Just found this on the Courtenay website, it is concerning the fitment of the VXR turbo and thier warranty, but if you read it it also tells you how to avoid the pitfalls of changing the turbo and how to prevent premature failure:
Warranty Information regarding the VXR (Z20LEH) Turbocharger.
Unlike some UK suppliers of this item, we are able to offer a 12 month, 12,000 mile warranty providing the following conditions are met and our recommended installation procedure is followed:
1 - The turbo must either be installed by Courtenay Sport Ltd or a recognised VAT registered garage. In the event of a potential warranty claim we will require evidence of this.
2 - The oil and oil filter must be changed at the time of installation. A 10w-40 FULLY synthetic oil of API SL classification or greater must be used. (The 5w-30 oil is too thin for this turbo unit and can cause smoking on idle)
3 - The turbo must be fully primed prior to the engine being fired up.
4 - Oil feed and return pipes must be checked for blockages.
The reasons why we stipulate the above during turbo install are because we have fitted over 100 units on our premises and have never had a unit fail, however we are seeing a number of claims from turbos supplied by us but fitted by third parties, sometimes at home on the drive, where the report back on the 'failed' unit is due to cleanliness of installation. Cleanliness is imperative to the installation of the turbo, which spins in excess of 160,000 rpm, and any dirt (including dirty oil) is a cause of turbo failure.
Turbocharger Installation Instructions.
1 - Check there is no foreign material in the compressor inlet, air intake or exhaust manifold. Even small objects can cause extensive damage to the compressor wheels.
2 - Avoid getting dirt into the turbo when installing.
3 - Install with a new exhaust manifold gasket.
4 - Ensure the turbo is securely mounted before making any rigid connections.
5 - Check oil feed and return pipes for kinks, blockages, restriction or any signs of deterioration. Replace with new if in doubt of their condition. Any oil starvation will be fatal to the turbocharger.
6 - Check and breather systems are not blocked.
7 - Use new gaskets where needed. Do NOT use any exhaust sealant compound on the turbo inlet flange or any form of instant gasket on the oil inlet or outlet unions.
8 - Change oil and filter. Courtenay Sport Ltd recommend a Fully Synthetic oil with an API rating of SL and viscosity of 10w-40. Do not mix with normal mineral oil. If in any doubt please contact us.
9 - Prime the turbo with oil. Prime the new oil filter. This is essential to prevent initial oil starvation to the turbo bearings inside the turbocharger. Crank the engine without firing with the return disconnected until oil runs from the oil return (it is suggested to place a clear bag over the oil return to catch the oil). Connect the oil return and then crank over for another short period to ensure turbo is fully primed prior to firing up.
10 - Once everything is fully installed start the engine and allow to idle for 5 minutes without revving it before running at high speeds.
Always ensure that for maximum turbo life the engine has regular oil changes (using the oil we recommend, and we suggest every 5,000 miles/6 months whichever occurs first) and the correct start up/hot stop procedure is adhered to.
Please Note: Failure to follow our suggested instructions can result in premature turbocharger failure and warranty denial.