McRat

Just got a 2010 ZR1 Vette, and will autoX it this weekend at Calspeedway.

SOOOO... If I'm reading the instructions correctly, when I get it in PTM on the DIC, and set it to 5, it turns off TC, turns off SC, and stiffens up the shocks also?

Or is there more than one step necessary to put it in comp mode?

(before anyone says it, while I'm not competitive, I have a lot of seat time in Fbodies, Vettes, CTS-V's and other RWD high HP cars on both dry and wet tracks. I run in ALL OFF in everything, even when it's raining.)

sd7ss

Yeah, yeah, you da man. Be careful, and don't be in a big hurry to turn everything off. That beautiful machine can bite you. If you stuff it and live, gonna be an angry crowd with pitch forks looking for ya.

Good luck! Drive smoooooth. Stay on the safe side until you get used to it. We'll be watching you. Don't mess it up, O.K.?

jvp

Congrats on the ZR1, and have fun at the autocross. Bear in mind: the PTM system wasn't designed with autocross in mind. It was designed to be used on a race track, where full throttle pulls out of corners are common.

The PTM mode has very little to do with the mode of the suspension. You'll want to set the suspension mode to "Track" before doing anything with the PTM. That said, Mode 5 of the PTM disables the yaw control, and loosens up the PTM to allow the most slippage possible.

FWIW, when Mero attacked the 'Ring in the ZR1 a few years ago, he did it while constantly switching between Modes 4 and 5.

I'm not sure you want PTM on the autocross as I mentioned previously. Just hold the TC button for 5 seconds or so and it'll disable the entire system.

Bill Dearborn

Two things make it hard to use any nannies when you are running an autocross. First, the sharp turns usually encountered in an autocross will reduce traction at one of the rear wheels as you are trying to exit the turn; Second, you will be running in 1st or 2nd gear and the extra torque combined with the low speed will make it a lot easier to spin the tires. Given the two together if you leave TC on it will cut throttle when exiting a turn and there will be a delay before throttle control comes back to the driver. It is better to turn TC off so you can let off the throttle and avoid the inherent delay in throttle application after TC intervenes.

Depending on the course there are situations where Active Handling can benefit a driver (it can apply just one brake to control yaw) but the driver has to know how the system works and how to use its capability to out perform others. I look at it not as a nannie but as a tool that can be used to solve certain problems.

Bill

McRat

OK, now I'm REALLY confused.

First it was traction control, then Active Handling, then Stabilitrak, then Stability Control, Magnetic Suspension, then Performance Traction Management.

ARRGGHHH!!!

OK, I'm trying to flip a switch to ALL OFF. No matter what button or **** I play with, it never says ALL OFF.

I'll RTFM again.

It appears to hint that the shocks, TC, and SC are all together when in PTM modes, and 5 is track mode, aka All Off.

I don't understand where Stability Control is on this car.

jvp

First, what is PTM? It's a way for the car to deliver the exact amount of needed torque to the rear wheels to allow acceleration out of a corner without tire slip. It does this by cycling cylinders very quickly. You'll hear a "BRRRRRRRRRRR" noise when it's active. It doesn't touch the brake calipers at all. It just monitors wheels slippage and delivers the needed torque.

The idea is to let you flatten the accelerator before mid-corner on a race track and smoothly drive through the corner without needing the feather or modulate the throttle. It'll take care of that for you in a far smoother way than you as a driver can do it.

I made this video a couple of years ago to try and explain it. The quality, quite frankly, sucks. But:


I'll try to clarify and use the earlier C6s as a comparison. First and foremost: the MSRC is needed for the PTM to function properly in the Corvettes, but the shock responses around corners, etc, aren't affected by the PTM setting. They're controlled by the same ****, but as shown in the video: it depend on whether you've pressed the TC button or not.

Think of PTM mode as very similar to Competitive Mode in the regular C6s. It's two presses of the TC button. However, once you do that, you can no longer make changes to the MSRC. So it's recommended that you adjust that (Tour or Sport) before going into PTM mode.

