ABS on track / competition car?

[anonymous-user]

Question: Does anyone run an ABS system on their Track/Competition/Kit car? And if so, what system do you use and how do you find it operates?

[shoehorn]

There is a Fiesta,2 Golfs and some sort of Mitsubishi in the unit round the corner from mine,
All track cars of varying standards.
Having had a good look around them I can tell you that the Fiesta and Mitsubishi have the abs units fitted but not plugged in and the golfs have had the units completely removed,one having no servo either.

[PaulKemp]

For competition its is considered a disadvantage, for track day and road a safety feature
What is your car for?

[anonymous-user]

PaulKemp said:

For competition its is considered a disadvantage

Only because a road car has a system calibrated for stability rather than ultimate stopping power:

[davepoth]

ABS is banned in F1, which tells you everything you need to know.

[chuntington101]

davepoth said:

ABS is banned in F1, which tells you everything you need to know.

Exactly! Max isn't the bosch system supposed to be very good? Think it's a built in traction and abs system but poss only traction(??).

[anonymous-user]

The Bosch Motorsport ABS system is very good indeed. It just uses the std production ABS 8.0 Hydraulic/control module with a revised calibration enabling the driver to select the blend between yaw control (cross axle stability) and maximum longitudinal decceleration.
However, considering they are selling your something that comes tumbling out of a factory literally by the million, their prices are astronomical!

The 8.0 system is a 12 solenoid Hydraulic modulator, so it can do the full ABS/TRAC/DSC intervention, although i have no idea if the profesional teams using this system actually take advantages of the full functionality.

I was just wondering if anyone runs a road car system in their track car? Now that we are all so used to ABS in our road cars it seems a bit of a backward step to go back to a driver modulated system for racing? (where it is not prohibited by the rules obviously)

[Evoluzione]

Why do you ask?

I think you may be familiar with the Bosch system on an integrale? It seems (for it's age) very unobtrusive, but I took it off mine. Mainly to simplify the system (and go through a bias valve) and for weight saving, not because it was getting in the way. It was/is either very clever or (more likely) discreet because it was connect to full time 4wd.

I see ABS as an emergency driver aid - for when something unexpected happens, I don't need it on a racetrack as I'm giving it 110% concentration, not likely to have a kid walk out from behind a car and at the speeds you can get up to on there ABS isn't going to save you no matter how good it is.

[GavinPearson]

Just out of interest, how much is the Bosch Motorsport system selling for?

Additionally how do you select the correct calibration for the application?

[Fastdruid]

Last time I looked it was about 6000EUR
http://www.bosch-motorsport.de/content/language2/h...

Here we go
http://www.bosch-motorsport.de/content/language2/h...
6,302.00 EUR for 'production' connectors
7,415.00 EUR for 'motorsport' connectors

What I personally thought was cheeky was that it's an extra 720EUR for the comms lead, so it's 7k EUR for the production connectors version and 8.1k for the motorsport version as you can't do anything without the cable/adapter!

You can download and play with the software (for free), so you can see for yourself what you can do with it. Once setup you then select your different maps via a dial (on the wheel or elsewhere).

I had heard though that you really need one of their experts to set it up properly and that comes at an extra cost (of course).

Edited by Fastdruid on Monday 13th May 11:53

[Munter]

Max_Torque said:

I was just wondering if anyone runs a road car system in their track car? Now that we are all so used to ABS in our road cars it seems a bit of a backward step to go back to a driver modulated system for racing? (where it is not prohibited by the rules obviously)

I'm wondering if the question then is "Which OEM ABS system is closest to a race system, or is there one that can be easily fiddled with, which wouldn't cost anywhere near as much as the bosch setup"

Not that I have an answer.

[Fastdruid]

I had heard of someone doing a 'box' for the RX-8 that changed the DSC settings to promote either under or over steer.

I'm not sure how it did it, although I had a theory that it messed with the output from the yaw sensor.

[anonymous-user]

Munter said:

Max_Torque said:

I was just wondering if anyone runs a road car system in their track car? Now that we are all so used to ABS in our road cars it seems a bit of a backward step to go back to a driver modulated system for racing? (where it is not prohibited by the rules obviously)

I'm wondering if the question then is "Which OEM ABS system is closest to a race system, or is there one that can be easily fiddled with, which wouldn't cost anywhere near as much as the bosch setup"

Not that I have an answer.

That is kinda what prompted my question in the first place.

It clearly makes sense to use production h/w so choosing either of the best selling ABS systems would be a starting point (Bosch 8.0 or ATE Mk70 probably). This issue is one of software and safety imo.

I.E.

1) It is unlikely that one could easily gain access to the calibration data within the production systems, and even then, you would have to account for all the correct system integration to get it to work seamlessly (without popping up fault codes etc).

