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      03-02-2017, 08:25 AM   #13
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Drives: e90 335i, NSX, 997.2, 987.1
Join Date: Aug 2009
Location: Charlotte, NC

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I just posted the notes below in a different thread, but thought they'd be helpful here with regards to selecting the appropriate compound. I was specifically referring to our BBK customers, but the same applies to the OEM calipers (Ferodo offers all three compounds in the OEM M2 shape):

Just about all of our BBK customers use a combination of Ferodo DS2500 for sport/autoX use, and either DS1.11 or DSUNO for heavy duty use. The great thing about all three of these compounds is that they are made from the same core materials. As such, you can run them back-to-back without having to worry about them contaminating each other on the disc face. Many times when you run different brands of pads on the same discs and get them up to temp, the pad compounds intermingle and create high spots, smearing, and resulting judder and vibration. That doesn't happen with the Ferodo compounds. When you swap pads, you therefore don't have to worry about scraping the discs completely clean and doing a bed-in cycle. After your initial bedding of the discs, you can just put the pads in and do a few hard stops to get the pads seated/mated to the disc face.

The DS2500 is an outstanding pad with a fairly high temperature threshold, but it still has good 'manners.' On some applications they let out a little squeal or chirp on the last bit of roll-up to a complete stop, but they're typically more or less noise-free. They're also fairly kind to discs, and won't chew them up when run cold. Ferodo supplies many large sports car manufactures with a compound that is nearly identical to the DS2500 as the OEM spec pad. For example, the C7 Z06 (with iron brakes) comes from the factory with pads that are nearly identical to the DS2500. For many years the DS2500 has been widely considered one of the best 'tweener' or dual-purpose pads on the market. It's fairly high temperature threshold combined with it's good manners make it a bit unique. It does have its limits for track use however, which can be met on very fast and heavy cars like the M2. As such, we never recommend for track use on the front of the M2.

I'd say our customers are split something like 70% running same pad compound front/rear, and 30% running a slightly higher mu pad front/slightly lower mu rear. Our brake systems very closely mimic the OEM brake torque output on both axles. If you run just our front-only BBK, there are no ill-effects. We recommend starting with the same pad compound front and rear, then tweaking from there. The combinations of Ferodo compounds people run are as follows:

Front-DS1.11/Rear DS1.11: DS1.11 is a moderate mu compound that has nice wear characteristics on both the pad and discs, and a fairly flat torque curve. You have to press a little harder on the brake pedal to get the same response out of these that you would with the DSUNO.

Front-DSUNO/Rear DSUNO- DSUNO has a higher mu across the entire range than DS1.11. If you like pads with a lot of bite, this is a great starting point. You won't have to press as hard on the pedal to get the same response out of them. All other aspects of the pad are similar to DS1.11.

Front DSUNO/Rear DS1.11- If you like a slightly staggered mu. This setup shifts a little brake bias towards the front of the car, and the rears won't be doing quite as much work.

Front DS1.11/Rear DS2500- Some customers who use their car in many different environments and like to swap pads as little as possible choose to leave their DS2500 in the rear at all times, and just swap out the front for heavy duty use. As with other staggered setups, this will shift some bias towards the front.

Front DSUNO/Rear DS2500- Because the mu of the DSUNO is higher than the DS1.11, this setup increases the gap in mu on the two ends of the car even further. In other words, this setup is even more front-biased than the DS1.11/DS2500 setup. We typically wouldn't recommend this as a starting point, but some customers wind up with this setup and like it. Keep in mind that if you start shifting more and more of the workload to the front, not only will the feel be affected, the wear rates on the front pads and discs will increase.

Front DS2500/Rear DS2500- A great sport setup, which would also work awesome for heavy duty use in one of our kits on a smaller, lighter, less powerful car. For example, we have FT86 customers running the DS2500 in our front brake kit. Again, we do NOT recommend this as a full track pad on the front of the M2. The car is too heavy and fast.

Hopefully the above all makes sense. Thanks.
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