Re: Follow-up: Intake on a 5-cyl.

[Scott Fisher <sefisher@cisco.com>]

Huw rightly points out:

> And find out from the engineerly types on the list where the "high
> pressure" zones are, that's where you want your actual inlet to be.

I've given this a little bit of thought, though done no work (yet).  I
*will* say that this is an area where you can do a lot of damage and
achieve very little in the way of measurable, tangible results, so it's
truly one of the places where measure twice and cut once applies.  I've
frobbed a *lot* of air intake setups over the years, and have to say
that for the most part, messing with the factory setup will make your
car noisier and probably increase engine wear by several hundred
percent, while producing little or nothing in the way of measurable
performance enhancement.  And don't go by seat of the pants feel, either
-- the extra noise will make the car *seem* faster.  BTDT.

One thought I've had is since the lights on most Audis are so hopeless
anyway, just remove both right-hand headlamps and stick the intake of
the duct there.    No, it's not a serious thought, but half of Phil's
lighting system would provide probably nine or ten times as much
illumination as the stock lights on my car, so it's not completely
insane.

The one thing that's produced tangible results for me is locating a
low-restriction filter in a high-pressure area, as Huw suggests, and
preferably a cool high-pressure area.  High-pressure areas on the car
typically include the grille and, interestingly enough, the base of the
windscreen at the rear of the hood.  Of course, on the CGT the firewall
presents a real problem with getting air from the base of the windscreen
into the engine compartment.  The Detroit solution, of course, would be
to go with a high-rise hood such as the Cowl Induction Chevelles of the
late Sixties, which did exactly this -- ducting in cool, high-pressure
air from the base of the windscreen, then running it forward to the
carb.  (The Chevy also had a solenoid which raised a flap when certain
throttle/vacuum conditions existed; no, I don't know why they didn't
just leave the damn thing open all the time.)  On the canted-over I5,
it'd give the hood one of those weird asymmetrical power bulges, though,
which always make me think of the Seven Warning Signs.

On our cars, we're probably better off to go with the Alfa GTA/Lotus
Cortina approach, which is to run a tube from the air inlet (just below
the air metering plate on our cars, or at the nose of an airbox
enclosing the Webers on the two Sixties cars) forward to just beside the
headlamps and take air in from behind the grille of the car (which was
also in front of the radiator on the Lo-Cort and GTA).  Of course,
there's a ton of stuff up there under the hood of an Audi -- pumps and
pulleys and brackets that would make it very difficult to package
something effectively.  

I agree, though, that the dinky little inlet hose to the air box
certainly looks restrictive, but there's not a lot of room below/around
it to improve anything.  

I haven't given up, either.  One thought I've had is to duct air from
below the bumper, and then hope I always remember to come to a full and
complete stop before driving through standing water any deeper than, oh,
three-quarters of an inch.   I knew several people who experienced
hydraulic lock, and I'd rather not encounter it myself.

--Scott