Honda to Honda Brake Upgrade
06-28-2011, 06:14 PM
#1
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Honda to Honda Brake Upgrade
I wanted to upgrade my brakes on my 2002 S2000 and bought the kit which is described in the post:
Bigger 11.8" brakes for the S2000 - 99 Acura RL discs and CL calipers, By BrakeExpert, Honda-Tekh
http://forums.honda-tekh.com/zerothread?id=4898 .
“This is about the front brake upgrade using the CL calipers. I made some bigger brakes for someone who wanted this bigger caliper. It uses a pad of almost the same shape, but about 50% more in total area. It can work with the factory front S2000 disc, and bolts onto the knuckles. The caliper's piston is 2.25" compared to the 2" front S2k caliper piston. I've heard from some people that although this is a great upgrade, the fade resistance doesn't increase a whole lot with the heavier caliper. So, I figured how to mount thicker discs on. These would be from the 1999 Acura RL. They are 28mm thick and about 3lbs heavier per side. These rotors are taller and although they bolt onto the S2000's hub, the rotor does not clear the caliper bracket from the S2k or the CL. So the caliper bracket needs to be machined. It has to have the contact surface milled, roughly 7mm. I know this sounds like a lot, but remember that these are forged iron, they are very strong. And because the stock brackets did not use all of the threaded holes, when mounted, this new setup has almost the exact same number of rotations of threaded bracket to use. I removed as little material as possible, and though the bracket is not as thick, it is in fact less than half the material, and I do not feel this reduction in stiffness is enough to allow for any added caliper bracket flex or the potential for cracks or damage during operation. I realize some people will hate this idea because it does remove material, but it is safe. The S2k front knuckle and hub is an oddball compared to most Hondas, the rotors are shorter and the centerbore is the only one with a 70.1mm for the rotor but the "mid size" for the three diameters of the actual hub. That centerbore restricts rotor choices, so the only 11.8" to fit is the 98-04 RL's front disc.”
After starting the replacement there were two (2) issues that needed addressed:
1) dust shields needed to be removed because the rotor is thicker than the stock S2000 rotor and sets further inward towards the hub.
2) 7mm had been removed from the interior side of the caliper bracket and the stock caliper bolts hit the rotor when tightened. S2000 caliper flange bolts, 12x12.5x21mm, were purchased from Honda and length reduced to 18mm.
Installation was straight forward and there is plenty of clearance with the stock AP1 rims. I calculated the surface area of the Acura pads are about 10 sq. inches and the S2000 pads are about 7.5 sq. inches, an increase of 33%. While we didn’t look for the marks on the road from a ‘panic stop’ with the stock brakes, stopping with the new setup felt firm and was probably 15 to 20 feet shorter from 60 mph. Definitely an upgrade that I would recommend.
Bigger 11.8" brakes for the S2000 - 99 Acura RL discs and CL calipers, By BrakeExpert, Honda-Tekh
http://forums.honda-tekh.com/zerothread?id=4898 .
“This is about the front brake upgrade using the CL calipers. I made some bigger brakes for someone who wanted this bigger caliper. It uses a pad of almost the same shape, but about 50% more in total area. It can work with the factory front S2000 disc, and bolts onto the knuckles. The caliper's piston is 2.25" compared to the 2" front S2k caliper piston. I've heard from some people that although this is a great upgrade, the fade resistance doesn't increase a whole lot with the heavier caliper. So, I figured how to mount thicker discs on. These would be from the 1999 Acura RL. They are 28mm thick and about 3lbs heavier per side. These rotors are taller and although they bolt onto the S2000's hub, the rotor does not clear the caliper bracket from the S2k or the CL. So the caliper bracket needs to be machined. It has to have the contact surface milled, roughly 7mm. I know this sounds like a lot, but remember that these are forged iron, they are very strong. And because the stock brackets did not use all of the threaded holes, when mounted, this new setup has almost the exact same number of rotations of threaded bracket to use. I removed as little material as possible, and though the bracket is not as thick, it is in fact less than half the material, and I do not feel this reduction in stiffness is enough to allow for any added caliper bracket flex or the potential for cracks or damage during operation. I realize some people will hate this idea because it does remove material, but it is safe. The S2k front knuckle and hub is an oddball compared to most Hondas, the rotors are shorter and the centerbore is the only one with a 70.1mm for the rotor but the "mid size" for the three diameters of the actual hub. That centerbore restricts rotor choices, so the only 11.8" to fit is the 98-04 RL's front disc.”
After starting the replacement there were two (2) issues that needed addressed:
1) dust shields needed to be removed because the rotor is thicker than the stock S2000 rotor and sets further inward towards the hub.
2) 7mm had been removed from the interior side of the caliper bracket and the stock caliper bolts hit the rotor when tightened. S2000 caliper flange bolts, 12x12.5x21mm, were purchased from Honda and length reduced to 18mm.
Installation was straight forward and there is plenty of clearance with the stock AP1 rims. I calculated the surface area of the Acura pads are about 10 sq. inches and the S2000 pads are about 7.5 sq. inches, an increase of 33%. While we didn’t look for the marks on the road from a ‘panic stop’ with the stock brakes, stopping with the new setup felt firm and was probably 15 to 20 feet shorter from 60 mph. Definitely an upgrade that I would recommend.
06-28-2011, 07:39 PM
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awesome, I just used TSX calipers (which look like the same you have here) and the stock rotors with a 1mm shim behind the rotor to center it in the caliper bracket. Wish I could have bigger/ thicker rotors but seems like a bitch to get them to fit.
06-29-2011, 05:41 AM
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pretty cool but there are two concerns I have that I would have to do more research on with such an upgrade before actually jumping in:
1) Reducing the material on the calliper mounting bracket to me seems to be unsafe. A certain factor of safety has been calculated into the design of the mounting due to worst case scenario brake torques and critical calliper bolt torques. I don't know how good of an idea it would be to reduce the material without doing extensive research on it first, but that's just me.
2) I put a BBK on my old Civic from an ITR and noticed that the bias was thrown off towards. That was because I had less piston contact in the front with the new set up than the old stock set up. This upgrade increases surface area up front however this can impact braking negatively as well. I realized that brake systems allow for a % deviation in bias to allow for real world variations with pad compounds, tire choices, etc, however I would be concerned of actually reducing my stopping distance. Remember that brakes slow a car, tires stop it. If you are increasing the amount of brake torque up front, you are decreasing it in the rear, which means your rear tires are no longer doing as much work to stop your car as they possibly can. I would need to see definitive measured results to believe this stops shorter than stock.
Anyways, other than those two concerns, this is very innovative and a very cool upgrade. I hope we can get some facts and figures because this looks very promising!
1) Reducing the material on the calliper mounting bracket to me seems to be unsafe. A certain factor of safety has been calculated into the design of the mounting due to worst case scenario brake torques and critical calliper bolt torques. I don't know how good of an idea it would be to reduce the material without doing extensive research on it first, but that's just me.
2) I put a BBK on my old Civic from an ITR and noticed that the bias was thrown off towards. That was because I had less piston contact in the front with the new set up than the old stock set up. This upgrade increases surface area up front however this can impact braking negatively as well. I realized that brake systems allow for a % deviation in bias to allow for real world variations with pad compounds, tire choices, etc, however I would be concerned of actually reducing my stopping distance. Remember that brakes slow a car, tires stop it. If you are increasing the amount of brake torque up front, you are decreasing it in the rear, which means your rear tires are no longer doing as much work to stop your car as they possibly can. I would need to see definitive measured results to believe this stops shorter than stock.
Anyways, other than those two concerns, this is very innovative and a very cool upgrade. I hope we can get some facts and figures because this looks very promising!
06-29-2011, 05:56 AM
#5
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people have been milling the caliper brackets in this manner for a long time on hondas...
The same process is needed if you put ITR brakes on a civic. I have never seen a failure and there are a 100x more civics running the 11inch ITR brakes at the track than there are s2000's with any brakes on the track. The CL caliper is the same caliper as the ITR caliper, just the bracket is different..
The same process is needed if you put ITR brakes on a civic. I have never seen a failure and there are a 100x more civics running the 11inch ITR brakes at the track than there are s2000's with any brakes on the track. The CL caliper is the same caliper as the ITR caliper, just the bracket is different..
06-29-2011, 06:15 AM
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The 08 Civic Si I had doesn't require any milling to retrofit the ITR callipers (DC5-R Brembos). Are we sure the RL and ITR callipers are the same? A lot of people were under the impression the TL-S and ITR calipers were the same as well but when you take them apart (aside from the inverse staggered pistons between the two) the TL-S does in fact have bigger pistons and more mass than the ITR. My point is that a brake upgrade is a tricky thing.
For the occasional track goer, I'm sure it would be fine to slap on any brakes and have yourself believe you've upgraded the system, however from my past experience (and my level of OCD lol) I've found that without proper research and calculations, you could be hindering more than helping brake performance.
For the occasional track goer, I'm sure it would be fine to slap on any brakes and have yourself believe you've upgraded the system, however from my past experience (and my level of OCD lol) I've found that without proper research and calculations, you could be hindering more than helping brake performance.
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06-29-2011, 10:05 AM
#9
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Another thing to take into consideration is pad options. Having more pad surface area is great, but not at the expensive of having lesser compound options.
(EDIT - just checked TireRack, and both vehicles have the same performance pad options...so this point is moot)
A smaller pad that is designed to function in the higher temp ranges with higher torque friction numbers is going to out perform a larger pad with lower temp ranges and lower torque friction numbers.
Bigger isn't always better. ...and 3 lbs of rotating mass per corner is a HUGE gain! Also, the channel for vains on the inside of the TL rotor is quite a bit narrower, I would imagine the ability of this rotor to dissipate heat is quite a bit lower than the S2K rotor.
(EDIT - just checked TireRack, and both vehicles have the same performance pad options...so this point is moot)
A smaller pad that is designed to function in the higher temp ranges with higher torque friction numbers is going to out perform a larger pad with lower temp ranges and lower torque friction numbers.
Bigger isn't always better. ...and 3 lbs of rotating mass per corner is a HUGE gain! Also, the channel for vains on the inside of the TL rotor is quite a bit narrower, I would imagine the ability of this rotor to dissipate heat is quite a bit lower than the S2K rotor.