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Polybushes over standard new rubber?


phazed

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Technical question.

I am currently preparing my Boxster 986S for track day use.

Not going mad as we all know, this is a fun thing. Car needs quite a bit of work, (to say the least) and is progressing well .I have had to renew all the coffin arms and these have an inner pivoting bush and an outer bush where the control arm, (tuning fork) bolts on. There is also a rear control arm with a rubber bush to the chassis on the rears.

I’ve had to renew all these components as the existing 21 year old bushes were seized solid on the pivoting bolts and were far past their best.

Looking at all the new components with their new very firm rubber bushes in place I am wondering whether to continue with my plan of pressing these out and renewing with polybushes.

I have already bought the new polybushes, unopened packs so I guess I could return them. I have black for the inner pivoting bushes and the standard purple, (because black aren’t available for the outer bush where the control arm attaches.

Question: at this stage, am I wasting time fitting the polybushes? Will the benefit be so small that I will barely notice over the new rubber bushes.? This would involve pressing out 10 brand-new bushes and of course fitting the polybushes.

Car will be running standard engine, different exhaust, track brake pads, R888’s , polybushed ARB’s and some lighter seats.

Looking for fun days with a capable car, not a race car…
 

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All depends what you want to achieve.  Ride will be come less and less supple (something the Boxster is good at) the more hard bushes you add, as the flex of the OE rubber is part of the suspension design....

You need to decide what you want - Race car, track car that is tolerable on the road or road car that's pretty decent on track.  That the moment what you are doing seems to be heading at the middle option, but you seem to be saying you want the third option.

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I can do it. I have a press in the garage. It almost seems like sacrilege to push out the bushes on brand new coffin arms!

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12 hours ago, phazed said:

I can do it. I have a press in the garage. It almost seems like sacrilege to push out the bushes on brand new coffin arms!

So in theory you could run on standard for a bit, then fit the poly bushes and decide then...  As everything will have been apart recently it shouldn't take long to do the swaps.  🤣  Oh, and then the tracking after each fitment.

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I can sort of see that being a problem being too stiff on our roads given their quality! Should be fine on track as the track surface generally is like a billiard table by comparison.

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9 hours ago, phazed said:

I can sort of see that being a problem being too stiff on our roads given their quality! Should be fine on track as the track surface generally is like a billiard table by comparison.

I believe the said car was track focused and it happened on a track, from memory and he was running a quite a large negative camber

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I have had polybushes on my Cayman for about 3 years in which time I probably did ~30 track days. I have had no issues whatsoever and no cracks. I believe the snapped arm you are referring to was the tuning fork - this is a ball joint not a bush and so swapping the ball joint for a bush (of any material) will create issues.

On the road I have had no squeaking or issues of any sort. Yes there is a little more vibration in the cabin (it's the kind of high frequency vibration you get when driving over rough roads) but it is not an issue.

I no longer use my Cayman on track but will keep the polybushes on regardless.

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1 hour ago, Lennym1984 said:

I have had polybushes on my Cayman for about 3 years in which time I probably did ~30 track days. I have had no issues whatsoever and no cracks. I believe the snapped arm you are referring to was the tuning fork - this is a ball joint not a bush and so swapping the ball joint for a bush (of any material) will create issues.

On the road I have had no squeaking or issues of any sort. Yes there is a little more vibration in the cabin (it's the kind of high frequency vibration you get when driving over rough roads) but it is not an issue.

I no longer use my Cayman on track but will keep the polybushes on regardless.

It was the cylindrical bush that was changed. 

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I polybushed everything possible on my Subaru. The ride suffered but it was on coilovers anyway so it wasn't great in the first place.  On the positive side it just felt totally composed however hard you pushed it and they tyres wore absolutely evenly from side to side - not something Subarus are known for. I guess everything was staying in alignment better without the flex. That said I don't feel that the Boxster has a huge amount of slop in the first place.

You know that Spyder performance sells polybushed arms of the shelf?

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