Tech Talk

 

Tech Talk #84 – Dry Sumps Save Lives

DavidTechArticles

By David Reher, Reher-Morrison Racing Engines

“In a wet-sump engine, the rotating assembly whips the oil like a milkshake in a blender.”

It’s great to be back in the pages of National Dragster after taking a break from writing columns. I appreciate the many comments from racers and readers, and I’ll attempt to come up with interesting topics now that I’m back on the keyboard. Continue reading

 

Tech Talk #83 – Engines Are Engines

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“I’ve learned that engines with pistons and valves are fundamentally alike.”

I count myself among the fortunate people who enjoy going to work every day. The fact is that I love working on engines – all kinds of engines. After nearly 40 years of messing around with motors, I’ve learned that there are more similarities than differences in various types of engines.

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Tech Talk #82 – The 400-Horsepower Tune-up

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A basic nitrous oxide injection system can make a huge difference in fast Sportsman racing.”

I’ve been around drag racing long enough that I can remember when racers first reached many of the sport’s performance milestones that are being celebrated during NHRA’s 60th anniversary season. There was a time when a 6-second elapsed time was sensational. Don Garlits was so elated to run in the sixes that he famously shaved his beard on the starting line after winning the 1967 U.S. Nationals. Today, however, six-second runs are commonplace – and they have become the price of admission in fast sportsman eliminators like Top Dragster and Top Sportsman.

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Tech Talk #81 – Takin’ It to the Streets

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“It’s astounding to think about driving a car with 1,000 horsepower on the highway.”

One of the recurring themes in automotive advertising is the notion that racing improves the breed of production cars. There’s strong evidence to support that idea, at least in engine technology. Not too many years ago, 300 horsepower was a stout number for a showroom engine. Now it seems that every four-door sedan has 400+ horsepower, and high-performance models have more than 600 horses under the hood.

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Tech Talk #80 – Getting to Know Nitrous

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Something that looks simple from the outside is actually incredibly complex.”

There was a time in my life when I thought that Pro Stock was the center of the universe. I’d spend every minute of the day – and many sleepless nights – thinking about how to extract more horsepower from a 500-cubic-inch Pro Stock engine. Unfortunately, focusing so intensely on one combination can lead to a severe case of tunnel vision. I didn’t appreciate the much wider world of racing engines until I retired from Pro Stock.

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Tech Talk #79 – Are Burnouts Abusing Your Engine?

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“How a drag racing engine is treated during burnouts has a lot to do with its long-term reliability.”

In my recent back-page columns, I’ve focused on the mechanical side of drag racing – cooling systems, lubrication systems, fuel systems, and ignition systems. This time I’m going to address a different topic: How a driver’s burnout technique can affect the engine and chassis.

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Tech Talk #78 – The Big Chill: How to Avoid an Engine Meltdown

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Most drag race cooling systems are utterly inadequate to dissipate such staggering heat.”

An engine has two fundamental needs: lubrication and cooling. Racers typically devote a great deal of time and money to oiling systems, devising windage trays, baffles, deflector screens, and dry-sump systems to ensure continuous lubrication. In comparison, drag race cooling systems are almost an afterthought – and that’s a grave mistake.

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Tech Talk #77 – Back to Basics

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“There are some basic skills that must be mastered to build an engine successfully.”

I traveled backward in time last week. It happened while we were rebuilding a big-block Chevrolet engine. This particular engine won the 1982 NHRA Pro Stock championship, and overhauling it was like firing up a time machine.

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Tech Talk #76 – The Titanium Solution

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Installing titanium valves is simply the best way to improve a racing engine.”

The same properties that made titanium the metal of choice for nuclear submarines and high-altitude spy planes during the Cold War also make titanium an ideal material for engine valves. Depending on its alloy, titanium is 45 percent lighter than steel and twice as strong as 6061-T6 aluminum. Replacing steel valves with titanium is simply the best way to improve a racing engine.

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Tech Talk #75 – Year-End Observations

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A great car setup can’t overcome a bad engine, and a terrific engine can’t win in a lousy car.”

