Launching with 2 step question.

[Suprapowaz!(2)]

I understand why people slipped the clutch off the line with a turbo car. Keeps wheelspin under control, builds boost at the same time your avoiding bogging out.

I've heard of people with 2 steps still slipping the clutch then letting go when they launch. This is odd to me because I thought that was the purpose of 2 step was the build boost off the line. Why couldn't you just dump the clutch and go? You would still have 5+psi of boost off the launch wouldn't you? Or would you lose all the boost if you just dumped the clutch? I have no experience with 2 step. This is why I'm asking.

 

[toyotanos]

The slipping is to keep the momentum in the drivetrain going and also deliver a smoother launch to keep traction vs dumping the clutch. Dumnping the clutch may bog the engine and you lose all that boost you built up. As with everything, this is very much open to interpretation- and I am by no means an expert. This is just based off what I feel when I launched last year.

I'm going to load a couple vids onto youtube, they're going to be rough but understandable

 

[Suprapowaz!(2)]

I've seen MKIV's 2step off the line and dump the shit out of their cars. They launch like a bat out of hell. They don't slip the clutch. So what's the point of having a 2 step to build boost off the line only to slip the clutch to maintain that boost? If you have drag radials, or slicks shouldn't you be able to lauch hard by dumping and keep the boost up? You may be very little wheelspin, but your sticky tires will recover quickly.

 

[hvyman]

2 step you actually have boost built up. Keep the revs up in neutral is not exactly building boost

 

[Albert]

I've always loaded the driveline via handbrake and slipping the clutch. I'll be launching with anti-lag soon

 

[toyotanos]

I've seen MKIV's 2step off the line and dump the shit out of their cars. They launch like a bat out of hell. They don't slip the clutch. So what's the point of having a 2 step to build boost off the line only to slip the clutch to maintain that boost? If you have drag radials, or slicks shouldn't you be able to lauch hard by dumping and keep the boost up? You may be very little wheelspin, but your sticky tires will recover quickly.

Not always, its how you launch. I could dump the clutch at redline with the drags (26x10.5x15 ET streets, heated) and burn through 1st gear, but if I slipped the clutch from 5000 it launched much better and cut a half-second off the ET. If you go 28x12x15/16 full slick then maybe- but they are also race=prepped drag-only cars. Their suspension and drivetrain has been specifically setup to launch under those conditions where our (read: mine and yours) cars' are street cars that go to drag for fun. Not really apples to apples.

 

[Suprapowaz!(2)]

I know what 2 step does. So if your RPM's drop when launching you can lose that built up boost? If you still have to slip the clutch to keep the RPM's up and maintain that boost then what the point of having 2 step? You can slip the clutch off the line and build up boost without a 2step. Granted a 2step will net you boost immediately, but you still have to slip the clutch. That means you're not going any faster than the guy who's slipping his clutch that doesn't have a 2step. By the time you both let off the clutch both guys should have at least 5psi of boost... right?

Or am I completely wrong?

BTW, generally how much boost can you build with a 2step?

 

[Suprapowaz!(2)]

I've always loaded the driveline via handbrake and slipping the clutch. I'll be launching with anti-lag soon

Handbrake holds your car and you don't roll through the lights?

 

[toyotanos]

2-step is nice for getting consistant with your launches- since it determines what RPM the engine will be at- all you have to do is let the clutch out the same (or similar) every time. Its not explicitly for building boost (that's getting into anti-lag kind-of setups, which is what I use) You will launch more conststantly than some dude revving in neutral, but he also doesn't have the boost to begin with (all things equal) so you have a ~5psi leg-up on him.

I used a momentary switch to engage the 2-step, this year I have a toggle switch and the mode is exited/cancelled when a certain speed is reached. I was having trouble synchronizing all the events of building boost, slipping, holding the button, and shifting with consistancy.

2-step takes much more RPM for boost building, where as anti lag takes much less but is harder on your turbo.
Example with my 7M and 67mm turbo:
2-step at 5000 rpm got me ~10 lbs boost
anti-lag with timing retard at 4200 got me 21 lbs boost.

Handbrake holding if so you can start slipping the clutch before the lights g- that way the drivetrain is pre-loaded and you're already slipping for a slightly better launch


Edit:
Video's up, here.
Listen for the slipping and throttle feathering as I launch the car. Even though the street tires didn't grip very well I kept the launch better than it could have been by using the 2-step and slipping the clutch out.

 

[PureDrifter]

not legit until you have a modded slushbox+trans brake

 

[emericaskater285]

Video's up, here.
Listen for the slipping and throttle feathering as I launch the car. Even though the street tires didn't grip very well I kept the launch better than it could have been by using the 2-step and slipping the clutch out.

Hey at least you didn't loose against any of them.

 

[Suprapowaz!(2)]

not legit until you have a modded slushbox+trans brake

I'm leaning towards this. I just don't have the funds to do it right now.