As the title says, I know that different shifts mean different gear sizes bein used, but I don’t understand why it makes you unable to start moving the car. I have been able to start a couple of cars on the 2nd shift as an experiment and I understand that I could damage the car and I do it just once for testing purposes but I don’t understand why I cannot do so on other shifts. To clarify, I mean start as in start moving the car and not just turning the car on. Thanks
In: Engineering
Your engine idles at a certain speed, let’s say 750rpm, for various reasons. If the engine goes much below that, it will stop spinning, called a stall.
When you start engaging the clutch from a stop, your wheels are not moving, so the gears aren’t either. What that means is that the clutch must slip against the engine flywheel until they are both moving at the same RPM. This slipping is what brings the clutch (and by extension, the gears, wheels, and the rest of the car) up to speed.
In first gear, idle RPM may only be about 5kph / 3mph because it’s a very ‘easy’ gear. It doesn’t take a whole lot of energy to accelerate the whole car up to that speed, so the clutch doesn’t have to do a whole lot of slipping.
In your highest gear, maybe 6th gear, idle RPM may be more like 80kph / 50mph. That takes a *lot* more energy for the car to get going, so the whole time you’re doing that the clutch is slipping. This slipping generates heat from friction and wears away clutch material so it’s very Not Good for your car.
Instead, it is Much Better to get up to speed one gear at a time, slipping the clutch for the first gear (because, again, the engine can’t go any slower than 750rpm) but then adjusting RPM during each subsequent gear change so that theres minimum slipping.
Latest Answers