what is overdrive when talking about cars?
i was on a ford mustang forum just reading up on drivers who use NOS and one guy said "If it's hoppin into overdrive I'd put some upper/lower RPM limits on the nitrous."
what is overdrive? and how can you tell your "hopping" into overdrive?
Dec.24.2009
Overdrive is when in your transmission, you have a large gear being driven by the engine, and that large gear is turning a smaller gear to get the power to the wheels. In an automatic this will take place in a planetary gear set. You will have a sun gear being driven by your pinion carrier. In a manual, you will have a large gear on the input shaft in mesh with a smaller gear on the output shaft.
If the two gears are the same size, it is called direct drive. If a small one is driving a large one, it is called reduction drive.
Dec.24.2009
Overdrive is your top gear. It is called overdrive because the drive ratio is greater than one-to-one.
Dec.24.2009
Like my ’88 Mustang, it was really a 4 speed with overdrive, even though the shifter said 5 speed. The fifth gear, or top gear in an automatic, is meant for highway driving. This transmission gear doesn’t offer significant additional performance, but helps to lower engine RPM’s and save fuel.
I imagine that hopping means it goes into this top gear instead of keeping the engine RPM’s up in the second to top gear (more in the higher horsepower band).
Dec.24.2009
Normal gears in the transmission are 1st 2nd 3rd. In an overdrive transmission this would be gear four or in another instance would be gear five. Now there are even transmissions with a gear six in them. The top gear is the overdrive gear in any transmission with more than three gears. This can be easily located by looking at the shift indicator. It will have an O there with a smaller D inside the O.
Not all cars have them by the way.
Using nitrous oxide in the top gear (or overdrive) is really not needed because you are only gonna go so fast. It is recommended that some type of nitrous limiting device be installed to prevent nitrous from engaging while vehicle is in overdrive.