the new manifold that I have chosen will also improve the driveability of the vehicle, in conjunction with the new turbocharger and a number of other upgrades.
Manifold upgrade It’s common for the Td5’s cast exhaust manifold to warp and to pull out one or more of the mounting studs from the cylinder head – sometimes the studs may fracture. Temperatures are intense in the limited space that the exhaust manifold occupies between the cylinder head and the turbo charger. However, Allisport Ltd has developed an improved cast exhaust manifold with thicker flanges and stronger walls, coupled with an improved internal gas flow path. The company says that the manifold will not warp, and that it improves driveability and throttle response due to better gas flow.
Hybrid turbo This Discovery’s original turbo had developed problems with the waste gate actuator, and there was excess play within the turbo impeller. I’ve had a nasty experience of a turbocharger failing on a Td5 engine, followed by the dreaded engine “runaway”, where the engine is fuelled by its own oil via the failed turbo and runs at high revs until destruction. So I decided to replace the turbo with a recent addition to the Allisport range: a hybrid turbocharger which is a direct bolt-in replacement for the standard turbo. The hybrid turbo should be fitted with an upgraded intercooler, and I’ll be installing an Allisport intercooler before the Discovery goes on the road – more of that later.
The improvements, which these and other upgrades impart on the finished Discovery will be reported on in a future issue. For now, here is how they were fitted to the Td5 engine.