Inventiveness of the 650, 750 & 850cfm Blow-through Mighty Demon carburetors

Inventiveness of the 650, 750 & 850cfm Blow-through Mighty Demon carburetors

If there are six centrifugal supercharger manufacturers each supplying 15 to 20 kits per week and as many turbocharger makers doing similarly, you could conclude conservatively they are producing around 750 kits per month.

If you further assume that many of the buyers of those kits might be persuaded to invest $650 in a premium carburetor and avoid the high cost of converting to fuel injection—not to mention their apprehensiveness for laptop tuning—the number grows. For these cherished disciples Demon re-introduced three new Blow-through models.

 By Fergus Ogilvy

Demon Bow-thru carburetor - overhead viewDawsonville, GA: For turbocharged and centrifugal supercharged applications using a bonnet, Demon has now offers three Mighty Demon Blow-through carburetors. Operating with up to 18psi of boost they are available in 650, 750, and 850cfm.

To increase the vacuum signal to the carburetor under boost and to enrich the calibration, they are equipped with annular boost venturii, large screw-in power-valve channel restrictors in the metering blocks, and 0.130in needle-and-seat valves in the fuel bowls. The bowls also contain non-collapsible solid nitrophyl floats, unlike their brass counterparts. Air bleeds are appropriately sized.

These new calibrations are said to hold a flat fuel curve. Even at higher rpm the main circuits sustain constant BSFC (Brake Specific Fuel Consumption) values and air-fuel ratios. The idle circuits, which often carry the responsibility for part-throttle cruising, demonstrate fine non-boosted drivability.

On the bottom side of the base plate, machined, right-angle channels are visible. These introduce a source of boost pressure to four machined grooves on the throttle shafts. This innovation seals the shafts and prevents pressure escaping from the carburetor. For security, screw-in vacuum fittings replace the common pressed-in types.

Other interesting properties of these carburetors introduced by Demon over a decade ago are easily recognizable. These include billet metering blocks and base plate with the distinctive Idle-Eze air valve as well as replaceable air bleeds, and idle-feed restrictors. To prevent galling in the bores of the aluminum base plates, the throttle plates are mounted on Teflon-coated throttle shafts.

Introduced at the end of 2013, their part numbers are as follows:

650cfm 5282020BT

750cfm 5402020BT

850crm 5563020BT

For further information contact:
Demon Carburetion

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