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Yup, your right. After not driving the car for 6 months of winter storage I wasn't sure of that subtle difference. I switched (coded) back to 981 steering an the difference became quite apparent. Thanks for the info.
quick question. it has calibration for 981 and gt3, but not the gt4. is that to say the gt4 is calibrated with the 981 programing or the gt3 programing since the gt4 has gt3 front suspension ?
I wanted to provide an update on this. I plugged my PIWIS into a 981 Spyder (thanks @Feezy ) and it showed that there are actually unique calibrations for the GT4, 981 Spyder, and 991.1 GT3 RS. The EPS modules must be pre-loaded with whatever calibrations were available at the time each car was produced from the factory.
My guess is the GT4 calibration is a very similar variation to the GT3 calibration.
I wanted to provide an update on this. I plugged my PIWIS into a 981 Spyder (thanks @Feezy ) and it showed that there are actually unique calibrations for the GT4, 981 Spyder, and 991.1 GT3 RS. The EPS modules must be pre-loaded with whatever calibrations were available at the time each car was produced from the factory.
My guess is the GT4 calibration is a very similar variation to the GT3 calibration.
I wanted to provide an update on this. I plugged my PIWIS into a 981 Spyder (thanks @Feezy ) and it showed that there are actually unique calibrations for the GT4, 981 Spyder, and 991.1 GT3 RS. The EPS modules must be pre-loaded with whatever calibrations were available at the time each car was produced from the factory.
My guess is the GT4 calibration is a very similar variation to the GT3 calibration.
@nhnguy12 When you hooked up the PIWIS to a 981 Spyder did the drop-down menu show separate EPS calibrations for the 981 GT4, 981 Spyder, and the 991.1 GT3 RS? I recently bought a 981 Spyder, so I am curious as to what, if anything, can be gained by installing EPS software for either the GT4 or the 991.1 GT3 RS on the 981 Spyder? I can see how you changed the EPS software for the 981 Cayman Base, S, and GTS, as well as the 991.1 Base, S/4S, and GTS by going to the GT3 calibration, and that the steering was definitely improved. Did you change the software for @Feezy on his 981 Spyder to GT4 or GT3 RS?
I will have indy shop access to PIWIS, probably within the next two weeks or so, to hook up my Spyder, but you have already been there. One other thing that is confusing me is that I understand that the actual steering rack on the Spyder comes from the 991.1 Turbo. I can definitely sense that the 981 Spyder rack is quicker than the one on my '15 991.1 GTS RWD coupe. The Spyder rack also has a fair amount more feel than the 991.1 rack. In fact, the main reason why I sold the 991.1 GTS was that the steering, while quite accurate, was so lacking in feel that it almost felt numb.
@nhnguy12 When you hooked up the PIWIS to a 981 Spyder did the drop-down menu show separate EPS calibrations for the 981 GT4, 981 Spyder, and the 991.1 GT3 RS? I recently bought a 981 Spyder, so I am curious as to what, if anything, can be gained by installing EPS software for either the GT4 or the 991.1 GT3 RS on the 981 Spyder? I can see how you changed the EPS software for the 981 Cayman Base, S, and GTS, as well as the 991.1 Base, S/4S, and GTS by going to the GT3 calibration, and that the steering was definitely improved. Did you change the software for @Feezy on his 981 Spyder to GT4 or GT3 RS?
I will have indy shop access to PIWIS, probably within the next two weeks or so, to hook up my Spyder, but you have already been there. One other thing that is confusing me is that I understand that the actual steering rack on the Spyder comes from the 991.1 Turbo. I can definitely sense that the 981 Spyder rack is quicker than the one on my '15 991.1 GTS RWD coupe. The Spyder rack also has a fair amount more feel than the 991.1 rack. In fact, the main reason why I sold the 991.1 GTS was that the steering, while quite accurate, was so lacking in feel that it almost felt numb.
TIA
Yes the drop down menu showed separate additional options for the GT4, Spyder and GT3RS.
