Találtam egy érdekes cikket a fékolajról!
Lusta voltam lefordítani de ha kell megteszem.
Brake fluid... Bit of a mystery topic!
To help dispel some myths and for some good solid general info on the mysterious world of brake fluids I decided to contact Millers Oils up in West Yorkshire.
Their Technical Director, Martyn Mann was on hand to give us some useful info… below is Martyn's article on brake fluids.
There is a degree of confusion regarding the specification of brake fluid and this article sets out to clarify the situation.
The Department of Transportation (DOT) classifies brake fluids to defined specifications. These specifications relate to their boiling points and chemical composition, both of which are important. All currently available brake fluids are covered by one of the following specifications; DOT3, DOT4, DOT5 and DOT5.1.
The laws of thermo-dynamics dictate that the energy from motion is turned into heat through friction. A braking system only works efficiently if the fluid remains incompressible. If the brake fluid boils, it turns to gas, which is compressible and the braking system becomes “spongy” or in extreme cases fails completely.
A brake system is not perfectly sealed and moisture can get into the system and be absorbed by the fluid. The effect is to reduce the boiling point of the fluid, which reduces the efficiency of the braking system, as described above.
The DOT specifies two reference tests for brake fluids.
* Dry boiling point - the boiling point of fresh fluid
* Wet boiling point –the boiling point once the fluid has absorbed moisture (representing brake fluid after time spent in a real situation).
There are two main types of brake fluids:
* DOT 3, DOT 4, Super DOT4* and DOT 5.1 which are based on poly glycol compounds.
* DOT 5, which are based on Silicone.
Note the two types of fluid are not compatible and must not be mixed in a braking system.
SILICONE BRAKE FLUID (DOT 5)
Silicone based DOT 5 was originally introduced to give higher temperature performance over glycol DOT 4. Silicone fluid also has other advantages, it does not damage paintwork and it does not absorb water.
However, silicone fluid is a poor lubricant and does not lubricate ABS pumps as well as PAG fluids. It is also more compressible than PAG fluids, which can result in a sluggish or spongy pedal. It therefore requires special design considerations in braking systems. Further, because it does not absorb water, any water remains as globules, which can pool in low spots in the system and cause corrosion. This water can vaporise when heated under heavy braking giving a disastrous effect on braking efficiency.
DOT5 fluids are not recommended for motor sport applications.
POLY GLYCOL BRAKE FLUIDS (DOT 3, 4 AND 5.1)
Glycol based DOT 4 fluid is the current mainstream brake fluid, and you will see that the specification is considerably better than DOT 3 which it replaces.
DOT 5.1 has higher specification still and is for fast road and occasional track day use. It has a similar spec to DOT4 for the boiling point (>260) but is a lot lower viscosity @-40C typically 900 centistokes (compared to 1500 - 1800 centistokes for DOT 4 and super DOT 4).
Listed in the table below, are the minimum dry/wet boiling point specifications for each DOT level.
BOILING POINT:
DOT 3 - 205°C (dry) / 140°C (wet)
DOT 4 - 230°C (dry) / 155°C (wet)
DOT 5 (silicone) - 260°C (dry) / 185°C (wet)
DOT 5.1 (PAG) - 260°C (dry) / 185°C (wet)
Super Dot4 * - 300°C (dry) / 195°C (wet)
(racing brake fluid)
* Super DOT4: The main difference between DOT 4 and Super DOT 4 is the dry boiling point. Normal Dot4 is >260C whilst Super DOT 4 is more like >310C
Srt,a nettel jobban jársz.
Nem tudjátok szervo nélküli dupla főfékhengeres rendszerhez mi az ideális fékmunkahenger átmérő? Most alakítanánk át az offot, de nem tudjuk mekkorával próbálkozzunk? Jó lenne elsőre eltalálni, a 320-as tárcsák+ 4 dugós (széria) nyergek vannak fent.
Van 4 db radiális 4 dugós nyereg,300-320mm az ideális,hátsó nagyfék vagy első, akinek nincs olyan.
Porsche,új,betéttel van.
75/db
Van 4 db radiális 4 dugós nyereg,300-320mm az ideális,hátsó nagyfék vagy első, akinek nincs olyan.
Porsche,új,betéttel van.
75/db
Hello Kitty
Erdekelne valami nagy fek.Esetleg ha valki valamit tud.Nem fontos homolognak lennie,de lehet a nagy homolog brembo is.
Ha esetleg valaki tud
Project MU, FPC vagy gyári fékbetétet EVO IX-hez...
Érdekel az ár, szállítási idő(ha van ilyen)...
Privibe jöhet! Köszönöm...
Utoljára szerkesztette: lalow; 2011. 12. 04. 21:01-kor
Kezd elkopni az első betétem és a tárcsa sincs valami jó állapotban. Milyen betét-tárcsa kombót ajánlanátok elsősorban utcai használatra, néha pályanappal megspékelve? PFC-t már használtam, de most nem nagyon van 2 kilóm erre a projektre, persze ha nincs már értelmes megoldás akkor gyüjtögetek. Csak annyi minden másra is kéne, de az itt off.
Sziasztok,
Nekem is hasonló kérdésem van, az első fékbetét elkopott, a tárcsa még bírja.
Mit és honnan érdemes beszerezni, ha az autó alapvetően utcán van használva? Nem szeretném ha hidegen csikorogna, ezért valami utcai, max "félverseny" betétre gondoltam
Előre is köszönöm a segítséget!
Ádám
Nekem az EBC Yellow stuff parádésan bírja eddig a pályázást és utcán is teljesen rendben van. Hang nélkül teszi a dolgát...
www.nieszmotorsport.hu
06 30 9 715 133
Jelenleg 3 olvasó nézi ezt a témát. (0 tag, és 3 vendég)