7/1/2002
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Bench Racing and Dyno Testing
Business has been flat to down for many engine builders and their suppliers over the past year or more. However, there was still a great deal of interest from 140 registered attendees at the 12th annual Advanced Engine Technology Conference (AETC) in Colorado Springs, CO, held late last year at the Sheraton Colorado Springs Hotel.
Several significant changes this year made the AETC a more valuable experience. At check in, attendees were given a three-ring binder, with an itinerary for each day. This was a great improvement over past events, when literature was handed out during the breaks just before each speaker’s presentation.
For three days featured individual presentations brought together rabid gearheads, including master engine builders, design engineers, airflow experts, dyno wizards and performance system manufacturers to obtain and exchange information on cutting edge technology.
Here’s a brief review of some of the interesting information shared among those in the high performance engine building business.
Wade Congdon
Application Engineer,
Hi-Techniques Inc., Madison, WI
The presentation, "Inside the Fire Storm in the Combustion Chamber," covered high-speed data acquisition related to engine cycle analysis (ECA), and other pressure/cycle measurements. Congdon discussed the equipment required, different data acquisition systems, pressure transducer technologies, transducer mounting options, signal conditioning and analysis of the data collected. After a primer on equipment required for various types of pressure/cycle data gathering, he covered data analysis and interpretation, showing how ECA can be used to analyze combustion pressures, cylinder-to-cylinder variations, knock tendencies, engine harmonics, valvetrain analysis, and tuning individual cylinders for maximum power. This is technology used by top engine builders worldwide, and if you need to wring every last horsepower possible out of an engine combination, it is an essential tool of the trade.
Jeff Coughlin
New Products Powertrain Manager, Harley-Davidson
Milwaukee, WI
The new Harley-Davidson V-Rod 1131 cc, liquid-cooled, rubber-mounted, counterbalanced, dual overhead cam (DOHC), four-valve, 115 hp, 60-degree V-twin motorcycle is the first of a new family of liquid-cooled performance custom bikes from Harley-Davidson, according to Coughlin. It is not intended as a replacement for any existing models, rather it is H-D’s entry into the arena of custom high performance bikes. The V-Rod incorporates the elements of styling, sound and feel that are traditional to Harleys, yet utilizes contemporary technologies.
From the four-valve, overhead cam format of the engine, to the unique "two-into one–into two" exhaust system, it would appear that Harley looked at every operational feature of its existing bikes, and tried to apply as much of the latest technology as possible without losing the company’s identity in the process.
Ai (Woody) Wood
President, Detroit Racing Components, Ortonville, MI
In an encore presentation from a previous conference, Wood discussed the application of Apticote 2000, sometimes referred to as Nikasil (NiSiC), to cylinder bores for improved oil retention, friction reduction, improved scuff resistance and longer cylinder life.
In the case of cast iron automotive blocks, the coating can be applied directly to the bores in a block, or the block can be modified to utilize replaceable liners. If the engine already has freestanding cylinders or replaceable liners, the process involves simply applying the coating to the cylinder or liner.
The process can also be applied to aluminum bores, and has been used in aluminum two-cycle engines for some time. Piston ring recommendations for use with NiSiC-coated cylinders include plasma moly and ductile iron, with unplated oil rails.
Wood had a small block Chevy block on display that had been machined to accept replaceable liners, and some of the discussion centered on the problems associated with the area between cylinders where the liner flanges must be butted against each other. The valley area of the block had also been fully CNC machined for weight reduction, and was nicely done.
Harold McCormick
President, C-K Engineering,
Ballwin, MO
After retiring from his engineering position at TRW’s Piston Ring Division, McCormick formed his current company as a consulting and test facility.
In the first part of his presentation, McCormick illustrated the effects engine geometry, temperature and bore-finishing technique have on cylinder distortion. Different combinations of materials in the block and head, such as iron block-iron head, iron-aluminum, aluminum-aluminum, etc, all have different effects on cylinder roundness, cylindricity and straightness. Throw in the element of temperature, and you have yet another variable that changes the actual running conditions of those cylinders from what you probably had when you honed them.
Did you hone that block with a cast iron torque plate and then bolt on aluminum heads? Does the intake manifold cause bore distortion when it’s torqued down? How about the temperature gradient from the top to the bottom of the ring travel in the cylinder, and from cylinder-to-cylinder, and around each cylinder?
State of the art is to hone the block in as close to actual running conditions as possible, leaving no stone unturned in your quest for perfection, because ring seal is paramount to the successful performance of the engine.
