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Been wanting to ask this but always forgot. Just read Tadge's response to new GM MRC upgrade so here goes. Is the SUSPENSION the same in "normal" Track vs entering PTM Track? I realize PTM modes change the "nanny" inputs (less as you move the Modes towards Race), but does the car steer/track/compress over the road or track equally in both Track modes? Hopefully I will get real track experienced guys to respond. Hope I made myself clear. Thanks !
Last edited by madrob2020; 12-26-2017 at 10:21 PM.
The different track modes, Track Wet, Track Dry, Sport 1, Sport 2 and Race all use the same MRC calibration for Track Mode. The modes only adjust the strategies the car uses to maintain traction under the 5 PTMs.
Last edited by Steve Garrett; 12-27-2017 at 09:24 PM.
Been wanting to ask this but always forgot. Just read Tadge's response to new GM MRC upgrade so here goes. Is the SUSPENSION the same in "normal" Track vs entering PTM Track? I realize PTM modes change the "nanny" inputs (less as you move the Modes towards Race), but does the car steer/track/compress over the road or track equally in both Track modes? Hopefully I will get real track experienced guys to respond. Hope I made myself clear. Thanks !
Not sure exactly what you mean by both Track Modes. There are 5 sub modes when you put the car in Track Mode. Wet, Dry, Sport 1, Sport 2 and Race. If you are talking about moving the selector to Track and not pushing the center button twice you are pretty much in an undefined mode. The system works differently in the different sub modes. In Wet mode throttle inputs are dampened and stabilitrack is extremely sensitive to correcting unwanted yaw movements. As you move up from Wet to dry sensitivity and dampening are reduced. The steering and suspension don't change their mode of operation. I use Wet Mode, Sport 1, Sport 2 and Race. Some people have found they drive faster in Sport 2 since it keeps them from getting too aggressive on the throttle and dampens the movement of the throttle pedal to some degree.
Wet is very good in medium rain running on the Cup2 tires. I ran most of my first day at the track with my C7Z in Wet Mode and with the Cup2 tires. However, I did try running slicks in a downpour early this year at VIR and even Wet Mode couldn't keep the car from straightening turns. After two turns in a row where I turned the steering wheel at about 25 mph and had the car just go straight like I hadn't turned the wheel at all I slowed down, moved to the inside of the track and eased back to the pits. Anything over 20 mph and the car wouldn't turn.
First, thanks to all. Bill, you are correct that I simply meant is there a difference in the SUSPENSION by putting mode selector in Track w/o pushing center button to enter PTM & actually entering the PTM sub-modes or is it (SUSPENSION) the same with either Track setting. Djnice I had read Tadge's response to PTM settings & for the most part get it (not a techie/gearhead) about the TC & SC settings changing with each sub-mode setting in PTM. I do use them quite abit, especially this time of year (cold temps & wet). Mostly in summer I run Sport 1 on the street. Again-Thanks!
Madrob, you will also notice the table shows MRC (suspension) settings in each PTM mode. So the suspension settings are as follows: Wet = Tour; Dry = Sport; Sport1, etc = Track. My understanding is if you only switch to track and do not double push the center button your MRC is in Track, which is the same suspension as Sport1, etc. This mode is non-PTM track.
The other thing about the non-PTM track is it does not use engine torque management to control traction. It only controls traction and stability by applying brakes. This is the same with all the modes (Wet, Eco, Sport, Track) when PTM is off. The difference is that intervention is reduced. You can get the car more loose before it intervenes.
There is a third non-PTM track mode that I don't recall Tadge discussing much. If you hold the center button for 7 seconds it turns the "nannies" off. You can use this when you switch to Sport or Track. When you do this, the traction control, stability control, and engine torque management are completely off. When you do it in Sport it will have softer suspension than when you do it in Track.
At Spring Mountain one of the instructors discussed this topic and noted that some of their instructors are faster with nannies off while others do better in Sport1,2 or Race. This particular instructor preferred nannies off and gave reasons why. Basically the system cannot see what is coming (I will try to give a hypothetical example - not perfect but trying to give you the concept). The car doesn't know you are approaching a hill where traction will be increased and gravity will slow you down. So you could get loose in a corner that exists to an incline and then regain traction from inertia compressing the tires. The car doesn't know this is about to occur and would have unnecessarily reduced power when exiting the corner.
Whew! Thanks djnice. These darn things are so much fun to put the hammer down but then you lose traction & it can get "thrilling" real fast to say the least. It frustrates me & others from posts I've read, that we have all this power but it becomes such a challenge to use it all especially from a stop. I know about launch control, NLS, & the "go pedal" is not supposed to be used as an on/off switch but has to be feathered in as speed increases or steering line straightens. I would love to be able to WOT thru the first 3 gears, in straight line, w/o losing it due to traction loss when next gear grabs (actually doesn't-HA!). Have been to SM. Had a '14 Z51 'Ray M7 & could just let it rip! Maybe the DSC would be my best option but just reading how it works kinda makes me think a non-techie like me would be lost or make things worse. I do no tracking/strip but Boy Howdy do love to get it on when traffic/conditions allow! By the way I have '16 Z M7. Again thanks for your time! Fixing to go for my run (actual run w/legs), 18 but sunny!!
Madrob, you will also notice the table shows MRC (suspension) settings in each PTM mode. So the suspension settings are as follows: Wet = Tour; Dry = Sport; Sport1, etc = Track. My understanding is if you only switch to track and do not double push the center button your MRC is in Track, which is the same suspension as Sport1, etc. This mode is non-PTM track.
