[G4x to control isolation relay?]

OK, so that gets kinda messy and complex.

My original plan was to not worry about the run-down (just use a normal latch/reset circuit on the relay and a "Kill" signal to the ECU, which admittedly still involves running battery power to the switches).

To handle the alternator dump, I can use a relay to dump everything into a 3ohm relay (like a mechanical isolator), but a tidier alternative seems to be a TVS diode. Seems to be what the OEM would use for this situation - presents a very high resistance up to a 'breakdown' voltage, where they go to almost zero resistance (IE, keep the alternator from producing a voltage spike by dumping it to earth)

A couple of SLD16-018 would seem to be the correct thing - but I'd really appreciate any guidance.

[G4x to control isolation relay?]

4 hours ago, Adamw said:

In your existing drawing the coil for the isolation relay wont have 12V until the relay contacts are closed so it would never turn on. 

 

Ah, whoops. Foolish. Yes, it should be linked on the other side (to Bat+)

4 hours ago, Adamw said:

I havent thought through all scenarios in detail but you could possibly have the relay coil connected directly to batt+ if you have a spare ignition or injector output to use instead of the aux.   

I'm using all the Ignition and Injector drivers, but why not use an Aux? The relay coil will certainly be less than 3A

[G4x to control isolation relay?]

Following on from an earlier post, I’ve got a G4x (Xtremex) coming for my track car. In the process of sorting out the wiring, but it occurred to me that should be able to control the “kill” relay. Basically, I want the ECU to hold the relay in unless there is a monetary break in a +12v signal – in which case it should kill the engine, and release the relay as soon as the RPM is low enough to minimise the risk of alternator-induced voltage spike.

Appreciate any input…

 

Apologies for the crude diagram attached, but broadly:

• Isolation relay shown kills the main power to everything from the battery.
• Momentary “On” button brings the relay to life, after which power flows to the ECU etc
• 12v is sent through 2x NC pushbuttons to a digital input (say, D1) – this input is always live unless a button is pressed
• (some logic) is set so a momentary break in this input is maintained
• ECU output (say, Aux1) is set to hold the relay in according to the logic block below.
• As soon as the output is released, the relay opens and power is cut to everything

 

The logic controlling output Aux1 would look something like:

Aux1

OFF if

Killswitch

AND

RPM<100

 

Kill switch:

Latch If D1 voltage goes below 10v for more than 0.1 seconds

Shutdown process:

If Killswitch

Shutdown engine immediately.

[Link ECU for an LS1 track car (long post)]

Not currently - just for logging. I'm still using the GM LS1 ECU, but when I upgrade I'll certainly implement TC.

If you get tripped up by anything, I might have archived some document or another.

[Link ECU for an LS1 track car (long post)]

Hi mate,

Not sure if it's the same one, but attached is one I found somewhere else - might be enough to get you going. I also have a sheet from Motec with configuration info for different DBW throttle bodies, if you know what you're going to use. Assume the configuration info will also be usable for Link.

Attached also some information about the MK60 CAN, if you don't already have? Disclaimer that I haven't used this, just archived it when I saw it. Pretty sure it came from https://www.bimmerforums.com/forum/showthread.php?1768248-Teves-Mk-60-as-stand-alone-ABS

I ended up wiring the speed outputs from the MK60 directly to the digital inputs on the (motec) dash - works perfectly, but puts out 48 pulses/rev, so you need a fairly fast input. Also tapped the pressure output from the sensors to get F/R brake pressure.

971816740_LS3Labrat.pclx CAN Matrix Motorsport Bremse VW Audi english.docx Mk60e5_pinout.xlsx

[Link ECU for an LS1 track car (long post)]

Thanks for the extensive reply Adam, that's really helpful. The only outstanding question - is single-bank Lambda sufficient?

 

On 9/15/2022 at 6:24 PM, Adamw said:

The XtremeX is probably what I would go for.  Direct spark is not really an advantage over wasted with G4X, with an engine like this, you can still do individual cylinder knock control etc even with wasted spark.  Direct spark becomes more important for high reving engines where you run out of cycle time to dwell the coil twice per cycle for wasted spark.  The advantage of the Xtreme over the Fury is a couple of extra analog inputs which can be a precious commodity.  

I dont personally have an LS1 map, I could give you the map out of our LS3 track car that will be a good starting point.

That would be a great starting point, and I'd be interested in any other information about the build - is it written up anywhere? If you've got a wiring pinout from the car (or a even better, a diagram), that would be much appreciated, too.

I probably don't have a shortage of inputs - the dash has 2x temp/4analog, and the PDM has another 16 analog. Most of them will be unused once the ECU is reporting engine parameters over CAN. So maybe the Fury (unless there are other drawbacks?) would be handy (to have Lambda on both banks, at least in the future)

With the knock control - do you have any starting points on using the factory sensors for knock control?

On 9/15/2022 at 6:24 PM, Adamw said:

Launch is pretty easy, traction can be a quite a bit of work - firstly to get the control loop tuned well enough to achieve your desired slip quickly under a wide range of conditions - then lots of trial and error to find how much slip works best for your  application and driving style.

