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Discussion Starter · #1 ·
I was checking my air filter the other day, only recently having read some articles on the subject

I notice how tight and contorted the box is. I've read about drilling holes in the box etc etc, fitting K&N filter etc.

It struck me there seems almost no way of getting a real draft in there, save , dare I mention cutting a whole in the bonnet above the damned thing.

Ok don't panic, this may sound worse before it gets better but I noticed that the little air scoops fitted at the top of my neighbours J reg Rover 100 where exactly the right size and shape for this job. (Note N reg on rover 100 scoop diferent oval ones and not good)

So anyway this is the Madcap proposition:

Leave all existing Air box and tubing in situ. Remove lid from box. Cut large hole in box lid. Make homemade sponge filter to fit in lid. (Note ideal sponge filters can be bought from garden centres or aquatic centres, sold as pond filter sponges. usually in black or turqouse and available in a number of grades of fineness, those sold for Laguna filters look best)
Now original box it taking in air from above and below. Fit late model Metro/early Rover 100 air scoop above box in bonnet. Fit other side scoop to match.

Dispite the crappy nature of the Rover 100, I bet you can't remember how these scoops look, they are black, squarish with heavily lipped top edge, you'd never know where they were sourced from unless told. Other bonnet vents such as Pug 206 which may look groovy are angled all wrong and could not blent in with the car.

Oh, havent actualy done this by the way, but thought Id put this to someone else for discussion. Maybe if you realy want the added air flow and are using your alfa for track days or you need a new bonnet anyway you may give this a go.
 
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Discussion Starter · #2 ·
There is a lot to be gained in the air box. I tried the drill loads of holes in the air box approach, sounded like a MK1 escort , awfull. patched that straight up again, even though it did give more go at higher revs. The problem is that bendy pipe work and prefilter box helps with low down torque. if you remove it from the system its less driveable round town. Maybe the answer is to pipe cold air from the frount air damm into the trombone?
I have an ERAM installed on my car , but its not really in the right place , before the filter, there is not enough room in the induction tube to fit the 3 inchs you need for the ERAM.
 
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Discussion Starter · #3 ·
Blooming amazing how with all the elecric wizardry more air can mean less power. If the system is realy matching the fuel in perfect proportion. I can't claim to be an expert in this area but my reasonning leads me to conclude that when you drilled all the holes in the box due to the positioning of the box the intake was drawing in lots of hot air into a hot engine at low speed. At high speed the engine bay gets blasted with cool air and the problem subsides.
This is kind of where Im trying to come from with my maverick sugestion loads of free flowing cool air and at speed getting it forced in a bit.
 
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Discussion Starter · #4 ·
Hi guys
Not very sciencetific all this about drilling or cutting holes, is it.
I have had my 155 2,0 16v with (at the moment of test) 126k km/78 km miles on the “clock” tested on a rolling road before and after having a UniChip fitted and mapped.
I had in standard form 195,7 nm (+ 3.54%) and 163 HP (+ 8,66%)
After the mapping I got 215,4 nm (+13,96%) and 185,8 HP (+23,86)
() = more power than Alfa claims.
This shows (to me, anyway) that my 2,0 16v with a std. original Alfa filter (8k km/5k miles after fitting) is not starved for air.
Graham’s right, fettling with the air intake on a modern ECU managed engine is a science that is better left to those who knows what they are doing and have the necessary equipment.
Alfisti regards
Erik
 
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Discussion Starter · #5 ·
Blimey, are you saying you get that much power with just a chip and no other mods?? Surely you've gas flowed the head and modified exhaust.
I take it your running with a CAT?
 
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Discussion Starter · #6 ·
Hi Graham
No, I just one of the lucky ones. Cat's on, head never off. Std. sucktion and exhaust.
The issue of chip-tuning have been going on all the time here. I've allways said that you might get more go with a chip but engines have and still is very different even they shuld be the same, but they arn't. So, to get the optimum you'll need a mapable chip. They cost more (to map on a rolling road, but it's allways this way.
Alfisti regards
Erik
 
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Discussion Starter · #7 ·
AAAAAARRRRRRRRRRRRGGGGGGGGG!!!!!

Mr Romeo spends billions of lire developing a tuned intake and airbox to precisely match the characteristics of the engine and exhaust, then some hoon with a Black & Decker goes and torpedoes it!

The airbox is a precise volume, closed air chamber designed to work best based on the actual volume of air that is drawn in by the pistons on each inlet stroke and the amount of air that is suddenly passed back as the inlet valve snaps shut.

All these openings and closings of the valves also sets up a sort of tidal motion of air in the box that creates resonance (waves) which help the pistons suck the air in.

The airbox becomes pressurised at different points inside it (i.e some bits have more air in it than atmospheric pressure, others less) so that air tends to flow faster to the lowest pressure point of all (the combustion chamber).

Drilling holes in the lid depressurises it and knackers all this - making it LESS efficient.

As far as ramming cold air in, via a bit of hoover pipe to a duct behind the bumper - this method has some sanity in it (cold air is denser so you can effectively get more oxygen in the same volume of air) BUT by ramming air in against the designed tendency of the airbox upsets the harmonics of the box and may change the pressure differences so lovingly designed by Alfa's engineers. By all means feed a cool air pipe to the box but don't ram it.

