travisnd

GM knows many of us like to track our cars and I'm sure they know the C6 presented challenges in easily swapping between sets of wheels/tires. Now I see the C7 has a new patented tire temp sensor setup feeding another data channel to the car. Has anything been done to allow a more simple swap to track wheels/tires? Or, will every wheel/tire set have to be equipped with the TPMS and new tire temp sensors and then programmed to the car each time?

jvp

Question: why wouldn't you want the TPMS in your track wheels? The entire system is still based on the valve stems, and a lot of aftermarket wheels have the appropriate room for them. So... why not?

travisnd

I don't want to have to buy sensors for every set of wheels tires I own. I don't want to have to buy a scanner/programmer and program the wheels every time I change them. I don't want to have a car that goes into limp mode or reduced power mode when it gets a funky sensor reading.

I have four sets of wheels tires for my C5 racecar. If I get a C7 I will be running timetrials and instructing in it.

jvp

Then get ready to buy sensors. It is, IMHO, silly not to. It takes all of 1 minute at most to do a sensor reprogram after changing the tires. And they're not that expensive.

Hot Rod Todd

There are some reasons why having the TPMS in your track tires is a pain. First the things are not cheap, you have to buy an extra set for your track tires. Also, you need to buy a TPMS programmer and change the setting every time you change the tires. More expense and work.

Hopefully there is a way that they system can default if it senses no monitors (both pressure and temp), and not put the car into "limp" mode as we call it. Better yet allow the user to manually input the temp of tires. If you put on track tires there is only one temp, anything below hot is bad anyway.

travisnd

10-4... never had a C6 so maybe it just seems like more work than it is. When I saw the new tire temp sensor all I could think was more $$$ to spend on each set of wheels. It would be nice if GM programmed in a bypass for that data for those who track the cars.

travisnd

Also, how will these new fangled systems know when I'm on Hoosier A6s? I assume they are reading pressures/temps based on the OEM Michelin tire? I start my A6s in the low 20s cold for TT use. Will the car freak out and think I have flat tires and not want to run right?

What about the increased levels of grip from an A6 Hoosier? Will the car know what to do, or will it confuse the systems? I'd run the car in track mode with all the nannies off anyway.

jvp

Sorry, I just haven't found that to be the case at all. All new sensors in the C6, 2010 and up, are programmable with an air pressure change. No tool is required (I have the tool so I don't care). It'd be silly to expect GM to revert back to the tool setting, but perhaps they will.

Also, you've just purchased another set of wheels and track tires. Neither are an inexpensive purchase. A set of sensors isn't going to break your bank. And it'll give you all sorts of feedback while on the track, along with allowing the traction systems to work properly.

Again, I think you're making a much bigger deal out of this than it really is. Buy the sensors. They won't bite. I promise.

jvp

Pressure, volume, and temperature are directly related. I'd guess that they're assuming the volume is staying fairly constant given the size (not type) of tire used. That may cause some interesting results when using different sized tires, but again I'm only guessing.

I'm guessing that like today's system, if your tires are below 24PSI, it'll be unhappy. Will it go into a limp mode? Not that I've seen. But it'll bitch at you when you first start the car.

You'd be a fool not to run with PTM on. You're not faster than it, regardless of how good you are.

That said, the systems in the existing C6s all work just fine when stickier tires are put on them. They don't have a problem with it at all. I don't see why GM would suddenly change that.

travisnd

I held my class record at VIR for most of last year... I don't need PTM and don't want it. I run 2:03s with a basically stock C5Z on 245 Hoosiers.

Bill17601

I understand what you are saying. As technology goes on, however, you may find you are quicker with the new system. If not this generation maybe the next. I personally wonder how the sanctioning bodies are going to deal with cars that make the drivers as opposed to drivers who make the cars.

Kappa

You can always turn it off.

The temps for track tires should still register as warm to the sensors. I don't think anyone will have a problem with the car not allowing full performance with track tires.

As for being faster with PTM on, ehhhh, if you're running on the ragged edge, you could probably still tell its there. I'd probably go all off as well depending on conditions and how I felt like driving. Trackdays in the wet would probably be pretty cool with PTM set on 4 or 5.

AORoads

To the first question, I believe you will have a problem. It may only be in reading the pressure but it could also be what the car might do to prevent you from going farther w. those low pressures.

To the second, depending on what kind of racing you do and what size tires and diameters you choose, the car's computers may need some rework. I know that many road racers use 18s all around on C6s. See post 6. This may be changed for all I know in the C7 tho.

http://forums.corvetteforum.com/auto...ce-wheels.html

jvp

I have no doubts you're a great driver. PTM is better than you are because you can not control exactly how much torque is delivered to the rear wheels based on traction availability. All you have is the gas pedal and your ***. PTM has quite a bit more to it than that.

I've said it hundreds of times here, and I'll keep saying it until I'm black-and-blue in the fingertips: PTM is not a nanny. It's a cheater's aide. It makes your corner apex and exit smoother, and therefore faster. You get to the apex of the corner, plant your foot right into the floor, and steer. PTM does the rest and you never feel a thing (you'll hear it though).

You're making precisely the same noises that all of the professional drivers at GM made when the system was first introduced. All of GM's drivers are trained to squeeze the absolute most out of a car without the Stabilitrak system engaged. So they were, to the man and woman, doubtful that PTM would make them faster. Each was given a few laps with it off and a few with it on. One hundred percent of them were faster with it: on. Much to the shock of many of them.

(I know the guy that designed it. ;-))

RicK T

They did revert, all C6's produced since Jan 2011.

MikeyTX

I can see it's going to take some doing to make folks understand this isn't their grandfathers C5 or their daddy's C6 ..................

travisnd

What do you hear? Does it cut spark or engage the brakes?

I read the article when it came out about all of GM's test drivers being faster with it on. That said, was that using the street tires or with a proper racing tire fitted? I just don't care for the idea of the car being in control, but I'd try it out both ways. It'd be interesting to drive the car with the PTM in the most advanced setting on A6s vs. all off.

Another question will be, as mentioned above, related to wheel/tire diameters. It's nice to run a square setup so you can rotate tires. I wonder if the car will be able to handle an 18x10 on all four corners?

jvp

It doesn't touch the brakes. It's all spark retard, quickly deactivating and re-activating cylinders. There's a funny BRRRRRR noise, but that's it.

rijowysock

if one had a second set of sensors... what does vette do for "learning".

can it auto learn with input on screen, or does it require a dealer visit? i'm used to other brand vehicles where you can reset in dash and learn... but i know other brands vary.

as far as temp sensor, i'm sure they are in the sensor like most temp sensors... all built into one TPMS

TTRotary

I would not even attempt to run a second set of wheels on the C7 without the TPMS / temp sensor system. First, the car may well go into limp mode without, but more importantly, the whole system works together with the eLSD to enhance grip and the slip angle you can generate. The electronic management of grip is a whole new world, and the systems on the C7 will make ALL drivers faster. Even the pros.

If you are a traditionalist who wants the un-assisted feel, then I would submit that the C7 is not the right car for you, at least for the track.

I would also be VERY careful in trying to swap street tires. The entire C7 electronics and chassis tuning are specifically calibrated to the Michelin tire. This likely includes the tire temp algorithms, as they are matched to the characteristics of the 3 tread compounds in that tire and how these behave at different temps. Switching to s "stickier" or bigger tire will probably result in degraded performance.

Track tires are another story, but I suspect people will be surpised at how little they improve lap times, relative to what they were used to seeing before. This is not going to be the game-changer that folks were seeing on the GY-equipped C6s and C5s.