The other thing about the non-PTM track is it does not use engine torque management to control traction. It only controls traction and stability by applying brakes. This is the same with all the modes (Wet, Eco, Sport, Track) when PTM is off. The difference is that intervention is reduced. You can get the car more loose before it intervenes.
There is a third non-PTM track mode that I don't recall Tadge discussing much. If you hold the center button for 7 seconds it turns the "nannies" off. You can use this when you switch to Sport or Track. When you do this, the traction control, stability control, and engine torque management are completely off. When you do it in Sport it will have softer suspension than when you do it in Track.
At Spring Mountain one of the instructors discussed this topic and noted that some of their instructors are faster with nannies off while others do better in Sport1,2 or Race. This particular instructor preferred nannies off and gave reasons why. Basically the system cannot see what is coming (I will try to give a hypothetical example - not perfect but trying to give you the concept). The car doesn't know you are approaching a hill where traction will be increased and gravity will slow you down. So you could get loose in a corner that exists to an incline and then regain traction from inertia compressing the tires. The car doesn't know this is about to occur and would have unnecessarily reduced power when exiting the corner.
If stability control is on the EBCM will request torque changes (this is not torque management) to change yaw. Competition Mode or Sport 1 will disable Traction Control but the system will still use torque changes to control yaw as a torque change reacts quicker than brake application. If the EBCM detects a condition where the car isn't yawing at the appropriate yaw rate to go where the driver is pointing the steering wheel and the throttle is being applied it will reduce torque to make the car yaw faster or slower. Reducing torque during an understeer event (the most likely) causes the car to turn in better while reducing torque during an oversteer situation reduces turn in. If torque reduction isn't sufficient to correct the situation it will then selectively apply brakes to try and change yaw rate.
...If you are talking about moving the selector to Track and not pushing the center button twice you are pretty much in an undefined mode.
Bill
Bill,
Sort of LOL. I've been asking this question since I got one of the first C7Z cars in 2015 and nobody has been able to give a definitive answer. Lots of people make up **** and guess but nobody seems to actually know.
The conversation always morphs into the PTM settings but there doesn't seem to be an answer to question asked by the OP.
Your answer is the most accurate I've seen in nearly 3 years of asking. Specifically, you stating it's "pretty much an undefined mode" is as good as we're going to get.
The conversation went to PTM setting because that is something the OP asked about. The normal track mode when the Driver Mode Control selector is switched to track is defined in the owners manual by this table.
Real good thread here. Man... I needed a spreadsheet to fully decode and get my head wrapped around things. Attached for those that may find useful. If anyone notices that I have something out of place, certainly chime in.
Real good thread here. Man... I needed a spreadsheet to fully decode and get my head wrapped around things. Attached for those that may find useful. If anyone notices that I have something out of place, certainly chime in.
The engine power reduction in the lower right of the chart isn't quite correct. They don't limit power but they dampen throttle response so you get a slower progression to full power. In any of those modes you can get full power but it takes longer to get to that point.
Bill
Last edited by Bill Dearborn; 12-27-2017 at 09:32 PM.
I am nobody to tell you what to do, but I would prefer your last table has the five PTM's across the top. Then you can split engine power and throttle response, and we can consider adding other items. I would have to discuss this with Bill, but it is my understanding that torque is limited by retarding timing. So power is indirectly reduced.
I am nobody to tell you what to do, but I would prefer your last table has the five PTM's across the top. Then you can split engine power and throttle response, and we can consider adding other items. I would have to discuss this with Bill, but it is my understanding that torque is limited by retarding timing. So power is indirectly reduced.
Excellent chart deananderson! I do agree with djnice that for consistency have the 5 PTM modes across top as in normal mode chart. I am sure everyone who has viewed this thread has learned something (I did) & if folks have questions get in here while the experts are following this & ask questions. Remember, there are no stupid questions!
ROTFLAO. I bet you edit this comment once you've spent some time in the very strange world of the forum idiot, John Glenn. He holds the distinction of being the most blocked forum member.
Many have been trying to get moderators to have him set to "block" as a default setting when creating a member account.
I believe there are two different things that change as far as power between Sport 1, 2, and Race. The first, is that the point at which the car starts limiting power while cornering gets higher as you go up through the modes. In a straight line you're going to get the same power in every mode, it's just how early it starts reducing power via timing and whatever is causing that flutter sound (cutting fuel to specific cylinders)?
The other thing that I hear people saying here is that the throttle response is slower in the lower modes. I can't say I've ever noticed that myself but maybe I'm just not that sensitive.
Let me try again to explain the difference between the different PTM modes using an example with some semi-realistic numbers. Let's say you're passing the apex of turn 1 at VIR and go back to full throttle. The car knows that you have 17 degrees of steering input, are pulling 0.8 G lateral acceleration, and are in 3rd gear. The car is also programmed with an assumed coefficient of friction between the tires that came on the car and some standard model of asphalt that won't necessarily incorporate temperature, pavement condition, or tire condition.
However, given these variables the model in the PTM system of the car believes that you can give the car 80% of available engine torque before slip would occur. Should slip occur the car then starts to back off from there.
So if you have the car in PTM Race in my example you would get the full 80% of available engine torque. In Sport 2 you might only get 75% of engine torque, and in Sport 1 it would only be 70%. The next corner the variables will be entirely different as will the calculation for how much torque to use but the same back off strategy would apply based on PTM mode.
12-26-2017, 10:19 PM
Is Track Mode Same in Normal Modes As PTM Modes?
