quick PDAS switch question
12-05-2011, 06:43 PM
#17
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Location: Detroit (Rock City); 1990 C4
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Originally Posted by Goughary;9077005ina
it only took 20 years to figure it out....
12-05-2011, 09:27 PM
#18
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True. Just came back from a 20 minute test drive in the slushy rain.
First I verified that I could get the PDAS light to light at will. Hard launches off of a stop sign or light, no problem.
Then I pulled over and held the PDAS switch for a bit. First the amber light flashed, then the beeper beeped and the "!" and AWD lamps lit. I turned off the "!" with the switch provided (neat feature; weird, but neat...).
After that I could *not* get the amber light near the switch to illuminate. Also, at one point I launched hard off of a stop sign w/90* turn and I could hear one rear tire spin right up.
I verified that ABS does continue to function.
I was unable to turn PDAS back on via any type of switch manipulation, but stopping and restarting the engine returned everything to normal.
It will be interesting to see what it's like in the really loose stuff.
First I verified that I could get the PDAS light to light at will. Hard launches off of a stop sign or light, no problem.
Then I pulled over and held the PDAS switch for a bit. First the amber light flashed, then the beeper beeped and the "!" and AWD lamps lit. I turned off the "!" with the switch provided (neat feature; weird, but neat...).
After that I could *not* get the amber light near the switch to illuminate. Also, at one point I launched hard off of a stop sign w/90* turn and I could hear one rear tire spin right up.
I verified that ABS does continue to function.
I was unable to turn PDAS back on via any type of switch manipulation, but stopping and restarting the engine returned everything to normal.
It will be interesting to see what it's like in the really loose stuff.
12-05-2011, 10:43 PM
#19
Rennlist Member
Because...........nothing solves the understeer other than installing a proper suspension setup, and tweaking it to your desired driving style. I was shocked that mine felt most similar to all the early development we did on 944 Turbos in the mid-late '80s. (I'm sure the front engined 4 cylinder cars are wholly different today.) I never had any push through T9 at Willow, which is about as ballsy a turn as we have on the West Coast; and Thunderhill T2 just had a slight push, which was OK. Car weight w/ driver was about 3200 lbs. at that point.
12-06-2011, 04:16 AM
#20
As promised I tried it yesterday evening in dry conditions as well as this morning in the wet. The severe understeer I used to get when entering a corner with all feet of the pedels is gone (though I could usuly compensate that by giving it just a little bit of gas).
Unfortunatly (as expected) the car still won't power oversteer. I believe part of the reason is that the rear differential is deactivated as well (I definitely had wheelspin on some wheel/s).
I wasn't able to see what happens when you put the foot down under any noteworthy lateral acceleration. I'm going to keep testing in the coming days.
I would love a way to deactivate only the centre diff and leave the rear diff working. Still in my opinion even the deactivation of the whole system could be a benifit in performance oriented driving.
Unfortunatly (as expected) the car still won't power oversteer. I believe part of the reason is that the rear differential is deactivated as well (I definitely had wheelspin on some wheel/s).
I wasn't able to see what happens when you put the foot down under any noteworthy lateral acceleration. I'm going to keep testing in the coming days.
I would love a way to deactivate only the centre diff and leave the rear diff working. Still in my opinion even the deactivation of the whole system could be a benifit in performance oriented driving.
12-06-2011, 12:59 PM
#21
Race Car
Cant wait to hear abt lap time diffs on the track. Maybe someone will write a new article "Wringing out the Carrera 4 - Version 2, Part 1."
I imagine setup would be a bit different with a constant amount of power front and rear rather than having it change while driving...Still cant believe not only that it took 20 years, but that Adrian didnt catch it for his book....Seems like a pretty important piece of information...
I imagine setup would be a bit different with a constant amount of power front and rear rather than having it change while driving...Still cant believe not only that it took 20 years, but that Adrian didnt catch it for his book....Seems like a pretty important piece of information...
05-16-2012, 03:11 PM
#25
Instructor
Thread Starter
Happy to report that PDAS can be defeated. Turning it off definitely minimized understeer. This video is from Miller Motorsports Park last week. They run Wide Open Wednesday once a month that allows anyone with a car and a helmet out on the track.
Hard to quantify exactly how much faster I was with it off because I didn't do enough laps with it on (much better control with it off), but it was in the range of 1.5 seconds plus on a single lap. Fastest lap (west track, no straight) was 1:41.8.
Hard to quantify exactly how much faster I was with it off because I didn't do enough laps with it on (much better control with it off), but it was in the range of 1.5 seconds plus on a single lap. Fastest lap (west track, no straight) was 1:41.8.
Last edited by Derek Pedersen; 05-16-2012 at 03:28 PM.
05-16-2012, 04:39 PM
#26
Rennlist Member
It was only yesterday that I could sense the PDAS doing something while I was cornering. I was out on HWY1 and hitting some corners kind of hot and with feet off the pedals just coasting through the corners, I could feel what I could only describe as a pulsed scrubbing of the front end. It sort of felt like understeer but it had a pulsing, say, 2-3 times per second.
I've never sensed this before as usually I'm slow in and accelerating through the corner but as I said, I was pushing it a bit yesterday and trying to gain familiarity of what my car does closer to the limits.
Is this what you guys are talking about?
I've never sensed this before as usually I'm slow in and accelerating through the corner but as I said, I was pushing it a bit yesterday and trying to gain familiarity of what my car does closer to the limits.
Is this what you guys are talking about?
