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What is a Z20LEx engine?
This refers to the 2.0 Turbo engines (Z20LET/Z20LEL/Z20LER/Z20LEH) used in Astra G, Astra H, Zafira A, Zafira B and VX220 including VXR models.
The first development was the Z20LET engine fitted to Astra G, Zafira A and VX220. Z20LEL and Z20LER engines were fitted to Astra H and Zafria B (and the Z20LER made its way into the Lotus Europa) and were basically the same as a Z20LET engine but with different Bosch management. The Z20LEH engine is that used in Astra H and Zafira B VXR models, and features under piston cooling.
For all 2.0 Turbo Z20LEx engines we are able to offer a range of upgrades to comfortable take power above the magic 300 bhp mark. We can supply all the required items for an engine build, cast exhaust manifold to accept a Garrett turbo, 76mm downpipe and we even offer bespoke conversions supplied, fitted and mapped.
For any set up a big intercooler with good cooling and flow capabilities, a 76mm/3" free flowing sports exhaust and uprated fuel pump are mandatory. We can then advise on injector requirements and mapping as required. For tuning requirements above the 350bhp mark a replacement inlet manifold will be needed as the OE manifold does not allow enough flow and becomes a bottleneck, although we recommend our high flow inlet manifold is fitted to any car wanting to achieve over 300bhp. Our uprated Courtenay-Klasen high flow inlet manifold has been tested with excellent results and shows great top end power improvements without any loss of mid range torque.
For anyone who has undertaken their own build or conversion, we can bespoke map the ecu and carry out a full set up and map optimisation on our rolling road.
For significant gains in performance above the OE Z20LEH K04 exhaust manifold for those wishing to fit a Garrett turbo, this new cast manifold offers an ideal solution. Developed in conjunction with our German Tuning partner Klasen Motors, this manifold offers the OE durability of a cast manifold, unlike stainless steel tubular manifolds which are prone to cracking, has a high quality finish, is manufactured from high quality materials and has been flow tested to 600bhp, although Stephan has produced a 689PS conversion with the manifold. Features a TiAL V-Band mounting flange for any suitable turbocharger plus external wastegate, again on a TiAL V-Band flange. This can be capped if an internal wastegate option is required.
The V-Band flange provides better security of the turbocharger to the manifold, and is less prone to backing off unlike traditional 4 bolt garrett flanges, and also allows for the retention of the air conditioning system.
Garrett installation kit with tubular V band manifold (supplied without turbocharger)
As part of any Garrett conversion, for reliability and durability engine internal strengthening is required.
Z20LEH engines have strong pistons which are good for around 500bhp. Above 320bhp we recommend fitting steel rods.
The Z20LET/Z20LEL and Z20LER engines require stronger pistons when exceeding 310-320 bhp so a full engine rebuild is required using forged pistons and steel rods.
We can offer everything from parts supply, to a full engine rebuild. Pricing up of an engine build is again carried out for each individual customer and will vary according to requirements as well as current age and mileage of the engine we are being asked to work on.
Pricing up an engine rebuild is done on an individual basis depending upon what is required.
Supply and fit steel rods to Z20LEH engine from £1450 inc new big end bearings, gaskets, head bolts and oil and filter change.
To carry out a suitable rebuild on a low mileage Z20LEH engine prices will begin at £1760
To carry out a full strip down and rebuild on a Z20LEx engine including removal from and refitting into the engine bay prices start from £3750 - £5000
To carry out a full rebuild on a Z20LEx (non LEH engine) already removed from the car prices start from £2500
Additional Head Work and suitable high lift cams can also be specified depending upon individual engine build requirements.
Our recommendations for achieving the best power:
A Full 76mm turbo back exhaust system
A large full height intercooler for Astra/Zafira or extra large charge cooler system for VX220/Speedster
Minimum 80mm Air Flow Meter where not already fitted. A 90 or 100mm Air Flow Meter may be required depending on power requirements
High Flow Injectors to suit the type of conversion being carried out (fitted at time of mapping)
Uprated Fuel Pump, Replacement Map Sensor
Uprated Clutch Assembly and Replacement Flywheel
Our high flow inlet manifold and enlarged high flow plenum.
Head rework and high lift cams can be specified depending upon the conversion and required power.