Launch control

[vinkev]

Can anyone tell me which is the best selection in the rev limit mode for the launch control so I don't make any damage to the turbo and valve train components. Today I tried IGN hard and soft, I noticed that when I activated the launch control the A/F goes to lean. Is it normal ?? I am using the launch control on a Subaru STI 1999 with a PNP 1.99 chip. I appreciate if someone can help me.

[Wroom]

Since it is SMD v1.99 we are talking about twostep launch?

I will take this in two steps. And that is not because it is a "twostep". ;)

1)
If you don't want to build boost on launch then you can use "Inj H" to cut. With a rev limit range of about 50-200 rpm.
Same applies if you have a catalythic converter in the exhaust.

But if you want to build boost, and also have a good cut for normal overrev limit you should use "Inj S-H & Ign H" with a rev limit range of about 10-50 rpm. Put in a 1,152 or similar value in the W-U Enrichment Table at 120 degrees on boost to add some fuel. Be aware the exhaust will act similar to a Haubits gun when launching. ;)
This gives an impressive, yet pretty safe launch on boost.

If using "Ign H" to cut, the plugs will foil up almost immediately on launch.


2)
The impreza have rather long runners as it is a boxer. Please be aware that ALS and Launch with large exhaust bangs on theese engines will put a severe stress on the runners, turbo and exhaust valves, because of the large volume in the runners between the exhaust valve and the turbo. Also, earlier Impreza engines have outer shim tappets, where the shim has on occations come off during ALS. Inner shim tappets, or better shimless tappets, as from models 2004- STI do not have this problem, but the large volume runners still demand that one is carefull with aggressive ALS and launch.

To be safe - Use "Inj H"-cut for Launch.