On the upper end....yes. The more RPM's, the more airflow required.
I ran a 650 DBl-Pumper, a 780 Vac-Secondary, an 800 Vac-Secondary, and then
a 900CFM Projection-II system on my old BB Chevy. Which one worked the best
in the higher rpm's (above 6000) the 900CFM unit of course. You also
mentioned that Car Craft did a "Build Up" with a 750cfm Speed Demon (which
is a carburetor)...what about putting it on a stock engine? Or at that, a
stock engine with stock cam, stock heads, and headers.
Mark, read my posts carefully before jumping to conclusions: "Granted, this
would depend on Cam, Heads, Exhaust, S/C or Turbo, but that calculation is
for a "Bone Stock" configuration."
- Bernd
-----Original Message-----
From: owner-dakota-truck@buffnet.net
Subject: Re: DML: New 53MM Throttlebody
It may seem like 650 cfm is enough for a built 360, but, why else do
magazines use 750-800 cfm carbs on their engines. You have to remember that
ideal efficiencies are just that, ideal. Car Craft did a 360 buildup and
used a 750cfm Speed Demon to pull in 408hp and 434 ft lbs. I have seen tests
where 800 cfm carbs have added significant horsepower to a 340 engines that
were using carbs that were a little bigger that reqired. Those formulas are
good for street engines but go out the window with radical (race) engines.
Mark Kuzia
> In your case Will, sure it'll work...hehehe...you probably need it. But
on
> these stock R/T's (or 5.2/3.9L engines) that's just too much. Going by
the
> calculations that I have for max CFM rating, a 360 turning 600 rpm
requires
> 688CFM.
>
> Here's the formula: ((Max RPM * CID)/3456)*1.1 (The 1.1 is for that
extra
> air flow...just in case.
>
> Granted, this would depend on Cam, Heads, Exhaust, S/C or Turbo, but that
> calculation is for a "Bone Stock" configuration.
>
> - Bernd
>
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