Dual Mass Flywheels - OE for a reason

Supplier feature
Supplier feature
Dual Mass Flywheels OE for a reason
So why do they go wrong?
Just like any other component, DMF’s do eventually
wear out, and some conditions make them wear out
quicker than normal.
It is simple logic - a DMF is designed to absorb
Case study one: Mike, Headlands Garage
A conversion kit is usually sold on the promise of ‘long life’ and ‘reduced cost’, but
ON
SOLID CONVERSI
nothing is mentioned about its reduced capability to absorb vibration, the additional
weight, the potential for damage or the increase in fuel consumption! Which is why
fleet managers are returning to the original and best - the DMF.
vibration, and if it has to absorb more than it was
Mike from Headlands garage converted some of his extensive
designed for then service life can be shortened.
taxi fleet as a trial, thinking that he would save some money:
+15%
“We thought we could save a few quid but we monitor fuel
Over 120 million vehicles have been
fitted with a Dual Mass Flywheel as
Original Equipment since its launch, and
because modern engines continue to get
smaller, lighter and more powerful, they
are here to stay.
The DMF has been the answer to this
vibration, which instead will make its way into
of the car and include smaller, lighter engines that
problem since 1985, and it continues to be the
fuel bill for our fleet went up by almost £35,000 (15%) after
expensive components like the gearbox and,
produce high levels of torque at lower engine speeds.
go-to solution for pretty much every
conversion. On top of that drivers were slipping the clutch to
of course, it will begin to be noticed by the driver.
manufacturer building vehicles today.
The Ford Ecoboost engine is a good example, it
produces a peak torque of up to 200Nm at 1400rpm
Dual Mass Flywheels have been around for nearly 30
years now, and love them or hate them they are fitted
as OE for a reason. The 3 largest OE clutch suppliers
(LuK, Valeo and ZF) have all designed and produced
So how and why does it work?
What shortens a DMF lifespan?
• Enginechiptuning
The reason they are so popular is simple.
Vehicle Manufacturers are not only constantly striving
to meet ever tighter government emissions targets,
but also to satisfy vehicle driver aspirations for
Ford Ecoboost Engine
vehicles, so they have turned to DMF in their
The latest ultra-light 7 or 8 speed gearboxes are also
contributing to the rise of the DMF. Weight used to be
After many years of throwing emissions hardware at
the major vibration absorber - adding a weight
today’s engines - such as Common Rail, GDI, catalytic
(a mass damper) to a vibrating gear mechanism arm
converters, DPF etc. etc., there is still only so much
and you transform it from a poor quality flimsy
you can do to an internal combustion engine to
gear change to something a BMW driver
reduce emissions.
would be happy with. The big BUT is that the more
overcome judder issues which bought our average clutch life down from
!
70-100,000 miles for a DMF to just 20-25,000 miles with a solid...”
Case study two: Kevin, Spannerama
The term ‘dual mass’ simply means splitting the
• Prolongedmisfiresorimbalance
flywheel in two, and attaching one half (mass) to the
• Towingexcessiveweight
Conversion kits usually contain a Long Travel Damper (LTD) which provides a little
engine and the other half to the gearbox. Doing this
• Overloading(especiallyLCV)
more rotational movement than a standard damped plate, but still only a maximum
reduces the resonant frequencies to something well
• Constantlydrivingintoolowagear
of 29° compared to the maximum possible 186° (but usually around 100°) of a DMF.
below idle speed so they are virtually undetectable.
versions of the DMF for original fitment.
droves to provide the solution.
consumption accurately using tracking systems and the annual
It is now more common for VMs to take weight out
from a 1.0 engine!
improved refinement from ever more powerful
After a while it will not be able to absorb as much
To overcome the limited vibration absorption capabilities of the LTD,
In addition, a pair of large arc springs between the
The benefits of DMF:
two masses provide up to a massive 186 degrees
• Better fuel economy
of rotational movement in some DMFs, capable of
• Reduced emissions levels
absorbing even more vibration.
• Comfortable, vibration free driving
This extra weight brings its own problems, as broken crankshafts are not
• Tested and approved by the VM
uncommon in both Ford Transits and Skoda Octavias due to the extra strain
Newer designs incorporate additional springing to
• The originally fitted technology
put on the drivetrain - as Kevin from Spannerama in Glasgow discovered:
add further absorption capacity, and the very latest
• Protects the drivetrain
versions borrow advanced aircraft engine technology
• LuK warranty and technical support
- specifically in the form of the Centrifugal Pendulum
• Saves money in the long term!!!!
a solid flywheel adds weight, effectively putting back the mass that the
vehicle manufacturer removed by originally fitting a DMF!
“We look after a large fleet of Octavia Taxis and we saw
6 crankshaft failures in 6 months following the fitment
of Solid Flywheel conversion kits. We also had a spate of
Absorber (CPA).
early driveshaft failures after just 12 to 15,000 miles”...
First used in the emissions busting BMW ‘Efficient
Dynamics’ engines, CPA equipped DMFs are now also used
by VAG in low emission variants such as the Volkswagen
Case study three: Khalid, Universal Clutch
Passat, Audi A5, Seat Leon and Skoda Superb.
Using non-DMF technology, or parts not validated by the
weight you carry leads to increase in both fuel
VM can, in many cases, lead to critical component failure.
consumption and emissions levels.
Khalid from Universal in Luton, one of the UK’s
The Dual Mass Flywheel
76
Inform February 2014
All of these weight saving measures, such as the
For more information about Dual Mass Flywheels,
smaller, lighter engines and gearboxes, downspeeding
including leaflets and posters for your garage
and the engine running slower (to reduce friction)
customers, call LuK customer services on
simply result in an increase in vibration levels and
01432 264264 or visit:
hence the need for a different technology.
www.schaeffler-aftermarket.co.uk OR
DMF with CPA technology
largest independent clutch specialists, said:
“We never use 4-in-1 conversion kits, but we get a load of Transits in with bearing and slave cylinder failure
after they have been converted and we always convert them back to a DMF. We keep the bits that fail after
converting in stock now (like slave cylinders and release forks), because we are seeing loads of them...”
www.RepXert.com
Inform February 2014
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