Re: Hot air and Pflows

[aventari <Aventari@cts.com>]

At 05:06 PM 2/20/97 +0500, you wrote:
>>the reason you cant get a pflow is because a CIS(e) engine uses a mass
>>airflow plate over the airbox to tell the engine how much air is going in and
>>calculates how much fuel to use.
>
>True, but for those of us who are swapping injections systems down the road
>for one reason or another, the use of a Pflow might apply.  Also, some of us
>already have drilled airboxes and might now be wondering how to eliminate
>the hot-air factor:
>
>>You dont want to drill out your airbox (punched airbox) It or buy a pflow
>>type kit. they just make your car loud and suck hot air.  A scoop (ram air)
>>system is better because it draws cool air from outside the engine
>>compartment.  ABD now makes a kit to enclose your pflow to run it to a scoop,
>>why would you remove a airbox and replace it for the scoop?.....You shouldnt!
>> Fashion yourself a scoop and youll get all the air you need, VW's have good
>>intakes anyway, so save your $$$.  If I recall a drop of 10 degrees is good
>>for 1hp or something, May not sound like much but that engine compartment
>>gets hot.
>
>1.  If you run a scoop up into the engine bay (the kind that picks up air
>from below the car in the air stream and runs it into the engine bay), make
>it small in diameter.  Here's why:  when you're going 130mph, you're
>creating a vaccum-effect in your engine bay.  130mph winds are pushing UP on
>the inside of your car, and can give you a very floaty, dangerous ride.  
>
>2.   The swiss cheese airbox and pflow provide easier flow of air (good) but
>bring in hot air (bad).  It is believe (by me) that the two cancel each
>other out--but getting rid of the hot air will of course help a bit, since
>you're eliminating the downside--the hot air.  An EXPENSIVE way to cool your
>engine bay area is this:  buy a header and coat it w/ a protective,
>insulating material (ceramic).  I am buying a Velocity header (for
>8v--@$175.00) and having Jet-hot coat it for @$125.00.  They claim engine
>bay temperatures to be lessened by 30-40 degrees (F).  You get a few HP from
>the header plus a few more for the cooler air.  Your swiss-cheese airbox or
>pflow will also actually gain from it too.  The s.c. airbox and pflow
>provide easier flow of air (good) but bring in hot air (bad).  It is believe
>(by me) that the two cancel each other out--but getting rid of the hot air
>will help a bit.
>
>I saw a post once of a guy who had this general idea (cooling = power) and
>asked this question:  "Why not just put dry-ice in the airbox for some
>cool-ass air??"  <G>!!!!  I hope you all know what dry-ice is made of
>(CO2)!!!!!!!!!!  That'll burn REAL well in your engine, dumbass!
>
>Chris Taylor
>'87 Scirocco G60-to-be


With my 81 CIS engine they don't make a pflow or anything. Also with the
pflow, you just get hot (extremely hot) engine compartment air.  Doesn't see
smart in my opinion. 
My choices were to either drill out the air box so i get awesome air flow,
but then i would still get hot air. (I have a stock replacement K&N of course :)
My other choice was a lot better in my opinion, and it's what i did. First i
just got a 4 inch bracket and lowered the stock air intake hose from the
front 'air damn' body panel, and lowered it under the front. I get a ram air
effect, and even though it's the stock hose (1.5" wide) i could tell a big
difference. 
What i just did a few days ago is i got some 3" hose and ran it from the air
box to under the car. So i get a good ram air effect with the 3" intake
hose, and the car runs awesome at high speeds. It pulls easily up to 100mph
which it pretty good for 180k miles on the engine.

I was theorizing a while ago to myself about putting some dry ice, or even
regular ice in a zip lock baggie or something and put it in the air box out
of the path of the incoming air before a drag run, or and autox run. I dont
know how much it would help, i have yet to try it.

Kevin 
81 mk1 S

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