SEAT Ibiza - rwd turbo
Discussion
DanSaff said:
Cheers 
It was and I have re read the thread again and it you mentioned it when asked about the camber change on the strut and then followed on to say about the rally cars.
I was hoping for a bit of cheeky info as I wouldn't say struggling but more undecided on which setup to go with.
on searching around I have found since my posting that double wishbones suffer from scrub on compression, and since I'm wanting to drag race it on a Sunday and track it on the Wednesday it might not be the way to go.
Anyway top class car!!
You can of course set up a double wishbone architecture to practically reproduce any other suspension system, including reducing scrub to effectively zero.It was and I have re read the thread again and it you mentioned it when asked about the camber change on the strut and then followed on to say about the rally cars.
I was hoping for a bit of cheeky info as I wouldn't say struggling but more undecided on which setup to go with.
on searching around I have found since my posting that double wishbones suffer from scrub on compression, and since I'm wanting to drag race it on a Sunday and track it on the Wednesday it might not be the way to go.
Anyway top class car!!
You have to weight up the advantages and disadvantages of each suspension system and make a judgement call. There is no single "right" answer, just a different set of compromises.
Depending on the actual vehicle in question, simple details such as the type and details of the body structure may make a certain type of suspension system impractical. And it's worth noting, the more complicated and adjustable you make a system the more "wrong" ways there are or setting it up!
Struts in a saloon car makes sense, as long as the lateral g limit is going to be below about 1.5g (i.e. no seriously aero assisted cars). Struts are very tall and so simply can't be sensibly packaged in a single seater for example.
Thanks for the reply much appreciated,
I agree completely with the adjustability= difficulty setup and am trying to stick with relocating std equipment, but threads like these make me think I'm missing a trick (I'm leaving out details and not waffling to try not to deviate from your car) with the effort involved remaking floors etc. but the price of hubs etc make it difficult to justify to myself.
But those CAD drawings of the cradle angles are very interesting as it's what I would like to do with mine - did you do them yourself?
Have you got the quaife 69g gearbox is it's good as reviews I've been hearing? As that will be the biggest purchase of my build.
Cheers
I agree completely with the adjustability= difficulty setup and am trying to stick with relocating std equipment, but threads like these make me think I'm missing a trick (I'm leaving out details and not waffling to try not to deviate from your car) with the effort involved remaking floors etc. but the price of hubs etc make it difficult to justify to myself.
But those CAD drawings of the cradle angles are very interesting as it's what I would like to do with mine - did you do them yourself?
Have you got the quaife 69g gearbox is it's good as reviews I've been hearing? As that will be the biggest purchase of my build.
Cheers
My gearbox is the old Quaife 'HD' sequential, rated to 750Nm iirc. It's tough, but a bit clunky and really quite heavy. Swapping to pneumatic paddle shifting means i don't notice the clunkiness now, but i'd love to loose 15kg off the weight of the transmission. As a lot of people find, these days your transmission is more limiting that your engine. With modern EMS, finding 500hp/nm isn't actually too hard, but installing a reliable transmission to leverage that power to the ground is a lot harder (and mucho £££!)
Just completed a couple of minor "avionics" updates to enable the future installation of my prototype Antilock Brake and stability system. Initally just for logging chassis data and refining my realtime dynamics model.
Steering Angle Sensor swapped for a higher resolution absolute position sensor on the base of the steering column:
Bosch combined YAW rate & Lat/Long accelerometer (CAN output) installed on chassis CofG:
Bandpass audio spectrum amplifier for the next dyno sesion so i can log some Knock Sensor data:
ABS hydraulic modulator reverse engineering ongoing:
Steering Angle Sensor swapped for a higher resolution absolute position sensor on the base of the steering column:
Bosch combined YAW rate & Lat/Long accelerometer (CAN output) installed on chassis CofG:
Bandpass audio spectrum amplifier for the next dyno sesion so i can log some Knock Sensor data:
ABS hydraulic modulator reverse engineering ongoing:
Currently, for rig test i have just removed the orginal OTP microcontroller from the ABS unit, and control the solenoid driver ASIC over SPi (which i "sniff hacked" before removing the original uC). I have a vehicle model running at 1kHz on a STM32F4 micro and another of the same micro controlling the ABS solenoids/pump. I plan to build a HIL test rig next, and that should enable me to run full vehicle sims with the actual test hardware etc. I have done some basic sim work in Simulink, but as i am not autocoding, the actual test code is in raw C.
The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
Max_Torque said:
Currently, for rig test i have just removed the orginal OTP microcontroller from the ABS unit, and control the solenoid driver ASIC over SPi (which i "sniff hacked" before removing the original uC). I have a vehicle model running at 1kHz on a STM32F4 micro and another of the same micro controlling the ABS solenoids/pump. I plan to build a HIL test rig next, and that should enable me to run full vehicle sims with the actual test hardware etc. I have done some basic sim work in Simulink, but as i am not autocoding, the actual test code is in raw C.
The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
Is there an English version of this for us mere mortals? The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
DaveJH said:
Max_Torque said:
Currently, for rig test i have just removed the orginal OTP microcontroller from the ABS unit, and control the solenoid driver ASIC over SPi (which i "sniff hacked" before removing the original uC). I have a vehicle model running at 1kHz on a STM32F4 micro and another of the same micro controlling the ABS solenoids/pump. I plan to build a HIL test rig next, and that should enable me to run full vehicle sims with the actual test hardware etc. I have done some basic sim work in Simulink, but as i am not autocoding, the actual test code is in raw C.
