air box modification

[davedave]

have a vectra turbo what mods can you do to the air box

[Ziggy]

Drill it and remove the extra bit of plastic. Have a look at ian highlanders old threads

[Ian-Highlander]

Removing the bottom plastic "trumpet" is what's referred to on here as "the airbox mod" and is done by pretty much everyone.

It's not worth drilling the air box unless you've had the car re-mapped. I did mine as one of the rolling roads I used recommended it because it was struggling to get enough air at the highest revs, drilling mine cured that, but it only makes a difference at the top end of the rev scale and only if you're running a remap over 200bhp.

This is mine but as said this will give you NO benefit if you're not running quite a bit more power than standard and even if you are, it only helps the top end revs nothing else.

[kirby]

ive also found not meant to cut top trumpet part out, oops

[Ian-Highlander]

Yup don't remove the top one it's there to smooth out the airflow into the MAF.

[Gubmint Agent]

Doesn't drilling the bottom of the airbox like that not allowed grotty unfiltered air straight into the engine? Wouldn't drilling the top of the airbox (ie, above the filter) be better? I've always wondered...

[Ian-Highlander]

No fella, the air gets sucked from the outside through the tube in the bottom (next to where I've drilled the holes) then goes through the filter to the intake on the MAF in the top of the air box, so all air is filtered

[kirby]

Yup don't remove the top one it's there to smooth out the airflow into the MAF.

dont suppose you got dimensions of your top tube at all do you, as found couple in breakers from other vauxhalls & was just going to glue 1 in situ to hope it helps

[Signum-Steve]

Turbo engine......I introduced an extra cold air feed into my air box direct from my front grill. not from the engine bay where heat from the engine can be drawn into the air box.
Take a look at this thread. It works well with my engine which is also turbo forced induction engine. Cold is the way to go!http://www.vectra-c.com/forum/showthread.php?t=145973

[Ian-Highlander]

Turbo engine......I introduced an extra cold air feed into my air box direct from my front grill. not from the engine bay where heat from the engine can be drawn into the air box.
Take a look at this thread. It works well with my engine which is also turbo forced induction engine. Cold is the way to go!http://www.vectra-c.com/forum/showthread.php?t=145973

I used to think exactly the same and there's no arguing with the fact cold air is denser and therefore better, but with the air moving round the engine at speed from outside the car (underneath and sides) the heat soak is going to be minimal and all air from the turbo goes through the intercooler before it hits the inlet manifold anyway.

The above mod on my airbox definitely did the job that's for sure but as I said it was only for high end revs anyway, the standard airbox is more than adequate for most of the rev range even with a tuned car.