We have not tried the GT4/GT3 coding on the Spyder rack. Unsure how the coding would react given the Spyder rack is mechanically different than that of the GT4/GT3/base/S racks. I suspect there won't be a ton to gain since the Spyder's calibration is most likely already a version of the GT3/GT4 software.
Realize this is the 981 section but I have a 718 Spyder, its coded that way in the EPS module. But noticed the option for 982 GT4CS (and 981 GT4CS) which is the clubsport and wondering has anybody else seen that and tried it?
Realize this is the 981 section but I have a 718 Spyder, its coded that way in the EPS module. But noticed the option for 982 GT4CS (and 981 GT4CS) which is the clubsport and wondering has anybody else seen that and tried it?
I have not. Tempted to but I am unsure if the pump/rack are different between the CS and non-CS. Hate to find out the hard way pressures are different or something and cause a problem.
I have not. Tempted to but I am unsure if the pump/rack are different between the CS and non-CS. Hate to find out the hard way pressures are different or something and cause a problem.
There isn't a pump on these racks so nothing to blow up. I would verify the part numbers are the same for the CS car but I don't see why they wouldn't be. Keep us updated!
EDIT: Ok - I had incorrect information. The CS rack is NOT the same rack as the street car. Very different PN.
I did try the coding change. Can't say I felt much difference on a very short lunch drive... maybe it felt heavier? At any rate, I'll code it back this afternoon.
Was able to code the 'GT3' power steering calibration file without a hitch:
Originally I thought I would have to push the car on some twisty roads to appreciate any differences but the changes to the EPS calibration were immediately apparent. I strung together a few errands I "needed" to get done tonight and drove around for 45 minutes or so. It's tough to describe something as subjective as steering feel but I'll try my best. Here are my very early impressions of the updated EPS calibration:
The very first thing I noticed was that the steering is now much lighter immediately off-center than before when traveling at speed. I would say about 30-40% lighter than with the original calibration. The steering no longer feels artificially heavy to me. The reduced steering effort immediate off-center definitely gives the impression of a sharper turn in and makes the car feel smaller/more agile.
The steering now loads up much more progressively than previously. I would say this "ramping up" effect is at least double what it was with the original calibration. You get a much better sense of the front tires digging in and gripping than before. Even after a pretty short drive on public roads I felt a lot more confidence what the car was doing mid-corner and how my throttle/steering inputs were affecting the balance of the car. This was my favorite change with the new calibration.
I didn't feel much change in terms of road texture being transmitted to the steering wheel. I believe this was an actual hardware change in the 2nd-generation EPAS systems introduced with the 991.2 and 718 generations. I remember the technical specs mentioning the addition of a "steering pulse generator" to give the impression of more road feel. I didn't miss the extra texture though. I think the way the steering weights up provides more useful information.
Overall I'm really happy with the changes and am pretty surprised how much of a difference it made. I would encourage anyone with PIWIS to give it a shot. I'm excited to really test it out on some twisty roads this weekend!
Kudos again to @nhnguy12. I printed out the PIWIS 2 instructions for my dealership who performed the update. Since they use PIWIS 3, the instructions don’t carry over perfectly but they were helpful in guiding the techs through the update process.
In regards to how the changes feel, I agree with all 3 of the points made here. #1 being the biggest (positive) difference. Off-center weighting at speed is drastically reduced and that makes it feel more natural and nimble. It feels a lot closer to the lighter & more “twitchy” off-center feel of the hydraulic rack on my old 997.2.
And exactly like point #2, it loads up more progressively when cornering. This is better than the numb stock calibration but do note that it gets to a point where you have to use MORE force (than stock) to maintain a corner/radius at speed. Wasn’t a problem on a recent 3 hour drive for me but I could see it causing a bit more fatigue if you’re all-day rallying through curvy roads.
Another thing I like is that my 981 was not optioned with Power Steering Plus, but this calibration is a bit more assisted at parking lot speeds (probably related to the lighter off center feel from #1), so that was a nice bonus. Kind of gets you half way to full-on PSP.
