Poly bushes SPECIFIC QUESTION to Regular vs Sport Edi owners

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fish
Joined: Thu 07 Feb, 2013 17:04
Posts: 177

  Z3 roadster 2.2i
Location: Sandbach, Cheshire

Poly bushes SPECIFIC QUESTION to Regular vs Sport Edi owners

Post by fish »

Hi,
I am seeing mixed responses about poly bushes and concluded their are 2 or 3 kinds of owners out there....

1) Regular suspension
2 ) Sport edition with MTech/OEM sport suspension
and
3) Z3M of course (out of scope for this question)

I have noted comments about poly bushes being "harder" on the ride....I had a golf GTI before and a Regular passat and yes, the golf was much "thuddier" on the road, but drove like a roller skate, where as the passat tends to soak up bumps....example over....

So, when Z owners say the suspension is "harder", is that generally coming from 1) Regular suspension owners who have gone from soft to harder bushes or is it ALSO 2) Sport Edition owners who already have stiffer springs and ride....

I appreciate that bushes and springs/anti roll bars are the not the same thing, but am trying to gauge that if I swap my bushes to poly, as I have the MTECH suspension on my M54 2.2 sport that the difference is perhaps not as noticeable as say a 1) Regular suspension driver? Does that kind of make sense, as a theme to the question? Am talking hypothetically here....

My inspiration of the work was simply to give the 12 year old car a "mid life" refurb, i.e replacing all bushes as >10 years old, de-salt and clean the underneath and powder coat many of the parts etc....then once done, chuck on a new set of tyres....(another big debate)....Totally except that everyone will have an opinion and as a rule, am an OEM and keep it genuine kind of guy, but, if the part intend to replace has been surpassed by newer technologies or there is a practical reason to do so, then I would step away from OEM to other parts etc.....

Happy to discuss thanks
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BladeRunner919
Joined: Fri 17 Feb, 2012 20:18
Posts: 2225

  Z3 roadster 1.9

Re: Poly bushes SPECIFIC QUESTION to Regular vs Sport Edi ow

Post by BladeRunner919 »

I suspect most owners have gone from soggy old original bushes to either polybushes or new oem bushes. Unless you have an owner who has tried brand new polybushes and brand new oem bushes back-to-back, there is no chance of a fair and true comparison between different types on the same car, let alone between cars with different oem suspension setups.

Personally, I went to polybushes partly because they are easier to install and partly because I can't understand the idea of the oem bushes having large voids in them, which must allow a degree of movement and therefore be a less stable ride. But that's just an opinion, and comparing my new polybushes to the original bushes installed 14 years and 150,000 miles ago is worthless.
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Poly bushes SPECIFIC QUESTION to Regular vs Sport Edi ow

Post by Southernboy »

All things considered, the OEM bushes are very good...The voids act as mini shock absorbers. Also, there is an "expansion and compression" scenario as they work, so the actual movement is minimal. Granted, as they age, they will become less effective, but considering the choice to change them after 10+ years says a lot for their durability and effectiveness. :wink:
"Normal is overrated"
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Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2136

  Z3 roadster 1.9

Re: Poly bushes SPECIFIC QUESTION to Regular vs Sport Edi ow

Post by Del »

I think the manufacturers of polyurethane bushes tend to “sex-up” the performance benefits of their bushes over standard, good condition rubber ones. Bushes are primarily designed to absorb noise and vibration – for normal road use rubber ones do that better than say racing metal ones. I agree with Bladerunner in that they are easier to change – I would use them myself in a situation where a DIY job was made much easier by using them. I have tried to research the purpose of the notorious bush at the back of the wishbone and the information I’ve managed to glean is that they are there to absorb vibration on braking.
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PCSAM
Joined: Sat 13 Aug, 2011 01:19
Posts: 1002

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Location: Taynuilt

Re: Poly bushes SPECIFIC QUESTION to Regular vs Sport Edi ow

Post by PCSAM »

my car came fully bushed up when i got it ..... I did change all the shock absorbers when i got it. when changing them all of them wear knackered big time :shock:
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