Front calipers on the back

[foz01]

We will agree to disagree on this one

Disagree with engineering fact... fair enough.

Question - have you ever driven a car without servo brakes before? You know the Elise is unassisted, yeah - so you'll never get the sort of artificial initial hit that you'd get in a 'normal' car.

Lol

my last car had 330mm 4 pot AP's, unservo'd, so yes i have experience of brakes, i designed the bells and caliper brackets for it fwiw...

As for what the car previously did, thats all good and well, 20 minute races were they not?!

As i have already said the size of the pads is the limiting factor in the elise, fitting bigger discs will help, however the limiting factor is still the pads. All the points are valid and as i have already said they are more than capable of locking up the tyres.

Again as i have already said brakes are imo very feelsome, since when its it a problem wanting better brakes- the reason being that the aforementioned AP's on my last car were the single most impressive thign on the car.

All the points are valid, and if i was planning fitting carbon ceramics from a merc SLR you might have a point, and since when were brakes digital- the modulation comes from the nugget in the driver seat

[Rich H]

What rubber do you have fitted atm?

[Shug]

Fair enough mate. Point being that for almost everyone I've ever spoken to simple selection of the right discs (perhaps a little bigger - AP rotors - with a spacer on the front caliper) and pad combo delivers fantastic feel and more power than they'd ever be able to use.

Just trying to illustrate you don't necessarily have to spurt loads of money and add unsprung weight for the result you want.

[graeme]

Doesn't mean it couldn't be better....

The car used to have a K in it. The brake bias was fine (maybe optimal, who knows?). Then it got a Honda conversion, adding weight over the rear. Nothing was done to compensate for the extra front bias this causes (AFAIK). So there must be margin in there to put a wee bit of bias back to the rear, meaning work is taken off the fronts meaning better stopping power overall. Whether it needs it is another matter.

[Shug]

Doesn't mean it couldn't be better....

The car used to have a K in it. The brake bias was fine (maybe optimal, who knows?). Then it got a Honda conversion, adding weight over the rear. Nothing was done to compensate for the extra front bias this causes (AFAIK). So there must be margin in there to put a wee bit of bias back to the rear, meaning work is taken off the fronts meaning better stopping power overall. Whether it needs it is another matter.

Say an extra 25KG with the Linda (although it could be 50GK and not matter) Bit o bias, okay, one or two clicks on a balance bar - not fitting 2 piston calipers where there was a single piston (of smaller diameter IIRC)

Would be interesting to see the corner weights of the Yota cars (although I guess the weight would be more evenly distributed between engine and servo brake gubbins sound deadening etc.) Eff all been done with the brakes on them (apart from the aforementioned servo.)

[graeme]

Do you know nothing has been done? Components are all the same, but there could be a valve somewhere?

[alicrozier]

On Yota's there is a valve which completely locks out the rear brake circuit.
It only cuts in during extreme circumstances when it reckons you're being a muppet and are about to swap ends. Unfortunately the reduced braking means you might go off straight ahead instead...

I found this feature on the Exige at Spa (in the wet) and IIRC FBF found it at the bump before Duffus in the 'Tango Badger'. I thought it was an issue but I have a nice letter from Lotus telling me I'm wrong.


btw bias is set for the dry and probably allows for stick tyres. Biggest single improvement (in the wet) would be a balance adjuster IMO.

[mckeann]

Doesn't mean it couldn't be better....

The car used to have a K in it. The brake bias was fine (maybe optimal, who knows?). Then it got a Honda conversion, adding weight over the rear. Nothing was done to compensate for the extra front bias this causes (AFAIK). So there must be margin in there to put a wee bit of bias back to the rear, meaning work is taken off the fronts meaning better stopping power overall. Whether it needs it is another matter.

Graeme, no offence, but your just guessing that there would be a problem, you have no actual experience of it.

Short of repeating myself over and over, there was nothing wrong with the brake bias since i fitted the honda. There was nothing wrong with the brakes in general. Personally, i would spend the money on other things, but if Lowell wants to change the sheds brakes, its his choice.

I suppose you just wont get many people on offering you advice, as most people realise thats what is on it (caliper wise) is good enough.

[graeme]

I didn't say there was anything wrong with it dude. I'm just saying there has to be potential for a wee bit more. Tis fisics. Look, I even said "whether it needs it is another matter..."

I really can't say whether it needs it or not, as the last time I was in that car it had no brakes at all...

[mckeann]

The car can lock the front tyres with the clutch up, it can lock all 4 tyres with the clutch down, and it can last 1 hour (and a whole tank of fuel) on track without brake fade. But hey, that's only my experience, not something i read on seloc.

[graeme]

OK OK, I believe you! (And I don't read seloc!) My theory wasn't in relation to your old car in particular. Any car with more weight added over the rear axle could, in theory, compensate for the resulting change in brake-force distribution by increasing the rear bias slightly. I'm not saying your old car needs it, or that it should be done or how it should be done, ok? Pardon me for breathing!

[foz01]

That was maybe when the brakes were healthy- at the moment the rear pads are fag packet thin and the front grumbles like fcuk after 5 wet laps of KH and 10 mins on the road- my conclusion is that they are fcuk

How did this turn into a discussion on the pysics and brake bias is anyones guess

[alicrozier]

More fysics...

Any (probably imperceptible) changes to brake balance due to Honda conversion are far outweighed (sic) by the differences wet/dry and standard vs sticky tyres. Elise brake bias would (I guess) be optimised for dry and standard tyres? Hence safe in the wet...

Run sticky tyres and you may need a wee bit more front bias...
Run in the wet and would ideally want ALOT more rear bias...

Extra weight of a Honda may well be negated by increased engine braking...

[graeme]

Extra weight of a Honda may well be negated by increased engine braking...

Good point!

Not sure about the wet/dry thing or tyre choice though. That would have the same effect on the coefficient of friction at all 4 corners, wouldn't it? I really don't know. And I hate not understanding stuff.

Google...

EDIT: but if it's wet, you can't generate the forces (and thus the weight transfer) in the first place. Back to school for me.

[foz01]

At the end of the day, putting 4 pots on the front, and the front 2 pots on the back with uprated floating discs it aint going to make things any worse- even if it only increases fade resistance!