They used to call it “snake oil”, something of dubious value sold as a cure all for any medical condition. Nowadays, the consumer assumes that there are enough laws to protect the consumer from false advertising. However, in a highly specialized market like racing, companies can get around the “false advertising” rule by pushing the limits on what they say, but not going over the line.
A good example of this are the “split” electrode spark plugs. (We are not going to use actual product names, hopefully to keep us out of court.) The claim was that you had 2 sparks to better ignite the mixture. That would be an advantage if it were true. However, the spark will jump from just 1 electrode, not both, for each firing. On the next firing, it could jump from the other side, but never from both at the same time. If you notice the recent ads, they show just 1 spark from 1 side of the split electrode.
Something the racing consumer must realize is that products are made by companies who purchase advertising space in magazines. A magazine has no reason to give a poor product review to advertisers. The more advertising you see for a product, the more you have to take editorial reviews with a grain of salt.
Some recent products which are making some unrealistic claims include:
The “twister” that you put in the air inlet tube to induce swirl to the air/fuel mixture to promote better burning. Well, we sell swirl meters, and swirl induced right at the valve to the mixture going into the combustion chamber can effect burn rate and performance. However, any swirl induced up by the air cleaner can have little affect on the mixture motion as it enters the combustion chamber. What the “twister” can do is provide a huge restriction to air flow, drastically hurting performance. This is a product which actually does the opposite of what it proposes.
You’ve probably also see the carb spacers which induce swirl. Again swirl under the carb is gone by the time the mixture gets into the chamber.
One new product recently reviewed in a magazine was a variable restrictor plate. For those of you who don’t know, a restrictor plate is a thin flat plate with 2 or 4 relatively small, precise holes placed under the carb. It is required by some circle track classes (like Nextel Cup on the super speedways), to limit engine power and top speed to keep things safer. Well this device is being sold as traction control. It’s claim is the crew chief can dial in this air restriction to limit torque coming out of the corners. As I read it, I was thinking “The next generation of variable restrictor plate would be one where it could be controlled by the driver, maybe by his foot.” Oh yeah, we already have that. It’s called a throttle plate and accelerator pedal. The magazine review was favorable, probably to get advertising dollars. Even if you want to kill power for traction control, this is NOT the way to do it. A restrictor plate does not kill low RPM torque that much, like coming out of the corner where you need it for traction control. However, it does kill top end HP, where you want as much as you can get and are not worried about breaking the tires loose.
Now in defense of some of these products:
Carb spacers canhave an effect on performance, but not from swirl. Their insulating properties can effect the carb and fuel temperature in some conditions. Their height and design can effect plenum volume, intake tuning waves, and possibly A/F distribution. These can be real (although small) effects. But swirl is not one of them.
Also, in this era of Electronic Engine Controls, an engine modification could affect how the computer “sees” what the engine is doing. This in turn can affect the amount of spark and fuel the computer delivers. A good example of this is a recent claim that an air cleaner and inlet tube change produced a 50 HP power gain on a 500 HP production engine. There is actually some truth to this claim. What happens is the air filter and inlet tube “screwed up” the air flow going into the air meter. The controller thought the engine could use more spark and less fuel (leaning an overly rich condition) and it produced more power. The air cleaner and inlet tube by itself would likely have only a 10 HP affect by itself. Now, after you leave this modification in place, the controller adapts and most of the power gain goes away.
You may ask, why does the production tune not produce optimum power. For most engines, production tune is near optimum. However, new EPA requirements for emission tests to go into full power, government engine noise requirements, catalyst heat (grass fires) restrictions, emission component durability, general engine durability, put all sorts of demands on the automakers. When you have very high output engines, the automakers may have to limit full power for government requirements and to keep their warranty costs down. This is the reason for aftermarket chips and other calibration adjusters. They can improve power, but at some cost in some other area, typically an area of no concern to most motorheads.
So when you read the magazines, keep your guard up. Not everything is as it is sold.