rikhek

In a different thread there's a discussion of how much engine power is available in the various PTM modes. The way I interpret peoples response is that full power is available in all PTM modes.

Now I'm confused. I've always thought available power is reduced in the "lower" track modes. I specifically states so in the manual. What am I missing?

PERF TRAC 1 – WET ACTIVE
HANDLING ON
. StabiliTrak is on and engine
power is reduced based on
conditions.

PERF TRAC 2 – DRY ACTIVE
HANDLING ON
. StabiliTrak is on and engine
power is slightly reduced.

PERF TRAC 3 – SPORT
ACTIVE HANDLING ON
. StabiliTrak is on and more
engine power is available than in
mode 2.

PERF TRAC 4 – SPORT
ACTIVE HANDLING OFF
. StabiliTrak is off and available
engine power is the same as
mode 3.

PERF TRAC 5 – RACE ACTIVE
HANDLING OFF
. StabiliTrak is off and engine
power is available for maximum
cornering speed.

Rick

Poor-sha

They are referring to how much power is available based on cornering and other loads. Just think of it as how early the ptm will start modulating power to avoid breaking traction on corner exit.

BaylorCorvette

Yup. Can confirm that's how my 5th gen ZL1 was in the various PTM modes. The higher you go in PTM the more power you have available during a specific yaw angle. Basically in PTM 5 the car says screw it, you're on your own, where as in like PTM 3 it's saying no you don't need 650 hp for that turn you only get 400.

dar02081961

Very well said.
Its explained here with a video as well. (though not very technically)

http://www.corvetteblogger.com/2012/...gement-system/

rikhek

Well hell, thanks guys. That explains a bunch of "things" I've experienced driving the car at speed playing with the various modes. I've previously watched the Milner video a bunch of times but didn't really understand what PTM was doing regarding available power, or better yet, power delivery. You learn something every day.

BaylorCorvette

If you go into a corner and you hear the exhaust tone "stuttering" that's because it's momentarily cutting power/timing. Basically you're giving the car too much power too soon in that specific situation.

dar02081961

Yep. This goes back to the debate over the years about drifting around the corner being quicker or not versus modulating power and staying at the very limit of adhesion/traction. As you can see modulating power is generally quicker.

I wonder though if that is not dependent on the cars power characteristics?

Vettes and other high powered cars have plenty of lower rpm torque so after the apex they aren't penalized as much during the exit because they don't lose much by "falling off the powerband" so to speak.

Could a more peaky engined car or less torquey car be quicker drifting and keeping the engine on the boil and on the power curve so that after the apex there is no momentum lost trying to get back on the power curve during the exit? The drift might also be the shorter distance around the corner.

Just wondering.

BaylorCorvette

For the average person the power being cut in PTM 3 & 4 will make them faster around a road course. That's how it was for me when I was new to road course events. Fast forward a couple thousand track miles and yes the power being cut gets in the way, or it can.

My C7 is on coil overs and doesn't have mag ride, thus no PTM modes. However in competitive mode on slicks I seldom have computer intervention. I'm impressed with competitive mode on the C7's. I figured it would be too intrusive.

jvp

Then you move up to PTM mode 5. No offense meant, but you're not good enough to outdrive PTM at its best. No one is. It makes fast guys faster just like it makes slower guys faster. How much faster is different, dependent on the skill level. But you're not going to out-do it.

Take that one to the bank.

JohnC7

PTM is defiantly on in Track > Race. If you cannot feel it until you are going fast enough for it to kick in. Lack of power at corner exit. You can mash the throttle and nothing will happen until you straighten up a bit and then power will come back. You can drive the car like an absolute loon but ultimately it is frustrating.