What is the 2 Step Launch.

[aarias298]

So i was going through some video's on youtube and as i kept skimming through videos i came across videos on something called "two step launch". It also came up as "Launch Control". I was curious if anyone knew what this does or how it works. The majority of the cars that do this sounds like there is a machine gun shooting out of the back of there car, any explanation for this? Im assuming you can't do this on a manual, or can you?

[Redneck4csa]

I know about this subject from a couple of different cars that I am into. Launch control refers to an electronic device that is used to assist the drivers at the start of a race. Launch control mainly refers to an electronic setting on some modern sedans and coupes that let the driver take off from the line at a certain RPM without the wheels spinning too much. This device combines the effort of an electronic-driven accelerator and a computer program in the car. The software drives the accelerator according to engine specifications to make the car accelerate smoothly and as fast as possible, avoiding spinning of the drive wheels, engine failure due to over-revving and clutch and gearbox problems. This feature is only available at the start of the race, when the car is stopped at the starting grid. After the car is running at a certain speed, this device stops its work. In a nutshell, you can push the accelerator to the floor and the engine will only spin up to a pre-set RPM. It will then hold that RPM until you release the cutch. It takes all the guess work out of launching. Now, I am very interested in a Subaru WRX STi. Now, you can download a map onto an accessport that will let you run with launch control. However, they do not recommend it and do not take any liability for damages caused by it. I also test-drove a 09 Chevy Cobalt SS trubo. That car had launch control and a no-lift-shift feature. Basically, you put the accelerator to the floor and you don't move it. The ECU holds the RPMS at a certain point, you release the clutch and go. Once you are rolling, every time that you depress the clutch pedal, the engine will hold the RPM's at the point when you pushed the clutch in. Thus, you always have boost since the RPM's never drop. It is a nice feature to have, but I would not install it on a car that did not have it from the factory. There's too many things on that car that have not been tested for that specific feature. It's just more likely that something could break.

[aarias298]

Well that sounds like a nice feature to have. Thanks for the in depth explanation.

[bdis3]

I need a 2 step, but i have auto. A couple of my turbo tC buddies have it around here. They Rape me off the line... enough said.

[navylife59]

Can you explain what is it exactly that your friends have? With a manual, if you hold your revs at the right RPM based on your engine's max torque output, tires, LSD, and road conditions, then you will get maximum power to the wheels without loosing much traction. From a dig, all you can do with your auto is to hold your RPM just above your torque converter's stall speed which should be around 2570 RPM. I would say hold it about 100~200 RPM above your stall speed. Keep working till you find your sweet spot. Launching at any higher than 2800K RPM is just going to put undue strain on the 1st gear clutch pack, TC, and pump gear. If your peg legged and slick tires, then you might try launching from 200-300 RPM less than stall. RWD drive cars are easy to find the launch RPM. Just when the tires are wanting to spin under power your pretty much there. FWD cars are harder to find because all cars are more brake biased towards the front. Getting a FWD into brake torqued wheel spin will be much higher than stall speed. This is where you need to know what your stall speed is. This is how:

1. PERFORM MECHANICAL SYSTEM TESTS
(a) Measure the stall speed.
The object of this test is to check the overall
performance of the transaxle and engine by
measuring the stall speeds in the D position.
NOTICE:
• Driving test should be done on a paved road
(a nonskid road).
• Perform the test at the normal operating ATF
(Automatic Transmission Fluid) temperature
50 to 80°C (122 to 176°F).
• Do not continuously run this test for longer
than 10 seconds.
• To ensure safety, do this test in a wide, clear
level area which provides good traction.
• The stall test should always be carried out in
pairs. One technician should observe the
conditions of wheels or wheel stoppers
outside the vehicle while the other is doing
the test.
(1) Chock the 4 wheels.
(2) Connect the intelligent tester to the DLC3.
(3) Fully apply the parking brake.
(4) Keep your left foot pressed firmly on the brake
pedal.
(5) Start the engine.
(6) Shift into the D position. Press all the way down
on the accelerator pedal with your right foot.
(7) Quickly read the stall speed at this time.
Stall speed:
2570 +- 150 rpm

For more in-depth on torque converters and how all of this works, read here
Torque converter - Wikipedia, the free encyclopedia

[bdis3]

My friends have 5 speeds. I think we misunderstood eachother.