Thank you - it's mostly a thing to experiment with, the car's very controllable without it.

 

On 9/15/2022 at 6:24 PM, Adamw said:

You can do flat shifting no worries without a gear pos sensor.  If its a syncho box you may not get a lot of advantage from it.  If you mean rev-matching for downshift then you will need DBW for that.  Again gear pos is not needed, the ecu can determine what gear it is in from the speed/RPM calculation, it will index the calculated gear from the gear you are shifting out of as soon as the start shift signal is received and hold that until the shift end conditions are met, so it doesnt matter if the disengaged clutch messes up the ratio calc during the shift. 

Makes sense. Is it a simple blip, or does the ECU match the rpm based on the predicted gear and the ground speed?

 

On 9/15/2022 at 6:24 PM, Adamw said:

DBW is certainly a nice option.  With our LS3 track car for example it has a lot of torque and is a real handful to drive - so we have speed on one axis of the throttle target table so the throttle only opens to max of say 50% at low speeds and progressively gives you more torque as speed increases.  This also makes it much nicer to drive at low speeds in the pits etc as the throttle is much less sensitive.  Isnt there a factory LS1 DBW manifold/throttle body?

Sold. There are factory LS1/LS6 DBW arrangements, but they're a similar price to an 82mm bosch unit (albeit without the fabrication).

 

On 9/15/2022 at 6:24 PM, Adamw said:

Either is fine.  CAN is only 2 wires so is prob the easiest option if you ghave the data ID's and format.  I think I do for one of the BMW ABS systems which is probably the same. 

Ahhh, the wheel speeds (and front/rear brake pressure) are available on CAN from the Motec dash (IE, I will configure output messages). The MK60 unit does output wheel speed on CAN, but requires a 'black box' to clear the error messages first (I believe). If you've got any more info on this, I'm all ears!

I assume the CAN in the ECU is fully configurable in terms of being able to define custom receive/transmit channels and assign them to variables?

 

 

[Link ECU for an LS1 track car (long post)]

Hi, and apologies in advance for the long post – I’ve tried to condense my questions into one post.

I’ve got an LS1 powered Silvia as a track/hillclimb car – I’ve been running it for a few years and upgrading various things in the process. I’ve recently started on the various electrical and logging systems – so far I’ve installed and configured:

·         MK60 ABS system

·         ECUmaster PMU16

·         Motec CDL3 dash (with a Motec SLM and GPS)

·         Motec Lambda-to-CAN (single channel)

·         CAN Checked MCE18 (CAN input module)

I’ve left the ECU to last, mostly because it works OK with the factory ECU and I’ve been able to do the rest without missing any events.

I’m leaning towards a G4x (probably an XtremeX?) – the other option is Motec, but (price aside), it seems like Link have a much more open and helpful culture.

Features like launch control and traction control are one of the key reasons, as well as being able to communicate over CAN with the rest of the hardware – it’s frustrating not having access to a lot of the ECU data. I’m also having irritating drivability issues with the OEM ECU, particularly around idle and pit-speed driving (which can probably be solved with tuning, but it’s frustrating not being able to adjust things myself)

So, preliminary questions:

• ·         Is there significant advantage with sequential ignition, or should I consider a FuryX with the built-in Lambda?

• ·         Does anyone have a start-up or base map for an LS1? The engine is mostly stock except for a VCM710 cam, LS7 lifters and some general cleanup and porting (with a bit of extra compression)

• ·         Flat-shift/rev-matching (with a T56 H-pattern) – I’ve read a couple of posts on the Link forum – is there an established method to get nice results with only brake/clutch inputs, or does it really need gear-position sensors to work properly?

• ·         Traction/launch control – how fiddly are these to implement? Is there a base set of parameters that works reasonably well?

For hardware, I’d appreciate some feedback on the below:

• ·         Is it worth changing from a cable throttle to DBW? I like the apparent simplicity, and it seems like the smoothest way to implement TC/Launch control/Idle. If so, is an 82mm Bosch motorsport unit/bosch pedal the right choice?

• ·         Knock sensors – any advantage to fitting Bosch motorsport sensors instead of the OEM LS1 units?

• ·         Injectors – Is it worth upgrading to a more modern unit?

• ·         Lambda – I’ve got the left bank with the Motec unit, is this sufficient/acceptable for closed-loop tuning?

• ·         Temp/pressure – I was intending to monitor fuel, coolant and oil with bosch combined pressure/temp units – seem reasonable?

• ·         Wheel speed – I have 4-wheel speed into the dash at the moment (output as a 5v squarewave by the ABS unit. 48pulses/rev) – I can transmit over CAN, or send the input straight to the ECU?

I’ll retain the OEM sensors/parts for the below, unless they should be changed?

• ·         MAP sensor

• ·         Intake temp sensor

• ·         Crank/cam position

• ·         Coils

 Cheers,

-Robin