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Discussion Starter #1
This post will go against everything I've said before about Induction Kits.

My car is a 1994 1.8litre 8 valve with Squadra Chip and free flow rear exhaust box. I fittes a K&N 57i kit when I first got the car. Convinced myself that it made a huge difference (better). Then I chipped the car etc.
Played about with the air induction using a HUGE Green Cotton Twincone filter, ramming the air etc. Always convincing myself that the car was better, even though my fuel consumption was getting worse.

After all this, the car still lacked that "something". So 2 nights ago, I put the original airbox and filter back on.

Instantly, the car feels smoother, seems to pull better lower down and is a lot quieter.

I'll have to wait and see about fuel consumption.

I have a couple of ideas as to why the car now feels better.

1. With the induction kit and rammair, the car was taking in too much air, the injectors couldn't supply enough fuel at higher speed/revs.
If the mixture is weak (which after my MOT emission results, it may be), you will use more fuel trying to get the same power.

2. The Squadra Chip I assume is mapped using the OE air intake system. If you play about with this, you'll upset the way the car has been "tuned".

I've noticed that I don't have to press the throttle as far to accelerate quite hard. At higher revs (5500rpm) in higher gears, the car may be a little slower on acceleration, but I think a freeflow panel filter will help this.

So that's my new way of thinking. Am I talking guff ???..........completely wrong ???.........is it all in my mind ???

What's your ideas on the above.

Thanks for reading this

Marlon
 
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Discussion Starter #2
Hiya Marlon,

The Squarda chip shouldn't cause problems with a different air filter, the air flow meter should let the ECU adjust the fueling to compensate (to a point)

From what you say, I think the problem may be more heat related. With a K&N style cone filter in the engine bay, warm (less dense) air will be dragged into the system from the engine bay where as with the OE air box it's basically piped fron outside.

The most common setup (for serious tuners anyway) it to create a compartment with either metal or carbon fiber etc for the cone filter to sit in. in the 155 that should be quite easy as you only really have to stop air flowing from the radiator\manifold area into the filter. - you could also remove the plastic arch liner, I remember seeing somewhere that doing this can provide more cold air flow into the OE airbox or filter.

Hope this helps..

Cheers,
Alex
 
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Discussion Starter #3
Hi Marlon

There is a lo of disagreement about the subject of induction kits on AO.com. Som say they are a waste of time and too noisy, the best bet being a decent panel filter as you have done. I think if you are fitting a K+N type thing it needs to have cold air provided via some ducting from the wheelarch area as Alex sez. However, routing and length of the pipe may make a difference too. Another solution is to make a heatshield between the engine and the airbox. AO sell the carbon induction pipes for 156's and they are rated as they keep the air cooler.

wrinx
 
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Discussion Starter #4
Hey Marlon, when did you get all Squadra'd up?
Last time I saw you, you were moaning about a lack of oomph - did the Squadra sort it?

Air filter - this question has been discussed a number of times in different forums but I think you've got the main points there - the Squadra chip probably was mapped/tuned on a standard airflow car. How much of a difference that makes - ? who knows.
The main problem most people have stated (including a very good in depth trial, I'll have to try & did up the URL) is the heat problem
associated with the engine bay flow of air. Many cars have seen decreases in performance after having induction kits fitted - the previous reply explains this well (hello fade2grey).

I got a K&N replacement box filter for my 2L 16V, before getting the Squarda & it feels good. More low end torque improvement that high end performance boost, but nii-iice. I'll maybe get a supersprint back box at some point, but that's all I'm planning (servicing & parts costs are killing me too much at the moment).

Maybe you should go for Max Power look and attach a wheelie bin scoop on the bonnet with a tumble drier hose into the airbox.
Yeah baby, yeah!
:D
Get yersel a replacment flat filter & tell us how it goes.

What you up to these days anyway?
Seeya, Honkytonk
 
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Discussion Starter #5
Hi Mark, long time no see. Been hanging with your bro quite a bit (For those who are wondering, Honkytonk and Jason77 are brothers !!!).
Tried routing cold air to the induction kit, moved the filter into cold air at the front airdam via pipe etc. But since Squadra, the best performance has come from the OE airbox and pipework.
Got Squadra'd 2 or 3 months back. Car is smoother.

Got an adjustable splitter on the front too. Check it out via the link to the site in my signature.

I think a panel filter is the way to go. Induction kits I've had on other cars have made a posative difference. Unfortunately, on the 155, I think it's a waste of money.

Marlon

PS. anybody want to buy a second hand K&N 57i kit ???? :D
 
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Discussion Starter #6
I'll also agree with everyone here. Go for a flat panel replacement filter like K&N or BMC. Got the K&N in mine, with resulting mid range and top end improvement. With some (little bit) extra snorting noises too.
 
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Discussion Starter #7
Looks like we've all arrived at the right decision... unless you have the time & cash to build a heat barrier then a free-er flowing pannel filter is the way to go.

Though I do fancy one of those nice autodelta carbon fibre air intake pipes.. do you know how hot a Q4 gets?! :) though not for £150!

Cheers,
A
 
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Discussion Starter #8
hi i would like to add that i have a k&n 57i on my 1.8 8v & over the last 2 years when the car is very hot(slow traffic etc) it does not perform as well.i think the cold air feed is very important on these induction kits it has been discussed before on this forum. maybe if i get time i will try & find a way of feeding an extra pipe to the filter as well as the standard one wink .
cheers
 
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Discussion Starter #9
i know this isnt realy related to the 155 but i had a mini with a k&n filter on it and it ran like crap no amount of adjusting or re-jetting make any differance so i put the old filter back on and it went better than ever...i would agree that a good replacement panel filter is best..you dont see F1 cars with cone filters on they use panel filters.(not relavent i know) :)
 
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I think the Alfa designers got it right when they penned the air intake system.

