Your thinking of it has a higher RPM will produce a higher stage of power. When it will not for that gear setting. Ever seen a 3rd gear Dyno pull? You drive your car the same way as seen on the dyno's. Where the greatest powerband and load are. The motor is producing more power and using a shorter gear ratio is allowing the power to by pass once it reaches to the top of it's ratio. If using 3rd gear where such a great options, it would be done all the time. But again this really has a lot to do with him using stock turbo's and there efficiency range and the cars gearing ( both rear diff and transmission ).
Gearing (and gear ratio selection) is an important factor in quarter mile performance. Because selecting transmission gear ratios is probably not a possibility for the majority of readers but is availble through SPLparts ( see OS G gears ), so lets concentrate on optimizing gearing elsewhere. The two variables to consider are the differential ratio and the tire diameter. It is important to realize that tire diameter changes the final gearing just like a ring and pinion does and that this can often be a much easier way to make small changes to the final drive ratio.Going to a "lower gear ratio" will increase torque multiplication and provide quicker acceleration. When drag racers talk about going to a "lower gear ratio", they are referring to going from a 2.73 to a 3.23 (for example). This means you are going to a higher numerical ratio and increasing torque multiplication. If you want to retain the same final gearing while going to a larger tire you will need to change the differential ratio. One of the advantages of the BFGoodrich Drag Radial is that it is available in many of the common Original Equipment (OE) tires sizes so that you do not have adjust gearing to compensate for tire diameter changes. Most automatic equipped vehicles will come equipped with a roughly 2.8:1 ratio differential. This means that for every 2.8 turns of the input shaft, you will get one turn of the wheels. Manual transmission cars usually come equipped with differential gears that provide more torque multiplication - usually around 3.5:1 (although some small engined vehicles come with even lower gears, roughly 4:1). The manual transmission cars are usually so equipped because they do not have the advantage of the torque converter for torque multiplication (torque converters will be covered in an upcoming article) and because the manual transmission cars usually have more overdriven transmission ratios available to compensate during highway driving. Because most transmissions have a much larger gear spread between the overdriven gears as compared to the lower gears, you want to choose a gear ratio that will not require you to shift into an overdriven gear in the quarter mile. You want to select a differential ratio (and tire size) that will have you cross the finish line just past the power peak of your engine. Depending on the power band of your engine, rpm limiting devices and the safe operating speed of your engine - the proper rpm may be just above the horsepower peak or maybe several hundred rpm past the peak. "At 6620rpm, the stock turbos' HP curve has usually started to drop. Staying in 3rd gives lower ET while upshifting to 4th might yield higher trap speed." 6620rpm's? They are way falling before then. They efficiency is 4500 to 5500 and very short lived as anyone that's seen sheets can see. So taking a shorter gear to a higher RPM passing the the car's peak levels of power is slowing it's trust. Just my thoughts anyway
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