Brake upgrades - is bigger better?

[ESM]

I know I said Stoptech know what they're on about but I'll revise that opinion slightly - they usually know what they're talking about! They are wrong to suggest shifting weight distribution changes bias. It doesn't - it changes the point of lock but not the bias before lock.

[F1 LOTUS]

To help increase the ultimate work the rears are able to do relative to the fronts, I can:

1) increase the line pressure to the rear calipers
2) install a grippier rear pad
3) increase the size of the rear rotor
4) install stiffer springs in front to prevent dive and weight transfer
5) lighten the front of the car

Sound right?

6) Lower car / C of G

[Candles]

7) Strengthen the rear wishbone arrangement to cope with the extra torque.

Just a thought......

[ESM]

I reckon increasing rear braking won't cause a stress problem to the rear wihsbones, because

1) in spite of the fact the brake force reacts through the rear suspension arms the ultimate torque is effectively limited by the tyre adhesion and so the design will have been developed with an appropriate maximum torque capacity - increasing brake performance can never exceed tyre performance.

and

2) We are talking only about returning to a level comparable to stock performance anyway.

[johnbenk]

With all the technical information regarding brakes. Can some one explain WHY the car my belonging to my wife which is a 1,1
Hyundai Getz and has Dual Diagonal servo assisted brakes 10inch DISCS at the front and 8 inch DRUM BRAKES AT the REAR and is fiited with EBD can STOP far better than my Elan.

With only using the Elan for Car shows,High days and Holidays, after driving the Hyundia and then using the Elan for driving I find that using the
Brakes of the Hyundia again after getting use to the Elan Brakes after driving I nearly go through the windscreen when applying the Brakes on the Hyundia.

Is it the "EBD" that is making the braking THIS GOOD. CAN THIS BE RIGHT?????

Could a system using EBD be modified to fit a Lotus Elan .

[ESM]

It would be great to have such a system but its a bit complex for an enthusiast to develop.

The main thing that makes the Elan's brakes feel bad relative to current cars is the lack of pedal sensitivity bcause the servo assistance is relatively small (this is why the same pedal pressure throws you forward in one car but is relatively light braking in the other). The ultimate braking performance IS probably better in the Elan because the tyre performance will be better than most cars. The other issue, for me anyway, is that the stock system pedal had what I can only describe as 'numb' feel - there seems to a curious lack of feedback that I can't really explain.

[johnbenk]

Hi

Thanks ESM . I gather from this any ideas of using a "Chip" to control the Brake Proportional Valve pressure is out of the question????

[ESM]

Yes - the system present on other cars is there because they have ABS and already have a computer effectively in charge of braking so its easy to add bias control to the system. The Elan has no ABS and developing such a system and requires professionals with resources and a lot of testing (off the public roads). I'll stick to the simple system.

[stevo]

i already have hispec 4 pots on 285mm discs but im about to upgrade to 325mm rotors on bells. bigger=cooler=longer=better

[F1 LOTUS]

Stoppies

Post some pic's

[L.G.]

Hi,

Got a question, especially to ESM
I read stuff in your links, stoptech. You know they do a braking test with a nissan 350z and the best thing to do turns out to be an upgrade on all four brakes rear and front.
www.zeckhausen.com/Testing_Brakes.htm
Now the first question, is elan front biased (stock brakes)? And second question, if you change the rear disks relative to the fronts (I try to mean, by keeping the 258(front)/230(rear) proportion and making it for ex. 300/267) would that make the car stop better?

[ESM]

...

Redressing the frontward proportioning changes caused by front disc size and pot area increases is tricky. You want essentially the same front brake torque vs rear brake torque the Lotus set up (because they CAN set up a car to handle well). The problem is that the transition in the slope of the brake bias graph occurs at a certain brake line pressure not a braking torque - the braking torque of the transition is determined by the size of calipers & discs and you've been and gone and changed them. So if you up the rear efficiency in proprtion to the front you delay the transition - relative to stock - and move the bias much further to the rear than standard after the initial proportional slope. I've stuck a graph on that shows a stock setup, a Hi-Spec setup and a couple of hypothetical front & rear upgrades to show what can happen to the brake balance if you're not careful.

The graph's on page 2 of this thread, 2nd last post

[L.G.]

Sorry I've missed that bit of your write-up...
Thanks for answering