Driving under 3mph vs. slipping the clutch

[paulca]

Careful with the driving too slow, clutch up, as the load sensor will add throttle once the revs get too low causing the car to suddenly accelerate a few mph. Same thing if the air con kicks in as the engine idle revs pick up as it adds a notch of throttle.

I've never had a problem with lurching, cold or warm. I get the odd lurch as the clutch fully engages if I've slipped it too much leaving a stop, but that's just lazy driving.

With very careful throttle and clutch you can manoeuvre around at sub 3mph without raising the revs above idle but it takes lots of practice and risks stalling it. Certainly under 1000rpm is easy done. On hills it's wise to aim for the 1,000rpm, just remember to balance throttle and clutch together.

Clutch up, 4mph is easily doable, 3mph starts to get dicey, under that and you will labour the engine, get stutters and surges or stall and also run the risk of the load sensor or aircon accelerating you.

Slipping the clutch wears it, but it's meant to wear, it's what it's for, so if you have to do it, do it. If you don't, don't. Just be as gentle as you can. If you can smell it burning, you are doing it wrong.

[mazeroni]

What is worse for the clutch when depressed - feeding in power at low rpms, or off power at high rpms?

Being totally ignorant on the subject, I would think shifting at high rpms would cause the clutch to heat up faster and thus see excessive wear, when compared to holding the clutch while keeping the revs around 1-1.5K for several seconds to get over a bump.

I know you should try to avoid riding the clutch at low RPMs, but given this is a high revving motor that you need to get over 5K for any sort of power, low rpm "slipping" shouldn't be too much of a concern, right? or wrong?

[humfrz]

Originally Posted by mazeroni

What is worse for the clutch when depressed - feeding in power at low rpms, or off power at high rpms?

Being totally ignorant on the subject, I would think shifting at high rpms would cause the clutch to heat up faster and thus see excessive wear, when compared to holding the clutch while keeping the revs around 1-1.5K for several seconds to get over a bump.

I know you should try to avoid riding the clutch at low RPMs, but given this is a high revving motor that you need to get over 5K for any sort of power, low rpm "slipping" shouldn't be too much of a concern, right? or wrong?

When the clutch (pedal) is fully depressed, there isn't any wear on the clutch disk, in a properly adjusted clutch system........(jest ah messen wich ya .....)

I reckon you're right, slipping the clutch, at low rpms when necessary shouldn't cause excessive wear.


humfrz

[paulca]

Clutch wear is proportional to the heat generated in it. The heat increases the more power you put through the clutch plates as they are slipping. Power = Torque * RPM (when adjusted for units). The torque is how hard you pull the car with the clutch, the RPM is ... well the engine rpm.

So the best is low rpm and low pull, gentle and enough to get you to a speed you can fully engage it.

The worst is 7k rpm and hard pulling the clutch to spin the wheels and keeping it slipping till you get to 5k rpm power band. Fastest launch though. Car will stink of clutch though.