64 plate DMF?

[Andyp]

Hi. I have just purchased a 64 plate (Black Diamond) 2.0 TDI CR. Having had both previous versions with the dreaded dmf does the mk3 have this? I believe the 1.6 didn't have it.. Thanks AP

[peterposh]

I thought all modern diesels have them to cope with the torque

[Andyp]

2 hours ago, peterposh said:

I thought all modern diesels have them to cope with the torque

Not the 1.6 apparently

[langers2k]

Pretty sure the CR 1.6TDi has a DMF as standard but here is a SMF conversion kit which is popular  

 

The CR 2.0TDi will also have a DMF, some people have tried SMF conversations on them but have quickly put a DMF back in.

[chimaera]

6 hours ago, peterposh said:

I thought all modern diesels have them to cope with the torque

It's nothing to do with coping with the torque: DMFs are used to dampen down vibrations from the engine and reduce transmission noise, especially under light loads. One of the things that made older diesels so rattly at idle was gear chatter due to engine vibration rattling the shafts around.

 

Some transmissions cope better with a single mass conversion than others: it seems the VAG 6-speed 'boxes cope especially badly.

[peterposh]

Just now, chimaera said:

It's nothing to do with coping with the torque: DMFs are used to dampen down vibrations from the engine and reduce transmission noise, especially under light loads. One of the things that made older diesels so rattly at idle was gear chatter due to engine vibration rattling the shafts around.

 

Some transmissions cope better with a single mass conversion than others: it seems the VAG 6-speed 'boxes cope especially badly.

" Dual-mass flywheels were developed to address the escalation of torque and power, especially at low revs. The growing concern for the environment and the adoption of more stringent regulations have marked the development of more efficient new engines, lowering the cylinder number to 3 or even 2 cylinders, and allowing the delivery of more torque and power at low revolutions "

[Andyp]

Having had a two Vauxhall Carlton 2.3d as cabs going back many years the first one was non-turbo and did not have a DMF. The second one was and L reg and had a turbo and came with the DMF and was no reliable.

 

Jumping forward I had an early 2001 1.9d Octavia.. non-turbo with no DMF... and with 220,000 on the clock is still used in the family and just keeps going and only on second clutch.

 

I then had a MK 1 Superb 1.9td with the DMF and whilst I know it is used as a cab .. in 270,000 it went through a DMF every 50,000 miles.. which if it was only the clutch it wouldnt have been so bad....

 

I am currently retiring my 2010 Superb Mk 2 with 240,000 and even when I bought it brand new it had a DMF issue.. even though the dealer I got it from said there was nothing wrong with it it.. after 4,000 I tool it to another skoda dealer who confirmed the DMF needed replacing.... and since then it has been replaced every 50,000. Again not so bad if it was just the clutch... although the price has come down over the years..

 

Being in the taxi trade I know that Skoda Octavia's and Superbs owned by colleagues down her in Brighton have issues with the DMF but have had to accept this as a standard problem...

[chimaera]

3 minutes ago, peterposh said:

" Dual-mass flywheels were developed to address the escalation of torque and power, especially at low revs. The growing concern for the environment and the adoption of more stringent regulations have marked the development of more efficient new engines, lowering the cylinder number to 3 or even 2 cylinders, and allowing the delivery of more torque and power at low revolutions "

You left out this part: "The counterpart has been an increase in the level of vibration which traditional clutch discs are unable to absorb. This is where the dual-mass flywheels play a key role, making these mechanical developments more viable."

 

The source for that text is: http://www.schaeffler.com/remotemedien/media/_shared_media/08_media_library/01_publications/schaeffler_2/symposia_1/downloads_11/luK_kolloquium_en.pdf

 

On page 72 they start a discussion of the advantages of the DMF and open with the line: "The primary feature of the DMFW is the almost complete isolation of torsional vibrations."

Further on page 73: "In contrast, the DMFW almost completely filters out the engine irregularity. Resonance generally no longer occurs in the driving range. Gear rattle no longer occurs due to the almost uniform operation of the secondary flywheel side and thus also of the transmission input shaft. Annoying droning can also be almost completely eliminated."

 

Going on a little further in the discussion they mention that the crankshaft needs to be retuned to accommodate the different characteristics of the DMF. Taking full advantage of the DMF's capabilities could result in a very different crankshaft setup in terms of vibration tuning, which may be part of the reason newer engines cope so badly with SMF conversions.

[numskull]

4 hours ago, Andyp said:

Having had a two Vauxhall Carlton 2.3d as cabs going back many years the first one was non-turbo and did not have a DMF. The second one was and L reg and had a turbo and came with the DMF and was no reliable.

