2 Step? What Is It?

ECU, Wiring, Sensors
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2 Step? What Is It?

By vince72310
- Mon Jul 27, 2015 8:30 pm #354966 can someone explain to me what really is 2 step and its purpose? I know it gives you a rev limiter but is that it? can it make your car backfire? does it make you launch at a complete stop? :?

Shed some light on me :thumb:
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By Loaf31
- Tue Jul 28, 2015 12:05 am #354972 This is just what I've come to know it as and correct me if I'm wrong, but I think it's basically a chip you put in the Ecu that gives you a rev limiter, sometimes makes you backfire, and then when you let your foot off the clutch, you launch at your desired rpm. Correct me if I'm wrong guys :?
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By TrailerTrash
- Tue Jul 28, 2015 1:39 am #354974 a 2 step is a 2 step rev limiter.

basically it adds a limiter at a lower rpm that makes launching consistent.

depending on what engine management you have you can set it on a switch, on the clutch pedal, ect.
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By EconoBox
- Tue Jul 28, 2015 1:59 pm #354988
TrailerTrash wrote:a 2 step is a 2 step rev limiter.

basically it adds a limiter at a lower rpm that makes launching consistent.

depending on what engine management you have you can set it on a switch, on the clutch pedal, ect.


^ yep

Its an adjustable lower rev limiter added by your engine management it is typically active under a certain mph or when activated by a switch. It can be set at a point where your car launches best from to provide consistent launches at the track. A lot of people use it for the cool sound/backfire you can get when being a ricer showing off at meets. It can also be setup on turbo charged cars as a way to have boost pressure on launch, its what you are hearing when you see those badass Supra and GTR videos on instagram where they are shooting flames bouncing on this rev limiter.
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By ohDirka
- Wed Jul 29, 2015 1:47 pm #355028
EconoBox wrote:
TrailerTrash wrote:a 2 step is a 2 step rev limiter.

basically it adds a limiter at a lower rpm that makes launching consistent.

depending on what engine management you have you can set it on a switch, on the clutch pedal, ect.


It can also be setup on turbo charged cars as a way to have boost pressure on launch, its what you are hearing when you see those badass Supra and GTR videos on instagram where they are shooting flames bouncing on this rev limiter.


Not to be confused with anti-lag though. Rally cars (and other race cars for that matter) have a switch that changes the mapping of the ECU. This changes the timing so it keeps the exhaust valves open a little longer when off throttle so the expansive gasses keep the turbo spinning when off throttle. This way you have full boost when off the gas.

It is very rough on both the turbo and the exhaust valves from what I've heard.
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By EconoBox
- Wed Jul 29, 2015 2:26 pm #355029 That is correct 2 step is not anti-lag.

I'll break it down a little more since I have some free time. There isn't anything complicated to explain about a 2-step launch rev-limiter. The true antilag stuff has all sorts of stuff you can look up. I gave some basic explanations of why people say its bad for turbochargers and valves. You can look up all the stuff on secondary air injections and throttle bypass systems if you find yourself wanting to know more.

2-step rev-limiter:
Typically used for launch control on N/A cars. It is a second low end rev-limiter that is set in your engine management. It usually turns off a set mph or can be activated-deactivated by a switch. This is a driving aid to help get consistent launches.

Video of a Civic with a regular 2-step.
https://www.youtube.com/watch?v=AdH6MElplKA


Burn out rev limiter:
A lot of drag racing guys add a 3rd rev limiter activated by a switch to limit RPMs while doing their burnout before each pass. Its just less things for the driver to worry about to get consistent burnouts.

SFWD Honda dragster doing a burnout. Probably using some time of burnout rev limiter.
https://www.youtube.com/watch?v=KGPHxKhcH24

2 step antilag/launch control:
Operates the same way as your standard 2 step system but has additional parameters to adjust timing and fuel. With added fuel and retarded ignition timing the engine allows heated exhaust gasses to leave the engine by simulating load. This spools your turbo before launching. When used properly it is a great tool for drag racers to have consistent launches and no 'lag'. This can generate a lot of heat in the exhaust side of a turbo charger. If you don't know what you are doing or it is used excessively it can build up enough heat to cause damage to the turbo charger or engine.

Supra using 2-step antilag to launch/ roast the tires down the street
https://www.youtube.com/watch?v=TAAvTplSzJE


Antilag
There are multiple type of anti-lag. But the general idea is they keep air and heat moving through the turbocharger to keep boost up between shifts and while off throttle in rally cars so there is a less noticeable lag under those conditions and more immediate power when getting back on the throttle. These Rally style antilag systems can overspool turbochargers exceeding their mechanical limits and they also have the head issues listed in the above launch control antilag.

Watch until the white EVO slows into the corner that popping/backfiring is the rally style antilag. Probably a secondary air injection system.
https://www.youtube.com/watch?v=gCjubttEvWo
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By TrailerTrash
- Thu Aug 13, 2015 3:10 am #355280 :headbang: :headbang: :headbang:
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