linkg4+ latched launch control settings 2JZ

[Phil2JZ]

Hey team 

Im after some basic settings to start with for the "Latched launch control" feature.

ive wired my handbrake switch to activate the launch control on digital input 2

2jzgte S15 with a precision 6266 on e85

This is mainly for Brisbane roll racing events. 

Need to control rpm to stay on 40kph in second gear and some positive boost pressure so it takes off strait away. (not too much though as it will effect traction)

If i could get a basic settings list to start from that would be amazing.

thanks 

 

[Phil2JZ]

https://www.dropbox.com/sh/ox6r1m2hwvssje2/AACLCKKiH1JJjcXXNFyCTQCsa?dl=0

[Adamw]

So you are going to pull your handbrake up at 40kmh?  A button on the steering wheel may be better. 

[Phil2JZ]

Yea im happy to pull the had brake up to engage the switch input. it only takes a very small amount of travel and does not even start to engage the rear brakes in this small amount of travel. its very easy to feel the brake shoe engagement point and stay away from it.

wanted to use this and fine tune the latched launch control feature. then if in the future i want to move it to the steering wheel, its an easy mod.

ive searched the forums and online for more info but it doesn't seem that easy to find detailed info on the LINK latched launch control setup

 

Would love some basic setting to start from. No one better to ask than MR link him self.

[Adamw]

Start with something like below.  Add more retard and turn on the fuel trim table if you dont achieve the boost you want.  Make the limit range smaller for a more aggressive limiter or bigger for a smoother limit.

[Phil2JZ]

thanks Adam, ill test it out this week. 

[K3rm1tTh3Fr0g]

Would it still be advisable to trim -30 degrees of timing on a for example a 2.0L motor? 

Based on other rolling anti lag maps I've seen, the timing isn't retarded quite to that extent. 

Thanks. 

[Adamw]

In the example I gave above I have the retard mode set to degrees (not degrees absolute), so that "-30" means it will subtract 30deg from your normal commanded timing.  So if you normally had 25deg at 5psi boost then your timing would be 5ATDC with launch enabled at the same pressure.  

You can use the retard to influence the level of boost that is achieved during the latched launch limiting.  More retard = higher boost.   Positive fuel trim = more boost, more aggressive limiter = more boost.    

[K3rm1tTh3Fr0g]

Thank you for that distinction regarding retard vs absolute degrees.

Is it safe to say those guidelines regarding latched launch retard hold true when tuning normal launch control from a stop as well? Meaning would latched launch control and single launch control both call for a similar/same amount of retard and or fueling in those two different situations given you are comparing the same engine?

I was planning for standard launch control to start with retarding launch timing in -5 degree increments to see how if affects boost.

[Adamw]

The same fundamentals apply but the strategy used will vary a lot depending on the car and discipline.  Typically you will be more traction limited from a standing start than a rolling start so there will likely be set up differences, you may need lower boost, and/or lower RPM and/or a slower decay etc.