@Michael McKelvey posted:I have Karmann Ghia front disc brakes. I am wondering if they are any better than the front systems discussed here.
For some guys, Michael, KG front discs (as you know, a relatively inexpensive upgrade) are more than adequate. More pad with bigger multi piston calipers and even vented discs aren't really going to change things much, other than empty your wallet. Slowing down an 1800 lb. car with 2 occupants in a full panic stop from 75 or 80 mph isn't going to be a concern with stock KG discs and Type 1 drums in the back- once.
Now, start serious canyon crawling, road racing, parking lot slaloming, or any situation where you're on the brakes repeatedly and you're going to find your budget stuff's limitations pretty quickly. Yeah, the more expensive equipment won't stop you much faster the first time, but what it will do is shed heat and keep pad (and fluid) temps down, and those features allow you to hit those brakes again, and again, and again! And that's where the fun is...
@Tac422 posted:If you change the front drums to disc, do you also need to change the master cylinder?
KG front discs will work with the original equipment late Beetle master cylinder- you just have to pull the residual valve out of the front section. This worked with my Cal Look Beetle, even with Type 3 rear drums. I may be wrong, but I don't think the Karmann Ghia mc is a bigger bore than the Beetle unit (someone please correct me if I'm wrong). I haven't pulled apart a master cylinder in a while so I can't tell you if that trick is possible with today's replacement parts.
@Stan Galat posted:There have been a lot of advocates for rear drums over the years, with comments generally along the lines of "drums on the back are good enough". I understand the sentiment, but I don't agree. More braking power is always better. Always.
Something is important to note, however. Almost all of the commonly used disc brake packages are from EMPI or CB Performance, and these use the same front and rear calipers. It's a bad setup - the rear caliper bore is too big to be matched to the front. The net effect of this is that under hard braking, the rears will lock up before the fronts, which is less than ideal...
The reason for this long/boring piece is to say that whereas most aftermarket disc kits are biased to the rear, that would never be the case with a front disc/rear drum setup which may be why a lot of guys want to run them. That's the nice thing I can think to say about them. I personally don't think the answer to the riddle lies in reducing the size of the rear brake, so much as increasing the size of the front caliper. I'd want to talk to somebody smarter than me, but I think the typical Varga rear caliper (with E-brake), matched to a 2 or 4 piston Wilwood front caliper would be a much better way to go. I'd still want to know what MC would be best to use. I'm not trusting the brain trust at EMPI to have done any actual math.
To conclude, I'm not interested in reducing braking power to get better balance. But better balance with more stopping power would be great.
Stan brings up some great points. While discs front/drums back do work, you really limit yourself as to what you can do SAFELY. Imagine you've heat soaked the brakes to almost their limit through 3 or 4 corners in a row (just playing a 'little bit'), you come around the next corner, there's wreckage everywhere and you have to stop NOW- will you make it or just become part of the mess? As Stan says, "more braking power is always better. Always."
Re the rears locking up before the fronts on the less expensive 4 wheel disc brake kits- I'm guessing that while this is the case with these kits in a lot of Speedsters (with the same wheel/tire size all the way around) a lot of VW owners, being Cal Look fans with smaller tires/narrower rims on the fronts with taller/wider tires on wider rims on the back probably find their brakes much more close to 'balanced' than most Speedster owners do. As Stan mentioned in his post above (which I've since cut out for what reason I'm not sure of now) Henry has taken the time to figure out how to make the braking in his all disc brake cars much more balanced.
And Stan, your last statement- "I'm not interested in reducing braking power to get better balance. But better balance with more stopping power would be great." really says it all. Al