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bertzi43
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Bucse poliuretan vs cauciuc

02 Ian 2009, 22:47

deoarece trebuie sa schimb un tampon la motor si cunostintele mele de mecanica sunt minime,consultandu-ma cu un mecanic mi-a recomandat ceva de la powerflex cica sunt mai bune calitativ decat cele de cauciuc,am mai gasit cateva informatii si despre restul bucselor pe net.

BUCLSELE POLIURETANICE au fost create in scopul de a inlocui bucsele normale de cauciuc.
Sunt realizate din amestec poliuretanic, oferind astfel o durabilitate mult mai indelungata decat bucsele de cauciuc.
Cauciucul contine compusi naturali, iar in timp isi pierde proprietatile de duritate si devine din ce in ce mai elastic si mai moale datorita acestor compusi naturali. Elasticitatea si si materialul deteriorat mancat de vreme si eroziune duc la un balans si o miscare din ce in ce mai mare a elemntelor ce se fixeaza pe aceste bucsi de cauciuc. Unul dintre cele mai daunatoare rezultate ale bucselor de cauciuc ce devin mai moi odata cu timpul fiind schimbarea geometriei rotilor.

Poliuretanul fiind un material cu elasticitate mult mai redusa si avand in componenta substante ce isi pastreaza caracteristicile de duritate in timp si orice conditii de vreme, uzara acestor elemente fiind mult mai redusa decat a celor de cuciuc.
Poliuretanul si in special bucsele de acest gen nu provin din lumea motorsportului, aici se folosesc bucse metalice fara strat fonoabsorbant. Timpul de inlocuire a bucselor metalice se masoara in ore.
Pe langa rezistenta indelungata , ofera si o protectie fonica mult mai buna decat cauciucul , care produce rezonante. Masina va fi mult mai silentioasa la denivelari.
sper sa fie de ajutor aceste informatii :D
_____________________________________________

Seat Leon 1M Stella,1.6 16v,105 cp...
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Re: bucse poliuretan vs cauciuc

02 Ian 2009, 23:05

Powerflex rules!!!
Go 4 it, Emil! Trust the man!
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Re: bucse poliuretan vs cauciuc

03 Ian 2009, 01:38

Sunt mai durabile, cel putin asa se spune, dar va trebui sa le inlocuiesti pe toate, motor, cutie.
Personal cand vine vorba de flexiblocurile de la motor si cutie, prefer cauciucul, chiar daca este mai moale si cedeaza mai usor, este de preferat decat sa apara defecte in structura datorita vibratiilor.
Am vazut multe articole despre bucsele din poliuretan, montate la sistemul de rulare, directie, dar la motor au uitat sa spuna cum se comporta caroseria dupa un anumit timp, fiind supusa la vibratii mai mari. :D Parerea mea ca nu se bucura de loc. Pentru masinile de competitie, asta nu prea conteaza. :D
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Re: bucse poliuretan vs cauciuc

03 Ian 2009, 15:07

Eu am de 2 ani pe masina si pot spune ca pe partea de tren de rulare sunt impecabile. Modul in care masina negociaza curbele este mult imbunatatit,vibratiile le simt mult mai mici si masina mai sigura.La motor nu am inlocuit decat tamponul din mijloc,cel dintre carcasa ambreiajului si caroserie (dog bone),pentru ca atunci inca nu erau disponibile si celelalte. Per ansamblu,sunt extrem de multumit,mai ales ca trebuia sa schimb destul de des bucsele de cauciuc.Era o vibratie care aparea fix la 50 km/h,cand mergeam pe piatra cubica si care-mi spunea cand era timpul sa le schimb.
 
