Supercharger Fitting Guide Astra G


Stupid Bollocks
here is a brief guide to fitting a supercharger to an astra g

part required for a standard fit (stage 1)
  • supercharger
  • inlet manifold
  • manifold bracket
  • z20let injectors
  • 2bar map sensor (courtney sport)
  • bosch injector plugs
  • K'n'N filter
  • LSJ throttle body (optional)
  • belt pulley and bracket (courtney sport)
  • Manifold Gasket z20net (vauxhall)
  • various nuts bolts
  • wire for extending the loom
you will most likelly be supplyed the parts in the pic when importing a charger kit

when fitting the inlet manifold and supercharger there are many parts that need removing
  • battery
  • battery tray
  • air box
  • inlet pipe
  • fuel lines
  • fuel rail + injectors
  • inlet manifold
  • ecu + loom
once all the above is removed it should look similar to this

i pre made the injector plugs up with some wire ready for extending the main loom they were color coded to match the main loom but you can use what ever color just be sure to label them up with a pen and masking tape

the alternator will need the rear cover removing and one bolt cutting off short then also to fit a suppressor
you can get one from a scrappy off the rear of a z22se then just drill the hole out to fit the bolt the wire end of the suppressor will need to be earthed on the top screw
there is no difference in size on the 100 amp vs 120 amp (100 amp without heated seats) (120 amp fitted to most 2003 onwards)

here you can see the wire from the suppressor going to earth and the front bolt cut to make sure it won't short on the manifold
top tip: when fitting the alternator use 4 x M10 nuts on the block side to bring the alternators position further out :)

now back to the install
1st fit the lower manifold bracket
you will need some longer M8 bolts and be sure to refit the earth tags to the bolts

A/C pump
if your keeping the A/C this next step will need to be done if you're not keeping the A/C you can move on to the next bit :)
here you can see the a/c pump has been moved out on some collars i made up
the issue with keeping the A/C is the pipe is a right funny shape and always in the way
i removed the top plastic support from the radiator fan case and then bent the a/c pipe over and down to miss the inlet manifold be sure to do this slow you dont want to kink or crack the pipe
and with the extra collars i had to make new longer bolts from all thread bar and some nuts

right so now the A/C pump is dealt with or not :)
you can fit the inlet manifold with the alternator not fitted
the 2 M6 manifold studs will need to be removed to get the inlet down into place
new M6 pins and washers will need to be used when fitting the inlet as there a different length
dont forget to install the lower bracket bolt to support the weight of the inlet and charger

next step is to fit the z20let injectors in the z22se fuel rail
top tip: use bum lube (aka vaseline) on the injector O rings to aid there fitment
use the z22se injector clips to hold the z20let injectors in to the rail
heres a pic of before the swap (upper z22se lower z20let)

install the wire extensions and plugs to the rail and injectors then fit the rail to the engine the plastic of the plug on injector #3 is close to the manifold but will sit fine once installedthe new map sensor and the fuel vent wiring will also need to be extended to where ever you move the ecu to

now fit the alternator with the M10 nuts on the block and the longer bolts and belt bracket from CS
dont forget to fit the battery power cable and the plug to the alternator
for use with out A/C the bracket can stay as it is for use with A/C you will need to add a 2nd idler pulley to drive the alternator

without the 2nd idler when keeping the A/C the belt won't touch the alternator pulley so you need to source a z22se tensioner and use the pulley from it to push the belt back on to the alternator

using the slot in the CS bracket some washers and a nylock nut i was able to make the 2nd pulley system work giving the alternator drive
top tip: be creative :) the bolt in the top pulley came from the pulley fitted to the stock USA bracket :)

fitting the new map sensor requires some tape putting on the stub then the rubber fitting over the tape as the hole in the manifold is too big without the tape
the metal bracket from the map sensor on the supercharger can be used to hold the new map sensor in place
fit the supercharger gasket then lower the supercharger on to the manifold it will take a few tries to get it in but it will fit :) the front bolts on the charger are a right pain to fit i swapped the cap head bolts for som M8 bolt then used a small socket set with the universal joint to tighten the front bolts up

the top coolant hose was taken from a vectra C z22se it comes with a plastic tee the tee was squished in a vice to remove the metal band leaving the pipe free for me to use
top tip : be creative :)

