List,
Second installment...
I will preface this argument with this...Ron Armstrong, of RacePak,
tried to discourage me from trying to measure the scoop performance. He
said that there are too many variables that can affect the measurement.
I tend to agree with him, but I believe that if you use the same setup
with different induction systems, you still get useful information.
As most of you know, I have done extensive experimenting with air scoops
on our car. I am still not satisfied with the results, however, I have
gotten close to what I am looking for. I will give a little history of
my information gathered since I installed the RacePak system on the car
at the end of 2001. I now have had the third scoop on the car since that
time.
The one I was running at the time I first started gathering info at the
World Finals 2001, was one that I had built according to the calculated
air needs for the engine. The calculated opening for my 304 cu in engine
was 4.8 sq. inches. The actual size of the opening was a bit over 5 sq.
inches.
The RacePak system measures air at the front of the car for a reference
and the scoop pressure is compared to this reading. We look for zero or
a bit positive as a goal. With this scoop I was reading a negative 9.7
in hg from about 6000 rpm up. The maximum the system would indicate. It
went back to zero by the 5 1/4 after shut down. It followed a pattern,
as rpm climbed, the scoop pressure went more negative. This was at
Bonnevile, but it continued at the Lakes as well. While at the Lakes in
November 2001, I was talking to Bob Brissette about the problem. He
suggested that I cut the nose off the scoop and see what happens. I took
out my hack saw and went to work. I now had a 5" X 5" (25 sq. inch)
opening. On the next two runs, the scoop pressure was near zero or a bit
positive.
I will finish this in a third email.
Tom, Redding CA #216 D/CC
ELLEN WILKINSON FOR wrote:
> One reason for the small air scoop inlet on the 998 car might be when Terry
> was running the 444 car Rick Vesco designed a very similar looking scoop with
> a bigger inlet. I don't remember the year or exact speed but at about 280- 300
> at about the 5 mile the larger scoop packed enough air in to blow part of the
> body off.
> Gary Wilkinson
>
> ----- Original Message -----
> From: Ron Gibson
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