Link G4+ Launch Control Issue

Hi everyone.

Andrew here, and I am new to this forum & HPA

I am having some launch control issues with my vehicle, details are below

Holden Rodeo TF 1995 model, engine 1JZ, gearbox 2 speed glide, 9" diff, Link Xtreme Black Edt.

I am going to do my very best to explain my current launch control problem...

When engine is under no load, RPM limit set at 4000, ign retard at -5 the car does respond when I push my transbrake button (in neutral just testing) and I get the pop & bang and a little boost is made

When I click the glide into low, hit the transbrake, and change the ign retard to -5 higher up in the table (as its making more boost under load) when 4000rpm limit is hit, I am getting a soft ignition cut, not the pop & bangs - Also it takes around 8 seconds to reach 4000rpm

The Launch is activating in both situations using the transbrake button

I have attached my current tune, I did zero the ign retard table

two log files, one with engine in neutral and one with the gearbox in low gear

Hope someone can help, what have I overlooked here

Just came back from the drags Saturday just gone, and I managed to run an 11.00 @ 129mph

Thank you

So I have been having a think about my question for a couple days now, and I've also purchased the Launch Control Module

Would I be right to turn on Advanced mode Launch Limiting, as when my engine us under load, its not enough to engage the "hard cut" therefor making it quite soft and not building enough boost on the line

Cheers,

In your log that was done with the trans in gear, the ECU is not applying a limit at all until right at the end. This is because you are sitting in an area of your launch RPM table with zeros in it (zero applies no limit). The slow RPM increase when you first go WOT appears to be something like your converter stall too low, there is no cut or limiter being applied by the ECU. The converter appears to grab pretty hard at about 3000RPM then as boost slowly increases due to the load/heat, you make more torque and the converter slowly slips its way to 4000.

I would suggest you change back to single RPM launch mode so you have less variables to play with initially, that will allow you to get the basics such as retard and limiter settings working well before you go adding extra 3D table complexity.

Hi Adam

Thank you for the detailed reply, do you suggest I keep the launch RPM at 3000?

I have been told this converter has a 4000RPM stall

Going to test it out in a hour or so at work, again thanks for the information, this is slowly doing my head in haha..

OK

So I have gone back to single RPM launch, set it and test

The problem I have is when the RPM limit is reached, it kicks it back around 500RPM+ and it has to build back up again...How can I get it not to push it back so far from the RPM limit I have set

See log file and you can see the wave the RPM is doing at RPM limit

What am I doing wrong? Is it possible for someone to alter my tune file I have uploaded on my first post and attach back to me?

I have purchased the Launch Control course and it's main focus is on Manual Transmission, not much help for me with my setup

Thank you

Can you attach the tune file that was in place when the log was done.

Hi Adam

File attached as requested

Thank you

Something doesnt make sense here, the settings in your tune dont reflect what is shown in the log. For instance, your launch limit is set to 4000 with the default limiter settings (200rpm control range), that means it should start limiting at 3800RPM, but the log shows it didnt start limiting until 4700. Also the tune is set to 0deg "absolute" ignition advance, yet the log shows it is still using numbers from the ignition table with a variable launch ignition trim.

So I dont know if you didnt store it when you made these changes or you have posted the wrong tune or wrong log file?? You are also on a very old firmware that Im not familiar with so there is a slim chance could potentially be a problem with that.

I suggest updating to the latest firmware, load that same map in with the single launch RPM mode and do us another log.

Hi Adam

I have updated ECU, flashed with below Basemap (same one as yesterday) and logged it for you

Same issue, with the RPM wave

Do I have something set incorrectly still?

Cheers

At least the data in the log matches your settings now. It looks to me that the torque converter is absorbing most of your torque so as soon as the limiter comes in with the default 60% start cut it falls on its face and the RPM drops too low. So, in the attached file I have reduced the start cut to 20% and brought the launch RPM down to 4200 so it is not leaning on the converter too hard. I have changed the retard mode to single zone for now to take some variables out.

Hi Adam

We have progress, sounded great and did what I have been trying to get it to do. Three log files attached

Made around 13.5/14psi of boost at that RPM and did not take long to get there, around 5 seconds

Couple of questions

- When I am at the drags in the next three weekends, how do I manage to change the amount of boost (more or less for when I leave the line)

- Can that time be shortened also, 5 seconds is great better then 12 to 13 it was on Saturday (a bump box is on the cards, do you recommend any type?)

I dont have much experience with auto's but I think your converter is going to hinder you reaching launch boost quickly. Normally I would expect to have the launch RPM under the point where the converter is stalling but in your case that is somewhere down around 3000RPM so you are going to struggle to make boost down there. You could try dropping the ign trim activation RPM to come in earlier but its hard to tell if that will help or hinder.

As for adjusting how much boost you get, that can be manipulated with retard and to a lesser extent fuel. More retard = higher boost, more fuel = higher boost. On that map above we had no extra fuel and the ignition trim at 5deg "absolute" (fixed 5° BTDC), You can probably go down to around -15deg (15ATDC), and add 10-15% fuel if you want to increase boost.

For bump box the ECU can do that. You just need to connect the transbrake solenoid to the ECU with a solid state relay, then connect that to one of the PWM capable aux outputs (aux 1-8).

Just to get an understanding of the wiring diag. for the Bump & Transbrake and setup in the Link, are you able to confirm the below?

This has just saved me $800AUD

Hi Adam

Does the above look correct to you ?

I have noticed the Haltech ECU needs to have a 1K pull up resistor fitted between terminal 4 & 3, is this the same case with the Link ECU

Cheers

Yes, that wiring is fine, you will not need the pull-up, our ECU's have it builtin.

Im not sure where that picture of the ECU setup came from but there are a couple of mistakes in it. I will attach a new one below, and some notes about how it works.

That picture is of my ECU setup, as DI1 & 2 and AUX1 are already used in my ECU

What were the mistakes I made, so I can correct them?

I've had to use DI4 & 5 and AUX6

Regards,

Andrew

settings in pink below that need to be changed. Also, the 50% "bump DC" and the 0.01s increament are purposely set very conservatiive - it may not even feel like the bump is working with those settings. The last time I helped someone set this up the DC was more like 25% and the increament was more like 0.1sec from memory.

Thanks for the information, I will be wiring this up over weekend and will report back