alternatives to the butt strut and ground clearance

[Boysie]

I have a friend who has a lotus esprit. That is a car with clearance problems. He never complains about grounding.
Wayne I would imagine like must ///M owners you drive over road calming ramps at a snails pace.
I often hear cars crashing into the road after going over ramps and they are not even lowered.
Give it a go, as you will see its easy to remove if you keep grounding, I can't see that happening after you fit it


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[joey]

thank you all for the replies..(and the diagram brian)

this has clarified things for me somewhat,

as far as i can see from the opinions given and the technical diagrams I have looked at, the subframe bushes and the ARB's are the first port of call in stiffening up the suspension ,so the 2.8 ARB's i'm getting from koen will make a noticeable difference as will swapping out the bushings for the poly ones and using inserts on the subframe bushings..my current wheels are the 15" pepper pot so when I change those for the 16 or more likely 17 rims I am hoping in combination with the other changes it will make a very significant improvement.

if I have any of this wrong do chime in..!

re the butt strutt I can see the theory behind it as running parallel supports in the rear would tighten things up, but only in the event that the current set up is seriously insufficient in some way and to my understanding it would only restrict "outward movement" significantly, in short I am inclined to agree with deano and badman on the effectiveness of the rear strut,its probably minimal and considering the cost and potential ground clearance issues its worth looking elsewhere first for the improvements I would like.


once again thanks for the help.

 

[Boysie]

I thought Mark Badman was referring to the engine strut?

 

[badman gee]

Yes I was

 

[zedonist]

Just my thoughts, i can't see what it does, it sits between two bolted joints attached to a triple box section beam which is bolted to the bottom of the body in three points,(two ends and a one middle, two if you have a dual eared diff) any flex would be either side of the middle joint, and would not be felt as you have the suspension arms flexing up and down.

I would be very interested in any data strong strut have on the modification other than perception.

Body roll is controlled by the ARB, hence if you want less body roll you add thicker, stronger ARB's. Its worked for me, might work for everyone else

 

[swamper]

At last a good debate...
Having looked st the fitting kit I'm wondering if it's this that's coming into play ...?

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[zedonist]

I have spent thousands on my Z3, I have the Bilstein B12 kit fitted, which i really rate, but the one single modification I made was the H&R anti roll bar kit, with this and the Bilstein kit I have virtually no significant body roll. The only thing I can see the strong strut system doing is taking up slack in worn bushes........

And as said in many other posts people are welcome to come and drive my car to see the difference

Definitely not a placebo effect from some angle iron

 

[Boysie]

Reading Mike Fishwicks comment on stiffening a Z3,
The ///M has upgraded ARB's as standard
A good read
http://zroadster.org/wiki/bmw-z3/modifications/bmw-z3-subtley-stiffening-a-z3-by-mike-fishwick/

 

[Stormy_be]

If someone would install a camera (gopro or something similar) to the sparewheel mount (taking the spare wheel out for the test), could we be able to film everything going on with the mountingpoints?
Filming while doing some "quick driving", taking a roadabout, etc (I can't do that on open roads as my car is not registered).

Would someone be able to do this?
Just in the name of science (of course)...so that we can see for ourselves...pictures (or in this case video) is proof that can not be put aside.
That would make-or-break the use of the butt-strut.

Regards, Koen

 

[Boysie]

Don't we have a small forum member that could be strapped under the car
I could put forward a name

 

[zedonist]

I doubt putting a camera on the area will prove, disprove anything, my guess is, it will show movement of the bushes without the butt strut, and then movement of the bushes with the butt strut and that is all, at the end of the day the butt strut fixes to the two mounting bolts, the bushes are still allowed to move, and this is why i see no point in it, that said watching a small person strapped to the underneath of a Z3 might get a lot of views on Youtube, so go for it.

As the OP has a 1.9 then uprating the original roll bars to the sizes of the //M or 2.8 is going to give you a massive improvement, as discussed in the Mike Fishwick post and as scientifically proven by the large smile on my face when i upgraded my 1.9 to H&R.

The ARB functions as a big torsional spring, you can keep strengthening (enlarging) it until it does not twist anymore under the cars loading and then you will have no body roll whatsoever and it will be like a go kart, the butt strut on the other hand is, well, a lump of metal........which perhaps some may say has Magical properties........

 

[zedonist]

should have said "in my opinion"

 

[swamper]

Is was the effect on the bushes that keeps coming to mind.
Maybe it is the fitting kit that's tightening them up

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[zedonist]

No Swamper,

Have a look at item 4 in the diagram that Brian 4 posted, this bracket ties the bolt through the bush to the chassis, ergo the butt strut can have no effect, as it's intended purpose is already in place.

 

[swamper]

Hmmm...well there's only one way to find out and strap one on...I would love to see the data relating to the rear strut...like I said if got one here ..so I will run the test when I get chance.
The only note that I would put in first is that it's not a flimsy bit of kit...it's the same thickness as the front struts they make

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[Stormy_be]

Swamper,

Coudl you already do the test without the butt strut fitted?
We could already see how much movement there is (regardless of the question if the strut will or will not reduce that movement).
As zedonist said, it should already be tied down by "item 4" (if that does the job sufficiently).

Koen

 

[Boysie]

I've sent another email to strong strut
Hoping they will defend their product
I mentioned these comments end up on goggle searches, re Strong strut
Watch this space

footnote
Mike Fishwicks wrote a great write up on the benefits of having a strong strut fitted
http://zroadster.org/wiki/bmw-z3/mo...ic-suspension-modifications-by-mike-fishwick/

 

[swamper]

Good wright up by Mike...butt strut now on will give a push when I get chance

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[zedonist]

You can get an inclination measuring app for smart phones. You could use one, and find a good bend that causes body roll, and approach it 5 times at the same speed and line, and measure the average inclination, with the strut off, and then repeat with it on.

 

[swamper]

Or just kick it it round the bend and see when it starts to squirm..haha

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