As Elp says - the airbox is not the limiting factor in the system - more likely the ECU which is deliberately tuned "inefficient" to allow for duff petrol all over Europe and to get around noise/pollution regs.

Ralf S.
 
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Discussion Starter · #8 ·
Having had a quick read of all the above comments, I thought I'd stick my neb in. I have recently replaced the entire air box with a K&N 57i kit. We all know about the increased induction roar etc. This is the 3rd car I've fitted a kit to, and every time I have noticed an improvement in mpg and top end acceleration. At low speeds, the accelerator acts a bit more like an on-off switch which can be a bit jerky in traffic jams. The extra air flow should not be problem to the engine as the ECU, flow meters etc compensate to make the fuel/air mixture correct. If you drive "normally", you will probably see an increase in mpg. If you boot it all the time, the opposite will happen. Again, like I say, this is my 3rd car (all different) with a kit fitted, and all have acted in the same way.

Marlon
 
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Discussion Starter · #9 ·
Hi Marlon,

Can only speak from my own experience on this but since fitting a twin cone induction kit to the 164 the fuel consumption has plummeted! I have read many articles like most people here and have recently come to the conclusion that keeping the air box and perhaps replacing the panel filter is the best way to go, which is a complete change of view for me!! I think Danny's points are very realistic and relevant.

In regard to the airflow meter etc adjusting the mixture. I have been informed that they are not 'intelligent' systems on the 164 and I'd imagine the same for the 155. Later models may be more complex and do this constantly but this is something I have been told and so is not my view and could be wrong?

No doubt this will go on and on but to be honest I think we all get a bit carried away with this and the chip debate, neither is going to add 50 bhp to our cars and the difference between one or another will probably be less than 1 bhp :D !!!!

MAK

RACING AND WINNING SINCE 1910
 

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The extra fuel is the nice sound the new air filter make when you put your foot down, so you accelerate more Mak!! wink

I like my K&N and 180 bhp I had on the last car. I agree that an air intake system needs to be a tuned length like an ehaust system is, but Alfa also take into account the noise levels in the car and potential for nagging wives to stop husbands who will actually hand over the money, getting their dream car! All this despite the 155 brochure saying that many Alfa owners drive with the window down slightly to hear the engine!! I do!!
 
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Discussion Starter · #11 ·
You drive with the window down too. Wow, I thought it was just me !!! The radio in my car is never on 'cos I like to listen to the engine.
As for the higher fuel consumption in the previous post, you possibly are accelerating
a bit more without realising. It takes a strong will not to boot it to get that sound.

Marlon
 
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Discussion Starter · #12 ·
This great sound is intoxicating, my dad gave me a lift in my 155 (could drive myself due to medication), caught him doing 40 plus in second gear and smiling (this from a man who never drives his own corolla - he is 64- in anything less than 4th above 25mph). I asked him what he was doin and he said he loved the sound and just to prove it floored the throttle!! I suppose I can't complain after the stick I've given some of his previous cars wink
 
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Discussion Starter · #15 ·
got a nice 1.8 silverstone in the workshop at the moment its got a ram air induction kit on fits realy nice into the space left by the old air filter assembly
 
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Discussion Starter · #16 ·
Another part to this ongoing saga......

I've been running with a 57i kit on the car, and although the top end acceleration is improved, the bottom end both sucks and blows !!!

Then along comes Shug. Being a welder, he fabricated a stainless steel bracket and pipe which when fitted to the AFM, positions my K&N filter into the space left by the original airbox, close to all that lovely cold air !!!!

The result, I still seem to have an improved top end, but the car pulls like a "fist of fury" (sorry that's rude) at low revs. RESULT :D

The extra pipework seems to have improved the torque. Sweet.

Thanks to Shug for the part.

Marlon

PS. Shug, use a short filter for your pipe
 
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Discussion Starter · #17 ·
Hiya Guys

What about the V6, any advice for the beasty?

Shug, any chance of posting some drawings of your bracket for others, or do you fancy making a few up and selling them on???

I used to be a metalworker/welder/engineer and its easier to do a few, than "one offs", if you have access to jigs and the machinery etc wink

wrinx
 
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Discussion Starter · #18 ·
Hi Wrinx
This might be a problem as am waiting to start a new job and the potential for doing 'homers'will be non existant.I didn,t take sizes,angles etc but i,ve not fitted mine yet due to the cost of a filter(the wife,s still not to happy with me for ordering a chip)so i could post you the sizes etc then any one could make one for themselves.If any one can tell me how to post a drawing then i could do that.

Regards Shug :confused:
 
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Discussion Starter · #19 ·
Hiya Shug

Two ways of doing this, one to get a digital camera and photograph the drawing or use a graphics program to draw it up and post here.

Or a third way, send me a pm and we'll sort it out wink

wrinx
 
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Discussion Starter · #20 ·
Hi
If anyone wants to send,fax,post or carrier pigeon scrappy sketches or cad drawings to me i can probably have them fabricated easily and cheaply (laser cut and bent etc) as i am a designer for an engineering firm and we have to fabricate or get fabricated lots of bits...so shouldn't be a prob let me know whatever it is.
 
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