TPC's DSC box and new Active suspention
08-31-2015, 07:27 PM
#16
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hysteresis
stiction
technical jargon is music to my auricles (external ears)
Thanks for posting.
Craig
09-01-2015, 02:42 AM
#17
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Thank you for your feedback.
I agree, DSC by itself doesn't work magic for the entire chassis- DSC module is only one component of the entire suspension system. Even though DSC itself has huge potential for shock damping control and makes immediate improvement, the vehicles performance is ultimately limited by mechanical components(i.e. stock shocks, springs, setup, even tires). One element in particular is mechanical hysteresis of stock PASM shocks as a result of the electro-mechanical mechanism's reaction time AND stiction. The difference alone in the reaction time between 6ms to 100ms at 60mph is ~8.5 inches* of distance travelled. As a side note, believe it or not, some of the popular brand conventional(non-electronic) racing shocks have hysteresis as well especially when the dampening force is dialed up. In any case, the hysteresis can be masked(to make the chassis respond better) by setup changes such as sway bars, spring rates, differential, geometry. Race teams have been "masking" damper stiction with setup for a very long time as tires got better. In recent years ultra high end motorsport shocks have reduced stiction to a whole new level. Tractive is able to provide low stiction feature at a reasonable cost.
Anyway, it has been my experience that majority of DSC users just plug and play, which is perfectly fine for street and light track use, whereas pretty much anyone who buys a set of any brand coilovers changes ride height and gets more aggressive alignment, and very likely other suspension component upgrade at the same time to improve the chassis as a whole.
Back to the topic of the stock PASM shocks, which at lower ride height levels the bump rubbers affect reaction time too. As far as the shock itself, the reaction time is based on the piston differential pressure and load. The DSC software anticipates the stock PASM shock's reaction. Our Engineer is offering a limited number of pre-user version of DSC software(basically Engineering version) if you want to tune your chassis for variables. Let me know if you want to tune your stock PASM shocks. We have advanced level track drivers and chief instructor in our local region running amazing times with DSC controlled Bilstein B16's and shock PASM shocks, with full setup of course.
I agree, DSC by itself doesn't work magic for the entire chassis- DSC module is only one component of the entire suspension system. Even though DSC itself has huge potential for shock damping control and makes immediate improvement, the vehicles performance is ultimately limited by mechanical components(i.e. stock shocks, springs, setup, even tires). One element in particular is mechanical hysteresis of stock PASM shocks as a result of the electro-mechanical mechanism's reaction time AND stiction. The difference alone in the reaction time between 6ms to 100ms at 60mph is ~8.5 inches* of distance travelled. As a side note, believe it or not, some of the popular brand conventional(non-electronic) racing shocks have hysteresis as well especially when the dampening force is dialed up. In any case, the hysteresis can be masked(to make the chassis respond better) by setup changes such as sway bars, spring rates, differential, geometry. Race teams have been "masking" damper stiction with setup for a very long time as tires got better. In recent years ultra high end motorsport shocks have reduced stiction to a whole new level. Tractive is able to provide low stiction feature at a reasonable cost.
Anyway, it has been my experience that majority of DSC users just plug and play, which is perfectly fine for street and light track use, whereas pretty much anyone who buys a set of any brand coilovers changes ride height and gets more aggressive alignment, and very likely other suspension component upgrade at the same time to improve the chassis as a whole.
Back to the topic of the stock PASM shocks, which at lower ride height levels the bump rubbers affect reaction time too. As far as the shock itself, the reaction time is based on the piston differential pressure and load. The DSC software anticipates the stock PASM shock's reaction. Our Engineer is offering a limited number of pre-user version of DSC software(basically Engineering version) if you want to tune your chassis for variables. Let me know if you want to tune your stock PASM shocks. We have advanced level track drivers and chief instructor in our local region running amazing times with DSC controlled Bilstein B16's and shock PASM shocks, with full setup of course.
thanks for ur reply
i may call u over the next few days to discuss in person - not sure i am following what you mean by 'tuning' my stock pasm shocks - sorry i am not very technically astute
but here, for the rl board, maybe can you clarify -- for a 7.1 gt3 application... what would be the most cost effective hardware (shocks and springs) that you feel would couple with your dsc controller/accelerometer to provide very good responsiveness for track applications? should the soft stock springs be replaced in this case? we all know that is weakness #1 for track bound 7.1 gt3's...
i assume that b16 damptronics or tractive gear would be the optimum solution, based on your comments above?
09-01-2015, 05:31 AM
#18
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TPC's DSC box and new Active suspention
Interesting details. Assuming lowering springs installed, are the reaction times of the B8's any better than stock PASM shocks?
