KING OF KLAMP

Ram’s single- and dual-disc assemblies for the Mustang 3.7 V6. By Ro McGonegal: It wasn’t that long ago (2008) when Ford’s 3-valve 4.6 Modular V8 produced 315 horsepower. Now, the 24-valve 3.7 liter V6 in the (2011-13) Mustang generates more than 305hp and 280 lb-ft of torque. To us, that indicates a very sturdy platform for safely increasing output. Concurrently, the ever-rising cost of fuel will likely be a natural promotion for the smaller displacement engine. Invigorate it with a supercharger or some other type of aggressive power enhancement and you’ll be experiencing nearly twice the engine’s original output. Since it is highly unlikely that the OE pressure plates and clutch cover could handle such largesse reliably and repeatedly, Ram offers seven new clutch sets (see chart), each with progressively increased clamping loads that facilitate torque increases from 450 to an amazing 1200 lb-ft. Three are single-disc designs and another four that maintain dual friction discs. All are engineered as direct fitments and each is paired with a billet Ram flywheel. Note that none of them require modifications to the factory release mechanism. Ram’s 10.5-inch single-disc clutch sets are offered as HDX, Powergrip and Powergrip HD and accommodate as much as 650 lb-ft of torque. All Ram flywheels are available in billet, either steel or aluminium. By nature, billet material weighs less than cast iron, so replacing the heavy factory dual-mass flywheel with a Ram billet unit reflects substantial weight savings: 10 lbs for the steel and 22 lbs for the aluminium version. And as everybody knows, a lighter rotating mass invites quicker acceleration. To facilitate even greater increases... read more

Demon wants to tell you how to tune carburetors—in minutes!

Text by Sam Logan. Pictures by Moore Good Ink. Download text and hi-res images here. Engines produce vacuum, and over the past 130 years engineers have contrived ingenious ways to harness its power to the engine’s induction system. Aided by barometric pressure, ignition and compression, the carburetor creates the air-fuel mixture that promotes combustion. Through a labyrinth of small-bore drillings in the carburetor, the vacuum draws a potent mixture of air and fuel. So formidable is the mixture, the carburetor has empowered naturally aspirated full-bodied 500cu in drag racing cars to speeds in excess of 213mph in a distance no greater than 1,320 feet! It works by pressure differential; high pressure flows toward an area of low pressure. On starting and at idle, the area of lowest pressure on a carburetor is under the almost closed throttle plates (see second illustration below) and as the engine gains speed, the area of lowest pressure switches to the boost venturii https://www.glass.net (see first illustration). On 4150-style carburetors, the boost venturii reside within the main venturii and low pressure is created by the constricting shape of their bores, which causes air speed to increase and, as a result, a siphoning effect is introduced at a boost venturi’s tiny air-fuel discharge orifice and through the air-fuel metering circuits back to the fuel bowls. (The faster the air speed passes through the venturii the more fuel is withdrawn from the fuel bowls and thus unleashing optimum engine power.) As the fuel bowls are vented to barometric pressure—an area of greater positive pressure than that of the discharge orifice in the venturii—the air-fuel mixture is... read more

How Clever Induction Systems Build Potency in World’s First Aftermarket Cleveland Crate Engine—The Titus

By Sam Logan, Photography by Moore Good Ink: The world’s first aftermarket Cleveland crate engine was unveiled recently by the Waldorf, Maryland, firm McKeown Motorsport & Engineering (MME). They call it Titus. Though MME’s Titus crate engine distinguishes itself from its mighty predecessor of the 70’s and 80’s in many ways—internally balanced forged crankshaft, deck-plate bored and honed, priority mains wet- or dry-sump lubrication systems and so on—it is the multiple choices of induction systems that set it apart from the conventional crate engine. To this end MME offers five different cylinder heads for five different duties, and they require specific information to select the correct cylinder heads and induction system for every engine. The most important element in building a high performance engine—an engine that accelerates quickly—is to know the crucial rpm range in which it will operate. It’s also helpful to understand that high average power output prevails over peak power output—always—at least in a muscle car if not a dynamometer. In addition to stating the engine’s operating range, which influences the runner lengths of the induction system, MME needs to know the car’s weight. The induction system of a Titus engine powering a 2,000lb Cobra is obviously different to that of a 3,800lb Mustang. Gearing also has an effect on induction choice. For example, a Titus engine powering a gear ratio of 3.25:1, used predominately to propel the car at 1,500rpm along the street, dictates a different cam and induction system to that of one empowering a 4.11:1 gearing, operating at 3,000rpm. Hood clearance is a further consideration, although the Titus’s 9.2in deck height usually provides... read more

How to keep your poise when installing a gearbox with an upgraded clutch

Installation Tips from Ram Clutches: Disengaging the quick-connect feed line when installing a new clutch system with an existing internal slave cylinder/bearing, ensures the bearing assembly remains partially filled with fluid. As a result the release bearing compresses against the clutch fingers as the transmission is being installed and requires more force to slide it in place than desirable. To avoid this hardship, alleviate the unwanted pressure by reconnecting the feed line before sliding the transmission fully into position. Thus the fluid trapped in the bearing can now return to the master cylinder. As the transmission is installed the bearing is preloaded into place. For further information contact: RAM Automotive Company 201 Business Park Blvd. Columbia, SC 29203 Telephone (803) 788-6034... read more