The modes 1-5 are basically more conservative-to-less conservative. Modes 1-3 still have the yaw control on (think: Competitive Mode). Modes 4 and 5 have the yaw control off, but PTM is still on.

So. The car still has Stabilitrak, which is comprised of 2 technologies: Traction Control and Yaw Control. Those are both active when you start the car (everything "on"). PTM only comes into play when you hit the TC button twice, as shown in the vid. At that point, the Traction Control part of the Stabilitrak system is disabled completely. The Yaw Control part of it is still active until you switch to PTM Mode 4 or 5. In those modes, PTM is still active, but the Yaw Control part of Stabilitrak is disabled.

If you want the entire system disabled, then you press and hold the TC button for 5 seconds. PTM will be off. Stabilitrak will be off. But you'll still have the MSRC working and will be able to change its mode.

Clear as mud?

McRat

THANKS!!! That is exactly what I was looking for.

OK, PTM is not what I thought it was. So it just stays off, and there is no AH button at all. Set the shocks, turn off TC, and I'm good to go?

To be honest the car is starting to **** me off.

Overly complex yet still primitive for normal operations. The C5 Z06 is vastly superior from a driver's use perspective. I never read the manual on the Z06. Especially just to start the engine or get out of the car when you park. I'm reading the ZR1 manual for the second time now.

jvp

What are you looking for from the car? Describe exactly what you want, and I'll help you get there. Your messages are all over the place here.

It shouldn't. It's not complex at all.

We'll agree to disagree there.

McRat

Car is Haunted.

It's owner died last Dec.

Needs an Exorcist.

I've named it Satan. It's already tried to kill me, and kidnap my family.

I'll get used to it's quirks.

z28lt1

I think what is confusing to the McRat is some of the things said in this thread are contrary to what is in GM's published information (including the owner's manual.)

Full disclosure, I don't have a ZR1, but have another car with GMs 5 PTM modes, and have read the ZR1 and other manuals, and watched a number of GM videos.

First, a few things that are spot-on:
-As mentioned, to shut everything off, like you might want to do on an autocross, just hold the button down for 5 seconds or so, and you'll get the message that TCS and AH are off
-As mentioned, the torque management component of PTM modes are designed to let you get on the throttle out of a turn and let the car control/prevent the wheel spin.

Now, let me add a few more notes.
The different PTM modes effect: Active Handling, TCS/Torque Management, and Selective Ride Control.

Active Handling is on in 1-3 and off in 4-5.
Progressively, from 1-5, the car allows more wheel spin before intervening.

The ride control is changed in the different modes, and not controllable. From the 2010 owner's manual:

"Performance Traction Management integrates the Traction Control, Active Handling and Selective Ride Control systems to provide improved and consistent performance when cornering. The amount of available engine power is based on the mode selected, track conditions, driver skill, and the radius of each corner.
<snip>
The Selective Ride **** will not display the Tour or Sport setting when the Performance Traction Management mode is selected. When this mode is selected, turning the Selective Ride **** will change the Performance Traction Management mode and the
suspension setting will be determined automatically."

I've never seen an official GM statement of Ride Control for the PTM in a 2010 ZR1, but in other GM cars with PTM it is:
1-2 Tour
3-4 Sport
5 Track

So, your choice would be to turn it all off (holding the button) and selecting the suspension settings using the ****, or go into to a PTM mode and use 1-5 which would control (together) Selective Ride, TCS and AH.

Have fun autocrossing!

McRat

Thanks!

You hit it on the head.

From reading the manual, you'd assume PTM 5 is the same as ALL OFF + Max Shock Dampening. Perhaps it is not.

