Deadweight in the Boot.

[paultv]

Hello all,

Whats the opinion of the 30kg damper in my cabby boot, I'm suffering from offside rear droop, oooh err misses!

Seriously, I know it's supposed to weight balance the car, although this appears a bit redunant if I have a full/empty tank of fuel.

With only me in the front and my friend in the boot, the cars looking silly. p.s I have new springs and bushes.....

any observations?

thanks

Paul

[jimbom30cab]

No noticeable change if you remove it.

But BMW put it there for a reason so if you can, it's worth keeping it

[jmc330i]

From a couple of other posts on this...

it's a harmonic damper - that's why it's mounted on rubber bushes. It removes some of the vibrations caused by a roofless shell's inherent reduced stiffness.

Whether or not you can notice the removal of the damper depends on the condition of the rest of the suspension and car. If the suspension is as new, then you'll notice it. 20 year old suspension and you won't.

[andysheep]

I put mine back in after resto,bmw know what there doing,but theres no diffrence in ride height on mine

[paultv]

mmm, taking mine out made no difference to the ride height imbalance anyway, what bothers me is that my springs and bushes were done by... well, see my prop-shaft thread - what I've not checked is my rear shock tops - that's next on the list.

Paul

[Brianmoooore]

The 'weight' wasn't specified by BMW for anything to do with ride height. It's a harmonic vibration damper.
A similar concept was used by Renault F1 a few years ago, when they were one of the top teams. It was hidden in the nose, and when discovered, and subsequentially outlawed, the car s suffered a considerable drop in performance.

[paultv]

Exactly Brian, I get the concept OK, just searching for the issue over my "tilt" The springs measure different heights on the car, under load. i.e. differently compressed - so they're settling about 3cm lower on the OS.

Very spooky.

Paul

[Sanchez]

Is the rear beam fitted on the new bushes properly? My old bushes cause slight ride height difference when I jack the cak up an the bush came out the beam and didn't go back in properly. All been replace now and all fine.

[paultv]

I also have this, jacking the body, the bush lifts upwards but does return correctly, the beam position to the body is the same both sides - but the spring compression is different between the NS and OS which means they are not a matched pair????

Paul

[paultv]

More measuring, the near side bush is not fully home, about 5 mm too high which accounts for a portion of the error between the two sides, but the basic spring compression is almost 2 cm different.

Paul

[GPW]

I tried mine without this weight, the car was very skittish over some rougher surfaces, on smooth road you'd not notice.

I popped it back in and back to normal, BMW engineers really did know what they were doing!

[andysheep]

Iv this problem on my driver,and it down to mismatched springs,its going into my workshop for its big sort out, rear seal and new clutch, cam seal and unresolved rot under fuze box but if my plans of bigger engine ,2.5 or stroker it neededs to be sorted,hope you sort ya issues,andy

[paultv]

I wish I could get to the bottom of this, I had new springs fitted, but they are not BMW or anything half decent, so I guess I'll change them for good pedigree ones. Can't think of anything other than springs that would affect the ride heights in this way - all the measurements show different amounts of compression on the two sides, so one spring must be weaker than the other.

I'll leave the lump in back - car feels fine to drive now the prop is running balanced and new torsion bar rubbers and drop links fitted.

This week its the Cam belt/water pump/thermostat/ and all that jazz -

Paul