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Re: bucse poliuretan vs cauciuc

18 Ian 2009, 13:20

[quote="dany19940"]Eu am de 2 ani pe masina si pot spune ca pe partea de tren de rulare sunt impecabile. Modul in care masina negociaza curbele este mult imbunatatit,vibratiile le simt mult mai mici si masina mai sigura.La motor nu am inlocuit decat tamponul din mijloc,cel dintre carcasa ambreiajului si caroserie (dog bone),pentru ca atunci inca nu erau disponibile si celelalte. Per ansamblu,sunt extrem de multumit,mai ales ca trebuia sa schimb destul de des bucsele de cauciuc.Era o vibratie care aparea fix la 50 km/h,cand mergeam pe piatra cubica si care-mi spunea cand era timpul sa le schimb.[/quot]





Zi-mi si mie te rog de unde le-ai luat si cam ce preturi au,ma intereseaza si pe mine pt ca vreau sa scap de scartitul care-l scot cele de la bara stabizatoare.
Leon 1M ASV

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Re: bucse poliuretan vs cauciuc

18 Ian 2009, 15:46

Le-am luat de pe http://www.superpro.eu.com/ . Am gasit momentan o singura factura,cu bucsele de la trenul spate. Au costat 74,3£. Daca gasesc si factura cu bucsele fata,iti mai pot da detalii.Dupa cum vezi,firma este in Anglia.Transportul a fost 26 £.La costul total(fara transport)se mai adauga TVA.Daca vrei mai multe detalii,da-mi pm.Nu m-a interesat prea mult pretul,pentru ca se saturase si sotia mea de scartaieli si vibratii si de schimbat bucse,pivoti,rulmenti (nu stiam ce cauza zgomotul respectiv).Am luat si telescoape KONI FSD. Asa ca am avut aprobarea "contabilului" :D . Ideea e ca nu sunt dezamagit de loc.Diferenta se cunoaste de la prima iesire pe strada.Nu fac reclama firmei respective.Cu siguranta sunt destule firme care aduc si in tara.

PS.Am gasit si pretul la bucsele bara stabilizatoare - £8.69 per bucata
 
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Re: bucse poliuretan vs cauciuc

19 Ian 2009, 08:24

Ok multumesc pt informatii o sa le studiez pt ca ma intereseaza ,daca am nelamuriri o sa te mai contactez.
Cu respect ! :salute:
Leon 1M ASV

Tote cele bune ! ! !

 
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Re: bucse poliuretan vs cauciuc

01 Mai 2009, 23:16

Revin cu noutati , poate unii stiu deja , dar scriu aici fiind topicul deja creat , sunt disponoibile acest tip de bucsi si pt Leon 1P , pret estimativ , fara bucsile de bara stabilizatoare , tot setul , 450 Lire sterline , sursa :http://www.powerflex.co.uk/products/Leon+Mk2+1P+(2005-)-2634/1.html
 
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Re: bucse poliuretan vs cauciuc

02 Mai 2009, 15:53

Au reprezentant si in Romania: http://www.****.ro. Tocmai am comandat un set pentru Arosa mea. Sa vad cum se comporta si bucsele de la ei, fiind deja foarte multumit cu cele de la producatorul amintit in postul de mai sus.
Ultima oară modificat 02 Mai 2009, 15:55 de către marian_iam, modificat 1 dată în total.
Motiv: reclama
 
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Re: bucse poliuretan vs cauciuc

31 Mai 2009, 15:35

Exista 2 tipuri de bucse la trenul de rulare al lui Leon 1M:

- bucse care lucreaza prin comprimare si/sau rasucire precum balamalele: la bara stabilizatoare fata, la bieletele barei stabilizatoare, la bascula de suspensie (bucsa cilindrica frontala), la tamponul de motor "dog-bone";
- bucse care lucreaza prin torsiune ca si arcurile: la bascula de suspensie (bucsa "cascaval") si la puntea din spate (Leon 1M tractiune fata).

Prima categorie pot fi inlocuite cu poliuretan, cu conditia ca bucsele de poliuretan sa fie foarte bine gresate cu o vaselina speciala de culoarea bronzului care vine impreuna cu ele, altfel vor scartai la cea mai mica denivelare.

A doua categorie de bucse nu trebuiesc inlocuite, fiindca poliuretanul nu cedeaza, spre deosebire de cauciuc, dar nici cadrul de metal in care e tinut nu poate ceda, deci dupa un timp sar afara din locasul lor.

Bucsele "cascaval" sunt de 2 tipuri: perforate (Leon 1M / Golf IV / Octavia I) si pline (Leon Cupra R / Golf IV R32 / Audi TT). Fiecare tip se poate inlocui cu celalalt. Eu am avut perforate si am pus pline, diferenta este evidenta. Bucsele perforate se puteau indoi cu mana si avea fisuri de 5-10mm dobandite in 50 000 km de rulare, cele pline nu puteau fi indoite.