Moving to the piston and rings as the second part of the cylinder sealing exercise, McCormick illustrated methods of measuring the pressures around the rings in an engine running at 9,800 rpm, thereby pinpointing the exact nature of the problem of improving piston and ring performance. He also covered the effects of piston motion on the rings, and some of the factors of piston geometry such as skirt profile, skirt area and pin offset that affect piston motion. How about cylinder flex in response to the changing pressures it sees?
Greg West
Senior Product Engineer, Federal-Mogul Sealing Systems (Fel-Pro), Southfield, MI
Understanding head lift is important because as the cylinder head lifts away from the block, it unloads the crush on the gasket, and if severe enough will lead to gasket failure. Using a linear variable displacement transducer (LVDT), head movement is recorded at several locations around each bore at a known cylinder pressure such as 1,700 psi, and then it’s compared with other cylinders on the same head, and with known data from other heads.
If the data is not in an acceptable range, modifications to the fasteners and/or the head are made. The internal structure of the head – the posts that run from the deck to the opposite side of the head, the port layout, the integrity of the bolt bosses, etc. – are the most important areas controlling head rigidity.
The latest head gasket intended to cope with this problem is the multi-layered steel (MLS) design. In the MLS-type gasket, embossed beads are used to provide the sealing compression by acting as springs that will maintain sealing pressure during head lift.
West indicated that there were 30 different variations of embossing, dictated by the amount of head lift. Because these are steel gaskets as opposed to the composition type gaskets we all are familiar with, they must have a coating both between the layers and on the head and deck mating surfaces. This coating is less than .001˝ thick, and so block and head surface preparation becomes very important. The surface irregularities must be less than the thickness of the coating, and shops should use a profilometer or comparator to verify their work.
West concluded his talk by leaving us with some gasket tips: Use thread gauges to check the quality of the threads on the fasteners. Remove any coatings with a wire brush. Use moly lube on the threads, and 15 to 20 lbs. steps when torquing. Cold retorque – break loose and retorque one bolt at a time, with intake manifold installed.
Don’t chamfer edges of seal rib on cap or block, use fine emery cloth to deburr (Chevy). Use RTV (but very lightly) on parting edges of seal, and an anerobic compound on block-to-cap register.
Verify the angle of the heads and intake manifold match. Map your head gaskets – measure the gasket bore before installing and when taking apart. If it gets bigger, it’s a sign of detonation. Look for carbon tracking across the armors. Measure the gasket body armor and alter torque as needed to equalize loading on the gasket.
Bill Hancock
President, Arrow Engine Development Group, Rochester Hills, MI
Hancock covered practically every aspect of building and operating a test facility, including placing and maintaining the air, water and fuel supplies, the electrical system, safety considerations, exhaust and cooling considerations and much more.
All the while, he liberally sprinkled his talk with choice bits of practical information such as: "When building a dyno room, make sure the door is big enough to get the engine in," and "Never store anything in the room that you don’t want to go through the engine." Hancock also recommends, "Make only one change at a time.
Make sure your fuel system will flow an adequate amount of fuel at the correct pressure to support the intended horsepower. Have a light on the console to indicate that the exhaust fan is on." And, Hancock says, "Keep good records of each run."
Michael LeFevers
Engineer, Advanced Engine Technologies Inc.,
Los Angeles, CA
After some preliminary discussion surrounding the Shelby 427 Ford aluminum blocks and heads that he has been involved with, LeFevers detailed some of the developmental aspects of an entirely new engine concept, the OX2.
The OX2 is an eight-cylinder, four-stroke engine that weighs 125 lbs., is 6.9 inches wide and 12.8 inches in diameter. It has six major components, only three of which are moving parts. The cylinders and the pistons lay parallel to the axis of the output shaft, are spread in a circle around the central axis of the engine, and are articulated by a cam that somewhat resembles the agitator in a washing machine. Displacement is 68.7 cu. in.
At 500 rpm, each cylinder fires two times per revolution, equaling the number of pulses per minute as a V8 at 8,000 rpm. The simplicity of the design results in low production and maintenance costs, and its inherent efficiency makes it an economical power plant.
Dave Burt
Concept Development Engineer, Sturman Industries, Woodland Park, CO
The irony of a presentation on camless engine technology at a conference hosted in part by Competition Cams was not lost on anyone. Burt detailed the development of Sturman’s digital hydraulic operating system, or DHOS, and its application to diesel fuel injectors and camless valve actuation.
He showed an ESPN video of a semi-tractor, making the trip to the top of Pikes Peak, using electronically controlled hydraulically actuated fuel injectors and valves. With the Sturman design, it is possible to electronically control valve opening time, valve closing time, valve lift, valve flank speeds and valve seating velocity.
