floatingkiwi

Mark - the pasm shouldn't have any bearing/input on the triggering of the PSM unit. In fact the OE PASM controller takes input from the PSM - don't know how DSC deals with this.
However it does change wheel corner to wheel corner stiffness in a high speed/G corner, hence changing the grip envelope and the detection of the corner height sensors and the yaw sensor/accelerometer in the car, and so somehow putting the cars parameters into the PSM controllers "I think I gotta do something now" envelope?
Maybe your tyres aren't quite up to the grip levels enforced by the higher stiffness of the DSC in that corner?

Except I just re-read your post and sport mode lasts a bit longer/faster so the extra stiffness idea gets blown apart....

Larry Cable

I agree

Tom@TPC Racing

Hello Hillsdonsmith,

I am sorry that your experience after installing the DSC is not the positive experience that other GT3/RS owners have.
As I said before this is the only car I have ever heard of this happening. I have driven many thousands of lap on tracks and tens of thousands of miles on street on 997 GT3's and RS's with DSC.
The car's SC +TC intervention is based on differential of wheel speed signal. They work even without a PASM controller or DSC controller plugged in, just won't be able to select Sport mode without a controller plugged in and of course will get fault messages on the dash without a controller plugged in.
Its really bizarre that swapping the controller changes the intervention SC+TC threshold. Even more bizarre is SC is suppose to kick in to reduce off throttle oversteer.
Are the tires OEM size? Changing tire size(tire height specifically) causes wheel speed signal to change.
Also a bad wheel bearing can mess with wheel speed signal and bad wheel speed sensor can do that too.
You could send your DSC controller to us to test. If there's a problem with it then we'll replace it under warranty.
Other than that, I am afraid I don't have anything useful to add.

hillsdonsmith

Thanks for the insight gents!

Tom - first off, generally I am v satisfied with the module wrt the usual accolades - definitely makes the car much more comfortable around town and flatter in cornering. This may have nothing to do w the controller but are just my observations. Communication also excellent.

Tires are OEM size. I will have these replaced and see if that solves issue.

Would a faulty wheel speed sensor trigger a computer code or not? Sorry, am biology guy and hence as much use as **** on a bull in matters mechanical.

Will keep you posted

Cheers

Mark

Tom@TPC Racing

If a sensor or wheel bearing magnet is faulty all the time then it will trigger fault code(s). If its only faulty during high lateral loading(momentary) then it won't trigger fault code(s) since the SC+TC system interprets it as tire spin.

DSC Sport

Checkout our newest video on DSC Sport Active Suspension featuring Tractive coilovers. Going from running 997 Cup car lap times on track to daily street commute in the same car, same suspension setting- No problem!

flsupraguy

Cool. Donyou have a link for this on your website?

dbbarron

I have been using a DSC V1 with my 997.2 GTS on the track for a few years and am very satisfied.
Lately, I have been using the 997 for autocross and would like some advise on DCS V1 programming changes to improve AX performance.

I note the car has stock dampers (PASM) but GT3 sways, Tarrett Cup car LCAs, drop-links, and full monoball setup. Running Hoosier A7s.

I have looked at the most recent 997 programming files and see in sport mode they stiffen both front dampers equally rather than the loaded wheel only.
Otherwise, the programing looks similar to the V1 stock 997.2 programming.

Our AX course (Devans, MA) is generally a 'fast' AX course with average speed in higher g elements in the 50's. Typical slaloms are run also in the 50's.
I typically see max lateral g's in elements in the 1.3 range, peaking at 1.4.

Any advise is appreciated!

floatingkiwi

What are the new "GRS" G tables all about?

Tom@TPC Racing

Hello. Glad to hear you've been very satisfied on track with DSC!
DSC actively commands the dampers to the driver's actions(braking, cornering, accelerating), whereas on old-fashioned passive dampers one would preset static adjustments for the type of driving and conditions.
Since DSC is programmed in each mode with a "dynamic range" for each table(each table represents each action of the driver) , it pretty much covers most, if not all, popular applications.
However, adjustments can be made by custom tailoring the dynamic range to focus on part of the range rather than the full range to favor a very specific condition and/or to a driver's personal preference. In order to hone-in on a specific range we'll need feedback from the driver.
For the most part, if I were to switch from track to AX, I would leave the DSC alone. And if I had to make a change to induce more entry rotation I would soften front sway bar and/or stiffen rear sway bar, and let the DSC command the dampers to the driver's actions as it has been doing.

dbbarron

We have recently been tuning tire pressures to address understeer/oversteer. Yes, could adjust sways or even DSC tables for specific conditions.

I was specifically wondering about the most recent Sport programs downloadable for the 997s wherein both L and R dampers stiffen in a corner rather than just the loaded corner. Can you please explain the rational for that program/table setting?

Tom@TPC Racing

You are referring to the new GRS (G Force table) that was releases in August 2019.

In the Summer of 2019, extensive testing was done on smooth and semi-smooth racing circuit with pro race drivers and experienced club race drivers. Collectively found that "tightening" up the inside front damper improves the car's composure when trail braking all the way to the apex where the curbing is smooth enough. Same affect on the exit. This feature can produce higher cornering speed. Another way of phrasing- its like having active sway bars, when the conditions allow.


GRS is in Sport Mode only. So for wet track, bumpy tracks, and street driving users can select the original DSC G Force table in Normal mode on the fly.
GRS is a free download file for DSC users. It took a considerable amount of time and resources to develop GRS. It may not have benefit for every users but its worth a try. If a user finds the original G Force table to work better than just save the original file and write it back.

floatingkiwi

why the drop to 60% at 0.4lat/1.0lonG and the drop to 40% at 0.6lat/-0.4lonG? errata?

This is interesting. Feedback from myself and some others (mostly on short tight tracks) was a feeling of the car "galumphing" on a diagonal axis around corners (for want of a more appropriate description...). I was going to go for equivalent g settings L and R axles to see if that was the issue but never got around to it. Just used the OEM box on track which was more predictable - but slower!! THis may mean the DSC stays in the car for all driving, both road and track, which would be great. It's a godsend for road work.

dbbarron

Tom - Does it make sense to adjust the g-grid so that the dampers are fully stiff at the limits of the typical autocross track design?
For instance, if I look at the traction circle log of a recent run on a typical course, the lat G's essentially cycle max-max or roughly 1.4-1.4.
However the long G stays in a more limited range as there is not much hard braking in AX, mostly punch and rotate. The Long G stays within roughly 0.7 braking and perhaps a bit less accelerating.
So does it make any sense to recalibrate the grid within that practical range? Is there a simple way to do this if appropriate?

Tom@TPC Racing

Good catch, you've got the eagle eyes! It is a errata made during a busy pitstop on track. That cell should be 100% instead of 60%. No worries at all in regard to performance, myself and other test drivers running OEM PASM dampers and Tractive on track didn't even feel the slightest hint of that cell because the g-force skips right over that cell regardless of the reaction time of the dampers. Nonetheless we will make this correction shortly. Thanks for noticing this!