The NASCAR Winston Cup engine...
The NASCAR Winston Cup engine you see here (below) is not that much different from the engines that run every Saturday night at your local short track. The techniques used to make the Winston Cup engines so durable and consistent are within a short-track, weekend racer's grasp.
Editor's Note: Months in planning, this multi-part series deals with fundamental areas of engine building used in Winston Cup that can apply directly to other classes of racing. Chuck Jencks and Jim McFarland, each representing decades of involvement in circle-track racing, compiled the material. Jencks is a mechanical engineer, formerly with Summit Racing, a past powertrain engineer for Joe Gibbs Racing, and currently doing engine R&D for a premier Cup team. McFarland is a product-designing automotive engineer, 30-year journalist, and member of the Circle Track Tech Council. Readers of this series will discover new thoughts and ample reinforcements for building consistent, powerful, and competitive "Saturday-night" engines. Jencks lays the hard-core foundation and McFarland provides the theoretical flavor.
There are certain aspects of Winston Cup engine programs that apply directly to engine building for other classes of racing. To make this clear, we must first examine some of the more important topics. So, first things first
Getting started Everyone wants to know the secrets of building a race-winning, 800hp Winston Cup engine. Well, here they are: excellent planning, a thorough understanding of the basics, an unbelievably hard-working and dedicated staff (team), fanatical attention to detail, a testing program second to none, and a budget to support the effort. And even if you can only adopt and apply portions of this set of "secrets," your engine-building program will improve, even if it's just you and your set of tools. No single piece of rocket science will make the power you want. Today's Winston Cup engine is an ultimate example of the process of continuous improvement.
Before you laugh and begin comparing the multi-million dollar budgets, scores of people, and state-of-the-art equipment to the appearance of your garage or shop, you may be interested in the similarities between successful programs on all levels of racing and how they might apply to your own. For example, a few years ago, a book entitled The Seven Habits of Highly Successful People was a best-seller. Its core message was that by adopting common traits of successful people, it's possible to become more efficient and more successful on your own. In a similar fashion, not all of what will be discussed here may be applicable to your particular racing program. But rest assured, the topics will at least be thought-provoking and worthy of consideration.
Many of today's Winston Cup head engine builders built winning engines at a variety of levels before rising to the top in Cup racing. So what goes on in a Winston Cup engine shop that could possibly benefit the "Saturday-night" builder?
What is Important
You must first honestly evaluate what part an engine plays in the entire vehicle performance picture. Further, what part of its performance is the most critical? Circle-track racing is not drag racing. In drag racing, engine output is as important as any single element in the sport. In circle-track racing, engine output alone is probably not even one of the top three factors required for a winning car. Engines are important, but any Winston Cup head engine builder will say that durability and consistency are the key performance factors for winning races and championships, not engine power.
When it comes to engine performance, it's production of torque and horsepower must be created in the rpm range that the driver will use the most. This is an important point to research and will be key information in the determination of what and how the engine will be built. For example, if the engine is to be raced at many different tracks and the rpm range varies widely, a much more flexible combination (in terms of rpm range) must be built. Also important, don't forget to take into account how much the rpm range drops on long runs due to tire wear.