Virtually any valve lift curve – square, elliptical, stair step or whatever – is possible, and with computer control, the valve action can be optimized for any load and rpm requirement. As of February 2001, performance had been demonstrated to 10,000 rpm. Idle at 100 rpm, if you want, and still rev to 10,000.
Navistar was to have had fuel injectors using this technology in production in the first quarter of 2002, with engines using them coming soon after. I have also heard that BMW has a 2002 model with a cam-less engine that does not use a conventional throttle. Engine speed is controlled by varying valve lift.
Rick Roberts, PhD
Director of Engineering, Edelbrock Corp., Torrance, CA
Roberts detailed the process of bringing an intake manifold or cylinder head through development into production. Taking us through a step-by-step process from establishing performance goals to volume production, he detailed the design process for a manifold and a head, how a pattern and casting sand cores are made, and how they are assembled into production core boxes in preparation for the casting process.
Roberts’ session also covered cylinder head port and valve sizing, which involved a mathematical discussion on one-dimensional compressible flow, and a comparison of various intake and exhaust ports.
Some useful information presented included formulas that can be used to calculate manifold and port runner sizes; how graphs of flow coefficient vs. lift-to-valve diameter ratio (L/D) can be used to assess the high lift flow differences; and how graphs of valve lift curtain coefficients vs. L/D can be used to assess the low lift flow differences between designs with different diameter valves.
Kenny Duttweiler
President, Duttweiler Performance, Saticy, CA
Duttweiler, president of Duttweiler Performance, provided a brief summary of points to consider when setting up a turbo installation including: engine assembly – billet crank preferred, forged next best; 030˝ top ring end gap; .150˝ to .185˝ wall wrist pins; prefer dished piston over inverted dome – inverted dome uses more fuel and high pressure on piston causes it to cock in the bore and gall; 8:1 compression ratio with 15 lbs. of boost for street; no roller lifters because of high pressure on exhaust side; cam of 210-220 duration for street, 240-250 for single turbo race, 250-270 twin turbo race, 7/16 pushrod on exhaust side; and Inconel exhaust valve.
Headers – short as possible, merge type collector, 321 stainless for strength. Boost should equal backpressure. Intercooler – air to water, 4˝ inlet and outlet, capable of 2,000 horsepower – downside is weight (5-7 gallons of water, plus pump, etc.).
Lance Ward
Senior Systems Engineer,
Fuel, Air, Spark Technology (F.A.S.T.) Inc., Ashland, MS
After a brief history on fuel injection, and noting the difference between port and throttle body types of injectors, Ward, who works in the field of software development for digital fuel injection systems, pointed out that there are different strategies in use on triggering injectors: batch fire, where all injectors are pulsed at the same time; simultaneous double fire (SDF), all injectors every 360 crankshaft degrees; bank-to-bank, all injectors in alternating banks every 180 degrees; and sequential, each injector in sequence, once every 720 degrees for every combustion event. Of these, sequential injection results in the best fuel distribution possible, and has the least fuel rail pressure fluctuation.
In terms of fuel management philosophy, each of the above systems can be: an Alpha N, rpm and throttle position; a speed density, rpm and manifold pressure; or a mass flow, hot wire air flow sensor type. The difference is how the system determines the fuel flow requirements.
An oxygen sensor or two can be thrown in to further refine the fuel management, and Ward pointed out that conventional O2 sensors are only accurate at 14.7:1 air fuel ratio, whereas wideband, 7-wire sensors are accurate from 9:1 to 16:1, allowing closed loop operation over the entire engine operating band; as a bonus it’s compatible with alcohol fuel.
In addition to the many presentations, Superflow held its annual open house, with engines running on dynos and various other Superflow products such as the Cycledyne towing dynometers, and of course a flow bench.
The conference closed with a Wednesday evening gathering that offered attendees an opportunity to give their feedback on any topic related to the conference. A panel of conference speakers then fielded technical questions from the audience.
Scooter Brothers of Comp Cams and Harold Bettes of Superflow are actively seeking ways to improve the conference, and last year’s "gathering" in place of the usual closing banquet was a chance for the masses to give them some feedback.
One problem Bettes says he faces is getting speakers. Many people who would have very interesting information to present simply don’t have the time available in their schedule. Others, though very knowledgeable in their field, have a very real fear of talking in front of a group, and thus won’t attend.
If you have attended past conferences and have any suggestions you would like to see included in future events, or can suggest a speaker who would be interested in telling a story, email me your thoughts.
For information about the next AETC, to be held January 9-12, 2003 in Colorado Springs, CO, call 866-893-2382 for more information or by e-mail at info@aetconline.com. Or get full details at www.aetconline.com.