User 121020

An STR-legal, lightweight rear brake kit has caught my tinkering interest, lately. I have a couple of sets of Wilwood Dynalite calipers: 1.75" pistons and 1.38" pistons.

If I use the 1.75" piston calipers in the front and 1.38" pistons in the rear, I end up with a similar front/rear balance to stock. However, the total piston area increases by ~40%.

So, my question is - have any of you increased the total piston area and used a similar front/rear piston area balance? How does ABS respond to this sort of change? Did you like the resulting brake system? Any other comments welcome.

marcrx5

My concern wouldn't be the abs. 40% additional piston size would have a linear correlation with pedal travel.

robrob

I don't think the ABS will have a problem with your suggested setup, but the stock master cylinder is really too small for such a large increase in piston area. You'll have a much longer brake pedal. Just moving to the Accord calipers made my brake pedal long, almost too long.

User 121020

Thanks for the thoughts, Rob and Mark. I hadn't considered the fluid volume difference.

I've run the 1.75" piston dynalites in the front (as have you, Mark?) with the stock rear calipers. The balance wasn't right, but the pedal travel was tolerable...or at least I didn't notice it much. This setup yielded a total piston area ~27% larger than stock. Mark, when you used this setup at the track did you notice the pedal travel difference much? The overheating of the front pads had my attention more than anything.

robrob

As mentioned in another thread, my heavy Accord calipers do not overheat and they greatly improved XP10 brake pad longevity. I have 2 1/2 inch cooling ducts but the stock calipers would heat discolor in one track day where my 2 + year old Accord calipers are still the original silver.

User 121020

After switching to the 1.38" piston Dynalites in the front, the balance was much improved and I stopped overheating my XP10s on track. I'm using the 3R Auto brake kit up front. Weight reduction is my overall goal, but I want to retain much of the stock brake system feel.

I have a set of Wilwood Powerlites on order, but they're on backorder until sometime in early April. They feature 4X 1" pistons, which would pair nicely with the 1.38" Dynalites up front and yield a 18% reduction in the total piston area over stock. Balance would be within 5% of the stock front/rear ratio. I figured since I already have the Dynalites, I'd see how they together in a front & rear application.

robrob

rado, are you sticking to stock size rotors? If not a larger diameter rotor offers more leverage and can shift brake bias.

User 121020

Slightly larger diameter up front, same diameter in the rear. The balance will be similar to stock...just trying to decide which route I want to try with regard to total piston area.

And...integrating a parking-brake feature is the most challenging part of it all.