I thought I had some braking G's recorded but apparently I erased them. Once I get my new pads (hopefully) I'll do some stops and report the G's (not really sure how I can calculates stopping distance)

 

Try sending a PM to arenared - he has lots of braking data.

 

If you can, you should get some wet-weather data too... that would be interesting.

 

I think it will be too hard to get repeatable 60-0 measurements. IIRC, my G-meter will only give me 60-0 if it gets a 0-60 first, and there's just not a whole lot of places where I can do that. What is fairly repeatable is peak Gs braking. You can also experiment with different levels of threshhold braking versus the number of wheels of ABS. By far, the biggest difference you will encounter is differences in tire compound, road/tread temperature, etc. For example, I regularly use the "Gs to ABS" as an indicator of how much traction I have, particularly as the temps drop and/or the tires are cold.

I had a decent brake thread on 6-Speed which I need to update and repost here. Just too much else going on. To summarize, there are some really nice gains to be made by shifting brake bias. Most other changes only solve heat-soak problems. Beyond that, tires are the main limitation.

 

I dont recall my exact figure, but at a resent DE, the instructor said only a few GT3s' ever stopped shorter than my CS, and then it was only 0.5M anyway. It likely had stickies on. I have PS2s'. Cool.

 

Okay.

At VIR's Patriot Course, with new Nitto NT-05s and somewhat worn PS2s in the rear, I saw a peak G reading of 1.07 under braking. Tire sizes were 245 in the front, 265 rear, and the temps were around 45 degrees. I also saw a lateral accel peak of 1.24.

 

Re: Okay.

I was actually thinking distances because my 60-0 stopping distances seem remarkably short as compared to the published 70-0 stopping distances. The Girodisc article has my numbers in it.

 

Re: Okay.

I was actually thinking distances because my 60-0 stopping distances seem remarkably short as compared to the published 70-0 stopping distances. The Girodisc article has my numbers in it.

The extra 10mph makes a big difference, as I am sure you know.

 

Re: Okay.

Yes, but I am surprised that the extra 10mph would move the numbers from say 70feet to 106ft, in other words 36ft more or 1/2 the distance again just for another 10mph. We ran multiple runs, we tested and measured multiple times so I have to believe our numbers are accurate, but I also think I can beat the magazine numbers for stopping distance from 70. Maybe, maybe not...

 

Re: Okay.

Yes, but I am surprised that the extra 10mph would move the numbers from say 70feet to 106ft, in other words 36ft more or 1/2 the distance again just for another 10mph. We ran multiple runs, we tested and measured multiple times so I have to believe our numbers are accurate, but I also think I can beat the magazine numbers for stopping distance from 70. Maybe, maybe not...

I think the distances should vary like the square of the speed, so a 70 mph distance would be (70/60)**2 = 1.36 times larger than the 60 mph distance.

Neglecting reaction time, of course.

 

I have a g-tech so i can try this a little later. I also need to take it to hrp eventually and see what it can do there.

 

Re: Okay.

ABS cuts in to early as it is with my new standard disks and rs42 pads.

I can cut mine in easy at 60Mph so bigger pads and disks are not going to help 60-0 runs one bit. I already have to cadance brake to beat the ABS systems distance.

pointless doing test without a good GPS meter, mine can do 60-0 without doing any 0-60 stuff.

to see any real gains with bigger disks you will have to test from 100Mph or test 5 times in a row from 60Mph and mesure the last one where fade might cut in with a standard set up.

But for 1 off 60-0 distance only your right foot is going to better times/distance.

 

I'm just catching up with this thread now. Interesting stuff. I can sure see some of the challenges you had to overcome Ken. You did the best test you could without access to a test track and a pile of sophisticated equipment.

 

Re: Okay.

As a point of note I didn't do a "one off" test, before changing disks we did probably 10 runs from 60-0 and measured each one and they all fell within an 8ft range. After the install we did the same number of runs and again everything fell within an 8ft range but this time the range was 4ft shorter (went from 70-78 to 66-74). I said elsewhere either my neighbor mismeasured the distance with the tape measure or suddenly my speedometer is so far out of whack it doesn't seem possible since I can compare it to GPS as well as the GPS in my radar detector any time it goes off my speedometer is never more than 1 or 2 mph off at most and usually it is either dead-on or 1mph off. I think the original markings are still there from where we put items on the ground to mark the stopping distances so I'll get by that location again soon and re-measure for myself since I was relying on my neighbor to accurately measure.

 

Re: Okay.

As a point of note I didn't do a "one off" test, before changing disks we did probably 10 runs from 60-0 and measured each one and they all fell within an 8ft range. After the install we did the same number of runs and again everything fell within an 8ft range but this time the range was 4ft shorter (went from 70-78 to 66-74). I said elsewhere either my neighbor mismeasured the distance with the tape measure or suddenly my speedometer is so far out of whack it doesn't seem possible since I can compare it to GPS as well as the GPS in my radar detector any time it goes off my speedometer is never more than 1 or 2 mph off at most and usually it is either dead-on or 1mph off. I think the original markings are still there from where we put items on the ground to mark the stopping distances so I'll get by that location again soon and re-measure for myself since I was relying on my neighbor to accurately measure.

Neighbours are notoriously unreliable. That's what my neighbour says.