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Help me understand something. It seems to me the only way to get more air into the intake manifold is to decrease the constriction; increase diameter of the TB at the blade-a true bore TB. Ported TB's don't do that nor do TB spacers.
The "venturi effect" in airflow(as opposed to liquids) argues that speeding the air through the TB increases power down low(Airaid TB spacer is 77mmon a stock 80mm TB). However, the venturi effect states there is a pressure drop when speeding air through a constriction on the backside of the constriction(into the intake manifold). This is measured by the MAP(before TB and after TB).
Now, it makes sense that speeding air into the intake and by extension into the cylinders jams more air into the cylinder-a ram air effect. But, doesn't the pressure drop negate the argued venturi effect. I need someone to straiten me out on this.
Also, Janittie Racing demonstrated that a Hellcat TB on a 392 increased down low torque (15 ftlbs) and minor effect on HP(2 hp, which falls within +/-). Am I confusing HP effects with torque effects on my previous statements? know this is very pedantic, but, curious mind wants to know.
Only can tell you is if a 650 carb is winning and you put 1010 on it and you lose = you will figure it out. bbmac
In theory a carb spacer increases the plenum area also, they make some pretty tall ones. On my 70 Challenger it was suppose to have a carb spacer, kind of a rubber gasket like material. It was long gone when I bought it. I had a heck of a time with hot starts, the heat soak would boil the gas in the carb, I even had a carb fire once. When I found a factory spacer in a junk yard it helped a lot, and amazingly all the linkage fit better. So yes, the insulating qualities was a big part.
Old school - a insulating spacer under carb is good... bbmac
 

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You can’t look at venturi‘s and spacers the same way you could on older cars. They just don’t work the same. Mopar or No Car has it right in his post. Chrysler probably sized the TB for a lot of things, emissions, mpg, drive ability, and performance but bigger isn’t always better. If you do other work, ported heads and intake, headers, cam, better exhaust, then a bigger throttle body would help.
Totally agree with you...14 years old I helped a guy change his 2 barrel carb for a 4.... He lost the race... Hey change injectors to Giant size and think you will win the race??? You will find out who mother FY is... bbmac
 
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