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Launch Control being limited

11K views 16 replies 15 participants last post by  TorchRedStingray  
#1 ·
2015, Z51 w/MRI (not Z06), automatic with 2600 miles

When attempting Launch Control my rpm's are limited to 2000 rpms before releasing the brake.
They are limited to 2000 rpm's whether in Dry/Sport1/Sport2 or Trac modes.

The best launch time to 60mph is 4.4 seconds. This is pretty disappointing.
I don't know if my ECU is controlling too low or am I just missing something?

Kendug
 
#2 ·
Just got back from Spring Mountain where they demonstrated the launch control for both manual and automatics. The instructor clearly stated, as does the owners manual, that RPM is indeed limited. Once engine RPM stabilizes, release brake with the accelerator full down. Should be in Track mode, double click the TCS/Stabilitrak button to enter PTM mode. Go to town! I haven't done this yet as I am still in semi-pampered break in mode (1000 miles)...but I will!! I'm guessing the advertised 3.7 second 0-60 is under extremely ideal conditions (tires, temps, etc). Maybe warm the tires up really well on a nice warm day and practice, practice, practice! Looks like a lot of fun:cool:
 
#3 ·
I have a 2015 base and don't have the 2000 rpm limit that you're experiencing. I put the car in Track mode, push the traction control button twice so that Competition mode shows on the screen, and it works great. No rev limitation.
 
#8 ·
My understanding from the school:

Manual = RPMs stabilize at 4500
Auto = RPMs stabilize at 2000

Your foot is to the floor on the gas pedal and the brake is hard down (auto) or clutch down (manual), otherwise the engine would hit rev limiter. And yes, I think you'll need very good conditions to get a sub 4 second time. If there isn't enough traction the engine management will do whatever is necessary (reduce power) to maximize forward acceleration.
 
#9 ·
Yeah. In RWD performance cars like this, or my CTS-V, it's very hard to actually get the power down to the ground in lower gears, because there is a lot of power and torque available at all RPM. The issue with getting a sub-4 second 0-60 time is not the car or the power, it's just traction, and to a lesser extent external conditions like elevation. The Vettes have sensors on the rear end that detect wheelspin and talk to the ECU, so what launch control is actually doing is just reducing the power going to the rear wheels until they are gripping well, at which point it increases power again.

Under ideal conditions, sea level, warm day, tires warmed up, sticky surface etc it should be possible to hit 4 seconds or quicker on stock tires using launch control but it does come down to having the traction to do it. In less than ideal conditions, it's not going to happen.

The important thing to remember is that 0-60 is a measurement of traction, not performance. Don't use it as a yardstick for performance, because it is 100% entirely dependent on traction. That's why AWD cars always have better 0-60 times. Not because they're faster, but because they have better traction. This, specifically, is the reason Car & Driver has a 5-60 test, to eliminate the traction variable. Examples:

Car & Driver tested the Nismo GT-R:
0-60: 2.9 seconds
5-60: 3.9 seconds

And the Z06:
0-60: 3.0 seconds
5-60: 3.2 seconds

That right there is what traction does for 0-60 times. The 5-60 test is a rolling start from idle and that's a much more accurate test of how fast the car actually is since the times are not being artificially lowered by AWD and launch control. When you take the GT-R's insane launching ability out of the equation, the 5-60 test shows it to be much slower than the Z06. Also:

0-60 times are total bullshit

The bottom line is don't worry about 0-60 times. They're never going to be as good as cars that have traction from a stop, and a mid-4 second 0-60 time doesn't mean your Vette is slower than GM claims it is. It just means you don't have the same perfect traction conditions to test in.
 
#10 ·
having driven race vehicles with 5 disc clutches and 7000 plus hp, I can truthfully inform you that wheelspeed is very important at launch and should never slow to the point it slows the engine rpm below optimum HP zone. This in lay terms would be called "bog" resulting in tire shake etc. The best acceleration is accomplished with some tire slippage throughout the complete acceleration exercise. I was not a crew chief, but feel I am imparting how the laws of physics work on a properly prepared track.
 
#16 ·
Welcome to our forum. This video may be of help
. Also, if you use our Search Community and put in "how to use launch control" you will find a lot of related posts that may be useful.
 
owns 2018 Corvette C7 2LT