[Crawdaddy]

how did it affect his fuel mileage?

 

[Crawdaddy]

supposedly the ones with the swirls help increase turbulence, which would in turn get more air into the cylinders, or preheat it, or some BS like that...I don't particularly buy into TB spacers. How can it increase power/performance AND increase fuel mileage? However, if they work, I'm ll for anything that can buy me more MPG...