Although it’s been several years since Reher-Morrison Racing Engines last competed full-time in NHRA Pro Stock competition, I still follow the category with interest. The fact that we have expanded our engine business with customers competing in classes ranging from Pro Mod and Top Sportsman to tractor pulls and 400 mph Bonneville land speed racers has given me a fresh perspective. Since this issue of National DRAGSTER celebrates the accomplishments of this year’s Pro Stock champion, I thought I might offer some observations on the state of the class.

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Tech Talk #74 – The Oil Pan Paradox: Power or Reliability?

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The most powerful oil pan is not necessarily the best oil pan for a sportsman drag racing engine.”

It’s an article of faith among racers that there is “free” horsepower to be found in an engine’s oiling system. Reducing windage and cutting frictional losses can indeed improve engine performance. Unfortunately, the unintended consequences of these horsepower-enhancing techniques can be a loss of reliability, followed by a big repair bill.

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Tech Talk #73 – The Pinnacle of Piston Engine Development

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Building better engines was literally a matter of national survival.”

As a professional engine builder and a self-confessed motorhead, the development of internal combustion engines is both my livelihood and my passion. While unlocking a few more horsepower in a racing engine is always rewarding, I recognize that ultimately it’s not a matter of life and death. There was a time, however, when the fate of the world literally depended on engine development.

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Tech Talk #72 – The Price of Knowledge

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Quality is remembered long after price is forgotten.”

Anyone who buys a “Rolex” watch on the Internet for 25 bucks has a pretty good idea that it’s not the genuine article. Producing and selling counterfeit products is a lucrative global business, and it’s not just high-end luxury goods like watches and leather goods that are knocked off. There are black markets for everything from blue jeans to perfume. In the traditional auto parts business, name-brand oil filters, spark plugs, and brake pads have been counterfeited by unscrupulous operators who sell low-quality parts in familiar looking boxes.

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Tech Talk #71 – Racing Through Hard Times

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Next year, when the weather turns warm and the days grow longer, racers will still be racing, and fans will still be watching them.”

Along with death and taxes, the third inevitability in our lives is change. Certainly the world has been going through some major changes in the last few months, and most were not for the better. But I’m not going to join the drumbeat of depressing news – there’s already a surplus of doom and gloom on television and the Internet. The fact is that racers are going to find ways to race in good times and in bad times.

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Tech Talk #70 – Airflow Fallacies: Avoiding the Pitfalls of the Flow Bench

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The pursuit of a big cfm number has ruined countless cylinder heads.”

“What’s it flow?”

Whenever a conversation about cylinder heads begins with that question, I cringe. I know where this discussion is going, and it’s not good. When a racer wants to distill the performance of a highly developed cylinder head down to a single number, I know I’m dealing with someone who is fixated on the flow bench.

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Tech Talk #69 – The Land of the Giants

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A new generation of 800-cubic-inch engines has turned those old Mountain Motors into molehills.”

Back in the early days of Pro Stock match racing, any engine with more than 500 cubic inches of displacement was labeled a “Mountain Motor.” Now a new generation of 800-cubic-inch engines has turned those old Mountain Motors into molehills. Continue reading

 

Tech Talk #68 – Playing With Fire

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The bad fires are the ones that happen away from the race track.”

Last year I watched my neighbor’s house burn down. I don’t mean he had a barbecue fire that singed his hamburgers. No, he had a blaze that took the house right down to its foundation. A small fire that began as a short circuit under a deck quickly became an inferno when it reached the chemicals and solvents that were stored in the garage. Fortunately no one was injured, but the house was left in cinders.

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Tech Talk #67 – The Hidden Cost of Free Horsepower

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“For sportsman racers, using low-viscosity oil is a lot of hassle, expense, and risk for a few horsepower.”

There are two paths to improving engine performance: increase efficiency or reduce parasitic losses. An engine is like a balance sheet – the power produced by burning fuel is an asset, while internal friction, pumping losses and windage are liabilities. The difference between the power produced in the cylinders and the total losses is the engine’s net output.

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Tech Talk #66 – Go Big or Go Home

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Increasing cylinder bore diameter is the proverbial free lunch – and for once, it really is free.”

