ABS override
12-13-2002, 10:29 PM
#16
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Chris: most likely what you're talking about is because of the use of prop valves, and safe tuning for stability. On a car with electronic proportioning (newer tech) you can get a whole lot more out of the rears (as you note). The tuning is necessary to match it with the surface and driving conditions. Of course, on the 951's that's been noted even on the street cars, hence swapping out the prop valve...
J Richard: Agreed, for race useage I'd prefer (just my own, non-professional opinion) an adjustable prop valve and no ABS. My professional opinion I cannot give here - I wish to retain my employment! Likewise I won't get into the legal issues you mention - just remember that the legal standards here in the US are quite different than Germany. BTW, when you say remapped ECU - you don't mean the ABS ECU, do you???
I haven't driven the Pilot Cups but I believe they're similar (based on those I race with who do) to the Hoosiers. In my limited experience running Hoosiers w/ ABS, I'd say the behaviour noted was similar to what you noted - modulation prior to optimal decel. No surprise there...
J Richard: Agreed, for race useage I'd prefer (just my own, non-professional opinion) an adjustable prop valve and no ABS. My professional opinion I cannot give here - I wish to retain my employment! Likewise I won't get into the legal issues you mention - just remember that the legal standards here in the US are quite different than Germany. BTW, when you say remapped ECU - you don't mean the ABS ECU, do you???
I haven't driven the Pilot Cups but I believe they're similar (based on those I race with who do) to the Hoosiers. In my limited experience running Hoosiers w/ ABS, I'd say the behaviour noted was similar to what you noted - modulation prior to optimal decel. No surprise there...
12-13-2002, 11:47 PM
#17
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924RACR,
Yea, the ABS ECU, you have to wonder (well you don't, you already know, but for the rest of us...) why not an adjustable ABS? If you have the system in place it seems too bad that it can't be re-mapped to dial in the ultimate threshold.
I think most would prefer the flexiblity of flat spotting a hooser to dial in our own internal ABS (Right foot) and still have the Bosch system in place for the "hail mary" saves...
I would assume that the system runs on a response profile mapped in the same manner as other ECU systems? The ability to switch to a less intrusive profile would give quite a bit of flexiblity for different setups, tires, tracks. Or perhaps a profile which ignores certain fault modes to eliminate the "rumblestrip reset".
After all, the brakes still work if the abs is off, as you said, the only safety issue is a driver that thinks they have abs and they don't...
Any aftermarket potental here?
Yea, the ABS ECU, you have to wonder (well you don't, you already know, but for the rest of us...) why not an adjustable ABS? If you have the system in place it seems too bad that it can't be re-mapped to dial in the ultimate threshold.
I think most would prefer the flexiblity of flat spotting a hooser to dial in our own internal ABS (Right foot) and still have the Bosch system in place for the "hail mary" saves...
I would assume that the system runs on a response profile mapped in the same manner as other ECU systems? The ability to switch to a less intrusive profile would give quite a bit of flexiblity for different setups, tires, tracks. Or perhaps a profile which ignores certain fault modes to eliminate the "rumblestrip reset".
After all, the brakes still work if the abs is off, as you said, the only safety issue is a driver that thinks they have abs and they don't...
Any aftermarket potental here?
12-14-2002, 09:12 AM
#18
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Not a chance, the SW is way too complicated for that. It takes us 1-2 years to tune about 1000 parameters. This when starting with a known good, mature, proven algorithm. This type is system is way too complicated to ever hit the aftermarket, IMO.
Plus, if you screw up, there's a far worse failure mode - no brakes at all! We call it hardpedal.
Certainly a calibration could, and has, been done for track work. However that requires the support of the OEM and the supplier. Seems like Porsche's done it with the Cup cars, and I can't help but wonder if GM's done it with some of the Z06 Corvettes (though not publicly available). Just my guess on that last one, BTW.
As far as the fault modes - some of that can be improved/eliminated by SW development. The classic rumblestrip problem sounds like faulting out a wheelspeed sensor, most likely improved in newer SW with better monitoring algorithms.
Plus, if you screw up, there's a far worse failure mode - no brakes at all! We call it hardpedal.
Certainly a calibration could, and has, been done for track work. However that requires the support of the OEM and the supplier. Seems like Porsche's done it with the Cup cars, and I can't help but wonder if GM's done it with some of the Z06 Corvettes (though not publicly available). Just my guess on that last one, BTW.
As far as the fault modes - some of that can be improved/eliminated by SW development. The classic rumblestrip problem sounds like faulting out a wheelspeed sensor, most likely improved in newer SW with better monitoring algorithms.
