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Discussion Starter #1
I drove my 1750 home from winter storage without the factory intake and filter setup. It's a euro with webers. The car sounded meaner and more guttural, obviously. Which I liked, and got me thinking. Besides the increase in sound, are there any advantages in abandoning the factory setup and installing velocity stacks?
 

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I too like the noise. Bought a set of filters and stacks and base plate (Alfaholics) to mount it all to my dellorto equipped 75. Doing some engine work this spring and will go full on then. Performance gains/drawbacks? Doubt much notable either way in my case but I do note some of the potent engines use tuned pipes as it were. ciao jc
 

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I've tried them all.
Standard set-up, ok and more relaxing, but not quite the noise that floats my boat.
Swept, movable rampipes, very loud, and no point in using them at all without a sock filter on each pipe, for the reasons stated above, the pipes as they come with the mesh are not much better than having no mesh at all, it only keeps the big bits out.

KN Filters, 45mm to 55mm depth. (no rampipes inside).
The best compromise for me. 55mm depth not as loud as the 45mm depth, retains the guttural sound but more muted. Very little clearance between the filter front plate and the inner wing.
That's what I'm running now. I don't think that there are any performance gains over the standard set-up, if there are, it's too small to be noticeable in "normal" driving..

Steve
 

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If you think about it, velocity stacks are effective only at wide open throttle. If you want more power at less than WOT, all you have to do is press down farther on the gas pedal.

Once at WOT, the stacks will tend to accentuate the airflow within a relatively limited range of RPM. Above or below that range, they can actually reduce the airflow slightly.

The shorter the stack, the higher the RPM band affected. At a certain point, the RPM band is higher than what the engine is designed to operate at. Thus, these short stacks do little to nothing for the engine.

The factory air plenums on Alfas are well thought out. The remote float-air pickup points helps to avoid transient flat spots. The non-ram tube intake puts the counter-wave creation above the operating range of the engine, also helping to avoid flat spots.

So - why ram tubes? If you are racing and intend to operate your engine within the targeted RPM range mostly at WOT, using a close-ratio gearbox to largely stay within that band.

If you're just after cooler sound, put playing cards where they will rub on your spokes. ��
 

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The standard airbox plenum can be modified to improve the flow into the carbs. The sharp edges are radiused and blended. They can even be opened up to match 45mm Webers. I can post a picture if required.
I prefer the sound of the exhaust to the sound of the Webers but music is in the ear of the listener.
 

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Discussion Starter #7
Thanks for all the input. The factory housing and filter are back on the car. Sound was fun while it lasted, but a bit too loud for everyday driving. Kind of took me back to high school where I flipped the lid on the air cleaner on my dad's Olds 88.
 

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I tried all of the above mods and got to the store 2 seconds quicker !!!

AND people looked at me !!
 

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Drill a few holes on the removable cover's inner ring where the wing nut sits. This is on the intake side of the air filter. This way you can get the best of both worlds , filtered air and nicer sound. Best of all , you can change back in seconds if you own a second lid.
 

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Richard Jemison
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Air Horns (Ram Pipes?)

On the 1300/1600 motors of the `60s Airhorns increased the length of the intake passage improving the nearly non existant torque/power at low and mid range RPMs. Im that same configuration they made the intake length too long for high RPM. Note at the time of this "Popularity" these Airhorns were encased in a cold air box that had a cover reasonably close to the airhorns openings to reflect power pulse waves back into the system. They were not open to the engine bay`s hot air, dirt etc.

The proliferation of Airhorns in the engine bay is probably a result of the common phenominon "Monkey see, Monkey do" common im all kind of auto preparation. (large valves is another)

The stock later 1750/2 liter Euro air box, plenum including the filter canister attached to it, has adequate volumn for most applications. These with internal mods to fit 45mm Webers with the webers themselves tapered to widen the opening and loose the step in the opening have the approiate length to function over a wide RPM band, and improce the effectiveness of the pulses at higher RPM.

As well it`s easy enough to modify the opening to run an intake hose forward of the radiator area for cold air intake.

You might want to visit the BB thread:
http://www.alfabb.com/bb/forums/motorsports/146536-air-intake-webers-105-track-car.html
 

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Drill a few holes on the removable cover's inner ring where the wing nut sits. This is on the intake side of the air filter. This way you can get the best of both worlds , filtered air and nicer sound. Best of all , you can change back in seconds if you own a second lid.
I did this years ago, with the addition of a very flexible rubber disc behind the lid to act as a valve of sorts at low speed air can be sucked through holes at high speed ram air pressure from front of car may push disc rearward and block flow (or prevent ram air pressure loss). Never tested this, just an assumption that it will work that way. It is a little louder.
 

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"This way you can get the best of both worlds , filtered air and ricer sound. Best of all , you can change back in seconds if you own a second lid."

FIFY !
 
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