I have this document on my PC. Unfortunately there are no pictures. From memory I saved it from a now unmaintained Polo website that looked to be someone's personal site. I am not the author. All credit goes to the author, whomever he/she may be.
----------------------------------------------------
Boost return removal modification for Polo G40
What you will need to carry out this mod:-
1 metre of hose 1" in diameter. B&Q sell pond hose in this size.
A bottle of your choice – 1 litre Coke bottle will do.
Some spare bolts to block up the vacuum lines.
Some metal sheeting if you don’t want twin induction kits.
Blue Hylomar sealant or equivalent.
If you want twin induction kits then you need an inlet collar, a 2nd induction kit and 3" hosing.
Spray grease to lubricate the charger periodically – PSD sell this.
Step 1: Removing Charcoal Canister and Purge Valve (aka ‘flying saucer’).
Firstly, remove the airbox from the car (obviously, if you have an induction kit instead, just remove that or move it out of the way as necessary) After unclipping the top, remove the filter and remove the 3 nuts holding it in place. Slacken off the jubilee clip on the charger intake hose connected to the airbox lid and slide it off. Remove the airbox from the engine bay – remember to block up the pipe going to the supercharger to stop anything getting into it – I used some kitchen roll. You will now see 2 pipes which are connected to the charcoal canister. (The charcoal canister is located in the hole at the bottom of the pic below – I removed it before I took this pic however!) Remove the charcoal canister by removing the 2 bolts holding it in place, then slide the 2 pipes off.
Below is the charcoal canister after removal:-
The next step is to remove the purge valve (some people refer to this as the ‘flying saucer’). This can be seen in the picture below:-
The small vacuum pipe to the top of the valve goes to the throttle body, simply bung it up with a small screw or bolt as close to the throttle body as possible. The pipe from the bottom of the valve goes to the inlet manifold, bung that up with a screw/bolt as well. Smear both screws with a little silicone before screwing them into the pipes to ensure that both are airtight. The other pipe used to go to the charcoal canister so that can be discarded along with the purge valve.
The only pipe to leave unblocked is the clear plastic pipe that comes from under the car that used to connect to the charcoal canister. This is the fuel tank breather and needs to breathe.
Step 2: Removing the Boost Return hose and one-way breather valve.
Remove the boost return hose from the throttle body and rocker cover, then remove the black plastic mushroom shaped one-way breather valve at the other end of the hose. This valve is located under the inlet manifold at the back of the engine block. It just clips onto the metal breather pod which is pushed into the back of the block.
Removing the boost return hose from the throttle body to the rocker cover:-
One way valve located below the inlet manifold:-
One way valve removed from the outlet pipe. Note the clip on the right hand side that clips it onto the pipe:-
Once you've removed this valve you'll be left with an outlet sticking up from the breather pod:-
Fit the end of the 1" hose you've bought over this breather dome's outlet pipe and route it to where your catch tank will be:-
Step 3: Fitting the catch tank.
Drill/pierce several holes in the neck of the bottle – these holes will allow the vapours to vent from the catch tank.
Decide where you want to keep the bottle in the engine bay (the bottle will be your catch tank) and secure it to ensure it won’t foul any other engine parts.
Making sure the hose doesn't kink, route the hose to your catch tank and shorten the hose to the required length. Slide the hose into the top of the bottle and secure it using Duct tape or cable ties etc.
Step 4: Fitting the Supercharger blanking plate.
Remove the boost return hose that runs between the rocker cover and the supercharger. The hole that is left in the rocker cover does not need to be blocked up as it is simply a straight-through bypass tunnel.
The final step is to cut the metal sheet to the required size to cover the inlet on the supercharger, then mark out and drill holes for the bolts. You should be left with something like this:-
Smear some of the Blue Hylomar sealant onto the plate and bolt it in place. Obviously, if you opt for twin induction kits you would fit the second kit onto the supercharger instead of making a blanking plate.
Blanking plate secured in place on 2nd supercharger inlet:-
All you need to do now is refit the airbox/induction kit and you’re ready to go!
Step 5: Maintenance.
Periodically, you will need to lubricate the supercharger to ensure smooth running and avoid killing it! Pitstop Developments sell spray grease that is perfect for this task. Some people have stated they do this every 500 miles, and others every 1000 miles. I don’t do much mileage so will probably just do this once every month instead.
To lubricate the charger, take off your blanking plate then start the car, hold the revs at around 2k and spray the grease into the charger for 10 seconds. Refit the blanking plate, resealing with gasket sealant if necessary.
