I keep thinking about putting a CDA air box on the octy, but when I think about doing it I think of my friends K&N and all the other boy racers around here who have one and how chavy it sounds.

So will I get the same effect with a CDA also what will I really gain from adding one?

The CDA is one of the better induction kits as the filter is shielded from engine bay heat in a carbon chamber. But it's also one of the most expensive.

Personally I've just stuck with a performance filter in the OEM airbox as that seems to give slightly better torque.

It would be interesting to see dyno graphs from a heavily remapped / modified VRS running an induction kit and then the same car running a performance filter in the standard airbox and see if there is much difference

The CDA is one of the better induction kits as the filter is shielded from engine bay heat in a carbon chamber. But it's also one of the most expensive.

Personally I've just stuck with a performance filter in the OEM airbox as that seems to give slightly better torque.

It would be interesting to see dyno graphs from a heavily remapped / modified VRS running an induction kit and then the same car running a performance filter in the standard airbox and see if there is much difference

What is a good panel filter to go for? Pipercross or just a green panel filter? Will they make it sound any throatier? Because even though I don't want the OTT sound I would like a bit more of a burble

What is a good panel filter to go for? Pipercross or just a green panel filter? Will they make it sound any throatier? Because even though I don't want the OTT sound I would like a bit more of a burble

Pipercross is cheaper and made of foam (I think?), K&N and Green are a bit more expensive and you need to clean and oil them once a year or so.

With a panel filter you won't get the sucky noise you get with an induction pipe and cone filter (sounds like Darth Vader having an asthma attack) but I find on mine you can hear the turbo spooling up a bit more loudly and the DV sounds a little bit louder.

derestrict the box

derestrict the box

Won't that suck in all the hot air or am I thinking of the wrong mod?

Won't that suck in all the hot air or am I thinking of the wrong mod?

no it involves smoothing out the inside of the airbox, you could also drill the bottom of the box on the cold side of course whether it gives any more noise i'm not sure i'll let you no when ive finished mine its a popular mod on the c20xe vauxhall engines from my gsi days

also run a cold feed direct from the bumper in the airflow into the airbox where the original rubber pipe from the inner wing fits into the airbox

I would be interested to see as if this "de-finning" really makes a difference or if it's placebo effect. Do the said fins really reduce airflow?? Or more likely just reduce induction sound?

Edited 10 June, 201016 yr by Jcb.

either way its free to do...

I just got this last week

My link

Im happy with it and if your not then its not costing you big amounts of cash

Hoping to smooth my airbox out and larger cold air feed to mine within the next few weeks. Did it to my last car Vectra 2.5 V6 did make little bit of induction roar but not enough that most people would notice, for noise on the Vectra had a Cossie Ramair induction kit for that, but it was only worth doing in winter when plenty of cold air about, far too much heat soak in summer. Apart from pricing heard good things about BMC CDA.

Hoping to smooth my airbox out and larger cold air feed to mine within the next few weeks. Did it to my last car Vectra 2.5 V6 did make little bit of induction roar but not enough that most people would notice, for noise on the Vectra had a Cossie Ramair induction kit for that, but it was only worth doing in winter when plenty of cold air about, far too much heat soak in summer. Apart from pricing heard good things about BMC CDA.

i had the 2.6 gsi vectra which had the airbox modded with a panel filter and it did sound nice

I smoothed out the air box and did look at fitting some 3" diameter flexi alu-pipe like a cold air feed, but it was too difficult to route with all the LPG stuff in the way. I ended up using some 1+1/4" plastic flexi cable conduit with the gland connectors drilled into the bottom of the airbox and routed to the same area as the existing cold air trumpet in the wing. I managed to get four in so the increase in air intake area is increased by about 50%.