The tests I did for the air movement was first on the flow bench. I mounted
the stack on the air inlet then used smoke to get the indication where the
air was coming from. For a simple test I put my hand over the stack and it
didn't make a bit if difference until it was about 2" away. The smoke
indicated that the air was coming from the back of the stack thus the
manifold side. In the dyno with the engine running under full power at
about 5000 I used a flat board and slowly moved it up to the stacks, nothing
happened until I was ABOUT AN INCH away from the stack again indicating that
the air was coming from the manifold side. After this I then made the stack
with big roll on the edge, that is when I picked up the big change and power
improvement. Like I said, simple minded tests. I would think that stacks on
Webers that had rolled edges would improve the flow. You could probably do
that by mounting in a lathe, heating the edge with a torch, turning the
lathe on the back gears so that it was low revs then use a wooden paddle to
roll the edge over. OR just buy some that do the job. The latter sounds
best.
What all this did was relieve me from worrying about the air inlet being too
close to the inner fender well. But it also showed the worth of having a
heat shield between the headers and the carbs and manifold.
----- Original Message -----
From: "MARK J WEATHERS" <markjwea@email.msn.com>
To: "kas kastner" <kaskas@cox.net>; <fot@autox.team.net>
Sent: Friday, October 17, 2003 2:44 AM
Subject: Re: velocity stacks and stand-off
> I would be interested in teh details.
>
> Mark
> 72 TR6
> ----- Original Message -----
> From: "kas kastner" <kaskas@cox.net>
> To: <fot@autox.team.net>
> Sent: Thursday, October 16, 2003 8:46 AM
> Subject: Re: velocity stacks and stand-off
>
>
> > The early velocity stacks that I did had a sharp edge and no roll back
of
> > the outer edge. They did not make the big difference that we achieved
> later
> > with a rolled over edge. In tests we found the inlet air was coming
from
> the
> > back of the carburetors. I'll explain our tests another time if
interest
> is
> > demonstrated. It's no big deal.
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