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NHRA EXPLAINS F-M FUNNY CAR SUPERCHARGER RULES CHANGES

By Len Imbrogno

[chromeblower.jpg] Editor's Note: One of the "hot button" topics in NHRA's Sportsman drag racing ranks is all of the problems NHRA Federal Mogul Funny Cars and dragsters are having in the area of attendance, performance, and cost of racing. It is no secret that those classes have become increasingly expensive to participate in and the gap between the haves and have-nots is getting increasingly wider, causing the participation to drop off. Recently NHRA issued some new rules regarding blower overdrive limitations, which has caused some racers to cry, "foul" while others to applaud their decision. DRO's position is that we support any rule changes that will make the class more affordable or bring more players to the party. NHRA Director of Sportsman Racing and Member Tracks Len Imbrogno, who occasionally writes for DRO, has taken the time to explain the steps NHRA has taken and analyze the reasons why.

One of the most talked about rule changes for the 2001 NHRA season is the overdrive reduction rule for screw supercharger equipped Federal-Mogul Funny Cars. After discussing this issue with NHRA President, Tom Compton and Sportsman Racing liaison, Bob Devour, we all felt that an explanation of why a change was needed would help everyone better understand the reasoning behind the decision.

After accepting my new position as Director of Sportsman Racing and Member Tracks in late June, I spent a great deal of time talking with a cross section of Federal-Mogul sportsman racers and engine builders at NHRA division events across the country. When it came to the FM/FC class, most agreed that the cost to compete in this class has increased dramatically over the last five years. As a result, many competitors with good equipment and smaller budgets have fallen by the wayside.

Overwhelmingly, the reason most often sited was the advent of the screw supercharger and the subsequent increase in overdrive ratios through its history of usage in NHRA competition. Many felt that the effects of the screw supercharger to produce higher levels of boost than the roots style supercharger have resulted in two major problems:

Higher attrition rates of drive train parts and subsequently higher expenses for stronger, more expensive components.
Loss of ability to be competitive for the less expensive to operate roots style supercharged cars.

Firstly, racers and engine builders will generally agree that by reducing available levels of boost pressure at any given rpm, the life expectancy of engine and clutch components can increase. Cylinder pressure is a function of boost pressure and in every form of racing (with or without superchargers) where cylinder pressure has been effectively reduced (Formula one, Indy car, NASCAR, drag racing) engine life has been substantially increased.

In fact, many experts argue that reducing cylinder pressure in Top Fuel cars is a method that should be used to reduce engine explosions. True, rpm's can be increased to get back some of the boost, but in looking at the current rpm levels in FM/FC, racers are already exceeding the outer envelope of performance limits for valve train components. Not changing the blower overdrive will not stop racers from further attempting higher rpm's to increase performance, regardless of where the overdrive is. True, static compression can be increased, but it is no substitute for boost pressure, as any engine builder will agree.

Secondly, there are many that feel the overdrive rules change will allow the roots style supercharged cars to be more competitive. Diversity in the usage of the two types of superchargers is an important element in the continued growth of the class. Simply put, a roots car can be run more economically than a screw car. There are still a number of sportsman racers at the division level with roots equipped cars competing at assorted non-NHRA events across the country.

The biggest reason given by them for not running NHRA events has been their inability to be competitive against the more costly to operate screw supercharged cars. Racers and engine builders feel the rules change will now give roots supercharged cars an incentive to once again race at NHRA events.

Last of all, It is apparent that something had to be done to help this class. Doing nothing would only compromise its continued existence. Everyone at the NHRA, especially Tom Compton, knows how important the Federal-Mogul Funny Car and Dragster classes are to our future. We cannot forget the heritage of this great class or the sportsman racers for which the blown alcohol classes were created.

NHRA drag racing legends such as Dale Armstrong, Ken Veney, Joe Amato and many others have all come up through the Federal -Mogul style Funny Car and Dragster ranks. We cannot stand by and allow these classes to get further out of the reach of true sportsman racers that aspire to race blown alcohol cars.

Have we done enough? Probably not, but what we are doing by reducing overdrive limits is a step in the right direction.