Tamponul dog-bone de poliuretan elimina "caderea motorului peste cabina" la acceleratii puternice, dar va vibra usor volanul la relanti dupa montarea lui. Putin mai sus in turatii, cam la 800rpm, vibratia dispare.

~Nautilus
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Re: bucse poliuretan vs cauciuc

31 Mai 2009, 15:49

Scuze de intrebare,ai gasit scris asa ceva undeva? Eu am toate bucsele inlocuite de 3 ani si pina acum nici una din ele n-a dat semne ca ar vrea sa sara din locas. Inafara de bucsele de la bara de torsiune(pe care le am in punga originala), la care am o problema cu un filet in lonjeron si n-as mai umbla daca nu e nevoie, toate celelalte stau la locul lor. Si vaselina cu care au venit este alba la culoare si pare siliconica. Mi se pare ciudat ca o firma sa produca bucse inlocuitoare pentru o masina anume, stiind ca ele vor sari afara in functionare. Plus ca ele trec de niste omologari destul de dure. Daca ai gasit undeva scris de vreo firma asta, da-ne si noua linkul, sa studiem problema.
 
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Re: bucse poliuretan vs cauciuc

31 Mai 2009, 17:33

Era pe vwvortex pe undeva, mi-a confirmat si tipul de la ATP Tuning Viena. Sunt putine sanse sa gasesti prea multe informatii despre asta, nimeni nu-si pericliteaza afacerea...

Eu am doar dog-bone de poliuretan de la Powerflex si s-ar putea sa ii pun si la bara stabilizatoare, dar bucsele de bascula raman, cu tot regretul, cauciuc plin. Pe drumurile noastre riscul e si mai mare...

~Nautilus
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Re: bucse poliuretan vs cauciuc

31 Mai 2009, 21:06

Am dat cautare pe vwvortex si am gasit doar 2 referiri la acest subiect:

Re: Poly steering rack bushings. Any thoughts? (VW Tuna) at 9:55 AM 2-13-2009
Poly steering rack bushings. Any thoughts?

I am thinking of gettin some of these for my jetta, not sure what I'm going to do yet tho...
One thought is that the factory bushes deteriorate and split over time... Polyurethane will probably last for ever.

Forum » Golf II & Jetta II
Creator » VW Tuna
Posts » 13
Re: Tell me about... MG ZR (backintown) at 1:49 AM 1-18-2009
Tell me about... MG ZR


...lloys, most of the changes that truly transformed the ZR were made to the parts that most buyers would need a hydraulic ramp to see. The car was lowered by 20mm and fitted with stiffer springs and meatier dampers. Suspension bushes are made of rigid polyurethane instead of rubber to give more road feel and sharper reaction to the driver, who can now react to said changes more effectively thanks to a quicker and more accurate steering system.
Bigger brakes mean that you can now scrub off that ...

Forum » The Car Lounge
Creator » MidnightSpecial
Posts » 3

Nicio alta referire n-a reiesit la "search". Si din astea nu reiese ca ar face ceea ce zici ca ar fi posibil(sau asa ti-au zis altii). Dog-bone am si eu, si aici pot confirma ca la relanti parca suna mai metalic motorul. Dar schimbatorul este mult mai precis ca inainte.
In concluzie...nu mai inteleg nimic ! Chestia cu periclitatul afacerii poat fi valabila si invers: oare acel tip de la ATP Tuning Viena nu putea sa zica ce a zis doar ca sa-si apere afacerea lui(sau a a patronului lui)?
 
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Re: bucse poliuretan vs cauciuc

31 Mai 2009, 21:24

Eu l-am intrebat de bucse de bascula si daca e adevarat ca "sar afara" si a spus ca asa e.