09-01-2015, 09:47 AM
#19
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__________________
PCA National Instructor
TPC Racing stats:
2023 Porsche Sprint Challenge 992 Cup Am Champion
2023 Porsche Sprint Challenge GT4 Pro-Am Team Champion
2022 Porsche Sprint Challenge 992 Cup & 991 Cup Champion
2020 IMSA GT3 Cup Challenge 2nd Championship
2018 IMSA GT3 Cup Challenge 2nd Championship
2016 IMSA GT3 Cup Challenge Champion
2013 IMSA GT3 Cup Challenge Champion
2006 Rolex-24 @ Daytona GT Champion
2004 Grand-Am SGS Class Champion
PCA National Instructor
TPC Racing stats:
2023 Porsche Sprint Challenge 992 Cup Am Champion
2023 Porsche Sprint Challenge GT4 Pro-Am Team Champion
2022 Porsche Sprint Challenge 992 Cup & 991 Cup Champion
2020 IMSA GT3 Cup Challenge 2nd Championship
2018 IMSA GT3 Cup Challenge 2nd Championship
2016 IMSA GT3 Cup Challenge Champion
2013 IMSA GT3 Cup Challenge Champion
2006 Rolex-24 @ Daytona GT Champion
2004 Grand-Am SGS Class Champion
09-01-2015, 09:51 AM
#20
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The B8's are designed to be lowered to some degree so I'd say minimum affect if any at reasonable ride height. However, the vehicle(not the shocks) should respond better(and "feel" better) when cornering as a result of the increased negative camber from lowering and lower center of gravity.
09-01-2015, 10:30 AM
#21
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Welcome.
No worries. In case you haven't seen this DSC software tutorial video, here it is- https://rennlist.com/forums/997-gt2-...on-thread.html
Basically DSC/Race Car Engineer, Michael Levitas, will work directly with you, if you want, to improve the anticipation of the delay in reaction you are feeling via software be it shock related or chassis setup related.
Most cost effective would be to work with your stock PASM shocks, as long as they are in good working condition. Is the delay in reaction you are feeling on entry or exit or both? Tell us more about your setup so we can help- we know the springs are stock, what sway bars and the setting, alignment, ride height, diff setup. All these items influence chassis reaction. I understand not everyone refer to share these info, email me directly is fine. Email is: tchan@tpcracing.com
As far as shocks themselves go, Tractive DDA is the optimum pairing for DSC for its ultra wide dynamic damping range, fast electronic to mechanical reaction time, low stiction, and superior build quality. B16 on ebay cost half of Tractive DDA, but B16 doesn't include front and rear ball bearing top plates and more ideal springs for advanced track use so by the time these items are added its not as appealing cost wise. But B16 is a very good product for replacement of the worn stock shocks without doing the add ons.
In case you haven't seen this DSC software tutorial video, here it is- https://rennlist.com/forums/997-gt2-...on-thread.htmlBasically DSC/Race Car Engineer, Michael Levitas, will work directly with you, if you want, to improve the anticipation of the delay in reaction you are feeling via software be it shock related or chassis setup related.
but here, for the rl board, maybe can you clarify -- for a 7.1 gt3 application... what would be the most cost effective hardware (shocks and springs) that you feel would couple with your dsc controller/accelerometer to provide very good responsiveness for track applications? should the soft stock springs be replaced in this case? we all know that is weakness #1 for track bound 7.1 gt3's...
As far as shocks themselves go, Tractive DDA is the optimum pairing for DSC for its ultra wide dynamic damping range, fast electronic to mechanical reaction time, low stiction, and superior build quality. B16 on ebay cost half of Tractive DDA, but B16 doesn't include front and rear ball bearing top plates and more ideal springs for advanced track use so by the time these items are added its not as appealing cost wise. But B16 is a very good product for replacement of the worn stock shocks without doing the add ons.
09-19-2015, 07:09 PM
#22
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Tom,
How does the module work with the B16 units? Is there different software for them? I see there are two different part numbers for the B16 PASM units. One is a "comfort" and the other is a "sport" version. Which one do you recommend for a 90% street /10% track car? How is the reaction time for these units compared to stock?
How does the module work with the B16 units? Is there different software for them? I see there are two different part numbers for the B16 PASM units. One is a "comfort" and the other is a "sport" version. Which one do you recommend for a 90% street /10% track car? How is the reaction time for these units compared to stock?
09-21-2015, 12:52 PM
#23
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DSC works great with B16. I've had DSC and B16 on my car and liked it a lot. Many DSC users have B16 and they too like it a lot. As discussed previously in few other threads, the B16 electro-mechanical mechanism is pretty much the same as OEM PASM which is also made by Bilstein. B16 comes with stiffer springs than stock so the "compounding stiffness" of the stiffer springs paired with the damping commands of DSC is most welcomed on track and other high-g situations. Many users such as myself have further increased the compounding stiffness to favor track use by replacing B16 springs with stiffer springs and stiffer adjustable sway bars. Note: Compounding stiffness is good up the point where grip/feel is at peak.
Reaction time is the same as stock, in the 100ms range, but usually when putting a set of B16 or B8 on the car feels better even without DSC simply due to the fact that aging stock shocks were replaced.
No. Stock PASM and B16 have same reaction time so no change in that regard. The compounding stiffness is well within the range of standard DSC mapping even will stiffer springs and bars.
