Kancamagus

Many of these alternative steering "tunes" are for cars that have different corner weights, track widths, tire widths, steering geometries, etc. Why do you think Porsche chose to select the specific ratio profile, weight progression, and on-center attributes for the 981 S/GTS? How did they get it so wrong? Seems like those who have done it consider it transformative, and it's not like Porsche had to bend to comply with some regulatory crap like emissions, so what gives?

VRShader

My take is that 991/981 generation is the first electric steering rack generation. They wrote the first iteration of the steering program and can't change it until a new car comes in because the line up has to stay consistent.
Also I do believe 991/981 default steering program might be desgined for regular street driving, not really for track or spirited drive. For example I feel like the default program has more road feel at street speed. Where as the almost zero off center weight of GT4/GT3 program might seem a bit too light at low speed.

my "proof" is that GT4 steering program is much closer to the GT3 than to the 981S one. i think physically GT4 is much closer to a 981 than to a GT3.

I do disagree that it is transformative. Only thing it can change is the centering force and weightning of steering wheel. (a force feedback steering wheel for gaming) I think the GT4 and GT3 program is simply more suited for track/spirited drive.

nhnguy12

I briefly discussed my thoughts on this earlier and posted something similar on the adjacent 991 thread. But I believe the EPS software for the non-GT 981/991.1 was Porsche's first attempt at using this type of steering rack. It clearly wasn't perfect and a lot of motoring journalists pointed this out during the time of release (2011-2012). A year or so later Andy Preuninger (head of the GT department) and his team got their hands on the software and tuned it over tons of track hours:

Whatever they did worked and the 991.1 GT3 (~2013) was lauded for having the best electric power steering in any car made up to that point (per Chris Harris and other prominent journalists). But Porsche had zero financial incentive to retrofit this improved software into the outgoing models of non-GT 981/991.1 cars. Like all companies they are in the business of making money so why would they do that for free if people are already happily buying the outgoing cars. Instead they saved these updates for the next generation of cars and marketed it as one of the reasons why people should drop a bunch of cash on a brand new car. That's why the non-GT 718 and 991.2 cars are regarded as a return to form in the steering department, even without the fancy suspension components.

kwikit356

I think @nhnguy12 has really performed a valuable service for all 981/991.1 owners. I was never happy with the steering feel in my 991.1 GTS, which was a big factor in my decision to sell it. I recall asking the service people at the Porsche dealership if there was a software update, especially given that the 991.1 GT3 clearly had better steering. "Nothing available."

I now have a new-to-me '16 981 Spyder. I have to say that the steering in the Spyder is almost night-and-day better. I know that this car has the actual physical steering rack from the 991.1 Turbo/S, which does make a difference. Does anybody here know if the 981 GT4 or even the 991.1 GT3 has the quicker rack? Ii know this isn't the 718 Forum, but I'm curious if the 718 Spyder or GT4 have quicker steering than the other 718 cars?

nhnguy12

The 981 GT4, 991.1 GT3, and non-GT 981/991.1 all share the same physical rack that has a 16.5:1 ratio. (991-347-005-18)
Only the 981 Spyder and 991.1 Turbo has the faster rack which is a 15:1 ratio (~10% faster on-center). (991-347-005-58)

I'm not as familiar with the 718/991.2 platform but a quick look at the official spec sheets show that the 718 GT4/RS and 718 Spyder share the same rack with a ratio of 17.1:1. (991-347-011-38)
Which is actually slower than the racks used in the non-GT 718 models that have a ratio of 15:1. (991-347-011-67)

So clearly the GT-department at Porsche does not think faster steering = better steering.

Kancamagus

I dunno NH, ultimately Porsche's cachet is performance based. If something as simple as a PIWIS change delivered a remedy for something that was so widely panned it should have been seen as an opportunity, even from a business perspective.

nhnguy12

I don't think it's worth spending too much time debating what Porsche should or shouldn't have done in their development process. I'm just happy there's an inexpensive way to get better steering feel from our EPS racks and wanted to share my findings with others. The feedback is there from myself and other drivers but ultimately steering feel is largely a subjective quality. Give it a try and decide for yourself whether you like it or not.

Kancamagus

Will do - Thanks NH!!

kechal

Just saw this thread and now feel like this is a must have for my 2014 981 S. Thanks to the OP and others who provided the info. I’m going to see if my indy will do this. I’m in Atlanta area (East Cobb) if anyone knows of an indy who will do this.

casil5d2

I’m interested in upgrade and in PHX area. Can it be done on 15 991.1 C2S Cab?
thanks

nhnguy12

Currently out of town for a wedding but more than happy to once I'm back. Let me shoot you a PM.

edit: it seems you have elected to not allow PMs.

casil5d2

I made change to messages. I can wait until you get back, there is no rush.

Cayman Ed

Any US-Canada Pacific Northwest members willing to do tuning party this summer to do this mod? Fellow Planet 9 member in Seattle has PIWIS and willing to help after modding his to GT3 calibration.

cfkid

I changed my mapping to the GT3 yesterday and then went for about a 90 minute drive. The car feels completely different. I’m not going to rave about it because it’s going to take some getting used to.

I agree with all of the other assessments. Steering is lighter. It does load up in turns and switching left-right or right-left is much quicker. I also feel like there’s more ‘road feel’ but that could also just be that the wheel feels like it wants to return to center more quickly.

I am NOT the ultimate driver, so I’ll have to learn the new setup before I decide to keep it or revert. I really need my son to drive it. He’s a much better spirited driver than I am.

Sajan

Yes you definitely feel a lot more road..the steering wheel "moves" a bit more since it's lighter.