the fuel line over the charger will need to be bent to miss the charger some people cut the pipe and use rubber fuel line and 2 jubilee clips at the ends of the rubber i wanted to try and keep it oem looking :)
the air filter is a halfords special £22 ripspeed
the rocker cover breather is just vented to atmosphere atm will be fitting it to the air filter at some point
the battery location most fit it in the boot but with the hole OEM look i wanted it up front
had to get a smaller size battery and modify the tray some

when getting your belt it's easy to just get a length of string wrap it round the pulleys tie it off then measure the string then go and buy the closet belt to the measurement mine was 5pk 1453 but i ended up using a 5pk 1463

and if your using the LSJ throttle body you will need to swap the wires in the T/B plug to make it work
if your using the z22se T/B all you will require is the adapter plate to make it fit the supercharger


the ecu will need to be sent to CS for supercharger base map to get you running

this is a brief guide to show the basic way to fit the supercharger some parts are not covered but any questions i should beable to answer here
thanks for looking :)


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Stupid Bollocks
understanding the charge cooler dual pass modification

the standard inlet manifold has a built in water to air intake cooling system
it has 1 inlet and 1 outlet in the factory supplied style
top is out bottom is in

the water passes thru the manifold in series and for each time it runs thru a laminova core the cooling efficiency drops as the water temp in the core rises
core pass.jpg

the dual pass mod requires the 2 lower laminova cores to be swapped round in the picture you can see the duel pass end plate this plate uses the middle pipe as input and the to outer pipes as out puts
duel pass.JPG

the dual pass converts the flow into parallel meaning the 2 center cores get the same input temperature water and the to outer cores get less heated before going back for cooling
dual pass.jpg

here is the generic ways to set laminova's up
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Stupid Bollocks
Charge cooler pump and Tank setup

the charge cooler for the inlet manifold runs on a separate system from the engine and requires more parts to work
pump bracket (should come with charger kit)
a header tank 1 x 3/4" outlet and 1x 1/4" inlet the cap should be a pressure relief type
charge cooler radiator with 3/4" hose tails
3/4" pipe and various fittings (tee/elbow/straight)
jubilee clips to suit the 3/4" and 1/4" pipe
a 0.9mm orifice for the bleed tube
ev1 style fuel injector plug to fit bosch pump

heres a pic of the bosch pump fitting in a modified LSJ pump bracket
it sits at the front of the engine block under the inlet manifold

the water loop for the cooling should be set up like the below image
the tank keeps the pump supplied with water the pump then sends the water to the inlet
then on to the radiator for cooling where it then goes back to the pump to complete its circuit
the green 1/4" pipe is to bleed the air from the radiator the pipe has the orifice installed inside to restrict the flow and only a small amount of water thru keeping the rad constantly bled of air
water loop.jpg

the only issue with the above setup is there would be some air trapped in the red pipe at the exit of the inlet i hope to revise this on my install as i will be running the dual pass endplate

the pump should be at the lowest point in the system and the tank in the highest point

if you dont recognize the layout its the same as the engine cooling loop except without the thermostat feeding the radiator :)
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Stupid Bollocks
yeah thats the other way (flow thru) you still get air trapped in the cooler

the expansion tank is the way i will be setting it up as i dont have the engine at the wrong end so no need to run 20ft of pipe to meet the cooler :) and it will be self purging

even the option B setup for the cobalt is different (shows dual pass) and pumps to the rad 1st then inlet but still has the expansion tank on the pump feed to keep constant water supply

heres the standard cobalt loop without duelpass
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the electric coolant pumps will push any air out of the cc system, so there is no need for an air bleed off.

The vx220 set up keeps the cc systems coolant much cooler, it uses the tank as storage for cooled water, otherwise the tank is just there to keep the system full


Stupid Bollocks
the electric coolant pumps will push any air out of the cc system, so there is no need for an air bleed off.
if i hadn't water cooled my pc i would've agreed with that but there is air in all the water blocks sat at the top :) its much easier to turn a pc upside down lol
the air will sit at the top and the water will take the easiest route to the exit leaving reducing efficiency on the rad unless the rad has a bleed screw that can be used

The vx220 setup keeps the cc systems coolant much cooler, it uses the tank as storage for cooled water, otherwise the tank is just there to keep the system full
yep keeping the system full is my goal while getting air out i have no need to have a tank of cooled water the system can only be as efficient as it is the loop with the inlet and rad is all thats required gm has more money to research this than i do :)
have read about more water = cooler but thats just a wrong statement as more water just take longer to get superheated the water will all get to the same temperature eventually


