Quote:
Originally Posted by mabbo
dude
cheers for that 
so, what sort of ratio should i be aiming for?
would you just stick with the stock bug master cylinder?
its a street car, there are loadsa people using the empi kit with stock master cylinder id imagine - the bias must be acceptable?
if the reason my pedal was 2 soft wasnt because of the 19mm bore (im sure it wasnt), it must have been because of a faulty master cylinder...
mabbo |
I would aim for a caliper/mc ratio of around 8:1 for both front and rear although as previously said the rear can be larger because the pressure can be adjusted with a proportioning valve.
I would stick with a standard bug m/c but make sure its all working 100%.
In a panic situation locking up the front brakes is infinitely preferable to locking up the rear so the Empi kit is intrinsically safe. However, you can't get maximum redardation because the rear never comes up to full braking force 'cos the front locked up long ago. Ideally, maximum stopping power will be acheived with both wheels on the verge of locking up. Using a balance bar arrangement is the best way to dial in the front/rear proportions.
Quote:
Originally Posted by mabbo
just a thought... eventually i was considering upgrading to some wilwood 4 piston calipers front and rear. i could do this sooner rather than later if i could use a bug master cylinder with them successfully, as it would save buying the uprated CSP master cylinder and fitting kit.
the calipers i want have the choice between piston diameters of 1.00" (25.4mm), 1.25" (31.8mm) or 1.38" (35.1mm) for the fronts, and the rear handbrake caliper has 1.00" (25.4mm) pistons.
if i used a stock bug 19/19 master cylinder, to keep the bias right, would you suggest something like the 1.25 for the fronts, and 1.00s for the rear, or the same front and rear then make adjustments using a regulator valve?
mabbo
|
Choosing the 4 pot wilwood calipers, I would go for equal sized units front and rear assuming that your discs (rotors) are of similar diameter? However, I would get the best out of your present system unless there's a fashion statement being made here. With your set up you could purchase/fabricate a balance bar unit that would allow you to adjust the braking effort front and rear to maximise the effectiveness of your current system. If after that you must have such braking force as provided by the Wilwoods then you will also have the best system to dial the Wilwoods in. A standard brake proportioning valve is a relatively crude unit that just limits the rear line pressure but doesn't apprortion the line pressure front to rear as will a balance bar set up.
I often see brake systems in bugs that are hugely over spec'd and more appropriate to very fast and heavy track racing cars. Most of these installations have poured money into just one end of the braking system without considering the whole (mainly I think that 'cos most of it is not visible).
evilC