1999 Z3 Strut Brace

UK forum for general and technical discussion about the Z3 roadster
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Joined: Fri 13 Oct, 2023 11:26
Posts: 1

  Z3 roadster 2.8

1999 Z3 Strut Brace

Post by BobKen74 »

Afternoon all, hail, rain and driving rain in Lancashire today which often gets me thinking about additions/improvements to my pride and joy.

I am a complete novice in all things mechanical and maintenance so bear with me!

Will a top strut brace from a 3 series fit my Z3 as the ones sold a a specific for the Z3 seem a lot more expensive. I have the 6 cylinder 2.8l wide body so it would be the straight brace type. Is this a worthy upgrade in people’s opinion?

Also looking at under bracing and poly bushes.

Looking to sharpen things up ready for the ‘summer’ and reduce the scuttle shake, rattle and roll.

All thoughts welcome!!


Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2094

  Z3 roadster 2.8
Location: Daglan, France

Re: 1999 Z3 Strut Brace

Post by Mike Fishwick »

You will have to measure the distance between the centre of the strut mounts on both cars, but I bet they ae the same!

'Scuttle Shake' is a meaningless description, spread by media hacks whose opinions are uninformed but accepted by most people - Top Gear is a prime example! Their usual claim is that, being a convertible, the Z3 body is rather flexible. They have to say something, after all, and only praise cars from a manufacturer they idolise, or who pays them to advertise in their magazine . . .

I find that the Z3 feels to be the most rigid car I have ever owned! What people mean by 'Scuttle Shake' is uncommanded steering inputs on rough roads, which - assuming that everything is in good condition - is produced by the 'gapped' rubber bushes at the rear ends of the front wishbones. These permit the wishbones and front wheels to move sideways under suspension loadings. This is worse when combined with 17 inch wheels which are fitted with front tyres with stiffer sidewalls than the similar sized 16 inch type. BMW should never have fitted this type of bush with 17 inch wheels.

The answer is to fit either M Roadster/M3 rubber bushes, which are almost solid rubber, or polyurethane items such as Powerflex - the difference is quite dramatic!

Do not expect great things from a strut brace - but they do make the steeering response slightly sharper. I found that the Strong-Strut 'Butt Brace' made the biggest improvement to steering response, folllowed by their 'Body Brace' - which does not brace the body, but ties the butt strut (and therefore the rear cross-member) to the cross-brace below the engine. This holds the rear wheels in line, and almost eliminates toe-in / toe-out as the suspension deflects. The result is a reduction in understeer, and better rear tyre life.

My car also has stiffening inserts in the gaps of the rear crossmember bushes (made from B and Q drain pipe!) poly bushes for the anti-roll bars, E46 strut mounts, a smaller RAID steering wheel, Bilstien Sprintline dampers, and Eibach front springs with standard rears (to maintain a useful amount of rear ground clearance) While these make only small differences by themselves, together they really transform the car - so do not expect a miracle from just a strut brace. They are low on my list of improvements, but look pretty! For a large improvement buy a Butt Strut, and later add a Body Brace, but of course you - or others - cannot see them! Make any modifications one at a time, and see if you feel any difference

The modification which always makes the greatest improvement is my home-made short-shift gear lever, which cost about 20 pence, and works just as well as the £500 AC Schnitzer equivalent! It feels good at every gearchange, even if just sitting in the garage!

Have a look at my articles on 'Stiffening a Z3' and 'Short-shift gear lever for a Z3' in the Knowedgebase.
A Z3 is not just for Christmas - it's for life!
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Robert T
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Joined: Mon 12 Jun, 2006 10:35
Posts: 10173

  Z3 roadster 1.9
Location: Cheshire

Re: 1999 Z3 Strut Brace

Post by Robert T »

Hi Rob,

Others have fitted them with success, though modification may be needed on some, whilst others have clearance issues.

Take a look at this thread: https://www.zroadster.net/forum/viewtop ... =5&t=28579

Also try searching for: E36 Strut Brace

There are quite a few threads on the subject.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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