Is bigger always better? It depends on the circumstances. A bigger transporter, a bigger horsepower number, or a bigger budget is usually a good thing in motorsports. But a bigger mortgage, a bigger gas bill, or a bigger headache is not usually desirable.

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Tech Talk #65 – The Right Tool for the Job

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“There are several tools that I consider absolutely essential for racing.”

I can’t remember how many cars, trailers, and trucks I’ve owned since I started racing. Most of them are long gone, but I still have many of tools that I used in the back room at Mansfield Auto Parts when I first started to mess with engines some 40 years ago. Good tools are an investment that lasts a lifetime.

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Tech Talk #64 – Why Stuff Happens

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“If a racing part never fails, then it’s probably too big, too heavy, or too slow.”

Washing machines, refrigerators, and pickup trucks come with warranties. Race cars don’t. You can get reliability ratings on televisions, lawn mowers and bicycles from Consumer Reports. You can’t find out how reliable a racing engine is from a magazine.

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Tech Talk #63 – Spare the Rod and Spoil the Engine

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Connecting rods tend to be taken for granted – until they break.”

Imagine riding an elevator that makes a 10-story round trip 7,000 times a minute, alternately stretching and compressing its occupants with every cycle. That’s exactly the kind of punishing treatment a connecting rod endures. A connecting rod must bear the compression force of thousands of pounds of cylinder pressure, withstand the tension loads produced by the piston’s inertia at TDC, and survive the bending loads that try to push the piston through the cylinder wall.

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Tech Talk #62 – The Truth Isn’t What It Used to Be

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“If you want to move forward, you have to look where you’ve been.”

In the 11th century, it was a fact that the world was flat. Any medieval scholar, astronomer or captain could affirm the self-evident truth that the Earth was the center of the universe and that anyone who ventured too close to the edge would fall off into the abyss. It wasn’t until centuries later that skeptics like Copernicus, Galileo and Columbus reasoned that our world was actually a tiny globe orbiting a distant star. Reality hadn’t changed, but people’s perceptions did.

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Tech Talk #61 – No Compromise? No Way!

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The best racing engine is usually the one that has the best set of compromises.”

There is a widely held belief among racers and fans that a racing engine is a no-compromise design. Auto manufacturers must balance the conflicting demands of performance, fuel economy, emissions, long-term reliability, smoothness and cost when they design an engine for mass production. In racing, the requirements are pared down to the basics: power, reliability, legality, and affordability

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Tech Talk #60 – How to Beat the Heat

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“On a blistering summer day, it’s unnecessary to warm up an engine excessively.”

As a Texas resident and taxpayer, I know about long, hot summers. Long before anyone on TV talked about global warming, I was enduring month-long sieges of 100-degree heat. Without the advent of air conditioning, Dallas would probably be just a sleepy gas stop on Interstate 20.

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Tech Talk #59 – Planning for Performance

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“We’re making more than 1300 horsepower with engines that were originally designed to produce perhaps 400 peak horsepower.”

Whether you’re remodeling a kitchen, coaching a basketball team, or racing for a championship, you’ve got to have a plan. In my last column, I wrote about the importance of the fun factor in drag racing. For the vast majority of racers, it’s not about the prize money – it’s about the enjoyment and personal satisfaction that comes with a fast run, a perfect reaction time or a round win. Developing a plan – and then sticking to it – is the key to maximizing the fun and minimizing the cost of racing.

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Tech Talk #58 – Just for Fun

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The reality is that racing is a form of recreation for most participants.”

I don’t know whether absence truly makes the heart grow fonder, but I do know that it changes your perspective. After living on the front lines of the Pro Stock wars for nearly 30 years, I’m now enjoying some time away from the trenches. While I still respect the intensity of the competition in Pro Stock, I’ve gained a new appreciation for a side of our sport that’s sometimes overlooked by professionals: Racing is fun.

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Tech Talk #57 – The CNC Fallacy

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A CNC machine can’t distinguish between a good part and a bad part.”

Every decade has its buzzwords. In the ’30s, it was “streamlining;” in the ’50s, anything “atomic” was cool (except perhaps The Bomb). The ’80s were all about “turbo”, and ’90s were the Digital Decade. For many drag racers, the buzzword for the 21st century is “CNC,” an acronym for Computer Numerical Control.

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Tech Talk #56 – How to Avoid the Hop Up Trap

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“An engine is never worth more than when it’s assembled and running.”

Anyone who flies enough miles in airplanes or stays enough nights in hotels eventually qualifies for “free” upgrades. Of course, these upgrades come with a price – they’ve been paid for with time, money and the aggravation of life on the road. With a new racing season about to begin, many racers are thinking about upgrading their engines – but like first-class seats and hotel suites, there’s a price to pay for an upgrade.

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Tech Talk #55 – Keeping Cool

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Some racers have the mistaken belief that antifreeze improves cooling efficiency.”

With winter fast approaching, it’s the time of year when people start thinking about preparing their cars for cold weather. Anyone who lives in the Snow Belt knows that antifreeze is an essential part of winter survival. But I’m going to make the recommendation that you should never use antifreeze in a drag race engine.

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Tech Talk #54 – The Spark of Life: Ignition Systems for Sportsman Racers

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The most important electrical tool a racer can own is an ohmmeter.”

The combustion triangle we learned in science class defines an engine’s three essential needs: fuel, air and spark. If any of these three items are inadequate, the engine can’t achieve its maximum performance potential. I’ve written columns about fuel systems and airflow, but I’ve not previously addressed the importance of a reliable ignition system in drag racing. This month I’ll try to fill in that missing leg of the combustion triangle.

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Tech Talk #53 – Big Bore or Long Stroke: Which Is Better?

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“An engine produces peak torque at the rpm where it is most efficient.”

Recently I’ve had several conversations with racers who wanted to build engines with long crankshaft strokes and small cylinder bores. When I questioned them about their preference for long-stroke/small-bore engines, the common answer was that this combination makes more torque. Unfortunately that assertion doesn’t match up with my experience in building drag racing engines.

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Tech Talk #52 – Aerodynamics for Everyone

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A smaller, slicker car is the best of both worlds.”

Although I’m an “engine guy,” I’ve been around racing long enough to gain a working knowledge of aerodynamics. I’m also an avid amateur pilot, so I’ve developed an eye for airflow. While I don’t have formal training in the science of aerodynamics, I can look at a race car or a Cessna and come up with a fairly accurate notion of its aerodynamic characteristics.

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Tech Talk #51 – Crank Calls, Part II

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Under most circumstances, a cross-drilled crank is going to cause big problems.”

There’s big money in sequels. Just ask George Lucas; he’s managed to extend the Star Wars series to nine movies. Unfortunately I don’t think this second installment of my two-part column on crankshafts is going to challenge Revenge of the Sith at the box office. After all, a crankshaft is just not as exciting as a light saber.

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Tech Talk #50 – Crank Calls

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“These choices have serious consequences when a 75-pound chunk of machined steel is spinning in the heart of an engine.”

Once upon a time, a 454-cubic-inch engine was considered a big motor, and anything over 500 inches was referred to in awe as a “Mountain Motor”. But like Big Gulps and the budget deficit, everything is bigger in the 21st century – especially drag racing engines. While we’ve run 500-cubic-inch engines in Pro Stock since 1982, the rest of the drag racing world has adopted 600ci, 700ci, and even 800ci motors.

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Tech Talk #49 – Wrist Pins and Unintended Consequences

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“As power levels have escalated, many racers are using wrist pins that are just too light.”

I come from a family of teachers, so perhaps I’m genetically programmed to stand in front of a classroom. Maybe that’s the motivation behind the engine building classes that we conduct regularly at Reher-Morrison Racing Engines. What I’ve discovered, however, is that a teacher learns as much from the students as the students learn from the teacher.

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Tech Talk #48 – The Fundamental Things Apply

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Why does an engine with standard parts run better than one with all of the latest tricks, gizmos and gadgets?”

Sometimes technology can go too far. I recently purchased a cell phone that came with an instruction manual as thick as a brick. I use a telephone for one reason: to make calls. I didn’t buy a cell phone to play video games, take fuzzy photographs, download disco music, get directions to my house or monitor the stock market.

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Tech Talk #47 – Raising the Redline: Why RPM Matters

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“I’m excited about the emerging trend toward fast sportsman drag racing.”

