My $.039 (at the time) was that with the non-lockup 518 i actually got much
better performance and mileage on the highway because with teh 3.55 gears
and a 6er (again at the time) this put me into a much more usable power
range. I would not let this be a deciding factor for me if I had to
replace another automatic. I was very pleased with the results.
Chris
>Lockup converters contain another part: a torque converter clutch.
>When the clutch engages, it allows the converter to lock the engine
>to the transmission input shaft, providing a direct 1:1 communication
>from the motor to the transmission.
>
>Why is this necessary, or even desirable? In many ways, it comes down
>to fuel economy. Lockup torque converters have become popular since
>automakers have been stuck in a sort of Catch-22: Car buyers
>overwhelmingly prefer automatic transmissions, but automatic transmissions
>are not as fuel efficient as manual transmissions and automakers must meet
>government-mandated corporate average fuel economy targets. Overdrive
>transmissions have been one step along the path toward increased fuel economy
>from an automatic transmission. Overdrive transmissions allow the
>motor to spin at a lower rpm during cruising speeds. A higher final
>drive ratio (numerically lower) does the same thing.
>
>However, when the engine spins more slowly, it creates more slippage within
>the torque converter, and more slippage creates more heat. Heat within the
>torque converter reduces fuel economy and can harm both the torque converter
>and the transmission. The solution is to allow the converter to lock up at
>a 1:1 ratio. Lockup eliminates the slippage, which reduces heat and improves
>fuel economy.
>
>Usually, lockup converters are used in stock applications, but not in
>higher-performance vehicles. However, some drag racers choose to run
>lockup torque converters, too. It is possible to lock up the converter
>at wide-open throttle manually (by using a switch) or automatically
>(via a racing computer chip). It has been estimated that locking up
>the converter at WOT in a relatively stock doorslammer, such as a Buick Grand
>National, can pick up about a tenth in quarter-mile ETs; however, it also
>speeds up wear and tear on the torque converter clutch.
>
>I personally think that most drag racers prefer a non-lockup converter
>because of the loss of the converter's torque multiplication factor when
>lockup occurs (I could be wrong here). Most aftermarket converters have
>a 2:1 torque multiplication factor.
>
>Bob
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'00 CC, Packin a 287 Magnum, 5-sp, Gibson Duals, Traction Bars, Spring
Clamps, Magnum Front Plate, Quick D Intake, "Smoke Em" Decal, Paint
In bed-liner, More to come
http://www.intense99dak.com/chris.htm
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