Pe vwvortex era un topic cu si despre bucse pentru platforma Golf IV / Leon I / TT Mk I si au spus asa:

- bucsele "cascaval" nu trebuiesc inlocuite cu poliuretan fiindca nu se pot torsiona asa cum face cauciucul si "sar" sau se invart in lacas pana incep sa se miste liber (bucsa de cauciuc e gandita sa stea fixa acolo si sa actioneze ca un al doilea arc)
- bucsele cilindrice se pot inlocui cu poliuretan fiindca actioneaza prin rasucire ca o "balama" dar cauciucul din care sunt facute e aproape la fel de tare si avantajele sunt nesemnificative
- ei recomandau bucsele "cascaval" pline pentru imbunatatirea manevrabilitatii la o masina de strada sau bucse/rulmenti metalici pentru pista ("spherical bearings")

Uite aici cateva exemple:

Let's end it right here: Stock Rubber vs. Poly Bushings - discutia e pentru modelul Golf III dar poliuretanul e acelasi :)

Hello Luke,

Since you might be getting a trifle confused with the conflicting responses on this thread, I thought maybe it'd help to put things into a little context (no offense intended to anyone here! I'm just trying to give AtariMasta some background, so he can make the best use of the various comments....)

There are sort of two separate questions being discussed here:
(1) Are urethane bushings a good idea anywhere in the car?
(2) Are they a good idea in one particular part of the suspension?

In turn, the first question (is urethane a good idea anywhere in the car?) is itself broken into two parts:
a) Do you really want urethane to work as intended?
b) Does urethane actually work as intended?

So let's go through each question in turn:

1a) Do you really want urethane to work as intended?

One reason the stock rubber bushings are there in the first place is to cut down on the noise, vibration, and harshness (NVH) transmitted by the wheels into the car chassis. They damp down on NVH by introducing a carefully controlled amount of "compliance" (give and play) into the suspension, which unfortunately takes away some of the steering feel and precision you'd otherwise experience. When you replace the stock rubber with urethane, you're essentially accepting more NVH in return for getting more feel & precision (at least, if the bushings work as they're intended). Whether or not that's a good tradeoff is up to you; just be aware that you'll be letting more noise, vibration, and sharp bangs into the passenger compartment when you go to urethane, or indeed to any hard non-OEM bushing.

(As a side note: when the stock bushings are completely shot because of age & wear, replacing them with virtually anything that's new can feel like a great improvement. Hence if someone raves about how his car feels after switching to urethane, you should ask him if the bushings he took off were brand new vs. old & worn. For most people, replacing shot bushings with brand new OEM-style rubber bushings will completely transform the feel of a car, and it's often not necessary to go to a "performance" bushing to get the feel you want.)

1b) Does urethane actually work as intended?

This one is trickier. First thing is to consider where urethane should ideally be mounted: if you have a pivot with a single axis of motion (e.g., an arm spinning in a simple arc about a simple shaft), you have a candidate for urethane --- but the urethane bushing you install is not going to work in the same way as the stock rubber bushing.

The stock rubber bushing is "stuck" both to the thing that's pivoting and to the shaft that it's pivoting on; nothing is sliding or rubbing, and the only reason the pivot can move is because the rubber itself distorts and twists. Because there's not sliding or rubbing, there's no wear, and the only way the the bushing breaks down is through hardening of the rubber compound with age & heat cycle -- which can take many tens of thousands of miles to really take place.

In contrast, the hard urethane bushing doesn't twist or distort, but instead it has to spin around the shaft. That introduces a sliding, friction surface, and that's why you typically have to regularly lubricate a urethane bushing (whereas stock rubber bushings don't need lubrication at all). If the lubricant dries or wears off, or if sand and dirt ever works their way onto the pivoting surface of the bushing, the bushing ceases to slide on the shaft, and begins to grind away. You hear the initial stages of this grinding as a high-pitched squeaking noise, and if you don't do anything about it, the wear eventually enlarges the pivot hole of the bushing, and everything gets all sloppy and bangy.


Hence if you want to use urethane at all, you'll want to use it on a single-axis pivot, and you'll want to periodically check & replenish the lubrication. Keeping things clean and dirt-free would also help here -- but in any case, the bushing will probably not last nearly as long as will a stock rubber part (though judging from GTIus' comments, maybe they can last a few tens of thousands of miles?....).

A separate issue, however, is how often you really get a single-axis pivot on a suspension. Manufacturing tolerances and design quirks are such that even simple pivots often get a little misaligned, so that an arm that's supposed to describe a simple arc around a shaft, in practice has to swing somewhat off-axis. If the misalignment is really small, distortion of the bushing might accommodate it (though that distortion often increases the wear on the inner pivot face); but if it's moderate, then the bushing will begin to bind.