Rod stretch and rod bolt fatigue: Beerhorst talks boosted engines

Written by Moore Good Ink: When the crankshaft pulls the connecting rod downward on the induction stroke of a naturally aspirated engine, a stretching load is exerted on the con rod because the piston area is so much greater than the column of air being drawn into the cylinder. In contrast, when the inlet valve is open on a boosted engine, the rod is always under pressure, not a stretching load. Therefore the life of all rotating parts in the boosted engine is significantly prolonged. Of course, there is also a stretch on the rods when the throttles are closed and the engine is decelerating. It’s under these conditions where most con rods fail on oval track cars: when the throttles are closed as the car approaches the corner. Consider that situation for a moment: the piston is sealed to the bore by the rings and the crankshaft is pulling it down against huge resistance. Remember, the throttle plates are closed so there’s not much air pressure in the combustion chamber to assist.  A streetable naturally aspirated engine producing 2,000hp doesn’t exist. But if it did you’d be lucky if the engine’s rotating parts survived for more than a few quarter-mile passes. There are, however, large displacement maximum-effort engines operating near this power range, but they are not streetable and only the most durable could complete 50 quarter-mile passes without a rebuild. In contrast, when you boost the engine, it will make this vast amount of power and you could run it on the street. Using lower engine speeds and with less radical valve train it will run for... read more

Evil twins: first twin 625 Street Demon carbies on the first new 409 hotrod engine

Text by Sam Logan. Photography by Moore Good Ink. Download text and Hi-res images. In the dyno room, Lamar Walden’s first production road-going 409 fitted with twin 625 Street Demon carburetors revved with enthusiasm to 6,293rpm and generated 602.4 peak horsepower and 602lbs-ft torque at 4,600rpm. For some, the emergence of the new Street Demon and the re-emergence of a new 409 have been the biggest hot rodding news of 2012. Earlier in a comparison test, twin Edelbrock AVS carburetors had generated a commendable 553hp @ 5,800rpm and 575lbs-ft torque @ 4,470rpm. Why had the Street Demons triumphed by 49hp and 27lbs-ft of torque? “I imagine,” said Lamar, “its supremacy lies in the size of its secondary throttles.” Unlike any conventional 4-barrel layout, the Street Demon is a three-barrel carburetor inhibited by few restrictions—the secondary throttle bore is one big opening. It’s taken Demon a while to compose a convincing answer to the Edelbrock AVS. But once Larry Tipton, Demon’s distinguished senior designer, focused his creative energy on the new design in 2010, we suspected a beacon of carburettor ingenuity could be in the works. And when it appeared on May 25, 2012, it not only looked the part in a market where appearance is of primary concern but also it proved to be a very strong performer. Based entirely on a brand-new concept this innovative three-barrel 625 Street Demon has noticeably smooth contours especially around the air entries, unlike its Edelbrock counterpart. Though both carburetors have dual mounting points, accommodating square-bore or spread-bore manifold mounting without adapters, Tipton is particularly pleased with the effectiveness of his triple-stack boost... read more

Understanding Camshafts

An explanation of the basic terms and component relationships of the valve train. This story appeared in Hemmings Muscle Machines. To read the full story click... read more

Beerhorst on boosted engines and how a Spintron finds power and detects trouble

Written by Moore Good Ink: HOT ROD magazine has been at our industry’s forefront longer than most of us have been around. Though they’ve been sustaining the momentum of hotrods since January 1948, often it’s to their big ideas they owe their supremacy. Reflect for a moment on one of their biggest and brightest: HOT ROD Drag Week™. Presented by Gear Vendors, this may be the toughest test ever invented for the engine builders of high horsepower road-registered muscle cars. The rules require the cars to travel approximately 1,400 miles on public highways over the course of five days in late spring and participate in a week of drag passes. Those that survive the journey and record the best five-day average at the drag strips win their class. Clearly, the emphasis on survival is high, particularly in the Unlimited and Modified classes where some vehicles pack 2,000hp at the rear wheels. Of the approximately 186 starters in last year’s Drag Week, which also included Daily Driver classes, 106 powerful Muscle cars started but only 87 of them finished, 7 of them failing on the first day. So how do these extraordinarily powerful engines succeed in this most grueling test? Accomplished race engine builders are individuals with rare abilities. They have endlessly inquiring minds, unusual vitality, and remarkable resilience—Facebookers and Tweeters they ain’t. They simply don’t have time for it. So how can you reach them when they aren’t working? In a 25-minute chance meeting at the Trend Performance booth at last December’s IMIS show in Indianapolis, Norm Beerhorst agreed to answer a few questions on his successes with centrifugal... read more

Why introduce metallic-sintered materials to a regular clutch assemblies?

Written by Moore Good Ink Columbia, SC: Launched in 2010, Ram’s Force 9.5 dual-disc units are not new. What is new, however, is by combining it with their 900 series friction disc, the clutch assembly’s capacity is increased from handling around 700hp to around 950hp. These new clutches fit all popular applications, including Corvette, Camaro, Mustang, and early muscle cars. Using a metallic-sintered iron-based material that is compressed under high heat to bond it to the backing plate, the 900 series disc has a higher coefficient of friction than the standard organic materials. Thus it combats heat better and offers increased holding power. Also relevant is its light weight and that it operates with a six-spring hub instead of eight. The Force 9.5 is small and remarkably light—weighing approximately 38lbs compared with, for example, the standard LS arrangement, which weighs around 57lbs and measures 11.750in. This combination of compact size and light weight hastens engine response. The effects of faster acceleration and deceleration are unmistakable. Devised as an economical, entry-level unit, Ram’s Force 9.5 is guaranteed to meet the exact height dimensions of the original factory clutch-flywheel assembly, thus it’s a direct bolt-in fit. The Force 9.5 cover assembly with metallic-sintered 900-series clutch plate is priced around $1175 while the organic version is $950. For further information contact: RAM Automotive Company 201 Business Park Blvd. Columbia, SC 29203 Telephone (803) 788-6034... read more