| different. What plays a more significant role in their longevity is based on what kind of torque you are putting through them and what type of clutch you are using. Short shifters are also detrimental to longevity. There is only so much syncronizer surface area per gear, and it is less and less the higher the gear you are engaging. The 1st gear syncro is huge - it is the largest of them all.... and for good reason....1st gear is the largest gear on the main shaft and offers the greatest surface area for a syncronizer assembly. It simply comes down to the geometry of the parts in the tranny - you can't make the 4th gear syncro as large as the 1st gear syncro - there physically isn't enough room. The purpose of the syncros is to bring the clutch disc to appropriate speed to match that of the gear being engaged to the rotational speed of the driveshaft. From a standstill and accelerating through 1st gear, when the clutch pedal is depressed and the trans shifted to 2nd gear, the 2nd gear syncro decelerates the clutch disc to a speed that matches the gear ratio to the driveshaft. As soon as the clutch disc has decelerated to appropriate speed, the gear clutch hub is then able to engage 2nd gear to the output shaft. It is easier for the 2nd gear syncro to decelerate the clutch disc to matching speed than it is for the 3rd gear syncro. Simple reason: 2nd gear has a larger syncro. The cluch disc mass does not change, obviously - it is what it is. But your ideal shift RPM is nearly identical for all gears. This means that the higher the gear you are engaging, the less surface area you have available in the syncronizer to bring the clutch disc to appropriate speed for gear engagement. SpecialtyZ has a keen awareness to this principle which is evident by their R&D put into their latest "High-5" clutch kit. I've personally seen this kit and the mass of the clutch disc, or really lack there-of, is impressive. By lightening the clutch disc, the syncronizers only need to perform a fraction of work compared to other clutch systems having heavier discs. Another common issue I've seen comes from the use of short shifters. A short shifter is a simple device - the pivot point of the shifter arm, or the "fulcrum", is relocated so that it requires less movement of the knob to engage the gears. While this may appear to some as a benefit, it actually is hell on syncronizers. The reason is simple: the amount of force applied to the shift knob that is required to overcome the shift rod detents (the ball-spring locks that hold the shift rods in a given gear) will INCREASE as you shorten the shift. By increasing the required force to overcome the detents, it makes the shift process very notchy and causes the shift fork rods to move in a more "snapping" motion rather than in a smooth motion. This process does not allow the syncronizers to perform their jobs properly and ultimately results in either mis-shifts or severe grinding when trying to get the best acceleration out of the car. In my pro opinion it isn't worth the expense for these newer trannies. You can buy several used trannies for the cost of one and in my experience, you'll go more miles in the latter approach. I've seen newer trannies whine and grind as early as 8K miles while an $85 salvage yard tranny lasted 30K miles in my 550+RWHP pumpfuel Z I drive like I stole daily.
Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the
tailor.
Albert Einstein
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