Dual mass drag

[Steve Curtis]

I've posted up before about a sought of dragging noise and vibration I get from my car when its got a lot of wait in it. I had originally thought it may be to do with the diff.

A chance drive of another 940 also with Dual mass fly wheel exhibited the same noise/vibrating drag with no wait on board. I could only make it do it if I pulled away enthusiastically in first gear.

After speaking to Amazin he suggested it would be the Dual mass fly wheel. He had the same experience with his and after changing it problem solved.

This is all well and good and seems like the answer. Except, I get exactly the same problem with my 240 when its got a lot of wait on. So is it possible that this judder is coming from having Buckled fly wheels on the cars?

To be honest it doesn't cause any big problems. Its just a bit annoying/embarrassing.

My other theory's revolve around Universal joints or rear suspension but the suspension theory is a bit thin. My 240 rear suspension shocks and springs are new. The only thing all these cars have in common is they have all been lowered. Well the 940's are sports editions, lowered from factory. The 240 has spax adjustable and new springs on the back.

Thoughts?

[Steve940estate]

Is it the clutch itself or the release bearing. A friend has an old Triumph 2.5 pi and that sometimes makes an awful groaning noise when pulling away quickly. Not sure if that is the clutch or release bearing but it certainly isn't the flywheel.
Is the clutch very old or is there any chance the friction plate has oil on it ?

[Steve Curtis]

I have had that experience with a brand new clutch where it groans as you pull away. It not the same noise though. It literarily sounds like your back wheels are pressed up inside the rear arches. I have checked though and there is no sign of rubbing.
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[amaz'in]

Steve...

Trust me...i'm certain it's the Dual mass....i.e. the flywheel breaking down...I wonder if your 240 Flywheel needs a skim etc...but the end result would be the same as an 'out' of spec dual mass..it kind of adds up ..to my mind..

Hence my Silver Sport did it...but was totally cured with the solid Flywheel upgrade...

Lot's to tell on mails from John this evening

J

[amaz'in]

Also it's 'only' low down..i.e. pulling away in 1st gear...so under load...(torque) but not RPM...so taking up the drive and getting the Mass (as in Flywheel) moving...not at any higher RPM...

The Guru's on Volvo's are 940 turbo...Mollusc..and Clan.....wonder if they may concur? (or not)

J

[Steve Curtis]

It makes a lot of sense to me as well. You are correct. It does only happy low down. So pulling away or anything up to 3rd gear with the trailer and decent wait on.

I really believe this is the reason. Just as you say hoping for some guru like concurrence.

Look forward to hearing about Johns input.

[Steve940estate]

Shortly after fitting the manual box to my car I decided to fit a solid flywheel. I didn't get any noises but did get a strange vibration when pulling away. The solid flywheel swap seemed a good way to make sure I didn't have any more problems.
The dual mass flywheels seem to be a good idea while they work properly but the cost of fitting a new one if they fail is horrendous.
I thought it better to get the parts at my leisure rather than having to rush about if something broke.

[TonyS9]

Mines the same, vibration with alot of weight, but also does it in 2nd with 11psi boost. I'm pretty sure its the dual mass flywheel, probably brought on with the strain from the extra boost.