Now in it’s 7th generation the Holden Astra has been reborn a number of times, with each generation building on the previous.
A number of platforms were used over the years, the Nissan Pulsar, the GM Astra was later used then the Opel Astra underpinnings were used for later models meaning you have access to a wide array of parts if you know which platform and engine your Holden Astra is based on.
Some parts from the UK Vauxhall Astra will also fit and work quite well, so look at your import options if you are drawing blanks, the tuning scene in the UK is positively thriving.
You can do a lot to improve the performance of your Astra with our step by step tuning tips. The key to Astra tuning is balancing power and reliability you can waste loads of money if you do it wrong.
Handling modifications are usually your first port of call for the Astra. Drop the car by as much as 35mm and fit motorsport grade stiffer dampers, bigger drops will need other modifications in most instances.
Our aim in Astra engine tuning should be to increase peak power and Torque at the top end.
The best power gains come from larger engine sizes. The more you start with the bigger the return on investment so engine swaps are good value mods for small engined cars.
Engine tuning mods.
The following uprated parts are usually carried out by our members, decide how far you wish to go in your tuning project before you start.
Getting the right modified parts for your planned usage of the car is essential. Stage 3 motor sport mods just won’t work well on the road difficult in stop start traffic.
Stage 1 mods: Panel air filter, Lighter flywheel, Suspension upgrade (drop 30-40mm), Sports exhaust, Alloy wheels, Remap.
Stage 2 mods: high flow fuel injector, Fast road cam, Ported and polished head, Power/Sport clutch, fuel pump upgrades.
Stage 3 mods: Sports gearbox, Adding or upgrading forced induction (turbo/supercharger), Engine balancing, Internal engine upgrades (pistons/head/valves), Competition cam.
Peak power is good on competition cars but for a daily driven car you need a long torque band and perhaps extending the rev range.
The point of our advice is to give a little insight into the world of customizing mods and point you in the right direction, our forum is where you can ask for more detailed advice and tips on your modified car project, the best performance kits and all aspects of modding cars.Fast road cams offer one of the biggest performance gains for your money as far as a bolt on motorsport parts goes on a NASP engine.
It improves the intake and exhaust flow and increases the power if done right. Ideally you’d add other mods and finish up with a remap. TorqueCars would caution you not to go with a motor sport cam as this affects the engines idling and general town driving characteristics.Don’t forget to pay attention to the fuelling when you are increasing the power – it makes the car more thirsty.
Using high octane fuel is another option if you find you are suffering from detonation or premature ignition on your Holden project after fitting other modifications. Uprating the injectors is another beneficial modification and will deliver sufficient fuel. A fuel pump will only deliver a finite amount of fuel, so you may need to uprate this if your injectors are demanding more fuel.
Intake and Exhaust Tuning.
Breathing mods are usually next up. Contrary to popular belief there is often very little if any power gain to be had by fitting an induction kit, they only work well and are recommended after you increase the engines power to the point where the standard air intake box cannot cope! Induction kits can work well on turbo engines and larger engines (if supplied with a suitable cold air feed or air box), generally though we’d just recommend for Astra engines you should settle for a sports panel air filter preferably made from cotton.
Sports exhausts generally help improve air flow from the engine but do not go too big or you may end up will reduce the flow rate. Stick to 1.5 to 2.5 inches as a rule of thumb.
Airflow through the head can be dramatically increased with some professional head porting and polishing. These should match and be setup to take into account any other engine mods. Your clutch can slip as you increase the power if it starts to fail and the standard clutches are only ever good for power gains of up to 48%. Fit a power clutch to avoid power losses through the transmission. Turbo engines are just begging to be Remapped. You will see impressive power gains on most modern turbo engined cars including diesels making a remap one of the most cost effective and impressive modifications for your money.Despite the large cost involved adding forced induction to a NASP engine will give large power gains. Turbos are generally harder to add than a supercharger. Turbos provide boost in exponential proportion to th engine speed and this can make mapping difficult.
Superchargers will give a boost which is proportional to engine speed so is easier to map. To cope with forced induction you will usually need to decrease the engine compression ratio .
Alloy wheel upgrades.
The benefits of alloys include lowering your unsprung weight and more efficient brake cooling via the extra air flow they allow. Large Astra alloy wheels can decrease performance. If you get big alloy wheels you will be changing your final drive ratio.
Although some people have with bigger wheels without problems we would stick to a 16 inch rim size as the maximum.
For more information on Tuning your car please join us in our friendly forum where you can discuss Astra options in more detail with our Astra owners. It would also be worth reading our unbiased Holden tuning articles to get a full grasp of the benefits and drawbacks of each modification.
Please help us improve these tips by sending us your feedback in the comments box below. We love to hear what our visitors have got up to and which mods work best for them on each model of car. Comments are used to improve the accuracy of these articles which are continually updated.
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