"modded" my air intake :)

[astra_city]

Well all I know is, that ever since installing my CDA my car is definitely more responsive and also has more kick to it as well - I have the chance to compare whenever I want to my mums standard Astra :P

Also, speaking of modifications, engineers do a lot of things that can be improved upon. Exhausts are a prime example - yes the manufacturer puts effort into achieving the best balance of power and noise, but it is always a compromise, as they have to sell their cars to a large demographic. I guess there's arguments for and against both

[DoomTrooper]

the stock tube, starts smaller than it ends, therefore the air is more restricted at the entrance to the pipe, i merely made mine straighter and without any size changes hence a faster less restrictive pipe
not to mention the fact that pvc is less heat conductive than the stock pipe therefore the air entering the engine is marginally cooler,

from what i've read the air intake does starve the engine at higher rpm, and i personally have felt the diff between a pod and the stock box and tube and the engine is starved, the fact is that by dropping half a litre per 100km's on the fuel efficiency by sacrificing a few kw is going to improve sales as the majority of astra owners care more about their fuel efficiency than how much power the car has

the car is designed to make money not be efficient

i never once said that cutting it was the way to go

[NUTTTR]

Partially the reason i did cut the bits off was how hot those parts got, they basically sit on the radiator!!! All the heat used to come mainly from those bits into the air intake... now there's hardly any heat compared to before, the whole intake tube is cooler.....

[macquered]

from what i've read the air intake does starve the engine at higher rpm

Where did you read this?

[dan_kind]

not that i know much about fluid dynamics, engineering, etc...however, from my basic knowledge of workings the following are the assumptions i have made;

1. The 'intake' pipe design would create a substantial amount of 'noise'. therefore, the additional chambers, placed where they are would reduce this.
2. The 'intake' pipe design would also reduce strange occurances with air pressure/vacuum *being as though it is exposed to the front of the vehicle, where the air begins (i beleive it just in front) to splsit*
3. I have had a fluke multimeter with a thermo probe stuck smack in the center of the intermediate pipe to the air box, and while travelling, the air is +1C of ambient air.
4. I have also had the same thermo probe in the air box with and without the front 'intake' and found that even while at high way speeds, constant temperatures of +5 to +10 were recorded. In the m5 tunnel a air box temperature of 89degrees was recorded. After removing the air box, and located a pod as low as i could, with the original 'intake' piping left in place, the maximum in the m5 tunnel was 55 (-40 on engine bay temp), while cruising sees the in thermo probe i placed just above the butterfly reading +2, so for my vehicle at least, there is enough air flow to permit a pod filter without temperature issues...
5. The box design is again to reduce intake manifold noise, as much as it is designed to create flow so as to cover most of the air filter...removing the pipes on either side tends to have the air flow through the center of filter...
6. I would imagine the flow characteristics of the box are so as to allow maximum power while the following design considerations are taken into account;
- Maximum air flow
- Longest life of filter
- Quietest operation of intake system
- Coolest air.
7. 'derestricting' air boxes and/or changing intake design cant make a huge difference in my opinion.
8. The ECU will compensate for changes in air flow/temperature via the mass air flow sensor or 'hot wire', however these changes will mostly save you from any sort of major catastrophe (along with the knock sensor)..

[VF]

i have done a similar thing to my astra 1.8 5door.

i inserted a PVC section onto the air box and then fed a black plastic agri pipe to wards the bottom of the bumper.

The car's acceleration is great when temperatures drop below 15 degrees. Fuel efficiency is good too.

This is the first modificaton i did and I stronlgy recommend it. vehicle manufaturers have been restricting air flow on 4 culinders for years.