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The popular golden rod and rothsport shifters (or other variations of short shifters) can't be made to work in a standard C4 box from my understanding due to the lack of clearance from the drive shaft/torque tube. But once that has been disconnected, can the golden rod mod be installed as if it were a C2 g50 box from the start?
Hey guys, sorry it has been a while since i've updated my progress on this. It was supposed to be done earlier this year but there have been delays gettting the locking collar manufactured. We are now looking at October/November for the conversion to happen. There is an update on my youtube channel if you're interested
Since I recently had to repair a PDAS fault, I did a lot of reading and testing and here are some info I gathered :
- The hydraulic pressure for PDAS is an amazing 140bar and is reached a little while after the ABS needed pressure which is "only" 40bar, or not (that was the fault on the car, the pressure sensor yellow/blue wire never went to 12V, indicating that it never achieved the PDAS pressure)
Here is the main hydraulics circuit :
- On the faulted car, the 13 light was on, with the main alert light and this meant : fault in the booster circuit
- The ABS and PDAS functions are totally separated, even though they are managed by the same unit : on the faulty car, the ABS was still functionning but not the PDAS, obviously. It was simply repaired after replacing the booster pump.
Reading on the PDAS theory and experiencing the behavior myself, I arrived to these conclusions, and that might be usefull for this convertion project :
- The control unit can activated each differential via the hydraulic slave cylinder independantly (this can be tested with the Hammer) but of course the circuit has to be fully presurized
- When activated by the pressure valves, the slave cylinders lock the differentials. I never understood if the lock is 0% or 100%, or if the unit knows how to gradually lock them, sending only a fraction of the pressure it can send (again, these pressure steps can be tested with the hammer). The only thing that I know is that the C4 is an amazing car to drive in the rain on curvy roads, you may accelerate as much as you want while getting out of corners, and really enjoy how good the car is !
Indeed, we know that the PDAS strategy is to optimize the traction while managing lost of adherence from any wheel, and there is the most important info about PDAS :
- PDAS uses the ABS sensors and the electromecanic accelerator sensors to gather information about wheels speeds and car movements
- PDAS remains active only while accelerating, or not accelerating (throttle = 0) , but it deactivate as soon as the pedal brake is touched.
This, to me, explains the understeer which happens mostly when entering a turn without braking. The happy C4 owners can certainly confirm that, and if they never noticed, they may try to keep the brake pedal slightly pressed until the middle of the corner and feel no understeer. They may also try to enter a turn with enough speed and relieving the throttle, just to feel the understeer and then touch the brake pedal without really braking, just to feel the car recovering a "normal" trajectory. Those who drive like this all the time because it's how to drive a 911 may not have noticed a real understeer. Except on long curves and hard acceleration, maybe.
Now, let's go back to the C2 conversion :
From all the previous conclusions and facts, I infer that the active PDAS could likely keep on functioning, even though the front slave cylinder is removed (or remain attached to nothing and may activate for nothing) as long as the circuit pressure is achieved and all sensors are tested at startup and keep on feeding the control unit while driving.
I can't think of any reason why it wouldn't work, but I'm not sure it would be of any interest in harsh track condition, except that understeer is also caused by a very strong differential (very limited slip) on narrow corners, so a dynamically variable differential, as it was designed, might be an improvement anyway !
Anyway, the PDAS could be deactivated on purpose very easliy, just removing the accelerator sensors for instance. Only pb would be to manage the main alert light, but I think one of the Control Unit output is indicating this, so this output may be deactivated as well.
Of course, the circuit to the hydraulic valves could be removed as well, and blocked of course !
Last edited by ManuFromParis; 09-11-2016 at 04:39 AM.
Hey guys, sorry it has been a while since i've updated my progress on this. It was supposed to be done earlier this year but there have been delays gettting the locking collar manufactured. We are now looking at October/November for the conversion to happen. There is an update on my youtube channel if you're interested Video Link: https://www.youtube.com/watch?v=-J_YCvWx2z4
Like to hear the news about the conversion, interesting info about the ABS pump , I get that checked soon .
Cheers
K
hey guys, moving along slowly but making progress. Took some bits to Redtek last weekend. Basically the gearbox centre console and bits so the gear-lever has a pivot once the propshaft is removed. The design of the locking collar has been finalised, just waiting for the machine shop to make them up.
With regard to PDAS there is no need to deactivate it whether you use a C2 gearbox or convert a C4 box as I am doing. You just need to plug the outlet for the hydraulic fluid to the centre diff, the pdas has no sensor to tell it that the fluid is then not reaching he centre diff and will think it is working as normal. In my case as I am retaining the C4 gearbox and so the active Rear diff, this the hydraulic pipe for that will remain active. The question will be if the PDAS will work it as an effective LSD when the car is 2wd, only testing will tell. If it does not work well I will pug the that outlet as well and put in a mechanical LSD.
i know of lots of cars converted to C2 and aside from plugging the pipe to the centre diff the PDAS can be left untouched.
hey guys, moving along slowly but making progress. Took some bits to Redtek last weekend. Basically the gearbox centre console and bits so the gear-lever has a pivot once the propshaft is removed. The design of the locking collar has been finalised, just waiting for the machine shop to make them up.
With regard to PDAS there is no need to deactivate it whether you use a C2 gearbox or convert a C4 box as I am doing. You just need to plug the outlet for the hydraulic fluid to the centre diff, the pdas has no sensor to tell it that the fluid is then not reaching he centre diff and will think it is working as normal. In my case as I am retaining the C4 gearbox and so the active Rear diff, this the hydraulic pipe for that will remain active. The question will be if the PDAS will work it as an effective LSD when the car is 2wd, only testing will tell. If it does not work well I will pug the that outlet as well and put in a mechanical LSD.
i know of lots of cars converted to C2 and aside from plugging the pipe to the centre diff the PDAS can be left untouched.
so i assume, redtek has an approach for a kind of conversion set they`re going to offer, if your`s is working?
possibly or maybe just the collar depending.. the gearchange console I dropped off might not be economical to reproduce in such low numbers. So we'll see what happens
06-06-2016, 02:06 AM
