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Discussion Starter · #1 ·
I am just about to modify the airbox on my 96 9000.

I need to know what drill bit is recommended, how many holes will be sufficient and are they in a patterm (ie, spaced equally etc)?

I will also be removing the snorkel but would like to know what would work best.

Thanks
 

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i have considered further modification to the airbox on my c900 (beyond removal of the snorkel/whalefin thingy, which was tossed out in the hopes to reduce air restriction). i believe that any more 'performance gains' from modifications to the stock airbox would require some rather large diameter holes, atleast 1/2" (about 13mm i do believe) though probably larger would be better, nearer to 1" holes (25 or 26mm, i think).

personally, if i were to do this, i would keep all drilled holes at or above the lowest part of the stock hole in the airbox. if you were to drill right down near the bottom of the airbox, i would think that water induction could be an issue when driving through deep puddles (or even shallow ones, at speed). i would also want to drill only on the rear, outside and front of the airbox in an attempt to reduce how much engine heat is transferred to the incoming air.

are you currently running a 'performance' air filter? or using the stock paper filter?

i have heard, elsewhere, that drilling of the airbox would produce nothing more than an increase in the noise level created by the vacuum of incoming air. i have read, here i believe, that the snorkel, or whalefin, shape of the intake prior to the filter and airbox is designed to reduce the noise created by the intake. i cannot say whether or not the noise level was changed on my car, as the muffler i installed at the time (found here Summit Racing Performance 'Turbo' Muffler ) drowned out any other engine noise that could be heard.
 

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Discussion Starter · #3 ·
I'm running a JR airfilter. I have heard that it increases response times slightly, more of an exhaust burble and a louder induction noise.

Just fancied seeing what, if any difference it makes.

Thanks for the advice!
 

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I'm running a JR airfilter. I have heard that it increases response times slightly, more of an exhaust burble and a louder induction noise.[/b]
makes sense to me, so long as there is no wife/girlfriend to complain about the increase in noise
, go fot it!
 

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Discussion Starter · #5 ·
Originally posted by xassh:
makes sense to me, so long as there is no wife/girlfriend to complain about the increase in noise    :rolleyes:   , go fot it!    :thumbsup:[/b]
There is but she has no choice in the matter!!! Claims she is a Saab widow, sounds good to me
 

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Just dont go too extreme with the holes, as even if you have a recirc dump valve you will still here the "whoosh" noise on lifting the throttle.

Depending if you want that or not that is !
 

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Just dont go too extreme with the holes, as even if you have a recirc dump valve you will still here the "whoosh" noise on lifting the throttle.[/b]
so, the more that the box is drilled, the more noise it will make is confirmed then? maybe its time that i get out the power drill and bits then!
 

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Discussion Starter · #10 ·
I've done the mod, about 15 1.5inch holes around the top of the housing and removed the snorkel.

WTF!

It sounds like waking Darth Vader after he has been out on a heavy night on the beer. uuuuuuuuuuurrrrrrrrrrrrrrrrrhhhhhhhhhhhhhhh!!

Sound's good with an increase in exhaust noise...........................which I like! Took me all day though!
 

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When I did it, I removed the snorkel and cut a larger hole (than the snorkel hole). I then fitted a large speaker reflex port with flared entry and exit (exit being a flare inside the airbox onto the filter). Thought being to smooth airflow = less drag.
The intake area was about 5 times standard (figure that should be enough) but the sound is still quite smooth - smoother than just removing the snorkel which generates lots of flapping noises as the air is sucked past the sharp edges. I suppose if you drill enough holes then this impact will lessen.
I think I posted this before - I fitted a cut down version(it's bigger than it looks!)
http://www.falcon-acoustics.co.uk/Port-80M.jpg
The job was a fiddle and took a while to get right. At least 30+bhp more though
 

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Discussion Starter · #13 ·
Right......................

What I've done is drilled round the top of the box with 3 lines of holes offset. These continue down the side of the airbox until the middle. And a few are placed on the face.

The snorkel is removed but when easing off the throttle, the seems to be a groaning sound from the intake.
Could this be from where the snorkel has been removed and there is no bell-housing to allow are to flow freely, or is it that holes need to be placed all over the airbox (underneath included)?

Also, what sort of MPG have people been attaining with this mod whilst under normal driving?
 

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Any one got pictures (or know where they have been posted before)?

I shall be making this mod soon and will document what I find (and leave behind). Not too keen on increasing the noise too much though.
Do I understand correctly that this mod is as good as fitting an air intake kit, when considering pounds per increase bhp
 

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Hi Guys have a look at My SAAB Photo's this will show my various experiments with the air box.

The 1st was an extra inlet hole fashoned from a drain pipe with a flared intake (I used a hot air gun).I left the snorkel attached at this point.(more intake noise better spool up times)

2nd was snorkel removel, and 4 large holes drilled around the sides of the air box.More induction noise than before (You cannot realy hear it in the cabin with the windows up snounds louder in higher gears with low revs and full throttle withoutv the turbo spooling )much smoother and quicker spool up times

3rd an induction pipe made from more drain pipe elbows and a vacum hose. results much smoother throttle response speeds over 60 instant throttle response in 5th
which is great.The car now holds the higher gears at lower revs much better.The MPG is better too


After all the mods I have found the standard DPV to be slightly noisier however not that much (I havn't realy noticed any extra exhaust note )The strange sound you hear on throttle lift is the air recirculating into the air box which now floods out of the "extra" holes as it is not " contained" any more and is no longer really a recirculating DPV!!!

I hope this helps
 

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I've removed the snorkel and cut 3 * 1" by 3" slots on the top and rear of my Aero's air box.

I now get a induction whistle at around 2000rpm (before it's drowned out byt engine noise, and a bathroom type gurgle on gear changes.

The Carly with just the snorkle removed is a bit quieter.

Andrew
 
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