DanielB

I've been exploring various ways to improve the braking capability of the S2000 on track. I've noticed that there are a variety of approaches but very little real data on how they affect front/rear bias. My own experience is that when the brakes are not overheated, the balance is pretty good so I wanted to stay close to stock. To help me, I built this spreadsheet. Lately I've seen a lot of activity on this subject so thought it might be helpful to share here.

A few things:

• I am assuming that the stock brake system F/R bias is ideal so normalize all changes to it. If you're not happy with it, then you may not find this helpful.
• I'm pretty sure I have the mechanics of how changing rotor size and piston size affect brake torque. Still, it would be good if others double check that the formulas are correct.
• For pad height, I have tried to find a drawing for each one and estimated the height. Still, I may be a few mm off of what you measure in the real world. It won't significantly affect the bias, but if you have real world measurements that differ, please post them and I'll update.
• I am happy to add additional solutions - just send me the following: piston diameter(s), rotor diameter, and pad height.
• I have not created every conceivable combination on the Front & Rear Combinations sheet. Most don't make any sense given that the bias shifts more than 10%, hence the word "reasonable" in the sheet's title.
• If you're only changing the front, then focus on the FRONT sheet. Same for the rear, only focus on the REAR. If you want to see how changing both affects bias, focus on the combinations sheet.

Hopefully this will help people make a more informed decision on brake upgrades.

Midnightdennis

This is exactly what I was looking for. Nice work.

michaelnyden

Thanks for this! On the tab about reasonable setups though you missed spoon front calipers and 330mm ballade rear rotors, that would bring it near 100% stock balance again.

Also what would it be for spoon plus 330mm ballade front rotors and 330mm rear ballade rotors?

DanielB

Good suggestions, spreadsheet is updated.

flanders

Nice work. Should pad area not be included or is height the only important part?
Here is a couple more to ad:
Wilwood #140-10309 piston size 41.1 28.4 28.4 (6pistons) 327mm disc, not sure about pad height but check this picture for reference.
Essex/Urge BBK piston size 41 38 299mm disc, pad picture.

DanielB

Both added.

Question for anyone using Wilwood calipers that use a 7416 or 7420 pad, would you measure the height of the pad material at the pad center? Wilwood and others spec it at 43 mm but when I measure from the drawings, it looks more like 39 mm. It's not a big deal because it only changes the bias by 1 percentage point, but would be nice to know which is correct.

Only pad height matters. We're using piston area as a proxy for force and the torque applied is independent of the area of the pad. Pad height matters because it affects the effective radius of the rotor. I'm assuming that the surface of the pad is evenly distributed above and below the midpoint of the pad. That's not going to be accurate for some pad shapes, but the impact is small as you can see by my question above.

afzan

It doesn't really affect the brake bias but it'd be useful to have the brake pad thickness in your chart?

edit: also rotor thickness

DanielB

Thanks for the suggestion. I did think about including other parameters but the scope just kept growing. For example, I could also include if the rotors are single piece, two piece, floating. Does the caliper have anti-knock back springs? What is the finish of caliper (anodized, powder coat, paint). You get the idea.

I'll add that for some calipers, there are more than one pad thickness available. E.g. Wilwood 4 piston supports both 16 and 20 mm depending on the Pad manufacturer.

For now, I'm only going to focus on how bias is affected since that information was just not easily available.

_ju5t1n_

Where did you get the spoon caliper piston diameters from? I couldn't find any official information on it

DanielB

It might have been google searching but more likely it was from another thread here.