Stupid Bollocks
that is true but theres not a lot of room for movement not sure if the harrop will fit in the astra without more modification
the size difference is huge


Stupid Bollocks
Extension of the loom
now that the supercharger inlet is installed the ecu has no location to bolt to what with there being a supercharger there lol
the ecu will require moving to a location of your choice ether by the headlight,abs pump or where the air box used to be or other
i moved mine over the headlight as i kept the battery in the engine bay
with moving the ecu to any location the are a few wires that will require extending
  • fuel vent
  • map sensor
  • injectors
  • throttle body
there are 2 parts to the engine loom the main engine loom with plugs
part 1
  • lambda 2
  • lambda 1
  • water temp probe
  • suppressor
  • coil pack
  • egr
  • injector 4
  • injector 3
  • x22 pass thru
  • map sensor
  • injector 2
  • throttle body
  • ecu ground
  • knock sensor
  • crank sensor
  • oil pressure switch
  • oil level switch
  • injector 1
  • ecu
  • fuel vent
part 2
  • ecu
  • injector multi plug
  • main engine bay loom
the engine loom will require splitting open (removing tape and split tube) its advisable to mark each plug with masking tape and a pen so you can keep track of what's what

with all the parts in place rfit the loom to the engine then test fit to your location for the ecu

here are the ev1 plugs with wire fitted ready to fit the engine loom (ev1 plugs are used for z20let injectors)

the new wires for the injectors can be made in to a mini loom along with the fuel vent and map sensor
as shown here

once you have ran all the new wires back to you ecu location you can start to cut and solder each wire to the matching wire from the original places
i recommend soldering the joints and using shrink tube over the top of the joint for safe short free joint

here you can see the early testing stages of the wiring before it was all wrapped back up and fitted inside some new 20mm split tube
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Stupid Bollocks
heres a guide to fitted the bung that i sell for the map sensor on the charger
take the bung and some RTV or bearing fit

put a bead round the bottom of the bung

install the bung twisting while going in to spread the sealer

the bung is made to be a interference fit and will require taping home

use a hammer stale to tap it all the way in

wipe any excess off and leave for awhile for the bearing fit or rtv to set

if you ever need to remove the bung you can turn the charger over open the bypass valve then use a long screwdriver or punch to tap it out :)
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Great thread evocarlos, thanks for posting!
I'm looking to get more power out of my Z22SE and someone has pointed me in the direction of fitting a supercharger and I stumbled on your pretty much complete guide!
Hope you don't mind me asking, but ow much did it set you back to buy all the parts but do the work yourself? Courtney Sports are looking at upwards of 6k for the work to be done and to be honest I don't have that kind of cash. Besides, I'd be well willing to out the work in myself.
For the redoing of the wiring looms, do you have any more info/photos as I think this could be am area that would trip me up...
Also how long did it take you to get the work done start to finish? Just thinking if it would be feasible time wise as well.
If you don't mind dropping me a pm, I'd really like to know a bit more about what you did here and all the ins and outs. Any and all build photos would really help, although I understand if you're not keen on sharing private photos etc.
Thanks again for the post and giving me hope of breaking 200bhp with the Ecotec!!!


Senior Member
Does the supressor have to be fitted to the alternator or is it just to cut down on the noise? If so any better pictures to where it is mounted?

Also what length belt is used to keep the air con?


Stupid Bollocks
think its just for noise i fitted one there as the alternator rear cover has one built in so i just put one back in its place
this is the only pic i have of the suppressor you can see its just earthed to one of the mounting screws and then bolted to the +12v of the alternator the suppressor was a z22se one the one thats normally found at the rear of the engine block on the earth strap to coil pack

with a 3.1" pulley im using a p5k 1453-1463


Stupid Bollocks
Cool cheers totally forgot they have one built into the cover, should of known that I had some apart the other day :whistle:

Thanks for belt info (y)
no problem :)
when i 1st got it all setup i put string round the pulleys then measured it with the string folded in half then just doubled the measurement went to the local motor factors and bought 1 above and 1 below the measurement they come in 10mm steps
then after finding after 2-3 weeks of running the belt had bedded in and started to slip so went to the size smaller its not slipped since :)