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anyone tried replacing the rear beam bushing with a poly powerflex or DNA unit?

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Beverly Hills
#1
Curious if anyone's done this yet? Surprised whats out there on the powerflex is limited. Cannot find anything at all on the DNA part, maybe less surprisingly. Getting some bushings done later in the month and was considering whether to replace them as well.

here are the parts in question;
https://www.powerflexusa.com/shop/p...-mk7-mazda2-rear-beam-to-chassis-bushing-2040
https://whoosh-motorsports.myshopif...ing-rear-axle-uniball-kit-fiesta-st-2014-2019

thanks in advance!
 


Dpro

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Los Feliz (In the City of Angels)
#2
Curious if anyone's done this yet? Surprised whats out there on the powerflex is limited. Cannot find anything at all on the DNA part, maybe less surprisingly. Getting some bushings done later in the month and was considering whether to replace them as well.

here are the parts in question;
https://www.powerflexusa.com/shop/p...-mk7-mazda2-rear-beam-to-chassis-bushing-2040
https://whoosh-motorsports.myshopif...ing-rear-axle-uniball-kit-fiesta-st-2014-2019

thanks in advance!
The DNA stuff was largely unavailable stateside until sometime last year when Ron at Whoosh picked up their line. Powerflex has been here since the beginning. Most people have not done the rear beam bushings as they are really not that important. T shirt driving was one of the few that did the front control arm bushings and actually has a vid about it on his Youtube channel. He is no longer on the platform though after he blew his engine he put the car back to stock, sold it and moved on.

I will add while the DNA press that Ron put on his website sounds great there are a ton of guys tracking the cars laying down great times and I am not sure a lot of them have even touched the bushings on the rear beam. The car does handle incredibly well already . lol
I think you would get more benefit from doing the front lower control arms than the rear beam IMO.
 


kevinatfms

Active member
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Germantown
#5
Those DNA uniballs must be NVH central being solid. The poly bushings scare me as they barely keep together in the lower torque mount on our cars. Cant imagine them working for long on a track car smacking curbs.

The b-spec cars required the rear beam bushings to be filled IIRC. They were the regular fiesta bushings though so im sure they were more compliant than the ST beam bushings. But they were 3m window weld filled in the Ford Racing coilover instructions as a requirement(probably due to the insane spring rates). They did not run the poly bushings.

If you take out the rear beam for anything; slap some tape on one side and fill them with 3m window weld for $20. It cant hurt and the rubber is still intact for some sort of compliance.
 


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Paramus, NJ, USA
#7
As far as not “needing” to do the rear trailing arm bushings, check out some videos of the Euro fiestas from 2010-2012 where the plastic bushings are cracked or falling apart. I’d say it’s only a matter of time before everyone will need to do it.

I’ve noticed a firmer response in and out of turns in the rear. Only negating factor I’ve had is high speed weight transitions more aggressive than just doing a slalom. With less lateral flex of the beam twisting side to side in the pickup points, I’ve had quite a few spin outs. So I have some coil settings I need to optimize in the future.
 


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Location
Canada
#8
I have noticed witness marks from the bushing shell hitting the mounting bracket with the factory bushings. Anyone else run into this with a sticky tire?
Curious if the powerflex bushing would get rid of the lateral flex.
 


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Location
Phoenix, AZ, USA
#9
I bought a set of the powerflex ones, and once I looked at it and examined the angle it forces rotation for simple up and down suspension movement (jounce) decided it was a terrible idea twisting/flexing the chassis, and got a set of the DNA Uniball... quality piece, install went easy, no significant NVH and the suspension arms rotate smoothly. However, when running R888R tires, they seemed to transmit a little bit more noise (noisy tires) than the other Fiesta ST I have... but no other noticable effect, the car feels more solid than stock (solid also means less NVH).
 


OP
R
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Beverly Hills
Thread Starter #10
Thanks again for all the feedback.

I get some sense the poly rear bushings might induce more oversteer.

AZSP33D - many thanks for the feedback on the DNA unit. curious what you mean by car feels more solid than stock. do you mean the rear end is more planted? really wanting to try this at some point despite the higher cost of the part.
 


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Location
Phoenix, AZ, USA
#11
Feels like less movement/flex of the chassis under cornering load and dynamics, making it more precise... it's probably not the chassis itself that's moving flexing less but this is my description.

Thanks again for all the feedback.

I get some sense the poly rear bushings might induce more oversteer.

AZSP33D - many thanks for the feedback on the DNA unit. curious what you mean by car feels more solid than stock. do you mean the rear end is more planted? really wanting to try this at some point despite the higher cost of the part.
 




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