Air box mod??

[Mistar_T]

hey everyone... I'm trying to find info and a how-to for the airbox mod that i've heard about... i tried using the search feature and not really found what im looking for... any info/links would be appreciated.

also, what is the advantage of this other intake pipe i hear about aswell?

thanks peoples

 

[Matt]

viewtopic.php?f=14&t=10729

 

[Mistar_T]

https://z22se.co.uk/viewtopic.php?f=14&t=10729

GREAT!! cheers matt... thats EXACTLY what I've been needing mate... cheers..

 

[Mistar_T]

I've also been told its a good idea to drill an extra hole/holes in the airbox aswell as doing that mod...

can anyone give me more info on this... as in... which side of the airbox (front/back/wing-side - obviously not engine side...), how many holes, what size holes etc? and do you then need to give it an air feed or just leave the holes open where they are?

thanks

p.s. if it makes any difference, the car is a vectra

 

[Matt]

Drill the hole wing side in the bottom half of the airbox. Drill it big enough for an extra air feed, and you'll be well away.

 

[Mistar_T]

Drill the hole wing side in the bottom half of the airbox. Drill it big enough for an extra air feed, and you'll be well away.

swish... so do i need to put in another pipe for the air feed or does it get sufficient flow from behind the wing as it is?

 

[Matt]

I think a second feed is recommended, but should be OK with just the hole open inside the engine bay.

 

[Mistar_T]

cool. thanks for all your help matt

 

[dunowt]

Ive drilled five 1" holes in mine mate on the inner wing side at the bottom without an extra cold feed and havnt had a problem.

 

[Mistar_T]

Ive drilled five 1" holes in mine mate on the inner wing side at the bottom without an extra cold feed and havnt had a problem.

have you noticed it make any difference?

I was thinking one big hole... probably around 2 inch across...?

 

[dunowt]

It sounds lovely mate and in my opinion feels slightly more responsive!

 

[Mistar_T]

It sounds lovely mate and in my opinion feels slightly more responsive!

swish... sounds good... was hoping to get it done today but didnt work out like that... might give it a go tomorrow if i get time.

 

[Mistar_T]

Okies... I've done the de-restricting of the airbox... had a look at the guide here: viewtopic.php?f=14&t=10729

but i can only assume that is on a different car? (astra maybe?) as the airbox layout is different in my Vectra B.

Soooo... i did it a slightly different way. the plastic pipe in the top half wasnt too tricky to take out (pushed in a couple of bits of plastic with a screwdriver and then pulled it out) and the intake pipe in the bottom half was a metal coil covered in fabric held in by 2 plastic shells. i prized these shells out slightly and pulled out the pipe. I then positioned the shells and the pipe so that it was just inside the bottom half of the airbox, then cut the length of pipe down to the required length on the outside of the airbox so it still slotted into the intake.

I've got a few pics if anyones interested....?

One question... why the hell are those pipes so far into the airbox anyway? surely it would make more sense for vauxhall to have left those pipes as the are now?... there was only an inch or so of space between the end of the pipe and the airbox... cant have been good for air flow??

 

[slindborg]

It would have been for NVH (noise, vibration and harshness) purposes. And possible pulse tuning effects to get a particular point in the rev range to behave ina certain way.

Remember kids, 9/10 times more noise dosent always mean more power/speed its mostly the placebo affect.

 

[Mistar_T]

It would have been for NVH (noise, vibration and harshness) purposes. And possible pulse tuning effects to get a particular point in the rev range to behave ina certain way.

Remember kids, 9/10 times more noise dosent always mean more power/speed its mostly the placebo affect.

to be honest... since doing the mod i've not noticed it be any louder really (i didnt end up drilling the air box - just removed the pipes)... however it does seem a bit more responsive and maybe seems to pull a little better at lower revs. not bad considering its got the standard paper element in still (not got a K&N for it yet!)

Reason i didnt drill the airbox is because at the inner wing side, there isnt much clear space to drill... the element sits down to a certain point, and below this point the airbox slopes away to the bottom. Heres a pic... hope you can see what i mean...



There is space for a hole at the front (next to the normal/original intake) of the airbox... is it worth drilling it here or leaving it as it is? is there much point in drilling or is it more for that bit of extra noise?

 

[dunowt]

Dont mean to sound thick but thats not the same airbox as mine?

 

[Mistar_T]

Dont mean to sound thick but thats not the same airbox as mine?

it may be that the vectras and astras have a slightly different airbox design, even though the engine is the same... dont forget the astra is a smaller car with a different shaped chassis/engine bay... therefore the engine may be the same but airbox, coolant tank, washer bottle etc etc may have to be different shapes and sizes in order to fit correctly?... (im assuming the pic in your avatar is your car?)

Thats why i couldnt follow the guide (linked to above)... because it doesnt seem to be for a vectra... im guessing its for an astra...?

 

[BURT150]

You can drill about 5or 6 1/2 inch holes in the sloped part. I did mine it makes a nice noise but thats about it. I dont think it adds to performance. Up to you tho.

 

[Mistar_T]

You can drill about 5or 6 1/2 inch holes in the sloped part. I did mine it makes a nice noise but thats about it. I dont think it adds to performance. Up to you tho.

cheers for the suggestion... if its not really going to add to performance i dont think I'll bother... not too fussed about how it sounds at the moment. may end up getting an exhaust system on it for that side of things.

I've de-restricted the airbox by removing those pipes... next step on that side of things will be a k&n panel filter and then we'll leave it at that i think... unless doing the vectra C intake pipe conversion is worthwhile?... what difference does that mod make by the way?... the pipe would have to be the same length in order to fit correctly so i cant see how it improves anything over the vectra B intake pipe?...

(also... is the Vectra C intake pipe conversion suitable for vectras... stupid question i know, but as said above, it may fit an astra but not a vectra for example...)

 

[BURT150]

Yea Vectra c intake will fit perfect. or the other option is to make up a silicone hosed one. I dont know about power gains but if you,ve done the three pipe mod , stick a k&n in and change the intake you'l notice a difference not big but every little helps. T/b port and polish would go well with those mods too.