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-   -   2 step? (https://www.homemadeturbo.com/engine-management-10/2-step-81110/)

fuse 08-07-2007 12:10 AM

2 step?
 
Researching what 2 stepping a turbo is. Searched this site found a little. So some one correct me if im wrong. 2 stepping a turbo retards the ignition timing so fare that you have a lot of pressure build in the exhaust manifold thus spinning your turbo for a good launch. I have also heard something about a spark plug in the exhaust manifold igniting a rich air fuel mixture on decal (Rally Cars).

may questions
1. Did I get any of this rite?
2. Is 2 stepping damaging to any thing (exhaust valve, turbo, exhaust manifold)?
3. Is it only stand alone systems that have this function or are there any eeprom chips, piggy back systems that have this?
4. Will this just help boost of the line or will the turbo stay spooled all the way down the track?

Any help is greatly appreciated. This site is looks bad ass.

Chris Harris 08-07-2007 12:19 AM

Re: 2 step?
 
2 Step is more or less launch control

What you are thinking of is boost building or antilag. Yes, it can shorten the life of a turbo and make your exhaust valves crispy.

fuse 08-07-2007 12:27 AM

Re: 2 step?
 
Ya just studying for the future. So it just for a nice launch sounds like its not worth it considering the damage it can do. Do you have 2 step how dose it feel like a nice launch and then a dead spot till the turbo spools back up.


Is the boost builder or antilag the one with the spark plug in the manifold.

Confused?

Eville140 08-07-2007 10:31 AM

Re: 2 step?
 
2-step normally cuts spark, but on a turbo application pulling timing at the same time helps build boost. As long as you are not expecting your turbo to last 150,000 miles I doubt it is going to hurt it to much, not good for it though.
When the spark is cut the unburnt gas is pushed into the exhaust manifold and then the next cylinder that fires lights off the mixture. The manifold turns into the combustion chamber and the turbine wheel kind of the piston. Retarding the timing helps get more unburnt fuel into the manifold and also helps light it off.
It doesn't take much to be able to leave the line with full boost.

Launching off the two-step
http://www.eville140.com/video/1088.wmv

testing the 2-step on my present car
http://www.eville140.com/video/2step.wmv



lock-pop! 08-07-2007 05:59 PM

Re: 2 step?
 
good to see a dude that likes old schools on this site. i had a starlet but my dad sold it. also had a 74 mango. dad sold that too. i guess i shouldnt leave anymore cars at his house!!!

fuse 08-07-2007 08:24 PM

Re: 2 step?
 
Nice ok I think I get it. So you are back firing in your exhaust to spool the turbo (all the popping). How may cylinders will it cut spark on 2 out of 4. So lets say you have a Honda your firing order is 1-3-4-2 would it cut spark to 1 and 4 and retard timing on 3 and 2 (every other cylinder in the firing order). What ignites the mixture the retarded timing or a hot exhaust manifold.

Sorry I get how it works now but still want to know more.


zccr-xsi 08-07-2007 09:19 PM

Re: 2 step?
 
all it does it help u get your luanchs consitent so u can take off at the same rpm eveytime.being consitent is what wins races.

its done by ehtier fuel or ingtion,most likely if u have a msd box it is a ingtion cut,99% of chipped ecus use fuel cut.i highly duobt ethier one will hurt or motor.i would think racing it will hurt it more then the 2 step will. and as for a turbo going to 150k miles of hard use i would pay to see that.eville140 what editor are u using and where is it set at?

fuse 08-07-2007 11:46 PM

Re: 2 step?
 
Again just studying (do not have 2 step yet). Ok did more research on the web I think I under stand now thank for all your help everyone. A 2 step is 1 used for building boost with now load on the engine by retarding timing and burning fuel in you exhaust manifold spinning the turbo and 2 creating a rev limiter at launch so you launch at the same rpm (to prevent tire spinning).

What I have found is the 2 step is turned off by the vss (moving forward). So if you are at the line not moving you can 2 step. When you start moving the 2 step turns off. I also found it can be turned off or on by a switch at the clutch pedal.

At least I think I understand.

zccr-xsi you have confused me once again by saying fuel cut (this goes against everything I have learned so far) Did you maybe mean fuel enrichment? Fuel cut means lean=heat and plugs burning up and or pistons. So vary confused again sort of. LOL Plus if you are lean how is the extra fuel going to burn in the exhaust manifold?

zccr-xsi 08-08-2007 09:48 PM

Re: 2 step?
 
comeon guys someone help me out here with this guy!

Chris Harris 08-08-2007 11:19 PM

Re: 2 step?
 
Fuel cut means cutting ALL fuel...cutting ALL fuel means no boom boom can happen. Perfectly safe...

2 step or sometimes 3 step (hondata) is called that because it is 2 or three separate rev limiters...all with CONDITIONAL cases.

yes, generally the launch rev limit holds you on the line based on your VSS...if you are under the point you set the VSS launch at, it will hold you at that particular rev limiter until you pass and meet the condition (IE >6 mph)

the 3rd step in 3 step would be Full Throttle Shift...figure that one out.


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