Me like, looking at doing something similar, although not with a engine that puts out more power than a nuclear power plant
As has been discussed elsewhere to run the 848 dtc the rear sensor needs to see 4 counts per rev but the 999 wheel/disc has 5 bolts. This disc was made with 4 pips and one inserted into one of the Ti bolts. As the disc now sits 2mm further out, the caliper has been shimmed over 2mm and the back of the caliper bracket machined out to get clearance for the bolts and pips. Front dtc sensor Some more dry fit Rear cowl roughly placed to see what's needed to fit. Tank raised to give clearance underneath. All parts will be anodised/p coated.
Because if the system is intelligent enough it would see the uneven bolt spacings as a different wheel speed to the front?
My bad for not reading the post twice.... Tho having said that, do disc bolts offer enough resolution for accurate tc calculations?
If you did the calculations you could work out the maximum wheel speed (in revolutions per second) for the maximum speed of the bike, then it would give you the number of times per second you would need to sample to accurately read the speed. I think it works out (quick Excel mumbo jumbo) at around 34 revolutions of the wheel per second at max speed (~ 150mph = 2.5 miles per min = 158,400 inches per min, 180/50x17 wheel = 77.9", ~2,033 RPM = 33.89 revs per sec) You'd want to x4 for the pins, so a minimum sampling speed of 4 x 34 = 136Hz That's not a massive ask for a dedicated processor these days!
Working 136Hz backwards - let's round it up to 140Hz for simplicity sake! - you'd get a resolution/response time of 0.0071 sec, or just over 7 thousands of a second. I think that would be good enough for traction control...
I can't find anything on the resolution of DTC but I would expect that they've used one system across all bikes, probably with an arbitrary 250mph calculated limit which would be a 56.5 revs per second on a 17" wheel with tyre. Round it up to 60 samples per second, x4 pins = 240. Round it up to 250Hz sampling... still not a massive overhead in today's electronics. This would give you a 0.004s response time - 4 thousandths of a second.
Yes, I was looking at some of the Dhurban stuff and their "high resolution" sensors have a 15Khz bandwidth! The specs says that the traction control can sample at 1" intervals on the road, and we know that the rear wheel with tyre is ~77.9" so it is probably working at 80 samples/rev and at a safe 60 revs/sec makes it a nice 4.8KHz sample. The speed/TC sensor disks that he sells have a 40 point interval so would be approx half this.