As a side note here, I don't know the quirks of the VW chassis (my own bushing experience was on a different type of car), but it sounds from the comments on this thread that there's enough binding potential that the real racers use metal spherical bearings, which combine zero compliance with an ability to turn in any direction (i.e., no binding) But that's just on the basis of a couple of posted comments....


2) Is urethane a good idea on one particular part of the chassis?

This one (fortunately!) is easy to answer: while it's at least debatable whether urethane can be acceptable on a single-axis pivot, there's no question at all that it will not work on a pivot that has to move along more than a single axis. With a stock rubber bushing, a suspension arm can move in variety of directions, as the rubber simply distorts to accommodate the motion. But with urethane, the pivot has to spin about a shaft -- and that means the suspension arm can move only on a single arc. Thus if you put it on the end of something that has to move along two or more axes, you will either get binding, or else you will quickly wear away the urethane until it's sloppy enough to accommodate the extra motion (which sort of defeats the purpose of the urethane in the first place).

As I have an A4, I don't know where the verboten parts of the A2 chassis lie, but on an A4, there's really very little place on the rear that seems suited for urethane. The A4 rear shocks, for example, describe a variety of irregular arcs depending on whether the car's rolling or hitting bumps, and the trailing arm pivots get twisted all over the place when the car rolls. (Perhaps maybe on the lower shock mounts?.....) But that's with an A4 -- perhaps the A2 has single axis pivots that might work?

In any case, we can summarize the above into the following list:

1) compared to OEM rubber bushings, urethane bushings will let more noise, vibration, and harshness into the passenger cabin, but have the potential of increasing steering feel and precision.

2) they will wear out more rapidly than OEM rubber, and will wear particularly rapidly if unlubricated and exposed to dirt.

3) on a true single-axis pivot (e.g., a control arm spinning about a simple shaft), they can function as a sort of poor man's spherical bearing -- though if you can afford true spherical bearings, you're much better off (even less compliance, zero chance of binding due to misalignment, longer life, etc.).

4) on a multi-axis pivot, they will bind badly until they are so worn away as to be sloppy.


As a final note, your original question was why are they so popular? They're popular in large part because everybody sells them, and everybody sells them because they're sort of a dream product (from a seller's point of view): a given bushing costs only pennies to manufacture, it's very small and light so storage & transport costs are low, the markup is absolutely enormous, and it's very easy to explain the "performance benefits" to eager customers. A more telling question to ask is why a shop like Dick Shine's doesn't sell urethane: clearly they can make money on urethane like everyone else (there's absolutely nothing to stop them from doing so -- *you* could call yourself a "Tuner" and start selling urethane bushings out of your basement tomorrow, they're so cheap and available), and yet they go out of their way to discourage their use. Now why would that be so?

Anyway, I have no experience with urethane (I did my penance with nylatron and Heaven-help-us milled aluminum back in the old days), and I don't want to slight the fellows that believe in the stuff: on the right pivots, and with the right maintenance, maybe they can be made to work acceptably enough for the right people. And here's where I bow out of the discussion.....

Cheers!

- Ceilidh


Sublinierile imi apartin. In acest topic nu a spus decat ca se uzeaza rapid si ca ajung sa joace in locasul lor, dar asta e deja un neajuns la o piesa care costa cateva sute bune de lei plus montajul. Altii au spus ca "ies" putin cate putin afara, cand gasesc un topic despre asta il pun aici.

Poate ai noroc si poti conduce ani buni cu poliuretan - eu n-am riscat.

~Nautilus
1966 VW (Broscuta) 1300 - "steaua" spotului publicitar la Orange
2005 Seat Leon FR 1.8T
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Re: bucse poliuretan vs cauciuc

31 Mai 2009, 21:27

Aici se explica ce tipuri de bucse se folosesc la platforma Golf IV si de ce:

MkIV OEM control arm bushings?

~Nautilus
1966 VW (Broscuta) 1300 - "steaua" spotului publicitar la Orange
2005 Seat Leon FR 1.8T
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