How To….. Fit a Z22SE Airbox on a Z20LET Astra-Sport Disclaimer - Please note that this is a guide only and Astra-Sport take NO responsibility for any damaged caused to yourself or vehicle whilst using this guide. If you are unsure how to do something leave it to the professionals. Your Insurance and warranty might be invalidated if this modification is done. Why do this mod? •
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More direct route to the turbo, thus decreasing pressure loss in the inlet and theoretically increasing power. The shorter route increases noise from the turbo making the dump valve more audible. (This is possibly why Vauxhall did not choose this arrangement as standard). The extra noise may or may not be desirable. Less heat soak due to removal of the metal crossover pipe. Theoretically increasing power. Easier to change spark plugs as they are no long obstructed. Tidies up the engine bay.
This mod can be done by either using Samco silicone hoses or standard Z20 LET pipes Procedure - Using Samco Hoses Parts required • • • • •
2.2 Airbox Part Number 9129077, this comes complete with everything you need to fit including a new standard air filter. Retail £48.95 + VAT Silicon hose - AFM to Turbo. 70mm reducing to 63mm through 90 degrees. Samco pt no. RE90.70.63. £19.50+vat. Silicon hose - Airbox to AFM. 70mm to 70mm through 45 degrees. Samco pt no. E45.70. £22.50+vat. Pipercross crank case breather filter pt no. C9025. £19.23+vat. 1m 20mm ID crank case breather pipe.
(Samco hoses can be ordered from Merlin Motorsport on 01249 782101). Prices are correct at time of writing. Thanks to MattS & Mike Warner for the “How To”
Note - Both silicone pipes will need cutting down to suit. The easiest way is by eye, i.e. holding them over the components and marking them up. To cut a straight line, fit a jubilee clip over the pipe and cut along the edge of the clip. 1. Remove the following parts - 2.0 Air Box, Cross over pipe, AMM and all hoses as far as the turbo inlet. Cover the turbo inlet with a cloth to stop anything from falling into it. 2. Fit the 2.2 Airbox - it sits directly onto your existing mountings, taking no more than 5 minutes. However it is worthwhile de-restricting the airbox before it is fitted. 3. Loosely fit the 45 degree hose between the airbox and the AFM, making sure that the AFM is fitted the correct way round and aligned as in the photograph (right). 4. Loosely fit the 90 degree hose between the AFM and airbox 5. Using the other 90degree hose, place the thinner end onto the turbo inlet and the other to the AFM 6. Once you’re happy that everything is lined up correctly, refit your existing jubilee clips and tighten. 7. The AFM wiring will no longer reach the AFM, so this will need to be extended. If you are lucky, your loom may have excess wiring inside the loom tray at the rear of the engine. To check, remove the top of the loom tray along the rear of the cam cover and locate the AFM part of the loom. If there is enough slack to reach the AFM, make a new exit from the loom tray approx 1" from the end and make the existing loom exit here. This should give you enough length of cable to plug straight in. Alternatively, you can simply cut the loom and extend it. Make sure you do one wire at a time so that you eliminate the risk of connecting the wrong wires together, cover all new wiring in black insulating tape. Try and route the wires away from moving and hot parts.
Thanks to MattS & Mike Warner for the “How To”
8. From the back of the cam cover, fit the new breather hose to the breather outlet and at the other end of the hose, fit the Pipercross crankcase filter. This can be positioned wherever you wish – the photo right shows a neat suggested location. Once complete, give the car a test drive. You should notice an increased in induction, turbo spool and dump valve noise. You may also notice that turbo spool-up is quicker and an increase of power. note:: that at the time of writing, we are Please note unsure if venting the crank case fumes to atmosphere would be an MOT failure. If it is, it may be necessary to revert back to standard for your MOT. This is not a problem as it would take no more than 10mins to revert back – just keep all the old bits somewhere safe. Procedure – using standard Z20let pipes Procedure Parts Required • • •
2.2 Airbox Part Number 9129077, this comes complete with everything you need to fit including a new standard air filter. Retail £48.95 + VAT Pipercross crank case breather filter pt no. C9025. £19.23+vat. 1m 20mm ID crank case breather pipe
1. Remove the following parts - 2.0 Airbox, Cross-over pipe, AFM all hoses as far as the turbo. 2. Fit the 2.2 Airbox, as detailed above. 3. Locate the 45° hose, (originally fitted between the 2.0 airbox and AFM) onto the new airbox. As the outlet of the new air box is slight smaller than the old one, you will need to make a small V shaped cut on the bottom lip of the pipe to ensure it clamps up correctly. Thanks to MattS & Mike Warner for the “How To”
4. Insert the AFM - making sure that it is fitted the correct way round and aligned as in the photograph (page1). 5. Using the other 90° hose, place the longer section on the turbo inlet and the other to the AFM 6. Once you’re satisfied that it is all lined up correctly, tighten the jubilee clips. 7. Refer to step 7 above for details of modify in the AFM harness. 8. Refer to step 8 above for details of routing the new breather pipe.
Thanks to MattS & Mike Warner for the “How To”