Last month, we walked you through the creation and assembly of a high-end Eagle 331ci stroker small-block built for JME Enterprises' Project Elvira by John Da Luz of JMC Motorsports in San Diego. This month, we're going to put Elvira's 331 through its paces on Westech's dynamometer in Ontario, California. Our objective is to show you what works and what doesn't. What surprised us most about this series of dyno tests was that they contradicted a lot of theories out there about power and what it takes to get more.
When we took Elvira's 331 stroker to Westech, there were actually two trips, and two very long days of dyno testing. Our first trip to Westech on May 2, 2002, consisted of 17 dyno pulls in different induction configurations and tuning. There were also minute adjustments to the ignition timing. Not convinced we were as successful as we could have been, we went back to Westech more than a month later on June 19 for nine more pulls. We're eager for you to see the results. But remember, you have to go through hell to get to heaven. There was a lot of work ahead of us.
May 2, 2002
It was a warm day in Southern California. After a 150-mile drive from San Diego up California's I-15, Julio Mayen and John Da Luz were ready for coffee, an engine hoist, and a dyno cell. More than anything, these gentlemen were interested in results. It had been a long and difficult engine buildup, with all kinds of problems that kept them assembling and disassembling the short-block until they had it right. Arriving at Westech to find out what this engine was made of was both bitter and sweet. Julio and John both knew it could go either way.
When John Beachtel and Steve Bruel of Westech installed our 331 on the dyno, there was lots of apprehension. Our goal for this engine was 500 hp. Were we being realistic? And were our struggles during the buildup an omen for things to come? Turning the crank and lighting the mixture would be the only way to know. There is something religious about starting an engine for the first time. We had a brand new 5.0L Ford block from Summit Racing Equipment. Everything inside that block--pistons, rods, crankshaft, camshaft, and valvetrain--was all brand new. It would be this engine's first time hot and under the gun.
When Westech's Steve Bruel fired the engine, he ran it at a fast idle for good warm-up, then did some lightweight pulls from 3,740 to 3,920 to get the Castrol 5W-30 oil good and hot. Timing was located at 34 degrees BTDC. Race Demon carburetor jetting was out of the box. On Warm-Up Pull No. 3, Steve leaned on our 331 and took it to 5,200 rpm. It was at this moment one of the freeze plugs blew out of the block, forcing us to shut it down for a fast repair. Par for the course with some dyno pulls. Steve looked at our numbers and decided to swap up on jet size to 78.
June 19, 2002
Convinced they could make more power, Julio Mayen and John Da Luz hauled Elvira's 331ci stroker back to San Diego and went to work. These guys closely examined the engine's data as it sat on the Superflow dyno. Overall, the Edelbrock Performer RPM Air-Gap intake manifold made 8.9 lb-ft more torque and just 5.5 hp less than the Victor Jr.--pretty good for a dual-plane intake manifold. Not bad for most folks, but not for Julio and John. They were determined to blow the benchmark off the map. Here's what they did.
Air Flow Research (AFR) provided JME Enterprises with AFR 205 heads with larger 2.02-inch intake valves for better breathing, and springs designed to accommodate solid roller lifters. These castings and stopcocks would surely close the gap, being so close to 500 hp. But would they? For added insurance, John and Julio fitted Elvira's 331 with 1.7:1 Comp Cams roller rockers to compensate for valve lash and maximize valve lift. Because they didn't want valve float at 6,500 rpm, they opted for mechanical roller lifters, also courtesy of Comp Cams. These lifters would ensure valvetrain stability to 7,000 rpm. Also added to Elvira's 331 for Round Two is a Meziere 5.0 electric water pump. This pump will ensure a constant water flow and reduced parasitic horsepower loss since a belt will no longer be required to turn the pulley to pump water through the motor.
Although John and Julio were convinced they had taken the Edelbrock Performer RPM to its very limits with the cam and cylinder heads chosen during the May 2nd dyno experience, both the RPM and Victor Jr. would return for the next round of pulls. A Wilson 11/4-inch open-plenum spacer tops the Victor Jr.Castrol 5W-30 engine oil is an outstanding lubricant for high-performance engines. But Royal Purple synthetic 5W-30 is slipperier. With less friction throughout, we stand to use power where it counts--at the crankshaft.
The Long Road
As you can see, making horsepower and torque isn't as easy, or as simple, as many of us perceive. It takes a lot of mental and physical energy to make power. Mental energy is the creative side, where we determine what to do next. This takes a lot of thought and a vast knowledge of what happens inside an engine to make power. Physical energy is the effort involved--swapping components, making adjustments, and testing, testing, testing.
When you study the numbers above, it becomes clear you're only going to make just so much torque with a given amount of displacement. Despite every single change made to Elvira's 331ci small-block, torque never varied more than 13 lb-ft across 14 dyno pulls. Horsepower baselined at 480.5 and peaked at 505.9. Our message here is simple. There is no such thing as bolt-on magic. To make 500 hp and 420 lb-ft or torque from 331 ci, Julio Mayen, John Da Luz, and Steve Bruel had to put every ounce of their wits into the end result. Two days' worth of dyno testing netted just 25 hp and a variation of 13 lb-ft of torque. Persistence and the willingness to try seemingly useless adjustments and changes can often make the most significant changes in power. In this case these gentlemen not only met their goal of making 500 hp from a naturally aspirated small-block 331, but the horsepower/cubic-inch ratio ended up being 1.53 hp per cubic inch. Any engine builder will agree that this is a very respectable accomplishment.
Rejetting the carburetor and regapping the spark plugs netted the greatest improvements in power. Yet a head swap did very little for power. What does this tell you about what you can do for your engine, without even having to order a set of heads? Be modest in your power expectations and work from there. Little by little, one step at a time, you will meet the goal. And remember something else. You must plan for power. It does not happen by accident.