Intrax suspension failure

[kbird]

Originally Posted by azrael

So whats the general concensus on this then. I've got intrax and turner bush limiter kit. Seems to be a few different options with plates...?

I have fitted the plates as a precaution, have you asked Anthony/Julian what they think?

[NZ_M3]

In my opinion the Z3 reinforcement plates will do bugger all - you are not spreading the load to other parts of the chassis, merely sandwiching the weak ass top shock steel - the failures are in the whole shock tower, not just the mounting points.

[Thorney]

I have to say I agree, the top plates will help for sure and it maybe enough (failures are relatively rare) but BMW state the entire suspension tower must be supported or at least tied into the chassis floor to properly 'fix' the issue, that why we did a lot more on the harness bar (it would be dead easy just to run a bar from one side to the other and knock em out for £150).

[The Gorilla]

Hi,

NZ_M3- Interesting statement you make.

I have never seen a rear BMW Turret damaged
with them fitted but have seen plenty of damaged
ones without them.

Regards,

The Gorilla.

[shane@mbtech]

Originally Posted by The Gorilla

Hi,

NZ_M3- Interesting statement you make.

I have never seen a rear BMW Turret damaged
with them fitted but have seen plenty of damaged
ones without them.

Regards,

The Gorilla.

Serious question, are you really a gorilla?

I think it will certainly help with the problem as where the shock comes through will no longer split.

Was this splitting the only fault with rear coilovers?

Although im only running front coilovers it will be interesting to know for future reference.

Thanks

[The Gorilla]

Hi,

Lawsy- accordingly yes, or so I am told.

The Rear Turret problem as previously explained in
not caused by 'bump' its caused by the 'drop'.

In the drop, the weight of force of the rear suspension
dropping, that's the complete, wheel, hub, brake/disc, trailing arm,
wishbones, and coilover is all transmitted to the two nuts
that hold the rear top mount in place.

This situation is increased when running shorter suspension
than say stock where you encounter rear wheel lift.

By inserting the Z3 Plates, or a rear strut bar, you push
the load across a larger flat surface rather than the the two
small point loads, of the original two nuts.

By spreading the down force load, instead of creating a
load point, the shell metal does not fatigue.

If not running a front strut bar, you should also really run
large custome washers plates in steel or alloy on the front struts
under the top mount locating nuts, as they, to a lesser degree
are incurring the same downward forces.

On bump, the top mount itself from underneath speads
the load across the turret top.

It also helps in spreading load across the turret top into the shell as
opposed creating a small load point.

Better chassis dynamics and so on.

Regards,

The 'Real' Gorilla.

[azrael]

Originally Posted by kbird

I have fitted the plates as a precaution, have you asked Anthony/Julian what they think?

I've ordered the plates as a precaution too, car going back next week to have the suspension re fettled now its settled

[shimmy]

Fitted mine last week

[Nords]

As mine spends much of it's time on the road, I'm going to swap back to std suspension, have the Intrax serviced and brought up to the new spec (if reqd) and then make a decision about staying on std or refitting.

If I do, then those plates or a Thorney set of bars will be going in...

[NZ_M3]

Originally Posted by The Gorilla

By inserting the Z3 Plates, or a rear strut bar, you push
the load across a larger flat surface rather than the the two
small point loads, of the original two nuts.

Sorry but I disagree.

The Z3 plate is smaller than the actual top mount flat surface, all it does is sandwich something inherently weak with a smaller mount surface - it doesn't affect or change the strength of the surface you are sandwiching (not when it is actually smaller).

The load is first taken up by the Rear shock rubber mount - that mount spreads the load to the whole shock tower which is inherently weak to take a full coilover in the first place.

I am not saying that it will or won't necessarily develop the failure with the Z3 plate. All I am saying is if you are relying on it as a "fix" ... then you are placing way too much faith in it.

You need to properly spread the load to use a full coilover on these cars - period - just look at the ALMS M3 GTRs - that's exactly what they have done.

If you don't believe, go grab a piece of tissue and place two pieces of cardboard on either side that is slightly smaller but in about the same shape as the tissue paper - put a bolt through it and pull hard - I bet you the tissue paper will still tear - it does nothing to add strength to the inherently weak part. Now try the same experiment but this time spread the load completely - you'll get a different result.