Dual Mass Flywheels - Your views?

[tt82]

Originally Posted by Volvo2002

My mum used to do this until I gave her an earful, she now does what I do, hold the brake and push the clutch to the floor! I never use the handbrake though.

So what happens when your rear ended by another motorist? Feet come off the pedals, car is already being pushed forward now drives itself forward in gear.

[Daim]

Originally Posted by tt82

So what happens when your rear ended by another motorist? Feet come off the pedals, car is already being pushed forward now drives itself forward in gear.

Yep, exactly that will happen!

I was taught here in Germany to stop the car from rolling with the FOOT BRAKE and to keep the clutch pedal pressed (sitting in gear).

As soon as I got my C30 (my first experience was gathered in a 960 auto) I did what my dad, former British driving instructor, said to do:

Approch lights using gears and stay as long as possible in gear. Only use the last few meters until you stop, you apply the clutch.
Whilst waiting for the lights to turn green, take the car out of gear and pull the handbrake.

My dad's rules:
Footbrake is for stopping
Handbrake is for staying stopped
Clutch is to move the car off the first meters and to change gear. Any other use is not what it's purpose is for.

Think as well, when you press your clutch, you are forcing the crank shaft towards the front of the engine. I.e. you are putting force on the sides of the bearings which aren't made for that. So you will wear these bearings and can naff the engine up quicker. You also cause more friction, which costs more fuel. So sit at the lights with the clutch depressed and you'll be forcing the engine to do something it shouldn't making it wear more AND use more fuel.

Little things and considerations like that drop your fuel consumption, engine wear and clutch wear

[Volvo2002]

If I am sitting at the lights for say 2 minutes I apply the handbrake. If it's a short wait, clutch down to the floor and in gear.

[Shadeyman]

As the design of diesel engines evolved they produced more power and as a result huge torque spikes.

Something had to be designed to stop the impact of these huge torque spikes trashing the drivetrain.

The DMF was the answer, it prevents these spikes being transfered to the rest of the drivetrain thereby increasing the drivetrains longevity.

If you abuse a DMF setup it will fail just like a SMF setup will fail if you abuse it.
SMF and DMF last about the same amount of time/miles but the DMF costs more.

The most common reasons for DMF and clutch failure are riding the clutch and remaps.

Respect your clutch and your DMF will last as long as the car.

I drive a 1.9 Diesel that has 120,000 miles on it and it still has its original DMF installed.

+ YouTube Video

[CJL]

I always put it in neutral clutch released either on the foot or parking brake depending on duration of wait. You are not actually supposed to move off until the light is green anyway - that's what red and amber is for in the UK.

Noticed on my V70 D5 that if you are in gear and start to release the clutch to move away, the engine revs increase on their own. Similarly when changing up throught the gears the revs are held at the matching revs for the next gear.

Wonder it this is to protect the DMF?

[Shadeyman]

Originally Posted by CJL

Noticed on my V70 D5 that if you are in gear and start to release the clutch to move away, the engine revs increase on their own. Similarly when changing up throught the gears the revs are held at the matching revs for the next gear.

Wonder it this is to protect the DMF?

The torque spikes are at their worst at low rpm so I'd say yes the slight increase in rpm is to reduce the strain on the DMF.

[CJL]

Yes, so contrary to conventional thinking a few more rpms and a bit more clutch slip when moving off may actually be better for the clutch.

I also have a '99 V40 T4 and i must admit I'm often in too higher gear.... try and go round the corner in 4th when really 3rd was needed. Don't do that in the V70 and try and try and keep above 1,500 minimum.

[Volvo2002]

Vauxhall Vectra CDTI DMF noise video

http://www.youtube.com/watch?v=ADiINEwg68E

[Volvo2002]

Originally Posted by tt82

So what happens when your rear ended by another motorist? Feet come off the pedals, car is already being pushed forward now drives itself forward in gear.

Should use my handbrake more, agreed.

[Shadeyman]

Originally Posted by CJL

Yes, so contrary to conventional thinking a few more rpms and a bit more clutch slip when moving off may actually be better for the clutch.

Not better for the clutch, better for the DMF.

"Slight" is the key word here.

A small increase in rpm will have very little impact on the clutch but is much better for the DMF.