Dual mass Vs solid flywheel

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lowpugV2

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What are the pros, cons and anything in between of these different types of flywheel?

Specifically (and hypothetically) a 1.6 thp engine putting out 270bhp into a 6 speed?

Terrible idea to swap the the dual mass for a solid billet flywheel? I'm purposely ignoring the lightening aspect for now.

As I understand there will be more vibration and noise but nothing outrageous. Any other possible issues?
 
Luk and Valeo make these things, as well as conventional clutch systems, and have very good material online in pdf format.
 
I fitted a solid flywheel conversion kit to the 407 here years ago. I've never had a problem with it. I can't give you a "before" and 'after" as dual mass flywheel was flogged to death before I replaced it (it died at very low milage).
 
These are primarily to enhance NVH characteristics at low RPM to even out acceleration and deceleration of the crankshaft between combustion of each cylinder. More necessary in modern low boost turbo cars where there is plenty of torque available lugging around at low rpm. For a fun/weekend car I would happily goto a lightened single mass wheel for the performance gain. If it's a daily you lug in traffic to work you might notice a bit more vibration, but unlikely to be an issue.
 
After countless days and more than a few dollars spent to have french car specialists and auto electricians shrug their shoulders at me, I narrowed down a running problem (hunting idle, poor power and pinging) to the fact that Valeo listed a diesel DMF for my petrol Megane sedan... It fits and runs, but is a different weight and I thinks its screwing with the ECUs ability to calculate load and hence timing/fuel delivery needs.

Car is in storage awaiting a warranty refund on the flywheel and finding an OEM for a price that doesn't make my eyes bleed...
 
You’ll notice a difference. Weather it annoys you or not will depend on how you drive and how you expect your car to behave. When my 407 HDI manual needed a clutch (due to a DMF issue at 170k) I replaced it with a new DMF, I looked at options and, I was happy with the result. I sold the car anyway a year or so later.
I bought a 308HDI manual with the same motor, that has had a single mass flywheel fitted at 145k and I bought it at around 155k. The bloke I bought it from told me that if he had the chance to do it again he would have gone for a dual mass as he found the single mass harsh, he also told me that his wife who was the main driver of that car couldn’t notice a difference. I don’t know if this is relevant or not, but he stated that the fuel economy had been negatively affected by the fittment of the single mass. I don’t know if this is true. I do find the car harsher than one with a dual mass, and I would prefer it to have a dual mass, even with the issues of longevity and cost.
 
A manual diesel is the perfect use case for a DMF. No torque converter and and lots of low rpm lugging.
 
Dave said:
A manual diesel is the perfect use case for a DMF. No torque converter and and lots of low rpm lugging.
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Even my petrol 1.4 Alfa has one... Hopefully the surely minor second order vibration from such a small engine means it will last a long time - the LUK DMF for the Alfa DCT is as eye watering in price as the dual clutch kit is...
 
I'd get rid of it every single time .... the one here started rattling at 48,000km from memory and disintegrated at maybe 85,00km? (maybe it was 125,000... it was quite a while later).

I'm not spending big $$$ on something that doesn't even last a cambelt change.
 
Life depends a lot on your diving style, since starting from idle affects it most, eg stop start Sydney traffic. One way to avoid one in a high torque engine is to buy an automatic - the torque converter does the job.
 
seasink said:
One way to avoid one in a high torque engine is to buy an automatic - the torque converter does the job.
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Hi. Correct - until the torque converter lock up clutch applies, then its direct drive, thus transmitting torsional oscillations.

Cheers.
 
Hmm, thanks all for the info and links. Will read up.

The 308 GTi that I currently have has a slight clutch slip under full load so sometime in the future I will have to replace. The dual mass plus clutch comes as a kit and is around $2k...

So I figure time to research alternatives if I balance performance plus upgrade plus cost.
 
I should also say this isn't a daily driver. This is "last chance to own a real (in modern terms) GTi before they're gone for good.
 
Whippet said:
Hi. Correct - until the torque converter lock up clutch applies, then its direct drive, thus transmitting torsional oscillations.

Cheers.
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above idle they are high enough in frequency thats its not really an issue. Under any sort of load the DMF is locked essentially anyway, it only really operates at idle.
 
I think from memory the DMF in our 308 T7 RHR did about 180K kms before I replaced it - might have been more. It was fairly rattly by that time but still working fine. Ironically the clutch itself showed negligible wear - you can see the wear measurement in the 'auto-adjusting' feature of the clutch plate.

I bought a new DMF / clutch kit (probably Valeo) from the UK at the time and it wasn't expensive from memory - even with postage from the UK. Local prices were certainly off putting...... I didn't see the point in fitting a SMF as the DMF made the RHR nice and smooth

Cheers

Justin
 
N5GTi6 said:
I think from memory the DMF in our 308 T7 RHR did about 180K kms before I replaced it - might have been more. It was fairly rattly by that time but still working fine. Ironically the clutch itself showed negligible wear - you can see the wear measurement in the 'auto-adjusting' feature of the clutch plate.

I bought a new DMF / clutch kit (probably Valeo) from the UK at the time and it wasn't expensive from memory - even with postage from the UK. Local prices were certainly off putting...... I didn't see the point in fitting a SMF as the DMF made the RHR nice and smooth

Cheers

Justin
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My previous Megane rebuild project had its original DMF in at 220K kms. It wasnt rattling but it was far enough gone that it wasnt worth reinstalling.

I suspect those gross cancerous rattly shitty diesel things wreck DMFs faster than petrol engines...
 
Haakon said:
My previous Megane rebuild project had its original DMF in at 220K kms. It wasnt rattling but it was far enough gone that it wasnt worth reinstalling.

I suspect those gross cancerous rattly shitty diesel things wreck DMFs faster than petrol engines...
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Another thought is that it's related to the type of use the car and the clutch receives as well, whether it be cancerous petrol or diesel engines involved.

Cheers

Justin
 
N5GTi6 said:
Another thought is that it's related to the type of use the car and the clutch receives as well, whether it be cancerous petrol or diesel engines involved.

Cheers

Justin
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That too. Obviously a lot of steady highway work will extend its life.

But those wonky stinky diesel shitboxes sure do rattle stuff to death faster all other things being equal ;)
 
Haakon said:
Even my petrol 1.4 Alfa has one... Hopefully the surely minor second order vibration from such a small engine means it will last a long time - the LUK DMF for the Alfa DCT is as eye watering in price as the dual clutch kit is...
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Renault Scenic full clutch kit with DMF is $1600, at least that is what we paid.
 
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