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OKXXFE · 05-17-2014, 08:47 AM

While I was cleaning/rebuilding the carburetor on my old truck, I thought about how it works as compared to the eTB of my car. I remember from experience and the handy-dandy Haynes manual (best 40$ you can spend IMO), that the secondary throttle plates dont open until the engine looses vacuum. So the old Q-Jet would operate at normal temps and cruising as a small two-barreled carb at WOT, which is what made it so efficient (for a carb). It was only when pedal to the floor that the HUGE secondary's would open to give the engine all 650cfm the carb has.

So my query is this: If a 4-barreled carb operates as a small, unrestricted two-barrel at anything below WOT, would a multiple throttle plate system be of any use to a modern EFI? As in, staged throttles which could provide *unrestricted* flow but still not full power flow. If that makes any sense?

Anyway, that old truck would do 16-18mpg so long as I kept it about 60mph, I thought that was alright for a brick of steel as old as me and no overdrive.

05-17-2014, 08:47 AM	#1 (permalink)
OKXXFE EcoModding Lurker Join Date: Apr 2014 Location: Central OK Posts: 24 Slow Silver - '09 Chevy Cobalt XFE Coupe 90 day: 37.56 mpg (US) GMC pickup - '86 GMC C1500 Hephaestus - '09 Kawasaki Vulcan 900 Custom 90 day: 47.13 mpg (US) Thanks: 1 Thanked 2 Times in 2 Posts	Multiple Throttle Plates While I was cleaning/rebuilding the carburetor on my old truck, I thought about how it works as compared to the eTB of my car. I remember from experience and the handy-dandy Haynes manual (best 40$ you can spend IMO), that the secondary throttle plates dont open until the engine looses vacuum. So the old Q-Jet would operate at normal temps and cruising as a small two-barreled carb at WOT, which is what made it so efficient (for a carb). It was only when pedal to the floor that the HUGE secondary's would open to give the engine all 650cfm the carb has. So my query is this: If a 4-barreled carb operates as a small, unrestricted two-barrel at anything below WOT, would a multiple throttle plate system be of any use to a modern EFI? As in, staged throttles which could provide unrestricted flow but still not full power flow. If that makes any sense? Anyway, that old truck would do 16-18mpg so long as I kept it about 60mph, I thought that was alright for a brick of steel as old as me and no overdrive.