Does giving gas while releasing the clutch cause unnecessary wear?

Question

I drive a 2013 Ford Fusion SE with manual transmission. I learned to drive a manual as a kid but picked up a lot of bad habits. In particular I tend to naturally ride the clutch. Now, of course in 1st or Reverse you have to let the clutch slip a little, but I'm having difficulty not letting any slipping from 1st to 2nd.

When shifting from 1st to 2nd, will I wear out my clutch or transmission by giving the car some gas as you release the clutch?

My feeling is that the answer should be no, I just need to practice and do: "clutch. switch gear. release clutch. gas." but at the appropriate engine speed.

I'm confused because many people on various fora say that it's ok to give gas while you're releasing the clutch, but I'm skeptical because this seems like it would wear on the clutch. I obviously do not want to wear out my car.

Answer 1

Is it ok to give gas while releasing the clutch?

Yes, but your goal is to give exactly the right amount of gas.

The thing to remember is that the clutch is a consumable part (it's really a whole system of parts that can be consumed but let's pretend that it's a single unique piece for the sake of discussion). As such, it has a finite supply of work that it can do over its service life, useful or otherwise. To clarify, this is what it means to slip the clutch:

Between these extremes of engagement and disengagement the clutch slips to varying degrees. When slipping it still transmits torque despite the difference in speeds between the engine crankshaft and the transmission input. Because this torque is transmitted by means of friction rather than direct mechanical contact, considerable power is wasted as heat (which is dissipated by the clutch). Properly applied, slip allows the vehicle to be started from a standstill, and when it is already moving, allows the engine rotation to gradually adjust to a newly selected gear ratio.

As noted, the clutch is a friction-based part (rather than a direct gear). The above quote means that your goal as the driver is to attempt to ensure that the clutch is spending more time in a static friction mode (i.e., where the frictional surfaces of the clutch are turning at the same speed, pressed tightly together) rather than a kinetic friction mode (i.e., where the frictional surfaces are turning at different speeds and are slipping past each other).

This means that the answer to your original question is that it is ok to give exactly the right amount of gas when releasing the clutch pedal. Any more or less than the optimal amount will lead to some slippage of the clutch. Some slippage is to be expected, with wear increasing super-linearly as the difference between target and actual revs increases.

The better you are at rev matching, the longer your clutch will last (and the more comfortable your passengers will be).

tl;dr: You have to slip the clutch from a stop. In higher gears, your goal is to avoid slipping the clutch. You do this by matching engine speed to transmission speed before releasing the clutch pedal.

Answer 2

Yes it's okay. As long as you are letting go of the clutch by a little bit and at the same time, you give it a little bit of gas. If you just let go of the clutch without giving any gas in first gear, you can go forward/fast then the car will just stall. I'm only 14 and I just know about this because of my brother.

Answer 3

Just think of the this way-

When you use a higher gear, the RPMs will be lower than a low gear at the same speed. However, while shifting to a higher gear, you let off the gas which will cause your RPM to drop low- most of the times I find it a little too low, even for a higher gear. So you want to add some gas, just as Bob wrote, so your engine can catch up to the clutch speed. But just enough so the engine can pick up from idle. You don't want the engine spinning slower or faster than your clutch at a higher gear. Just feel it out and try to match the clutch and RPM as best as you can.

Same thing with downshifting- you are going to have to add gas more aggresively when downshifting since lower gears need to spin at a faster RPM to match the clutch speed. If you don't add enough gas, the slow engine could catch your clutch and cause your wheels to suddenly lose speed and skid. You have to always be the computer that matches engine speed with clutch speed.

Answer 4

Once you have found your next gear with the stick-shift great: basically you have to let go of the clutch so it can engage the gear, but you have to do it smoothly enough that it doesn't slip abruptly. The next part is timing. Engage and release the clutch before the rpms get too low, but not too fast where the Tachometer will have to adjust downward. Have you ever felt rushed in-between shifts? This is because we haven't built up consistency yet, so we feel like it's a race to shift before the RPM's drop. A lot of times we can give gas while releasing the clutch to compensate the drop. Remember: the lower the gear, the faster the rpms will drop in speed because the gear ratio is smaller, obviously. Therefore: the lower the gear, the more gas is required in-between shifts. That is why it is normal to apply gas while releasing the clutch while starting in first gear. On the way up; it will require less gas in-between each of the higher gears. For downshifting it is opposite but the same; It will require the most blip of the throttle at lower gears then for high gears. If I am downshifting from 2nd to first...well i better blip really high...( btw I dont do that). You should only really downshift from 3rd to 2nd and then to neutral. That is all.