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Brake Bias / EBD

PostPosted: Sun Apr 03, 2011 9:27 pm
by teK--
I'm just doing the numbers whilst in the process of planning installation of GT calipers/rotors on the front.

My goal by fitting the GT fronts is improved thermal handling.

Using the figures from the workshop manual and punching them into this calculator:

http://www.tceperformanceproducts.com/bias-calculator/

It gives me the following front brake bias % results:

Stock GT Brakes F/R: 72.60% front bias
Stock 2.5i Brakes F/R: 69.00% front bias
Stock GT Front Brakes, Stock 2.5i Rear Brakes: 74.90% front bias

According to the other info on that site they suggest that up to 5% increase in front bias would not be detrimental and may in fact be of benefit.

My question is, whether EBD adjusts F/R bias only when the ABS is activated, or whether it is working during all braking. Also I gather that it would not be too much to ask of the system to compensate for the 5.9% increase in front bias when fitting just the GT fronts?

The other alternative is that I fit GT rears as well, but that would only reduce the bias difference (over what I have now) to 3.6% which is probably not worth the money.

Re: Brake Bias / EBD

PostPosted: Sun Apr 03, 2011 9:49 pm
by rickerty
I have read somewhere that the EBD only effects the rears and is only active/called for when the ABS kicks in...
I realise this doesn't answer your question but I'll dig through my bookmarks for the article/more info.

Re: Brake Bias / EBD

PostPosted: Mon Apr 04, 2011 6:26 pm
by kiks
You will not notice any difference at all.

Re: Brake Bias / EBD

PostPosted: Mon Apr 04, 2011 6:50 pm
by teK--
Which part Kiks? :)

Re: Brake Bias / EBD

PostPosted: Mon Apr 04, 2011 8:02 pm
by Viper
To put it simply, EBD will be active without ABS kicking in, but only under very limited situations and high decel situations.
I.e. EBD will be doing it's thing when you put in decent pressure, approaching the point where the wheels are getting to their maximum decel and the system needs to level out the pressure as the rears are getting close to high slip. Unlikely you will get there on day to day driving.

The OEM's select their calipers/pads/discs/etc. to get close to the ideal bias, then use the ABS/ESP system to do the rest.
And yes , it is only the rears, but having more bias to the rears... could be interesting ;p

I see its more to the front, in which case, you wont be getting 'ideal' decel for EBD only, but who cares ;p

Re: Brake Bias / EBD

PostPosted: Mon Apr 04, 2011 8:38 pm
by kiks
The disti. Just don't worry yourself with it. Brembos and track pads wih stock 200,000km old rears feels just as fine as brembos and a1rm's all round. Free surface effect in a half tank of fuel is your biggest concern....(not much).

Re: Brake Bias / EBD

PostPosted: Tue Apr 05, 2011 8:15 am
by 3rspecb
teK-- wrote:I'm just doing the numbers whilst in the process of planning installation of GT calipers/rotors on the front.
My goal by fitting the GT fronts is improved thermal handling.
Using the figures from the workshop manual and punching them into this calculator:
http://www.tceperformanceproducts.com/bias-calculator/
It gives me the following front brake bias % results:
Stock GT Brakes F/R: 72.60% front bias
Stock 2.5i Brakes F/R: 69.00% front bias
Stock GT Front Brakes, Stock 2.5i Rear Brakes: 74.90% front bias


where did you get the information regarding CF of the stock OE pads, my workshop manual doesn't advise this ?

I'm trying to see what difference my new pad setup (FRT & RR) has made vs OE.

Re: Brake Bias / EBD

PostPosted: Tue Apr 05, 2011 10:13 am
by teK--
I don't have cf for OE stock pads, so I just put an approximate figure of 0.30 into the calculator. It wasn't so much the braking torque I wanted to work out, but rather the front bias using a fixed pad cf, but changing variables such as rotor diameter and pad size to simulate upgrade to GT brakes.

3rspecb wrote:
teK-- wrote:I'm just doing the numbers whilst in the process of planning installation of GT calipers/rotors on the front.
My goal by fitting the GT fronts is improved thermal handling.
Using the figures from the workshop manual and punching them into this calculator:
http://www.tceperformanceproducts.com/bias-calculator/
It gives me the following front brake bias % results:
Stock GT Brakes F/R: 72.60% front bias
Stock 2.5i Brakes F/R: 69.00% front bias
Stock GT Front Brakes, Stock 2.5i Rear Brakes: 74.90% front bias


where did you get the information regarding CF of the stock OE pads, my workshop manual doesn't advise this ?

I'm trying to see what difference my new pad setup (FRT & RR) has made vs OE.