Tech Talk #31 – To Good To Be True

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

The 21st century has been called the Information Age, but I’m beginning to wonder whether it might be more accurate to call it the Infomercial Age. The advent of long-format television commercials has blurred the distinctions between advertising and reporting. If the production is slick enough, it’s difficult to discern the difference between a sales pitch and a documentary.

Many of the products that are pitched on late-night cable TV are simply too good to be true. Diet pills that melt fat, electronic stimulators that give you rock-hard stomach muscles and car waxes that make 20-year-old paint look better than new are certainly enticing – but how realistic are the claims? No magic pill or vibrating electrode is going to make my 52-year-old body look and feel like a teenager. But obviously enough people dial those 1-800 numbers with credit cards in hand to keep the TV merchants in business.

Unfortunately, I see some drag racers searching for the mechanical equivalent of the magic diet pill. They’re looking for that one part that will turn their race car into a winner. They want that magic cam or miracle carburetor that will add 50 horsepower, increase the engine’s operating by 2,000 rpm, extend engine life and produce perfect reaction times. Sound too good to be true? It is.

Racers who wouldn’t spend $19.95 on dubious diet pills will spend thousands on questionable engine parts. It’s unfortunate that the unrealistic claims for improved performance and trouble-free reliability made by some manufacturers, dealers and engine builders poison the water for all of the conscientious and knowledgeable people in the racing industry.

Whenever I see an ad that promises trouble-free performance from any part used in a racing engine, my skepticism shifts into high gear. By definition, racing parts are used under extreme conditions that push them to the limits of endurance – and sometimes beyond. A new coating or exotic material might be helpful in preventing bearing wear, but I guarantee that if you do several burnouts with zero oil pressure, the crankshaft is going to be in bad shape regardless of what you put on the journals.

I’m also suspicious of claims for absolute power increases. The interaction between engine components is simply too complex to assert that bolting on part “X” will produce “Y” more power. A new manifold might produce a measurable power gain – but only if the manifold it replaced was wrong for the application. It’s just as likely to reduce power if the original manifold was optimized for the combination. And when you consider the infinite combinations of suspensions, shock absorbers, converters (or clutches), and gear ratios that affect a race car’s elapsed time, it’s simply impossible to predict accurately how one part will improve or impede performance.

I’ve been told by people who should know better that a trick new fuel regulator or a top-secret carburetor float would improve the performance of my Pro Stock by a tenth of a second. I don’t know whether people who make such statements are dishonest or simply ignorant. If I added up all of the performance improvements that were touted in magazines, catalogs and ads, we’d have the first Pro Stock in the fours.

Let’s face facts. The power an engine produces is the result of how much fuel it can burn efficiently. All of the laws of chemistry, physics and thermodynamics apply to a racing engine. The push on the piston – otherwise known as brake mean effective pressure, or BMEP – determines how far the needle on the dyno moves and how fast the car can ultimately run on the racetrack. There are a lot of ways to make an engine perform below its potential, but there is no way to make a well-developed engine perform beyond its physical limitations. If you really want to raise the power level, you must either increase the engine speed or increase the pressure on the pistons.

Some parts have more miraculous attributes than others. No one buys a valve cover or connecting rod with the notion that those parts will add 100 horsepower. But a carburetor or a camshaft – those have mysterious properties in the minds of some racers. The reality is that a carburetor doesn’t increase manifold pressure. If you have a fuel curve that fits the engine’s needs and sharp throttle response, that’s about all you can ask for. At least carburetors are cool to look at and offer lots of adjustments, which adds to their air of mystery. Camshafts, in contrast, all look pretty much alike; without special fixtures and software, you’d be hard pressed to find the differences between two cams. So if a profile is promoted as being 50 horsepower better than anything out there, how can a grassroots racer separate truth from fiction?

My advice is to ask an expert. There are engine builders who are good at what they do, and you can identify them if you pay attention at the races. Years of racing experience have given them the insight to select parts that complement each other and to analyze results accurately. The good builders are graduates of the University of Hard Knocks, where the course curriculum is building engines, dyno testing engines and running engines on the drag strip. Experience matters.

Maybe the success of the infomercials says something about our society. We’re looking for the quick fix. Fifty pounds overweight? Take these pills or drink this potion and the pounds will just disappear, without dieting or exercise. Bankrupt, unemployed and under indictment? Just dial this telephone number and get the brand-new luxury car you deserve. Diagnosed with cancer? Our offshore clinic can prescribe magic pills that kill the bad cells without harming the good ones.

In drag racing, as in life, if it sounds too good to be true, it probably is.