Philip, when I had my 57i kit on (same engine as yours), I routed extra cold air via more pipes, but the car was still crap after slow traffic, the hot air still gets blown over the filter. After a long drive, lift the bonnet and feel how hot the filter is !!! You'll be amazed at how hot it gets.

Off to order a BMC from AO.

I'll let you know if I see a difference.

Marlon
 

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The panel filter is defintely better as it has larger area than the cone filter, but the problem is usually the intake and exit of the box itself. I don't know what it looks like on your cars, but on my Giulietta -84 it is excellent while it is disasterous on the Q4. Now I have modified the Q4 as you might have seen in my posts on that topic earlier this summer and my impression is that it helps a lot.
 
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Discussion Starter #12
Don't forget guys, the longer the airflow for the inlet the more torque - hence the bizzare airbox configuration from the factory. with shorter, straighter & free-er flowing air you should get more BHP, but most likely at the expense of torque.

don't forget BHP turns heads, torque turns wheels wink

A
 
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Discussion Starter #13
I've just read an article about all this stuff. Revs magazine tried different induction kits/panel filters and modified airbox (drilled holes in the base). The upshot is, more torque and BHP increase was seen with a modified airbox and good filter than the cone filter induction kits. This test was run on a Nova 1.4SR but I think the results are still relevant. Would you say drilling the airbox is worthwhile on the 155 as from what Alex says, that would reduce the torque.
Also Alex, you talk (or torque) of a longer air intake, is that before the filter or the total intake length ???

Marlon
 
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Discussion Starter #14
Drilled\modified airbox is the way to go. Andreas posted a few pics of his using Speaker bass ports as the holes to increase airflow but keep the turbulance down. Sounds like a good plan to me.

A
 
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Discussion Starter #15
Hi

If you are having problems with the filter getting too hot, you should get a heat blanket, im going to buy one soon, i have removed the airbox and im still trying to find a place to place the second air tube.

I have been working on installing a hole in the bonnet like on a impreza, but im not sure on how to awoid water getting pressed into the filter also..... will get back with pics when i have it done.

Niels
 
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Discussion Starter #16
Guys,
I don't want to sound like a "kill-joy" but, do you really reckon you're gonna improve an airbox by modifying it yourself with a drill?
These things are take years to tune to perfection using the most sophisticated CFD packages (that is Computational Fluid Dynamics) and incredibly powerful Workstations.

I really wouldn't bother drilling if I were you.

If you decided to go for the induction kit you could cut a hole in the wing just where the filter is, this should allow cold air to be sucked in when at slow speed provided you have also created and fitted a heatshield to the opposite side of the filter. To improve airflow to said filter you should then cut other vents in the front bumper where the number plate is (relocate this somewhere else!). This region is a high-pressure region i.e. air may be forced into a small duct relatively easily. The length of the ducting to the airbox should be smooth and relatively straight with no significant bends so as to not provide friction which would negate the benefits. The high-flow, low-pressure region found at the site where you've cut a hole in the wind would also aid sucking the air from the bumper vent through the filter.

Bear in mind that these are theoretical aerodynamics principles that should work in theory but might need a lot of fettling to obtain results in practice. Only for the serious DIY mechanics with deep pockets. I've been working on this idea for a year and have just managed to get the funds to apply a vent on the wing. Long time to go still!!

Best wishes,

Taz.
 
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Discussion Starter #17
Taz, the problem with the 8 valve kit is the filter is nowhere near the wing........it sits behind the battery !!!!

Incidently, I read an article on drilling air boxes/induction kits etc. They did all this to a Nova on a rolling road. The drilled airbox did make a little difference to power and torque output.

Marlon
 
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Discussion Starter #18
as far as I can tell, the problem with all of this 'ramming' air into the induction system is that you create pressure waves or differences with turbulant\smooth air flow at different speeds. If the air flowing into the plenum is not right then you may get inefficient burn in the cylinders, hence the bizzare collection of pipes & boxes we have on the cars. Allowing more air to flow into 'external' side of the induction system must be the way to go, more air (not rammed but cold) into the external side of the air box means that flow will then _not_ be the restricting factor.

Any opinions? :)
Alex
 

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On my brothers old 33 QV (which is dead and burried)was a prob some of the time, he got unwanted ram air and the engine stalled wich is normal, only good thing we can do is get enough cold air in the space where the filter box sat originally so the induction kit can suck in as much cold air as it needs and no more, creating a heat shield would also improve but bear in mind that the amount of heat isn't that big because when the hood is down it forces the heat down, still the shield would improve, can't we create some sort of pipe so the filter can sit near the wing?
 
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Discussion Starter #20
OK....here's another idea.....

I have a cold air feed from the front airdam to the original airbox (with BMC filter). The bottom of the airbox is drilled. If the presure in the box is too high due to the air ramming and the engine not sucking it in, will the pressure be released through the drilled holes ????
Then if more air is needed than supplied by the cold air feed (when moving off etc.) then the extra air is sucked in through the drill holes.

The position of the airbox means it is shielded from the engine heat anyway, so I should always get cold air anyway.

I think it'll work.

Marlon
 
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