I'll probably cut some laps using the 5 second method and see what it does. Then cut some in PTM 5 and see if there any effect on the car. You're right, you can't adjust the shocks when in any PTM mode. The same **** is used for both functions.

z28lt1

PTM 5 has a little bit of torque management, versus all-off having none. Curious to see your times and comfort level between them, let us know how it goes. I know on a road course, it's really hard to beat PTM 5, but will be interested in the autocross results.

jvp

I can't imagine it's going to make a lick of difference due to the difference in speeds. Unless this is a large autocross course where full-throttle pulls out of a corner are possible, then I really don't see how PTM is going to help.

05dsom

First, a few things that are spot-on:
-As mentioned, to shut everything off, like you might want to do on an autocross, just hold the button down for 5 seconds or so, and you'll get the message that TCS and AH are off
-As mentioned, the torque management component of PTM modes are designed to let you get on the throttle out of a turn and let the car control/prevent the wheel spin.


^^ This is correct.



So. The car still has Stabilitrak, which is comprised of 2 technologies: Traction Control and Yaw Control. Those are both active when you start the car (everything "on"). PTM only comes into play when you hit the TC button twice, as shown in the vid. At that point, the Traction Control part of the Stabilitrak system is disabled completely. The Yaw Control part of it is still active until you switch to PTM Mode 4 or 5. In those modes, PTM is still active, but the Yaw Control part of Stabilitrak is disabled.


^^ I don't think this is true.

jvp

Well, you'd be incorrect. The TCS half of Stabilitrak is disabled, the Yaw Control half is not. In Modes 4 and 5, the Yaw Control half is disabled.

Don't mix up their use of "Traction Control" for the Stabilitrak system. They're referring to the PTM Traction Control.

UrbanKnight

I usually play with PTM 5(race) and all off on the autox course, and ptm5 on the road courses... My times in autox are nearly identical (the local NCCC uses the same course every event) with it on or off, but ptm5 is consistently quicker if I averaged it all out..

PTM 5 will feel weird, almost like you are hitting a rev limiter or fuel cut when it engages, so don't freak out, nothing is wrong, but if you have an exhaust on your car, you will hear it hiccup and burp when it engages.

Id personally start in PTM 5, and if you hate it, then go full off

05dsom

Now I'm confused
so, are there two types of TC?
why does the chart I posted above never say anything about TC being disabled in PTM 1-5, while Yaw (ah) is disabled only in PTM 4-5?
it actually says Tc is fully enabled (as opposed to what you stated about in being fully DISabled in PTM mode)

05dsom

So, if I apply to much throttle, too soon at the apex of the turn in PTM 4-5, what nannies are activated to prevent the back from sliding out?
TC only?

If I do the same as above, in PTM 3 do the Yaw control and TC take effect?

jvp

Bear in mind: PTM is not a nanny. It's a cheater's tool to make you faster. If you do something stupid, the car is going to spin. That said, if you apply "too much throttle" as you mention, it'll modulate the torque to the rear wheels by rapidly deactivating and reactivating cylinders.

If you apply too much throttle too quickly, you're probably going to be chasing your own *** through the turn.

In Mode 3, the Yaw Control will kick in to help straighten the car out if yaw angle and steering input angle don't match within tolerances. The torque management of the PTM system is the same in Mode 3 as it is in Mode 4: It allows a good deal of tire slip; not as much as in Mode 5, but more than 1 and 2.

What folks who haven't driven w/PTM need to understand is that you don't feel it acting through the car. You do hear it though. Whereas a typical nanny like the Yaw Control or the Stabilitrak's TC: you'll feel it kicking in.

Nice and smoooooth.


Go to about 9:18 or so and listen to the car as I begin my pass of the Miata. You'll hear the engine sound like it's stuttering a bit, but it's really brief. You never feel that in the car as far as forward momentum is concerned.

05dsom

Ok, i have heard that sound before and wasn't sure what it was...this is the rapid dectivating/reactivating of cylinders?
Does it almost have a metallic rattling quality to it? I first noticed it at mid-ohio coming out of turn 10 hard on throttle into thunder valley and it definitely seemed to reduce power while making that same sound