2) The best approach is to subsitute your own microcontroller for the production version, giving complete control / calibration flexibility. But, as soon as you do this you open a nasty can of worms on safety and system failure modes for what is a "mission critical" application. Even Bosch themselves will not apparently fit their Motorsport system to a road car i believe?

In reality, production ABS systems are immensely reliable (i am not aware of ANY serious accidents being put down to their failure? ) but even a "track only" or a "limited liability" system would need to possess a robust software framework etc.
Of course, although most people probably don't realise it, many of the aftermarket motorsport parts (like throttle systems, pedal boxes, brake calipers, springs/dampers etc etc) all can cause death or injury due to unexpected failure and people fit these to their cars all the time! At least with a electronic system, a degree of sentience can be build in, and the system can indicate potential issues as they occur.

[stevieturbo]

How many forms of motorsport actually allow and use ABS ?

[ShaunTheSheep]

Fastdruid said:

I had heard of someone doing a 'box' for the RX-8 that changed the DSC settings to promote either under or over steer.

I have zero skills or knowledge, just chucking this out there in case it's a helpful data point. The Rx8 version of the Bosch system seems to be configured with less of an eye toward safety than other (VAG & BMW) versions i've tried. On the Rx8 it's much more lenient than i (naively?) expected for a production car, you could probably spin an Rx8 without too much trying even with DSC fully enabled.

I can only really compare to recent VAG and BMW versions of the Bosch system, but they are both much more strict and intervene much more firmly.

[ouninpohja]

stevieturbo said:

How many forms of motorsport actually allow and use ABS ?

FIA GT3 for a start, a big advantage for the gentlemen drivers.

[anonymous-user]

Here's the insides of a basic ATE Mk20 ABS system (ABS only, no TCS/DSC etc)

8 solenoids for 4 channel abs (1x isolator 1x pressure relief per wheelbrake)





And here's the control pcb side:



For the geeks the components are as follows:

1: ATE proprietry control ASIC (Application Specific Integrate Circuit). Almost certainly based on some Motorola / Freescale microcontroller for this automotive application. Interesting that a "single chip" design is used suggesting any safety supervisor system shares the same silicon (possibly a seperate die in the same package etc?). Most likely to be a 16b controller given it's age and relatively simple control task. It had a sticker on it, suggesting it's main memory is probably a OneTimeProgrammable (OTP) architecture, which makes sense for a mass produced safety critical device.

2: XTAL oscilator @ 6MHz. Good chance that the ASIC runs a 4x PLL for a 24MHz main system clock speed

3: Pump motor switching N channel MOSFETS. 2 in parallel of International Rectifier FR3303 (33V 20A @ 25degC) Very conservatively rated to drive the hydraulic pump electric motor (probably as this device is engine bay mounted and hence needs to maintain full operation to >100degC. Pump circuit detection is voltage feedback to ASIC via a 0.5MO pullup resistor and diode from the logic power input, relying on the pumps low impedance to pull down the voltage when connected / normal

4: at a guess this is a Quad schmitt trigger ABS sensor input signal conditioner (ATE ASIC). used to descretise the ABS signals into pure digital information with nice square edges to allow the comparitor in the main ASIC to identify edge-to-edge timing information (and hence wheel speed)

5: Controller Area Network (CAN) common mode data choke and 120Ohm split bus termination. Std automotive CAN bus termination architecture.

6: CAN tranciever: One of the few commercially availible IC's on this board, an NXP A82C250 soic8 packaged device. NXP CAN TCVR

7: Dual high side N channel MOSFET driver IC As the pump and solenoid power supply Fets are "high side" the gates of the drive devices must be lifted above the supply voltage. This driver IC must include an oscilator and charge pump to be able to do this at 100% duty.

8: ATMEL EEPROM AT25010A - 1Kb (128byte) EEPROM with SPi interface - likely to only contain specific vehicle "coding" info such as chassis number etc as this is only 128bytes of memory. Probably also might contain basic "model specific" data such as tyre size / mass etc) Easy enough to pull the data out for a look see ;-)

9: ATE ASIC, but it has got to be an octal lowside driver IC. Likely to be controlled over the same SPi bus as the EEPROM is on (due to their close physical mounting). This IC effectively switches on each of the hydraulic control solenoids as commanded. It is difficult to know if the device is purely ON/OFF or modulates the solenoid current via PWM for a "peak hold" type effect. (would have to log the output signals from a running system to see that)

10: ATE ASIC, most likely the system power supply regulator, probably a smart LDO (Low DropOut regulator) with built in diagnostic output (to identify a "healthy" supply) to allow the main control ASIC to suspend operation in low battery conditions etc

11: Power Gound terminals in I/O connector (earth for pump and logic/solenoids)

12: Pump power input terminal (Vbat to pump switching Fets)

13: Solenoid & Logic power input terminal (Vbat to logic/sols) - connected (via lower layer of pcb) to diode(16)

14: Pump output power terminals - pump motor plugs into the connector to which these are attached on the other side of the module

15: Solenoid power switch: High side N channel MOSFET (another FR3303) used to supply power to the hydraulic solenoids. Part of the safety concept because this is independant of the low side driver(9) that actually switches the solenoids on/off in operation. If power is cut to the sols, they default to "no ABS" mode, where the master cylinder is directly connected to the wheel cylinders.

