Adjusting brake bias-How to?

[maco5007]

Guys,Is it true that after changing to performance brake discs and calipers for example brembo etc we need to adjust the brake bias of the car? :blink: If so how can this be done? Can DIY or need special equipment? Plan to do this soon, so your expert advice will be appreciated...

 

[maco5007]

BTW, Im just replacing the front units...the rear stock...(for the time being)...until more funds comes up...

 

[teejay]

i'm no expert......but i'll tell you what i know

brake bias is controlled by a valve, some have it selectable in cockpit or at the valve itself e.g.. percentage bias front to rear like those WRC cars

if you have bigger brakes up front, chances are bias will float to the front, coz there's a bigger pressure build due to the huge diffrences in brake piston diameter

yuo would have to then calculate the differences of surface pressures differences from the front and back, from the original setup and new setup e.g. ori setup maybe 59%-41%, based on surface pressure, and the new setup maybe 75%-25%

so you would probably need to increase the rear bias to get a balance - i'm talking about surface pressure, then you'll have to calculate the appropriate braking pressure to fronts and rear

unless there's a significant increase in the fronts, then the rear would still be using the original bias, the proper way is to get the the rear pressure enough just before the lockup, else the front wil nose dive alot, and the rear will still have force to push the car forward.....

 

[3er]

f8 should be here to answer these.

 

[Jipster]

i think ireland engineering sells a brake bias control thing.... can buy on internet...

IMO if you have bought/installed a purpose made BBK for your car, u shouldnt have to resort to brake bias thingies....

People like Brembo etc would have factored in these things when they designed the BBK for you... IMO if you follow the recommendations of BBK manufacturer u shouldnt have to use brake bias adjustment, unless that is waht they advise u to do....

Unless of course u wanna go racing....brake bias adjust gives that extra bit of control that will give you the edge over your opponents...u can also tailor yr braking performance to characteristics of the track i guess....

If purely custom made e.g mix and match brake units from different models or different makes (except people like Movit who use porsche brakes for a lot of their offerings and do their own R&D), you may need to do some research yourself and calculate the brake balance between front and rear etc to avoid imbalancing the system..

Check out this site (http://www.bmwe34.net/e34main/upgrade/brakes.htm) where the writer actually researched the actual pound foot of torque generated at each end to get best results - see execrpt from site below :

To give an example, the E34 540i brakes develop 686 lb-ft of torque on the fronts at 500 psi line pressure; the rears produce 313 LB-ft, so the f:r bias is 69:31 (as a percentage). Adding the M5 front brake (rears are the same on US E34 M5's), which generates 720 LB-ft, changes the bias to 70:30. The '95 Euro M5 brakes generate 646 LB-ft front and 336 LB-ft rear, giving a bias of 66:34. Everyone raves about this setup, which is interesting as the front brakes actually generate LESS torque than the earlier E34 M5 (or the 540i, for that matter)! Chances are that this perception of awesome brakes has more to do with the better balance front-to-rear than the massive cooling capability, which only comes into play when you're driving the piss out of the car and the brakes are generating many kilowatts of heat. Unless you go to the track, you'll never encounter that aspect of their performance



......and all this from a guy who is still running drums at the back..... I need to get a life ....

 

[2cents]

......and all this from a guy who is still running drums at the back..... I need to get a life ....

Dat's wut happens when u dun cum to Friday tts! :rofl: :rofl:

 

[Zoggee]

wow..!! very good Jipster..

I upgraded my brake servo...Thanks to Teejay's help. and dun mind sharing infromation on the upgrading with you. No need to find the 123 brake servo...this wan even better!!

 

[The Necessary]

OK, is your car an e36 or later model?

OK, so they all come with ABS, right?

Problem solved.

Anyways, most good brake manufacturers (ie; AP, Brembo, Stoptech) will engineer their front BBKs to work on their own.

The only thing you will HAVE to change (that may not have come with the kit) is the rear brake hoses. Make sure you change those to Stainless Steel too.

 

[Alvin]

You do not need to worry about brake bias. 1st of all what upgrades are you talking about. Even if max you go with the 12pot AP racing BBK you still dun really need it. So just upgrade & have fun. After all most of the braking is altually in front only. Rear is just to assist.

 

[moots]

yar lor...agree wz alvin.if you wan to have fun fun onny and not serious giler like tracking and racing,no need lar all this bias mias thing.fit whatever performance brake you want and try it out first.if still tak puas,then u can fit the proportioning valve later on.
there will be no negative impact if this is yr daily driver and during your daily drives.

 

[moots]

Originally posted by Zoggee@Jul 27 2005, 01:43 PM
wow..!! very good Jipster..

I upgraded my brake servo...Thanks to Teejay's help. and dun mind sharing infromation on the upgrading with you. No need to find the 123 brake servo...this wan even better!!

koko zogg....you taroh brake servo from what car haaa?fit ngam2 aarr or have to modify a bit her and there....tell lar yr rahsia.i really do feel the e30 brakes are lauya...unlike the e34 ones. :yes:

 

[Jipster]

Originally posted by moots+Jul 27 2005, 03:03 AM-->QUOTE (moots @ Jul 27 2005, 03:03 AM)

 

[Zoggee]

Nope not the Merc W123 servo...will show it to you all in IAD... no harm sharing what...just minor mod to fit it in.

its a brake servo from a larger BMW. double layered Servo...when you step on the pedals..wow!!! melekat!! B) Cheap some more... B) but... but.. I still need the ABS la...

sorry ah...I'm using Malingish here.. :blush:

Jipster...I highly recomend this wan.. B)

 

[zaskar]

zoggee tell me more, tell me more........

 

[bmwky]

Originally posted by moots+Jul 27 2005, 04:03 PM-->QUOTE (moots @ Jul 27 2005, 04:03 PM)

 

[teejay]

as for the upgrade for the e30 servo-
abs or non abs car can still use the upgrade, just get proportion valve from older e30/e21 or even use a splitter, but suggest the proportion valve, as it evens out the pressure properly



for the BBK kits, newer cars that have ABS,ASC+T wont have a problem as the pressure is even out at the electronic pump ( as per Necc), only those without ABS or even first gen ABS may need the valve, then again, since its for daily road use , dont think it will ever be performing at a critical level.......it will only look cool if there's a lever in the car.....WRC style.....

 

[Zoggee]

Originally posted by bmwky+Jul 27 2005, 08:45 PM-->QUOTE (bmwky @ Jul 27 2005, 08:45 PM)

Originally posted by moots@Jul 27 2005, 04:03 PM

 

[magicfox]

hihi... i know koko zoggee secret.... i say it's even better than my e34....


h34r: h34r: :nyehehe: :nyehehe:

 

[teejay]

foxxy man

its my secret dude, i pass on to him......

 

[Zoggee]

Originally posted by teejay@Jul 27 2005, 10:23 PM
foxxy man

its my secret dude, i pass on to him......

and I have to say Thank you again.. :yes: