As I mentioned in an earlier post, the strengths of a big brake kit like this one lie not in its ability to reduce a car's single-stop distance from 60 miles per hour, but rather in its ability to endure sustained high-temperature operation by adding thermal capacity and maintaining consistent pedal feel.
Stoptech's brakes do exactly that. Even so, 60-to-0 stopping tests are a standard around here and both our previous M3 brake tests we performed from this speed. So, if for no other reason than to have an apples-to-apples comparison, we repeated this test with the new brakes.
And, what do you know, there wasn't a huge improvement. The M3 stopped from 60 mph in a previous test on these tires (Yokohama Advan Neova AD07s) in 109 ft. Last week it recorded a best stop of 107.6 feet and settled consistently at 108 feet. More importantly it could have repeated this test all day. Repeated stops from 60 mph don't approach overheating the system. In fact, it takes a few runs to get the pads up to temperature so the first few stops were longer than stock -- a compromise made by high-temperature pad material.
This result does speak to the fact that Stoptech's brakes maintain the M3's stock front-to-rear brake proportioning -- something which is commonly overlooked in many aftermarket kits. This balancing act is crucial to proper brake performance.
The real test will be during aggressive street driving which is what the Axxis Ultimate pads we're using were designed for. Look for further updates after we've had the M3 in the mountains.
Also, the M3's brake pad wear warning light is still on because the installer thought the aftermarket pads wouldn't work with the stock sensor. We've since been told that it will and are planning to reinstall the sensor later this week. Check back here for updates.
Josh Jacquot, Senior road test editor @ 59,202 miles
subytrojan says:
02:57 PM, 07/28/08
You make an excellent point about retaining the stock brake bias, Josh.
I'd be more interested in lap times around Spring Mountain (provided ya'll could pay that track another visit) than how things are better on canyon and mountain roads. I know the new pads aren't track pads, but it'd be interesting to see how well they would fare on a road course.
For those who are new to this blog, you can read how the long-term E46 M3 fared at Spring Mountain and on the street in Josh's previous comparison test between the LT E46 M3, E82 135i, and E90 335i:
http://www.edmunds.com/insideline/do/Drives/Comparos/articleId=125908
firstwagon says:
05:10 PM, 07/28/08
"In fact, it takes a few runs to get the pads up to temperature so the first few stops were longer than stock -- a compromise made by high-temperature pad material."
I really wish more people knew that. I know a couple guys who spent big money on after market brakes but only use their cars to drive around town. Basically they wasted their money and made their cars worse for bragging rights and to have their cars look cooler with the high dollar aftermarket rims.
sgude says:
03:42 AM, 07/29/08
Great point, Firstwagon. That's why although I have bought "upgraded" pads before (although truthfully, I just wanted to reduce the brake dust), a big brake kit would be a vanity purchase for me. I don't take my car to the track -- yet -- so why go so overboard? When I do start going to the track, I'll revisit the big brakes.
joefrompa says:
08:52 AM, 07/29/08
Great point....some daily drivers put on race pads that NEED to heat up before they offer reasonable stopping power and/or bite.
I'm about to replace the stock front brakes on my 06 Civic SI....I can easily overwhelm the tires with the stock brakes, so really stopping power is not something I need to upgrade. I want silent operation, low dust, and progressive feel. And I want rotors that don't warp.
For me, a blank rotor (non-slotted, non-drilled) that has been cryogenically treated along with a ceramic-material brake pad that has similar characteristics to stock, and then a switch to a good synthetic DOT 3 brake fluid will most likely increase my performance AND the secondary characteristics.
BTW - Regular old DOT 3 brake fluid will last longer than a fancy, super-high-temp synthetic. Why? Regular DOT 3 fluid absorbs water more slowly than the high-temp stuff, even though the high-temp stuff doesn't boil until a more higher temperature is reached. So for a daily driver, DOT 3 will suit you better for multiple years between flushes than something like ATE Super Blue.
Joe
lazyhater says:
09:22 AM, 07/29/08
So a shop specialized on installing aftermarket parts on highend Euro cars don't know if the OEM sensor would work with aftermarket pads on a M3? Interesting.
A 5 minute search on any Bimmer forum would get you that answer.
Tons of E46 M3 on the street got aftermarket brakes.
stingray454 says:
10:58 AM, 07/29/08
Do I get a prize or a cookie or a biscuit for predicting the results of this upgrade almost exactly? ;)
lazyhater says:
12:27 PM, 07/29/08
"Do I get a prize or a cookie or a biscuit for predicting the results of this upgrade almost exactly? ;)"
Look at the posts above, I think most of us that visit this blog already knew what you predicted.
cz75 says:
03:12 PM, 07/29/08
"BTW - Regular old DOT 3 brake fluid will last longer than a fancy, super-high-temp synthetic. Why? Regular DOT 3 fluid absorbs water more slowly than the high-temp stuff, even though the high-temp stuff doesn't boil until a more higher temperature is reached. So for a daily driver, DOT 3 will suit you better for multiple years between flushes than something like ATE Super Blue."
That's not true. DOT 4 or 5.1 have higher wet boiling points too. Brake fluid is considered "wet" at 3.7% H2O content, and 2-3% moisture is absorbed per year, so no one should go more than two years on the same fluid, irrespective and regardless. Since you're a civic Si owner, check out some of the 8th gen civic forum's stickied brake threads for some more technical info on brake fluids and comparisons of the top fluid choices.
cz75 says:
03:19 PM, 07/29/08
Interesting that you guys at Edmunds weren't asking that question about brake sensors a few days ago. I asked it here a few days ago in a previous blog entry on this project. Personally, I could give a damn if the sensors can be used or not, just so long as they can be turned off or otherwise be faked into believing there is no pad wear. Any moron with a flashlight can check the top of the caliper to see if they have pad material through the spokes in the wheel, or barring that, checking them when they get their tires rotated.
joefrompa says:
03:27 PM, 07/29/08
Cz75 - It's my understanding that the higher the wet boiling point, the more hygroscopic the brake fluid becomes.
And, for that matter, some stock brake fluids with low wet boiling points can actually last quite a long time (i.e. those people who don't flush for 10 years).
I will check out the thread sometime soon, thanks for the tip. I think I'm going to pick-up a Vacula to suck out the old fluid instead of the standard bleeding procedure.
Joe
cz75 says:
05:26 PM, 07/29/08
They may last, but they have very little protection against boiling or corrosion. I never changed the brake fluid in my first Acura until I had to replace the front calipers because they seized after seven years. Ford doesn't have a recommended interval, last I heard, but who benefits when you're brakes have a problem?
And there is no direct relationship between wet bp and how long the fluid lasts. Something like Castrol SRF will last a few years, but it better for around $80/liter. There are only rules of thumb and there's no prize for seeing who can drive the longest on old brake fluid.
stingray454 says:
07:50 AM, 07/30/08
"Look at the posts above, I think most of us that visit this blog already knew what you predicted."
So serious... It was a joke. Lighten up Francis.
karjunkie says:
08:33 AM, 07/30/08
cz75, as far as I know no manufaturer has a reccommended interval in their maintenance schedule for changing the brake fluid. I agree it seems very odd as nothing is more important for safety than the brakes functioning properly. Does anyone know why that is?
lazyhater says:
08:59 AM, 07/30/08
"So serious... It was a joke. Lighten up Francis."
I am serious, I am batman :)
cwc1 says:
09:55 AM, 08/ 2/08
There *are* some manufacturers who do recommend replacing brake fluid at regular intervals. Volkswagen is one of them, who specifies changing the fluid every two years.