I have never experienced what others have described as the brake delay issue, neither before nor after the ABS recall. I have even purposely driven over rough patches of road to try to duplicate. After two days of rain, I noticed yesterday that my brake rotors were rusty. I remembered a comment from qbee42 about putting the car in neutral while braking in order to remove regenerative braking and to force friction braking to clean rusty rotors. Yesterday I was approaching a stop light with plenty of distance and no one in front. I started braking around 45 mph with regenerative braking and then pulled the shift lever to neutral. When in neutral and with the regenerative braking removed, I felt the decrease in braking when transitioning to friction braking and I had to brake a little harder in order to have the same amount of braking as before in regenerative braking. I can see where someone can "perceive" this as a surge forward but I only interpreted this as a decrease in braking force, as others have stated here many times. I tried this again at the next stop light and felt the same "sensation" again and had to brake slightly harder when in neutral in order to have the same braking force. It was apparrent to me that for the same brake pedal position that the friction brakes do not exert as much braking force as the same pedal position with regenerative braking. Is this similar to what others are reporting as "brake delay" or "surge forward" issues?
Why under any circumstances would want to put the car in neutral and use just the friction brakes. Let the carefully developed electronics work their magic.
I think the "brake delay" issue has to do with the ABS and traction control working together poorly, causing a 1/2 sec. "braking release" when a sharp bump is encountered during regen braking. I suspect a third issue is actually involved, installed in the firmware to protect the HSD from sharp torque spikes during regen., but the firmware is probably installed in the ABS and traction control modules. Look for a sharp bump, and try braking over it. You'll have to use medium braking effort to ensure you are using regen.
If you read my post you would have noticed that I was trying to remove rust from my brake rotors. Under normal conditions, I would do as you say and let the electronics do its magic.
If the rotors are rusty enough, you'll feel an *increase* in braking force. Well, for a little while, until they clean off. . _H*
There was just surface rust on mine at the time. I was doing this more as an excercise than anything else.
Yes, that's exactly how i'd describe it, momentary loss of braking, then you need to push harder for the same braking effort.
Be aware the "sharp bump" I describe is very rough. I -suspect- the GIII works the same as the GII in this regard but I don't have any experience in that. For Pearl to release the brakes I have to hit a bump you would describe as a pothole, 3-4" deep, but narrow in the direction traveled such that the wheel gets back on the pavement right away. I've also seen washboard trigger it (this was potentially scary, as it was a -very- steep decent down a gravel road, about 18% grade, but as I knew it would trigger the release, I pressed hard on the brake pedal and Pearl slowed normally, bypassing the release). Our roads here in Edmonton see rather extreme conditions, and tend to crack across the direction of travel. This allows water to seep down and freeze and break the edges, producing a wide but canyon like pothole. Pearl used to brake release on one of these every time (it was 15-20 ft before a stop light). It never caused a problem, but the first time it happened it caused a bit of panic. That road is now repaved, so I can't use it to demo the phenomenon. It's probably perception only, but it almost feels like it's the shock to the chassis that triggers it, not the shock to the drive train.
Interesting experiment! I just tried it a few times at different speeds. From my tests, I have to say that yes I could feel the transition, but it was a very, very brief sensation. In contrast, the real world incidents last for somewhere around 1/2 second -- very noticable. It may very well be the same effect, but I suspect when the driver shifts to N, the software does not actually switch over to friction brakes (or go into neutral) until those brakes are actually ready. Good idea though. I will experiment some more to see if anything changes....
I have had the "surge" happen to me and I wouldnt describe it as casual as you. When it happened to me it felt like I was rearended without the severe whiplash. I think maybe my speed was a bit higher but nonetheless, it was still shocking and prominent.
