Rubber side down
That is mounted in my 2016 Mazda 3 sGT. I do not remember total cost, but it probably is not worth it to most Mazda 3 owners. Most of the cost is in my own labor: measuring, re-measuring, CAD design, hand cutting (caliper, center punch, drill, hack saw, and filing) the adapter plates for the Wilwood cylinder.Thanks for sharing, that looks pretty awesome! Is that cylinder on your Miata or 3? Taking out the clutch pedal assembly might be going too far for me (time-wise), but I'd be willing to try a different compatible master/slave cylinder if it increases pedal feel. The 3's clutch is just too light for me, and I'm driving in city traffic all day. I did this on my previous car, using a different model car's cylinder (same manufacturer) to increase pedal effort & feel. If I can't get the shorter throw, at least I'll have a better feeling clutch pedal.
What was the cost for you to do all of that if I may ask (and if you're allowed to post it)?
If you really want to feel more direct pressure from the pressure plate AND reduce pedal travel, this is the only proper way to do it. Using "spacers" to artificially change the resting height of the pedal, as has been warned in this thread, can cause issues. By changing the mechanical leverage between master and slave, you are still moving the clutch the same as oem components, just changing the "fulcrum" between the two.
The reason I used an old generation Miata slave cylinder is two-fold:
1. I do not like the idea of plastic components being used in hot, pressurized hydraulic systems like the clutch. The OEM Mazda 3 Slave and Master are both plastic parts. That bothers me. Yes, it works just fine, but it is more of a piece of mind issue to me. If I am pushing the car to its limits on a track day, I want a better margin of safety.
2. The OEM parts require specialized "quick" connectors on both the Master and the Slave hydraulic hard lines which is not something you can buy off-the-shelf or make custom. With the Wilwood master and older Miata slave, I am able to order a stainless braided, flexible clutch line with standard fittings on both ends (flared type), which can be made-to-order by any good race shop or custom brake line manufacturer for a reasonable price. You just need the required length, proper thread size and flare type. I doubt I will ever have to replace this part (PTFE liner, stainless braided jacket, pressure tested to loads built for braking), but if I do, it will be easy to get a replacement. I also have only two connection points with one single, reliable high pressure line direct from Master to Slave.