In my opinion, from my very narrow-minded performance perspective, the comfort version is BS. Maybe I'm too hardcore but who buys coilovers for comfort? Personally, for comfort I'd use stock shocks or B8 paired with .2 springs or GTS-4 Sport PASM lowering springs as they are "bell-shaped" with unevenly wound coils that are by design, more stable to the oscillation frequencies of street use. As for recommendation, I am afraid I am not in a position to make one for you. You have to ask yourself do you want the car to favor the 10% of the times that are on track or favor the 90% of the times on street? Only you can answer that. With DSC technology the gap between performance and comfort is closer than ever before, to the point which for some people the compromise between track performance to street comfort is zero. We have proven that DSC, B8, and bell-shaped springs to run incredible lap times for a given tire, but we always want more so we partnered with Tractive to narrow the gap even further.
Reaction time is the same as stock, in the 100ms range, but usually when putting a set of B16 or B8 on the car feels better even without DSC simply due to the fact that aging stock shocks were replaced.
No. Stock PASM and B16 have same reaction time so no change in that regard. The compounding stiffness is well within the range of standard DSC mapping even will stiffer springs and bars.
Personally, for comfort I'd use stock shocks or B8 paired with .2 springs or GTS-4 Sport PASM lowering springs as they are "bell-shaped" with unevenly wound coils that are by design, more stable to the oscillation frequencies of street use. As for recommendation, I am afraid I am not in a position to make one for you. You have to ask yourself do you want the car to favor the 10% of the times that are on track or favor the 90% of the times on street? Only you can answer that. With DSC technology the gap between performance and comfort is closer than ever before, to the point which for some people the compromise between track performance to street comfort is zero. We have proven that DSC, B8, and bell-shaped springs to run incredible lap times for a given tire, but we always want more so we partnered with Tractive to narrow the gap even further.
09-21-2015, 01:59 PM
#25
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B8 Sport Damptronic is an upgrade over .1 and .2 turbo PASM shocks. You will notice the ride is firmer but no harsher. Best words I can come up with is sportier controlled tightness. Some of the sportier feel is attributed to the inverted strut cartridge design(like GT2/3/RS) that's also designed to handle higher load and reduce stiction when subjected to heavy load. The B8 stroke is designed to play well with lowering springs within a reasonable lowering height. Just realized I'm doing Bilstein's marketing work for them... LOL.
http://cart.bilsteinus.com/search/mm.../drivetype=AWD
Eibach Pro Kit lowering springs is a bell-shaped spring and used to be my favorite for this car. They lower the car just enough, not too much that the car is riding on bump rubbers- Good. They are progressive rate that I estimate to be ~15% over stock- Good. They feel like floating on a cloud over street 1/2-inch bumps- Freakin Awesome. They were on top of my list for lowering springs for this bar ...But it has been my personal experience that after few years these springs sag to make the car lower than I like. So they are great for the first few years. All springs sag, some more than other, some sooner than others. I started liking stock springs because they seem to have better manufacturing requirement against sagging. For example, I have recently steered many 987 Cayman/Boxster customer who are looking to lower their car on stock shocks to Cayman R springs that're 20mm lower. In this case, Carrera GTS-4 Sport PASM springs that're 20mm lower.
09-21-2015, 04:52 PM
#26
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I'll chime in as a VERY satisfied street user! My 2009 C2S is lowered on H&R sport springs, stock PASM, using the DSC box. In complete layman terms, normal aggressive street driving, the car is now essentially flat in every direction. No squat under hard acceleration, no dive under hard braking, compared to stock it's FLAT through corners. For all the stupid interior carbon fiber crap and leather door sills guys buy for their cars, this is a no brainer for the cost, your car is instantly better with it.
09-23-2015, 11:48 PM
#27
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Tom, the springs you mentioned from the GTS, would those work on my 07 Turbo? If so would you happen to have the part numbers for those? I really appreciate all of your input and knowledge.
09-24-2015, 11:22 AM
#28
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I started liking stock springs because they seem to have better manufacturing requirement against sagging. For example, I have recently steered many 987 Cayman/Boxster customer who are looking to lower their car on stock shocks to Cayman R springs that're 20mm lower. In this case, Carrera GTS-4 Sport PASM springs that're 20mm lower.
A note on sag(aka settlement), its a common thing, usually not a big deal especially if its on threaded body coilover that can restored the original/desired ride height. I dislike having to change the suspension geometry more than I feel its necessary in order to do get wheel alignment to specs when there's no adjustment to restore height. If the car is never to be on a track then its no big deal. I only steer customers to use stock Sport springs only if they are looking for mild lowering on stock type struts/shocks because that's what I'd use in such application. I don't even sell stock springs.
For flat out track performance, the "straight" springs are the way to go. With our DSC/Tractive DDA program, we are getting straight springs to have street compliance near that of bell-shaped springs.
Here's the photo of the springs. Bell-shaped spring on the left. Straight spring on the right.
09-24-2015, 11:54 AM
#29
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I think there's also an optional front spring mounting pad listed in PET that lowers the front ride height additional 3.5mm.
Last edited by Tom@TPC Racing; 09-24-2015 at 11:57 AM. Reason: typo