Looking back at the 2004 season, I can attribute much of the performance improvement in Pro Stock to faster engine speeds. It’s difficult to believe that 500cid Pro Stock engines now routinely turn 10,000 rpm, but the truth is plain to see on the data recorders and on the time slips.

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Tech Talk #46 – The Simulation Situation

By Darin Morgan, Reher-Morrison Racing Engines
DARIN MORGAN, author of this issue’s Technically Speaking column, is in charge of cylinder head research and development at Reher-Morrison Racing Engines.

“Comparing the Space Shuttle to a racing engine may seem like a leap, but in fact the underlying variables in an engine combination are equally mind-boggling.”

With four national events in four weeks, including two round trips to Maple Grove Raceway, David Reher has been spending more time sitting on airplanes than on writing his column for National DRAGSTER. David asked me to pinch hit for him in this issue, and since my subject is computer simulation, you might think of this as a simulated David Reher article.

Engine simulation software is a hot topic in the automotive industry. Sophisticated programs such as WAVE and MANDY cost millions of dollars, which limits their customer base to auto manufacturers and Formula 1 teams. For the rest of us, there are engine simulation programs with prices that range from less than $100 to several thousand dollars.

I admit that I’m addicted to engine simulation software. I’ve played with numerous programs, and I’ve spent hours running “what if?” scenarios. But as a professional engine builder, I also understand the limitations of these programs. Unfortunately, some racers don’t.

In my conversations with simulation software designers and code writers, I’ve learned that these programs were never intended to design an entire engine. Rather, their primary objective is to note specific trends of individual changes. In other words, a program can tell you with reasonable accuracy what the likely result will be if you change the bore, stroke or runner length in a Corvette LS1 engine. It can’t tell you how to build a Quick 16 engine from scratch.

My specialty at Reher-Morrison Racing Engines is cylinder head development. I’m frequently asked about equations or formulas that can determine specific engine design criteria. Customers want to know how to calculate the perfect port volume for an engine, how to select the ideal intake manifold, or how to determine the optimum valve diameter for a runner. They want a magic formula that explains how a racing engine works – but such a shortcut simply doesn’t exist.

Consider the Space Shuttle. It’s just an airplane with rocket motors, right? But when you look into the details of launching, flying and recovering the Shuttle, it becomes apparent that this is a task of mind-boggling complexity. The variables are almost infinite.

Comparing the Space Shuttle to a racing engine may seem like a leap, but in fact the underlying variables in an engine combination are equally mind-boggling. If you don’t understand what these variables actually do, it’s tempting to plug numbers into a simulation program until you get the results you want. One likely consequence of this approach is to design an engine that’s not applicable in the real world.

Here’s an example. Recently a racer questioned me about all of the components in one of our Super Series bracket racing engines. I gave him the information he requested, and he modeled the engine with a simulation program. His results were fairly accurate, with an error of about 2.5 percent (20 horsepower), which I thought was reasonable. But the software stated that if the exhaust duration were increased 10 degrees, the engine would gain 25 additional horsepower. I just wish it were that easy!

We’ve built and dyno tested dozens of these engines. They’ve logged thousands of runs on drag strips. Now a customer tells us that we left 25 horsepower on the table. But what the simulation software didn’t allow him to do was input the discharge coefficient of the exhaust port. In other words, the program didn’t “know” the design specifics of the exhaust system. It based its calculations on simple airflow, and therefore didn’t have enough information to generate a realistic answer.

You still need experience and knowledge to get it right. The more complicated the software, the more essential this real-world database becomes. When dealing with ultra-high performance engines, the details become so subtle that no software can simulate them. In a high-end racing engine, a tiny change in the approach to the valve seat or the contour of a piston dome can produce a measurable difference in performance on the dyno and on the drag strip. Even Ferrari, with its whiz-bang Formula 1 simulation software, still has to build, test and validate any change in hardware before taking it to a race.

It’s a mistake to put blind faith in a computer program. Some programs are certainly more accurate in their predictions than others, but they all have shortcomings. Building an engine on a computer screen is no substitute for bolting together the parts and running it down a track. To my knowledge, a virtual engine has never won an NHRA national event.