This is my latest letter to the SEB (I write one or two a month):
SEB Letter Tracking Number #3167
Add weight to boosted XP cars or better: measure the horsepower
The minimum weights in XP are absolutely out of whack at the moment, specifically for forced induction engines. The current "1.4" multiplier forces competitive XP drivers looking for the best power-to-weight ratio into the smallest, highest boost level motors they can afford to build, in order to get the lowest minimum weight and best power-to-weight ratios. This means: A MORE EXPENSIVE and LESS reliable engine is going to be the norm.
Rumor has it that the extremely out of date, "1.4" displacement multiplier for forced induction "engine equivalency" is getting a look by the PAC (thank you!) and might go up to a more reasonable 2.2 factor. That's a good start, but its still behind the times.
Please look at this historic racing article to better explain where the magic "1.4 number" came from - the CAN-AM series in the 1970s. It was a farce then, and its a bigger farce now, almost 35 years later: http://www.classicandperformancecar....tor_sport.html
As we saw in Formula 1 and IMSA GTP in the 1980s, and even the SCCA's own Trans Am series in the 1990s, boosted engines kept getting smaller and the boost levels kept going up, to the point where there were 1.5L engines making 1500-1800 horsepower. This was all to be able to exploit loopholes in class rules to be able to run the lightest minimum weight and the most horsepower. Its not brain surgery - if you can do that, you greatly increase your chances of winning.
In GTP the lightest car on the grid had the highest power level. Ditto the Audis in Trans Am. Guess which cars won the most races back then? It was a blowout for the turbo cars, until turbos were completely kicked out of each series.
What did these "turbo equivalency" rules from decades ago teach us? You can't base a car's weight on displacement when it comes to boosted engines, and that when it comes to boosted engines, money is almost the only thing that limits horsepower. Also - you can almost never have turbo and non-turbo cars in the same class, unless you can make everyone have the same horsepower number.
The end goal of all this "equivalency trickery" is to really get equal power to weight ratios among all cars in a class, no matter what motive power is underhood. Multipliers do a terrible job of this, as boosted cars can make more power the more boost pressure you run, the stronger you make the block, the more exotic the fuels become (see the current trends with using ethanol and methanol in turbo cars), etc. This allows people with the resources to build a car with a much better "power to weight ratio" if they are willing to build their car around the smallest displacement, least reliable, highest boost power plant possible. Sure, some can say that "this doesn't apply to autocrossing" but they would be fooling themselves. Power to weight ratios are nearly everything in any form of racing.
The advances in turbocharging and other internal combustion advances have made weight to displacement rules in general simply out of date. Modern road racing classes (outside of the SCCA) are being built around actual measured power to weight ratios. These classes make (all racers beforehand and the the top finishing) racers prove the power level of the motor with a simple, portable chassis dynamometer, and then they weigh the cars. Two measurements, then its simple math from there. Give the XP class a power to weight ratio and measure both numbers on the top 3rd of the cars at Nationals. Hell, do this for ALL of the classes. Its done in NASA and it damn well works. No more 1970s-era trickery needed.
If this class were power to weight based, then racers could chose how they wanted to build their motors. They could build a lower stressed, larger displacement, naturally aspirated engine that didn't have to be pushed to the extremes to make the same power as a micro-engine with a power adder pushing 30+ psi of boost pressure. Or they could build a smaller displacement engine that revved to 10,000 rpm, or go boost crazy - whatever they wanted, so long as they stayed under their power to weight ratio. It would no longer benefit racers to build smaller boosted engines. It would give racers lower cost options to make the same ultimate power numbers, and not be saddled with hundreds of extra pounds of ballast.
Right now, with the old/broken XP min weight rules, if you are building anything other than a tiny boosted motor for this class you are going to get loaded with lots of extra weight. And you will lose to the lightest car in the class - which for 3 years has been a 1770 pound, carbon fiber, 1.6L boosted Lotus. That is getting a bit boring.