16: Solenoid/logic reverse battery connection diode - large T0252 diode that prevents current flowing through the logic circuits if the battery is connected backwards! Note the pump motor does not have a similar device (due to power losses) and so will run backwards for a bit due to the intrinsic diodes in the N channel fets (this almost certainly won't cause any damage)


And that is pretty much it, really quite a simple system, without all the extra complication of TCS/DSC etc. Of course, the really clever parts are locked up inside the main control ASIC software.

A few other interesting points are obvious:
a) pcb is thin (<1mm rather than typical 1.6mm) and mounted on a thick (>2mm) ally plate for support and thermal performance
b) Designers were clearly worried about EMC performance as the enclosure is not metal (limtied shielding for electrical noise) so they included a footprint for a dedicated EMC sheild "tinbox" over the main control ASIC. In fact, this part isn't fitted, and so there must have been no EMC issue!
c) Lots of ASICS - when you make millions of something, you can get your own name of the box ;-)
d) Physical size of hydraulic module dominates the pcb layout, hence no requirement for super small components and routing etc. Most descretes are 0805 sized or larger. Makes it easy to hack ;-)
e) Pretty much every signal track on the pcb has a "testpad". This suggests that they used 100% end-of-line testing after pcb manufacture to ensure zero faults. This will have been done via an automated EOL test device, using a "bed of nails" test fixture. This also makes it easy to gain access to all the signals for reverse engineering purposes.......
f) unusally for an automotive environment pcb, no potting or conformal coating is present on the pcb. Possibly to facilitate EOL tests, but perhaps because they were very confident in the environmental protection capability of the modules plastic enclosure etc


When i get a chance i'll try a quick attack on CAN using UDS(ISO15765), which might turn up some of the internal calibration info


/geek ;-)

Edited by anonymous-user on Tuesday 14th May 15:19

[Munter]

Fastdruid said:

I had heard of someone doing a 'box' for the RX-8 that changed the DSC settings to promote either under or over steer.

I'm not sure how it did it, although I had a theory that it messed with the output from the yaw sensor.

Rather than figure out how to reprogram the ABS unit. Fiddle with the inputs to get the effect you want... Given the signal is presumably a "square" wave with edge detection and all that, it'll take a bit more than a variable resistor on the output of the speed sensors. But I do wonder if it's a simpler way, and presumably transferable to many different ABS systems...

[anonymous-user]

Gen1 SAS and YAW sensors were analogue devices, and so quite easy to modify their output. Gen2 devices have pretty much all moved over to CAN output, so a bit trickier to fiddle with (still fairly easy to do however)

The issue i have with fudging the input signals only is twofold:

1) You don't really know what effect you are having on the control system ultimately
2) You still need to provide the std system will all it's normal inputs, and this is a large task for an aftermarket device. There must be a market for track/kit cars (like caterhams/Ultimas etc) where the owners would like that safety net of ABS (which you can easily turn off). Now that the latest systems are down to only a few Kg in weight, this looks to be an attractive option to me?

[Fastdruid]

ShaunTheSheep said:

I have zero skills or knowledge, just chucking this out there in case it's a helpful data point. The Rx8 version of the Bosch system seems to be configured with less of an eye toward safety than other (VAG & BMW) versions i've tried. On the Rx8 it's much more lenient than i (naively?) expected for a production car, you could probably spin an Rx8 without too much trying even with DSC fully enabled.

I can only really compare to recent VAG and BMW versions of the Bosch system, but they are both much more strict and intervene much more firmly.

The RX-8 is a bosch 5.7 IIRC, the only differences between it and the BMW/VAG is in the programming. I think it would prevent a spin, although had the RX-8 pretty sideways it starts to kick in when the tail is about a foot out of line. I liked the DSC in the RX-8, to the point of (after trying with it off) not bothering to turn it off on the road.

Munter said:

Rather than figure out how to reprogram the ABS unit. Fiddle with the inputs to get the effect you want... Given the signal is presumably a "square" wave with edge detection and all that, it'll take a bit more than a variable resistor on the output of the speed sensors. But I do wonder if it's a simpler way, and presumably transferable to many different ABS systems...

Actually IIRC the RX-8 is just a simple voltage jobbie. I'll try and dig out the manual with it all in. As max_torque says though it's not the best way.