Orthojoe's GT4 track thread and ramblings
04-05-2016, 02:31 AM
#181
I think Martin is doing okay with PASM and the stiffer springs.
However, it would be nice to get more data. Does anyone have a sensor for wheel position on their data loggers? If you have this data for stock and with the swift springs you could tell if the PASM increases the damping to match the springs by analyzing the decay of the oscillation when you go over a bump. If the suspension has more oscillations before the magnitude decays to 1/e its initial value with the swift springs than with stock, then PASM didn't correct.
I also think more data on the wear would be nice. The cup2s have specifically designed softer outside edges, so I wonder how tire wear looks with other tires that don't have this construction.
However, it would be nice to get more data. Does anyone have a sensor for wheel position on their data loggers? If you have this data for stock and with the swift springs you could tell if the PASM increases the damping to match the springs by analyzing the decay of the oscillation when you go over a bump. If the suspension has more oscillations before the magnitude decays to 1/e its initial value with the swift springs than with stock, then PASM didn't correct.
I also think more data on the wear would be nice. The cup2s have specifically designed softer outside edges, so I wonder how tire wear looks with other tires that don't have this construction.
04-05-2016, 04:40 AM
#182
Rennlist Member
Good to know, thanks for the reminder. Considering if I'm going to add springs to my to do list... (bar, discs, pads, wheels, suspension bits, track wrap, it adds up!)
04-05-2016, 08:24 AM
#183
Burning Brakes
^^^ BINGO!!! Martin has spoken! Stiffer springs, along with corner balancing and a good alignment, will TRANSFORM the handling of this car. This is what is needed if you want to resolve these small handling issues and reach the higher limits this platform offers. BUT the tradeoff is ride comfort on the street.
Ride comfort, as we all know, is very subjective. When Pete Stout, PCA Panorama Editor, first drove the GT4 in Spain one year ago he questioned how happy people would be driving the car on public roads. Now that more cars are in more people's hands the issue of ride comfort rarely comes up. Fortunately for us, GT4's have PASM. If you want to know what your car will ride like with springs similar to what Martin is using (450F/550R) just press the Sport button and see what you think. If you can live with that then you have your answer.
Ride comfort, as we all know, is very subjective. When Pete Stout, PCA Panorama Editor, first drove the GT4 in Spain one year ago he questioned how happy people would be driving the car on public roads. Now that more cars are in more people's hands the issue of ride comfort rarely comes up. Fortunately for us, GT4's have PASM. If you want to know what your car will ride like with springs similar to what Martin is using (450F/550R) just press the Sport button and see what you think. If you can live with that then you have your answer.
04-05-2016, 08:30 AM
#184
Three Wheelin'
:Street is all personal opinion...
04-05-2016, 08:49 AM
#185
Rennlist Member
997.1 always soft
997.2 ideally half half at Sebring
991 all hard everywhere at Sebring and Ring much more composed.
It's not GT4 but the suspension setup feels very similar to me.
I think they got it right, borderline OK for the track and very fast still but very drivable on public / bad roads.
997.2 ideally half half at Sebring
991 all hard everywhere at Sebring and Ring much more composed.
It's not GT4 but the suspension setup feels very similar to me.
I think they got it right, borderline OK for the track and very fast still but very drivable on public / bad roads.
04-05-2016, 09:29 AM
#186
Rennlist Member
FWIW, a friend of mine installed this in his 997.2 C4S for the track session last weekend and it made a substantial decrease in body roll. I was quite suspect that there would be any gain, but it did work quite well. No idea if the GT4 version will work but maybe it is an easy option to test. 4 half days in and my fronts are shot as well.
https://rennlist.com/forums/gt4/8952...sc-module.html
https://rennlist.com/forums/gt4/8952...sc-module.html
It was a lot of fun to chase down and pass cars that would walk away from my old Cayman R. I did one session with a lap timer, and was turning low 1:23's on Summit Point Main with a passenger and the Dunlop tires that came on my car.
04-05-2016, 12:17 PM
#187
I have a DSC box in my GT4, and finally had a chance to track the GT4 this past weekend. So far, the DSC is great! Fantastic body roll/dive control. Plus, they now have tuning software available, so you can tweak it yourself if you want. However, I am running their standard GT4 "tune". I didn't experience any heavy dive under braking that others have complained about.
It was a lot of fun to chase down and pass cars that would walk away from my old Cayman R. I did one session with a lap timer, and was turning low 1:23's on Summit Point Main with a passenger and the Dunlop tires that came on my car.
It was a lot of fun to chase down and pass cars that would walk away from my old Cayman R. I did one session with a lap timer, and was turning low 1:23's on Summit Point Main with a passenger and the Dunlop tires that came on my car.
04-05-2016, 01:47 PM
#188
Sounds like the collective is on to something to resolve this tire wear issue. Keep in mind that better dampers will make stiffer springs not seem as bad on the street. I run two-way non-remote MCS on my M3 with 600/700 and I think the car is great subjectively. In most situations it rides better than the stock setup.
Stiffer front springs will also keep the front end from loading up as much during braking, thus making life easier on the front brakes. If one can tolerate the ride on the street, sounds like a win-win.
Who makes springs for this car? H&R? I talked to John at BGB about this a few weeks ago and he said he'd have to look it up.
Stiffer front springs will also keep the front end from loading up as much during braking, thus making life easier on the front brakes. If one can tolerate the ride on the street, sounds like a win-win.
Who makes springs for this car? H&R? I talked to John at BGB about this a few weeks ago and he said he'd have to look it up.
04-05-2016, 03:02 PM
#189
Addict
Rennlist Member
Rennlist Member
04-05-2016, 03:29 PM
#191
Rennlist Member
No, this was my first time on the track with the GT4. I got the DSC based on my positive experience with it in my old Cayman R, without waiting for any pre-DSC track time.
That I don't know.
I don't have any first-hand info, but Mike claims the DSC made a 2-3 second improvement on his GT4 at VIR all by itself.
That I don't know.
I don't have any first-hand info, but Mike claims the DSC made a 2-3 second improvement on his GT4 at VIR all by itself.
04-05-2016, 03:43 PM
#192
04-05-2016, 03:50 PM
#193
04-05-2016, 03:52 PM
#194
Rennlist Member
I installed one of the first-available standalone DSC systems in my R. You can read about it here: http://www.planet-9.com/tpc-racing-g...uess-what.html . Not only did the install include a 987/997-specific DSC box, it included a custom 987-specific wiring harness and Bilstein Damptronic shocks. I also modified a factory switch panel to work with the DSC harness, so I had all three suspension modes available through the stock switch.
The R didn't come with PASM. However, TPC sells a standalone harness that allows you to install a DSC controller and PASM-type shocks (either stock PASM shocks or Bilstein Damptronics) into 987s & 997s that didn't come with it. See above paragraph.
04-05-2016, 04:01 PM
#195
you needed to say you retro fitted PASM to an R then,, the only thing which made the R an R was it's passive shocks and you took them of for the PASM crap every one hates !!!
O well we all make mistakes :-)
O well we all make mistakes :-)