General Question about OPC Astra Grilles

[Jerram]

I was looking at pictures of the cars of all you Astra people, and I noticed that the OPC style grille takes the liberty of having an inch or so thick band of solid abs running along the top as opposed to the OEM grille which just has slats or honeycombing there. Wouldn't that solid band work to block the ram-air intake? I know on the Vectra the air intake corresponds to where the top of the grille is and I seem to remember that the astra one is somewhere similar.

Thoughts?

[Vectracious]

Astra/Vectra/Corsa OEM air intakes are not a ram-air design - they just have an opening for the engine to suck air from - so what the grill looks like will have no effect on performance.

[Jerram]

Astra/Vectra/Corsa OEM air intakes are not a ram-air design - they just have an opening for the engine to suck air from - so what the grill looks like will have no effect on performance.

Oh ok I get you.


...Mind you, what happens if you replace the oem with a Pod filter (which is essentially what I did, though I installed a separate air feed as well as the oem one)

[Vectracious]

You basically want the air to be as cold as possible getting into the engine - colder air is denser air - ie more O2 - so the engine can be more efficient and generate more power.

Pod filters are generally less restrictive than OEM filters - therefore they let more air in - however - as they are usually just sitting in the engine bay - the potential to suck hotter air in is greater which means less dense air and therefore less O2 - so its a bit of a trade off. Some people build an enclosure for their pods to sheild them from as much engine heat as possible to ensure the air temp is as low as possible. PaulyJ did this with his old car.

This is a very simple explanation - I'm sure someone with more experience with this stuff will be more than happy to add or correct me. :)

[Jerram]

You basically want the air to be as cold as possible getting into the engine - colder air is denser air - ie more O2 - so the engine can be more efficient and generate more power.

Pod filters are generally less restrictive than OEM filters - therefore they let more air in - however - as they are usually just sitting in the engine bay - the potential to suck hotter air in is greater which means less dense air and therefore less O2 - so its a bit of a trade off. Some people build an enclosure for their pods to sheild them from as much engine heat as possible to ensure the air temp is as low as possible. PaulyJ did this with his old car.

This is a very simple explanation - I'm sure someone with more experience with this stuff will be more than happy to add or correct me. :)

Thanks though I've got a pretty good understanding of all of that (hence why I essentially have 2 air feeds to my pod)

The real observation though is just that the OPC grille looks by design to let a little less air into the radiator and airbox.

Not sure that it makes much if any difference, just a general observation.

[chrissn89]

Nope theres no air flow problem with the OPC grille. I think personally looking at both of them (OPC grille/OEM Holden) the OPC grille allows more air flow.

[CNBLU]

I had an OPC grill and i think my Irmy grill allows more air into the engine bay. Both do the same thing.

[tomtom]

may or may not be off topic but whats the general consensus regarding swapping out the stock Astra intake for the larger Vectra C intake? Waste of moneyyz?

[chrissn89]

may or may not be off topic but whats the general consensus regarding swapping out the stock Astra intake for the larger Vectra C intake? Waste of moneyyz?

Waste of money i recon. Unless your running forced induction, i dont think it would make that much of a difference, if any. Im sure others will let you know what they recon thou. If your after more air flow, remove the air-box, and replace with a fully shielded pod filter setup and a CAI. This will add a nice induction sound to.

[tomtom]

Yer that was what I was thinking, a CAI/Pod. From what i've heard gives a cool sound + little bit more response

[BEK-46P]

may or may not be off topic but whats the general consensus regarding swapping out the stock Astra intake for the larger Vectra C intake? Waste of moneyyz?

I've done this, in addition to replacing the stock filter with a K&N panel, plus de-restricting the air box, and the results are... well, quite minimal. I honestly can't notice any obvious improvement and it doesn't even sound all that different. As for being 100% correct about whether or not it makes any difference, I'd have to re-install the stock filter/intake and take it for a spin to compare.

As to whether it's a "waste of money", I think "waste of patience" is more appropriate when it comes to squeezing in that Veccy intake. There was a moment I thought I had ordered the wrong part because it was EXTREMELY hard to get in.

[Z20LET]

Just on the topic of the vectra C intake. The other week when I was changing my timing belt I had a go at removing my intake snorkel. I removed the 2 screws and then pushed out the clips and there was still no easy way of just sliding it out. Is there any easier way to doing this? To me it seems the only way of getting it out would be to drop the radiator or breaking the clips on the snorkel which I wouldn't want to do. By the way my car is a G SRi-T if that makes any difference.