The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
Is there an English version of this for us mere mortals? The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
DaveJH said:
Max_Torque said:
Currently, for rig test i have just removed the orginal OTP microcontroller from the ABS unit, and control the solenoid driver ASIC over SPi (which i "sniff hacked" before removing the original uC). I have a vehicle model running at 1kHz on a STM32F4 micro and another of the same micro controlling the ABS solenoids/pump. I plan to build a HIL test rig next, and that should enable me to run full vehicle sims with the actual test hardware etc. I have done some basic sim work in Simulink, but as i am not autocoding, the actual test code is in raw C.
The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
Is there an English version of this for us mere mortals? The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
Luckily the ABS unit i am using has a separate Application Specific Integrated Circuit (ASIC) that directly controls the electromechanical solenoids used to modify brake system hydraulic pressure. That ASIC is commanded over an industry standard serial communications bus using the SPi protocol. That mean't i could "eavesdrop" on the commands sent by the std microcontroller and work out how the solenoid control ASIC was commanded.
Replacing the original microcontroller(which i can't modify) with a modern 32bit ARM microcontroller meant i can play around with various control strategies and modify how the device operates.
In order to test how the device works, i have "built" a vehicle dynamics model that runs in real time on a second high speed ARM micro, and this means i can optimise the various input/output & control stragegies before i get anywhere near a real car (which is obviously a good idea when you're mucking around with brakes!)
The next step is to include the actual brake hardware in a Hardware In Loop (HIL) test. This uses the real mechanical parts, such as a brake master cyclinder, ABS modulator, and even brake calipers to assess how the entire system works before installing it in my car.
Simples
Trickiest bit?
Getting the transmission integration and control correct! Getting repeatable, fast, non damaging shifts across the complete range of road speed and engine torques is very tricky when you have a pretty basic EMS controlling the fuel and spark. Particularly the timing and shape of the torque interruption event and the actuator pressure preload on the shift system at that point. It's still not very good tbh.!
Getting the transmission integration and control correct! Getting repeatable, fast, non damaging shifts across the complete range of road speed and engine torques is very tricky when you have a pretty basic EMS controlling the fuel and spark. Particularly the timing and shape of the torque interruption event and the actuator pressure preload on the shift system at that point. It's still not very good tbh.!
The attention to detail in this thread is amazing, the level of OP's skill and knowledge is nothing short of incredible. Hats off to you sir, I can only dream (and quite often do) of ever being able to build something to this level but I will settle for slowly gathering bits and pieces to build a Locost first
Max_Torque said:
Currently, for rig test i have just removed the orginal OTP microcontroller from the ABS unit, and control the solenoid driver ASIC over SPi (which i "sniff hacked" before removing the original uC). I have a vehicle model running at 1kHz on a STM32F4 micro and another of the same micro controlling the ABS solenoids/pump. I plan to build a HIL test rig next, and that should enable me to run full vehicle sims with the actual test hardware etc. I have done some basic sim work in Simulink, but as i am not autocoding, the actual test code is in raw C.
The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
Were you not tempted to go for the Bosch motorsport ABS/TCS controller or was it more of the challenge of reverse engineering the original Conti controller that appealed?The STM32F4 is a massive overkill really (32b >200MHz with h/w ALU/FPP etc) but means i don't have to worry too much about execution latency etc
The thing that's probably going to be hard work is the bottomless pit that is the logic behind it all. To give you an idea of what's in the OEM software, there are around 20,000 to 30,000 individual signals and 7,000-10,000 tuneable parameters! Obviously some of this is value added function, but the VDC, ABS and TCS controllers and the interactions between all 3 takes up the majority of those.
N.B. Not in anywhere trying to be negative here by the way. Genuinely interested in what you're doing and, if you manage to get something working it'd be pretty awesome. There would be a lot of people very interested in what you'd done!
RacerMike said:
Were you not tempted to go for the Bosch motorsport ABS/TCS controller or was it more of the challenge of reverse engineering the original Conti controller that appealed?
The thing that's probably going to be hard work is the bottomless pit that is the logic behind it all. To give you an idea of what's in the OEM software, there are around 20,000 to 30,000 individual signals and 7,000-10,000 tuneable parameters! Obviously some of this is value added function, but the VDC, ABS and TCS controllers and the interactions between all 3 takes up the majority of those.
N.B. Not in anywhere trying to be negative here by the way. Genuinely interested in what you're doing and, if you manage to get something working it'd be pretty awesome. There would be a lot of people very interested in what you'd done!
Max has a thread for this. It appeals to my geeky side to see Max do it. Even if I only understand 10% of how.The thing that's probably going to be hard work is the bottomless pit that is the logic behind it all. To give you an idea of what's in the OEM software, there are around 20,000 to 30,000 individual signals and 7,000-10,000 tuneable parameters! Obviously some of this is value added function, but the VDC, ABS and TCS controllers and the interactions between all 3 takes up the majority of those.
N.B. Not in anywhere trying to be negative here by the way. Genuinely interested in what you're doing and, if you manage to get something working it'd be pretty awesome. There would be a lot of people very interested in what you'd done!
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Munter said:
Max has a thread for this. It appeals to my geeky side to see Max do it. Even if I only understand 10% of how.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Thanks http://www.pistonheads.com/gassing/topic.asp?h=0&a...
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