 

Jumping forward I had an early 2001 1.9d Octavia.. non-turbo with no DMF... and with 220,000 on the clock is still used in the family and just keeps going and only on second clutch.

 

I then had a MK 1 Superb 1.9td with the DMF and whilst I know it is used as a cab .. in 270,000 it went through a DMF every 50,000 miles.. which if it was only the clutch it wouldnt have been so bad....

 

I am currently retiring my 2010 Superb Mk 2 with 240,000 and even when I bought it brand new it had a DMF issue.. even though the dealer I got it from said there was nothing wrong with it it.. after 4,000 I tool it to another skoda dealer who confirmed the DMF needed replacing.... and since then it has been replaced every 50,000. Again not so bad if it was just the clutch... although the price has come down over the years..

 

Being in the taxi trade I know that Skoda Octavia's and Superbs owned by colleagues down her in Brighton have issues with the DMF but have had to accept this as a standard problem...

 

We have a MKI PD140 with 121k and it's on its original DMF and it's perfectly silent. We also have a 2011 MKII CR170 with 35k and it's on its second DMF, the 1st being replaced at 32k as it was clattering on the overrun on 1st and 2nd. The second DMF is now clattering on the overrun on 1st and 2nd. 

[bigjohn]

The 2.0 diesel will have a DMF

 

Later 1.6 diesels were fitted with a SMF as standard

 

The bigger petrol engines also have a DMF (1.8+)

Edited 20 February, 2017 by bigjohn

[lichfielddriver]

They can use torque limiting software instead of a DMF but wheres the million pound aftermarket parts sales in that?

[Andyp]

1 hour ago, bigjohn said:

The 2.0 diesel will have a DMF

 

Later 1.6 diesels were fitted with a SMF as standard

 

The bigger petrol engines also have a DMF (1.8+)

Ok.. thanks for the info...

[chimaera]

59 minutes ago, lichfielddriver said:

They can use torque limiting software instead of a DMF but wheres the million pound aftermarket parts sales in that?

Mapping isn't going to ease the torque spike that comes from a bunch of fuel exploding inside the cylinder and shoving the piston down. With multiple injection events you can smooth it out a little bit but ultimately you're dealing with a series of torque spikes as each cylinder lights up in turn.

[lichfielddriver]

 

Has anyone seen any actual data or any reports of high torque engines without a DMF having issues?

 

Isnt the industry standard LUK sprung DMF the 2nd best on offer after a planetary gear type?

 

What i HAVE seen (having been a Ford owner/Talkford member) is a high proliferation of SMF's replacing DMF's without issue, or at leat the vast majority report better running...

 

The torque generated at combustion can be diminished (we have plenty of onboard sensors and electronics) (and if they can cheat emissions surely a tickle on pumps/timings is in hand anyway) but is the benefit of a 50% increase in torque at the cost of a £1000 job every 70,000 mile worth it?

 

What we have done is create a monster, a dirty high torque engine with EGR, DPF, DMF, all ready to take a grand off the owner (assuming nothing else fails)................. from the need for speed and more power, Good for garages, parts departments and diagnostics services, bad for owners.

 

 

 

 

 

 

[octyal]

There are lots of things that kill DMF's early - one of the biggest is leaving the car idling for long periods with things like air con etc switched on. It's all well and good saying it only lasted 50k miles in one particular car, but think how that car has been used, 50k miles in stop start traffic equals a lot of clutch operations, couple that with long periods idling, and the dmf will suffer a early death. Flip that around, and some cars have been know to exceed 200k miles on the original DMF, it's all down to how they are driven and serviced.

Poor clutch control, changing up at low speed, carrying heavy loads/towing past the cars limit, poor servicing, poor quality fuel all contribute to early DMF failure. It's not the components that are the problem in most cases (<1% failure rate on DMF's) it's the way they are treated. These things are tested for months at a time on test rigs (BMW have recently hooked their engine/transmission test facility up to generators, so when testing engines for durability, they are generating power for the plant), as well as durability testing in the development mules that manufacturers use.

Read the info posted above regarding what they are for and how they have been developed, it will open your eyes.

Finally, we see a few manufacturers actually offering SMF conversions these days (Skoda even offer SMF conversions for new build taxi's from the factory), however, what they don't tell you is that quite often there will be other changes as well.....the ECU is calibrated differently so that the torque is delivered at a different point, they will also quite often change the front crank pulley (itself a sort of DMF) as well to dampen vibrations from the auxiliary belt drive, so swapping the DMF to solid isn't always straightforward.....