Launch Control Spark or Fuel Cut

[dazjb]

My ECU has a launch control option which im going to be wiring in tomorrow. Which is the best option for the VR4 engine, spark cut or fuel cut?

These are the options I can play with on the ECU ...

EMU Launch Control Settings.jpg

I was going to just leave it as 100% spark cut but have been reading that this can be bad for the turbos and exhaust system + can create excessive cylinder wall wash


Cheers

[Davezj]

Now I am not 100%. sure about this but believe point of launch control is you get a rpm limit when you mash your foot to the floor and the timing is retarded massively so the spark occurs when the exhaust valve is open and this make the explosion spool up the turbos giving you boost before you have moved off the line. When you drop the clutch and the car starts to move the launch control is disabled and you rocket off the line.
So to get the turbos to spool when you are on the stationary rev limit you would have to set the ignition retard to about -10 -12 degrees. Well something like that value.

Unfortunately I don't know which option you should use to limit the RPM.

Sent from my space-aged gizmo

[dazjb]

Cheers Dave. It's Activation RPM to limit the revs and Ignition Retard for the timing. I've got a good idea what all the settings are for in the ECU I just wanted to know whether it's best to cut fuel or spark as I can do either. Or even just partial cuts if i need to via Fuel Enrichment and Spark Cut Percent tabs

[Davezj]

on the standard ecu when load gets too high when turning up the boost on a standard factory car the limit is caused by the ecu cutting fuel. although it is more of a fuel cut wait 2 seconds re enable the fuel. not a fuel cut, fuel back fuel cut fuel back on 4 or 5 times a second.

but if mitsubishi use fuel cut then you would probably be safe to do the same.

i do't know but this is just a guess from me.

[adaxo]

Not sure myself but I would imagine you dont want to cut spark but still pump lots of fuel then bring back spark imo will either cause massive bang or stall flooded engine.
So I would say cut fuel.