When looking at brake effort, don't think so much about how many pistons or how big the pads are. What really counts is force on the pads, which comes down to piston area. Using the standard geometric method (Pie are square, cake are round) 3.1416 X (Radius squared) = area. Say you have the 52mm Sentra calipers, you have 26 X 26 X 3.1416 = 2123 mm2. A four piston caliper with 25mm pistons has 12.5 X 12.5 X 3.1416 X 4 = 1963 mm2. Not sure how big the Wilwood pistons are, but this at least puts it in perspective. A given amount of brake line pressure will generate more pressure on the Sentra pads than on the Wilwood pads if these sizes are accurate. Friction coefficients also come into play. The Wilwood pads are likely intended to withstand higher temperatures, and may perform better when both are really hot than the Sentras, but may be worse when cold. Heat is not an issue for a woods buggy typically. Add to this pad alignment, particularly when you use a fixed caliper. First set I ever put on a buggy 30 or so years ago, used the VW calipers and got them on a little crooked. As the pads wore at an angle they seated better and better on the rotor, and brakes gradually got better. If the Sentra caliper mounts were aligned better this would make a difference also. Basically bigger calipers (piston area) and/or larger diameter rotors (more leverage farther from the axle) typically results in better braking effectiveness. Smaller master cylinder results in higher line pressure but more stroke to take up free play. As an example, in the stone age before we started adapting disc brakes we would use the small 17mm bug master cylinder with Type 3 22mm wheel cylinders to get the most pressure on the old shoe brakes. Had to keep them adjusted up tight as it took a lot of fluid to fill them up and take up free play. Lots of factors involved, hope this helps. You also have to factor in that the Wilwoods look a LOT cooler, especially if they are painted to match the buggy. Not as much HP as chrome though. No offense to Wilwood owners, we all like to have sharp looking equipment, if I had the coins I probably would have a set too, just make sure you compare sizes, Wilwood and others make a lot of different calipers and there may be a better choice for what you are doing.
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