whats the best supercharger, carburetor combination,
for a 12a motor, considering mpg, and top speed for the
days you just want to floor it????

flier romeo


MPG and flooring it are incompatible.
If you use the HP you burn the fuel.
For every HP used for one hour you will burn .5 pounds
of fuel.

Lets say you pump it up to 300 HP. and you run it for one hour like that.
At that power level you will use 150 pounds of fuel or 23 gallons.
That is 2.5 pounds of fuel per minute or .38 gallons per minute.
Fuel weighs 6.25 pounds per gallon.

Lets say you accelerated to 2 miles per minute or 120 MPH in one
minute foot flat on the floor 300 HP with a load of lead or up a steep
incline. You have traveled only one mile. 2.63 MPG if my calcs
are right.

Carb or fuel injection matters not. My old RX7 with
a carb gets about the same MPG as my RX8 with EFI. About
25 MPG at a steady 70 MPH.

There are any number of turbo chargers and super charges that will
work. They all give about the same results. You will get slightly
better MPG using a turbo charger as the 10 to 20 HP to drive the compressor
must come from somewhere. Using a turbo charger most of it comes
from the waste HP in the exhaust.


Paul Lamar


Maybe he's asking about dynamic range?  Max hp with foot on the floor,
best cruising bsfc..

Wide ratio transmission to get the R's down while cruising.

A turbo is tougher to make easy to drive unless using an automatic
transmission unless using one of the more sophisticated turbos.  Turbo
lag.  Superchargers are always turning a multiple of the crank speed
and so they have boost available all of the time.  But, as you said,
they can't match the fuel economy of a turbo, all else being equal.


Matt-