Thank you,
Terry Fair - Owner, Vorshlag Motorsports
fair@vorshlag.com - www.vorshlag.com
The minimum weights in XP are absolutely out of whack at the moment, specifically for forced induction engines. The current "1.4" multiplier forces competitive XP drivers looking for the best power-to-weight ratio into the smallest, highest boost level motors they can afford to build, in order to get the lowest minimum weight and best power-to-weight ratios. This means: A MORE EXPENSIVE and LESS reliable engine is going to be the norm.
Rumor has it that the extremely out of date, "1.4" displacement multiplier for forced induction "engine equivalency" is getting a look by the PAC (thank you!) and might go up to a more reasonable 2.2 factor. That's a good start, but its still behind the times.
Please look at this historic racing article to better explain where the magic "1.4 number" came from - the CAN-AM series in the 1970s. It was a farce then, and its a bigger farce now, almost 35 years later: http://www.classicandperformancecar....tor_sport.html
As we saw in Formula 1 and IMSA GTP in the 1980s, and even the SCCA's own Trans Am series in the 1990s, boosted engines kept getting smaller and the boost levels kept going up, to the point where there were 1.5L engines making 1500-1800 horsepower. This was all to be able to exploit loopholes in class rules to be able to run the lightest minimum weight and the most horsepower. Its not brain surgery - if you can do that, you greatly increase your chances of winning.
In GTP the lightest car on the grid had the highest power level. Ditto the Audis in Trans Am. Guess which cars won the most races back then? It was a blowout for the turbo cars, until turbos were completely kicked out of each series.
What did these "turbo equivalency" rules from decades ago teach us? You can't base a car's weight on displacement when it comes to boosted engines, and that when it comes to boosted engines, money is almost the only thing that limits horsepower. Also - you can almost never have turbo and non-turbo cars in the same class, unless you can make everyone have the same horsepower number.
The end goal of all this "equivalency trickery" is to really get equal power to weight ratios among all cars in a class, no matter what motive power is underhood. Multipliers do a terrible job of this, as boosted cars can make more power the more boost pressure you run, the stronger you make the block, the more exotic the fuels become (see the current trends with using ethanol and methanol in turbo cars), etc. This allows people with the resources to build a car with a much better "power to weight ratio" if they are willing to build their car around the smallest displacement, least reliable, highest boost power plant possible. Sure, some can say that "this doesn't apply to autocrossing" but they would be fooling themselves. Power to weight ratios are nearly everything in any form of racing.
The advances in turbocharging and other internal combustion advances have made weight to displacement rules in general simply out of date. Modern road racing classes (outside of the SCCA) are being built around actual measured power to weight ratios. These classes make (all racers beforehand and the the top finishing) racers prove the power level of the motor with a simple, portable chassis dynamometer, and then they weigh the cars. Two measurements, then its simple math from there. Give the XP class a power to weight ratio and measure both numbers on the top 3rd of the cars at Nationals. Hell, do this for ALL of the classes. Its done in NASA and it damn well works. No more 1970s-era trickery needed.
If this class were power to weight based, then racers could chose how they wanted to build their motors. They could build a lower stressed, larger displacement, naturally aspirated engine that didn't have to be pushed to the extremes to make the same power as a micro-engine with a power adder pushing 30+ psi of boost pressure. Or they could build a smaller displacement engine that revved to 10,000 rpm, or go boost crazy - whatever they wanted, so long as they stayed under their power to weight ratio. It would no longer benefit racers to build smaller boosted engines. It would give racers lower cost options to make the same ultimate power numbers, and not be saddled with hundreds of extra pounds of ballast.
Right now, with the old/broken XP min weight rules, if you are building anything other than a tiny boosted motor for this class you are going to get loaded with lots of extra weight. And you will lose to the lightest car in the class - which for 3 years has been a 1770 pound, carbon fiber, 1.6L boosted Lotus. That is getting a bit boring.
Thank you,
Terry Fair - Owner, Vorshlag Motorsports
fair@vorshlag.com - www.vorshlag.com
Comment