Only slight negative for me is that there are times, mostly at a STOP, when the assistance feels a bit unnatural (like it’s either assisting too much when I’m not actually giving the wheel that much force OR it’s resisting against the force I’m applying, sort of reacting to my input in a slightly delayed manner). Not sure if anyone else has observed this but I wonder if some of that can be attributed to my specific alignment, suspension, tires, etc (X73 on PS4S in my case). After all, the calibration was meant for a totally different car so maybe it doesn’t do this on a GT3. It only comes into play if you intentionally wiggle the wheel when you’re at a stop and you might feel it kick in when parallel parking, but honestly I’m already getting used to it and my muscle memory is adapting around it.
Overall, I like this calibration much better than stock 981 and wouldn’t go back. Thanks again to the OP for discovering such a gem.
Only slight negative for me is that there are times, mostly at a STOP, when the assistance feels a bit unnatural (like it’s either assisting too much when I’m not actually giving the wheel that much force OR it’s resisting against the force I’m applying, sort of reacting to my input in a slightly delayed manner). Not sure if anyone else has observed this but I wonder if some of that can be attributed to my specific alignment, suspension, tires, etc (X73 on PS4S in my case). After all, the calibration was meant for a totally different car so maybe it doesn’t do this on a GT3. It only comes into play if you intentionally wiggle the wheel when you’re at a stop and you might feel it kick in when parallel parking, but honestly I’m already getting used to it and my muscle memory is adapting around it.
Hmmm I wonder if you're just feeling the flex/scrubbing of the PS4S tires. I did notice that I can feel the tires flex and skip over the surface of the road more than before when I'm cranking in steering angle for parking maneuvers. Maybe this is what you're feeling.
Kudos again to @nhnguy12. I printed out the PIWIS 2 instructions for my dealership who performed the update. Since they use PIWIS 3, the instructions don’t carry over perfectly but they were helpful in guiding the techs through the update process.
In regards to how the changes feel, I agree with all 3 of the points made here. #1 being the biggest (positive) difference. Off-center weighting at speed is drastically reduced and that makes it feel more natural and nimble. It feels a lot closer to the lighter & more “twitchy” off-center feel of the hydraulic rack on my old 997.2.
And exactly like point #2, it loads up more progressively when cornering. This is better than the numb stock calibration but do note that it gets to a point where you have to use MORE force (than stock) to maintain a corner/radius at speed. Wasn’t a problem on a recent 3 hour drive for me but I could see it causing a bit more fatigue if you’re all-day rallying through curvy roads.
Another thing I like is that my 981 was not optioned with Power Steering Plus, but this calibration is a bit more assisted at parking lot speeds (probably related to the lighter off center feel from #1), so that was a nice bonus. Kind of gets you half way to full-on PSP.
Only slight negative for me is that there are times, mostly at a STOP, when the assistance feels a bit unnatural (like it’s either assisting too much when I’m not actually giving the wheel that much force OR it’s resisting against the force I’m applying, sort of reacting to my input in a slightly delayed manner). Not sure if anyone else has observed this but I wonder if some of that can be attributed to my specific alignment, suspension, tires, etc (X73 on PS4S in my case). After all, the calibration was meant for a totally different car so maybe it doesn’t do this on a GT3. It only comes into play if you intentionally wiggle the wheel when you’re at a stop and you might feel it kick in when parallel parking, but honestly I’m already getting used to it and my muscle memory is adapting around it.
Overall, I like this calibration much better than stock 981 and wouldn’t go back. Thanks again to the OP for discovering such a gem.
Great detailed feedback👍
I’m guessing the reason for varying/lighter feel from almost dead stop, as you describe, should be expected when switching GT steering maps to lesser models. The GT3 cars run heavier cambers, harder bushing, larger sized wheels and tyre etc, and are all adjustable for the track, so lighter assistance at low speeds would seem about right…?
04-13-2023, 04:41 PM
