Fuel pumps: Fuelab’s electronic combo has two things that stand out

Text by Jim Mozart Photos by Moore Good Ink  Download hi-res images and text here Fuelab of Litchfield, Illinois has developed a unique fuel pump and electronic regulator. First, unlike any other, this fuel pump has a variable-speed motor. Hence it can deliver prodigious amounts of fuel at fully open throttle and minimal amounts at idle. Its variable-speed ability overcomes the chief trouble with big, powerful, high-flow single-speed fuel pumps—heat. Because high flow pumps work just as hard at idle as at fully open throttle they become hot at slow engine speeds and consequently overheat the fuel. Often they eventually self-destruct as a result. Second, unlike any other, this fuel pump is of DC (direct current) brushless design. Therefore current draw is significantly reduced and brush wear and brush drag are eradicated. For the uninitiated, an electric motor spins by way of a set of brushes that ride against a commutator on an armature. As voltage is applied to the brushes, it causes the armature to spin. Sound simple? It really is. However there are some problems with that design. In a brush-type motor, the brushes are constantly in contact with the spinning armature. As such, there is a small amount of drag on the armature at all times. In addition, the friction created by the contact also creates heat. Heat is not a desirable attribute in an electric fuel pump motor. In addition to this, a DC brush motor is only capable of operating at one speed. In the case of an electric fuel pump, this means the motor will continue to spin at the same speed and provide the same... read more

Canted valve Windsor Head: Ahead of of its time?

Jon Kaase’s P38 Canted-valve Windsor Cylinder Heads Aim For Better Cylinder Filling Text by Ro McGonegal Photography by Moore Good Ink Jon Kaase keeps his eyes peeled. Over the years, the engine builder has seen an endless string of improvements and aftermarket components visited upon the Windsor 302 but he was woefully aware that there were no real advancements beyond the original cylinder head configuration. He thought he could produce castings that looked like ordinary Windsor 302/351 parts on the outside but would be entirely different from the original blueprint on the inside. As a racer, he knew the value of stealth. But more importantly as an engine builder he knew the prime advantages of canting the valves to lean towards the center of the cylinders and so mitigate the natural shrouding effect of the cylinder wall.Kaase designed the P38 cylinder head primarily for the 302W (8.2-inch deck height, 4×3 bore/stroke, 5.095-inch rods); its derivative the popular 347ci (over bored by 0.030-inch and stroke increased to 3.400-inch); the 351W (9.5-inch deck height, 4×3.5 bore/stroke, 5.960-inch rods), and the 427-454W Sportsman-type Dart block (9.5-inch deck height with 2.750-inch Cleveland main journals). Typical combustion chamber volume is 60-62cc.To insure optimum cylinder filling, Kaase canted the valves at 8×4.5 degrees on the intake and 10×4 degrees on the exhaust. The fresh area created by the new valve angles allowed an increase in the diameter of the valve heads to 2.100 inches and 1.60 inches.Astute CNC porting would induce far superior air flow and cylinder filling compared with any conventional layout and it accomplished two things: the revised angles place the intake valve... read more

How to Make Key Adjustments to a Drag Racing Clutch

Text by Sam Logan: When we first take an interest in drag racing we soon realize that nothing in its mechanical history is more absorbing than the racing clutch and its operation. Multi-disc drag racing clutches are constructed in four or five different diameters. They range mainly from 6.25in (500cu-in Pro Stock) to 10in (Mountain Motor Pro Stock). Comp Eliminator and sport compact classes often run 7in twin-disc clutches while other engine sizes use 8 inches. Mountain Motor clutches comprise two discs while Pro Mod and Pro Nitrous use three. Obviously the object of these clutches is to transmit formidable engine power to the manual gearboxes and to the rear wheels, but also they must provide predictability and adjustability. Modern billet drag racing clutches feature five principal adjustment mechanisms. These include provisions to address the following: clutch disc wear; static or base spring pressure; centrifugal pressure generated by counter weights, which are positioned on the clutch levers; throw-out bearing distance from the clutch levers; and the air gap, which is the distance that the cover assembly separates itself from the clutch plates. Of course launch RPM could also be considered an adjustment mechanism. Clutch disc wear causes the clutch levers (the fingers) to move from their optimum operating position toward the release bearing. Adjustment is made by inserting a pin punch in the small holes and rotating the upper barrels of the titanium stands. This adjustment, which is made each time the clutch is installed in the car and sometimes between runs, returns the clutch levers to their proper operating position. Static or base pressure is altered by increasing... read more

Handy tuning tips for modular carburetors

Part 1 of 2-part tuning articles By Sam Logan The carburetor takes responsibility for the emulsification (mixing air with fuel) and the atomization (separating into fine particles) processes while the vaporization (transforming to a gaseous state) occurs in the induction tracts. The engine compresses the vapor and produces the energy. In addition, the carburetor must meet the air-fuel ratio requirements of the engine.To emulsify the air and fuel, small-bore drillings are placed in the air entries on the top of the carburetor. They are known as air bleeds. The emulsified mixture is then drawn rapidly through a multitude of small passageways and distributed into fast moving air streams for atomization. It is discharged through a dozen small ports, three in each throttle bore. They are known as idle ports, transfer slots, and boost venturii. The idle discharge ports and transfer slots are located in the throttle bores of the base plate and draw their source of fuel from the fuel bowls via the carburetor’s idle wells. The boost venturii and their discharge ports are positioned near the top of the carburetor and discharge into the narrowest part of the upper throttle bores. Boost venturii draw their source of fuel from the fuel bowls via the main wells.  In the following text and sequence of pictures and captions we identify some of the chief components of the modular, square-bore carburetor, illustrate their functions, acquaint you with common problems that can arise, and tell you how to prevent them. Idle-Eze. Sloppy idle-speed adjustment is the carburetor’s number 1 tuning problem. It causes the transfer slot to be overexposed and creates mayhem.... read more

Street Demon: An interview with its designer

by Sam Logan   In mid-January 2012, the new 625 Street Demon carburetor was debuted in Los Angeles, California during the MPMC media-manufacturers conference. Designed to suit a large variety of stock to mildly tuned engines of up to 450 horsepower, the Street Demon cuts an elegant figure and caused considerable interest at the conference. Then in mid-February 2012, during pre-production dynamometer experiments, it fuelled a 376cu in LS-3 engine that generated in excess of 450 horsepower. Of course during the normal course of carburetor selection few would consider installing a 625cfm street carburetor on a 500hp engine. Clearly an engine of this capacity ideally requires a bigger carburetor, probably one of 750CFM. Still, evaluation tests or not, the Street Demon carburetor’s performance raised a few eyebrows. The Street Demon’s production is scheduled to begin in early spring 2012 and given the chance to meet its designer, Larry Tipton, it seemed a fine opportunity to get to know more about what had inspired it and how it works. Larry Tipton has spent most of his life in carburetor design and development. He began with Carter in October 1966 in St Louis as a designer of carburetor components and later was appointed to the advanced design group for new carburetion. Today he is the inspiration behind the new 625 Street Demon. 1) What was the inspiration behind the Street Demon? “Since its beginning Demon Carburetion has specialized in racing carburetors, usually for drag racing and for oval track competition and for street-strip and muscle cars. Later the Demon SixShooter and the Demon 98 carburetors and their attendant intake manifold systems were... read more