Guys, I'm over here in the states where the Astras only come w/ one engine option, the Z18XER. This is the 1.8 Variable Valve Timing engine w/ 138 hp and it's very slow.
Now keep in mind there is absolutely no aftermarket support for this vehicle in the USA.
I tried for MONTHS to purchase parts and software for this motor from Dbilas and Regal and I got absolutely no where but another member of our US forum made some progress.
He had already gotten a cat back exhaust as well as a nice intake system and he had his base dyno numbers. (around 124 hp I believe)
He then managed to purchase a car tuning software system (I forget the name) and he had a custom electrical cord built so he could access the Astra's computer. He also had purchased a Dbilas plenum intake that was suppossed to be good for significant hp improvements.
Well first he found out when he went to reprogram the car that: 1) the stock air/ fuel mixture was quite good and there was no improvement to be had there and 2) as soon as he tried to advance the timing the engine pinged due to the 10.5:1 compression and furthermore 3) the Dbilas intake LOST around 10 hp and 10 lbs torque on the dyno.
Furthermore the Dbilas intake caused a cel because it has no provisions for the 'intake control valve'. To top it off Dbilas will not take his calls for technical assistance or possibly a refund.
He tried to order cams from Dbilas but they don't actually exist even though they show them on the website. So he looked into making his own cams but then found that it was cost prohibitive as he would need to make custom lifters as well.
We have one American that succesfully added his own turbo to his Astra and even though he is only boosting 5 psi the clutch can't even hold that and it slips badly.
So here we are in America and we are reaching the conclusion that it's basically impossible to modify the Z18XER engine for more hp at a reasonable cost.
Has anyone been able to successfully modify this engine? What did it take? Please be very specific.
~thanks and take care~