Hi Guys,
I am researching possible clutch/flywheel kits for a stage 1 chipped GTI. This thread has probably been done to death, but I have not found an all inclusive thread with information explaining the technical side to clutch/flywheels.
Dual Mass Flywheel vs Single Mass Flywheel:
The 1.8T GTI in stock form uses a Dual Mass Flywheel weighing approx 29lbs (13kg).
For information about 'What is a Dual Mass flywheel?', click on this link. It is a very easy to read and informative PDF produced by clutch manufacturer LUK.
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Dual Mass Flywheel Cliffs Notes
Benefits
- Comfort
- Very quiet in operation. Torsional vibrations passed down the drive train, and gear rattles are absorbed by the springs in the DMF.
- Saves fuel (I assume from the heavy weight of the DMF, helps with highway cruising)
Drawbacks
- Expensive to replace.
- Heavy
- The spring dampeners inside the DMF are optimised for the power and torque of the car. This starts to become problematic as people start to modify their cars.
This is quoted from the linked document above: (page 21 - Section 4.3 - Chip tuning)
This jolt is maybe what people experience when off throttle after a quick burst of acceleration.. feels like the engine is rocking? Just thinking out loud here.Usually the torsion damper system of a Dual-Mass Flywheel, just like the remaining parts of the drive train, is designed
for the engine for which it is intended. In many cases the safety reserve of the Dual-Mass Flywheel is used up or
exceeded by a torque increase, sometimes by more than 30%. As a consequence, the arc springs can already be completely
compressed during normal driving, which deteriorates noise insulation and can cause the vehicle to jolt.
This is the main reason why people swap over to a SMF, as this completely eliminates the damper springs and is just a solid block of metal.As this is the case at half of the firing frequency, very high loads are quickly produced and transferred not only to the Dual-Mass Flywheel, but also to the transmission, which could result in damage to drive shafts and the differential. Damage can range from increased wear to a catastrophic failure resulting in a huge repair bill. The operating point of the Dual-Mass Flywheel is shifted towards its security reserve by the increase in the power of the engine. During driving, the Dual-Mass Flywheel is permanently overloaded by the higher engine torques. This causes the damper springs in the Dual-Mass Flywheel to operate “fully loaded” more often than they are designed to and can destroy the Dual-Mass Flywheel!
It has been stated on other forums that if a person is not going to exceed stock power by 15% they should stay with a DMF. I am not sure where they have got this figure from. However, a Stage 1 Chip tune is roughly 20-25% increase in power and maybe exceeds the tolerances of the stock DMF.
Single Mass Flywheel Cliffs Notes
A popular option is the install of the G60 Flywheel which weighs approx 22lbs (10kg). (3kg less than the stock DMF)
Benefits
- Simple in design
- Low cost (Stage 1 kits)
- Reliability with modified cars.
- More responsive acceleration due to decreased weight.
Drawbacks
- Gear chatter when in idle and the gear lever depressed. Non issue.
As mentioned, the SMF are available in lighter weights. Car manufacturers make the stock flywheel very heavy. A heavier flywheel makes the engine very smooth and enables it to retain energy at part throttle cruise and up long grades for better fuel economy. A lightened flywheel allows the engine rev up very quickly and operate easier due to the reduced weight spinning around on the back of the crank. It seems to be debatable whether an excessively lightened flywheel is a worthwhile option on a road car, even if it sees the odd track day twice a year.
Clutch Selection
A popular choice is the Sachs VR6 clutch as it is bigger in size compared to OEM. (288mm instead of the stock 220mm)
Good information on this page: Clutch FAQ for VW and Audi TDI engines | VW TDI forum, Audi, Porsche, and Chevy Cruze diesel forum
Clutch Material (Quoted from above link)
Most street disks are made with organic faced material. This is similar to brake pad material. It has the smoothest engagement but can slip if it overheats. If you are shifting under high rpm and heavy load, this can overheat an organic disk, resulting in a burning smell and a lower coefficient of friction. Typical stop-go driving is not enough to overheat this disk but excessive slipping can. Full throttle drag races with heavy clutch slipping can glaze this type of disk. The nice thing about organic disks is that if it starts to smoke, let it cool and drive normally. It may regain most of it's clamping force. It is probably the best choice for a smooth, long life, lightweight clutch on a daily driver.Carbon clutches are normally used for racing applications where it is expected to slip a lot. They can withstand up to 2000 degree temps without destruction. Engagement changes a lot depending on temperature and they normally slip a bit under normal street use. This is a clutch that needs to slip and heat up before reaching maximum holding force. It's actually a clutch which you can slip without damaging the clutch material. Again, since "drivability" is a very subjective term, these suggestions are conservative. I would not use this on a street car.
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Originally Posted by Sirocco20348
) and was going to investigate if its worth upgrading or sticking to something simple on a stock and slow engine so was good to read the above
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