Currently putting together the loom following the diagrams within phatbobs guide, however, can't spot info on rev counter or shiftlight outputs.
Info that might me needed:
I'm running a wasted spark set up on 4 cylinder engine, smiths rev counter previously driven by alpha ecu (it's variable in that I can select from 4-8 cylinders).
Recommendations for each appreciated.
Alex
Rev counter output can be any of the outputs. It's selected through software. I use "Misc 2" or something.
The same goes for the shift light, only this time you can use one of the "Misc out" settings in the software. The same thing applies - it can use any of the physical outputs you have spare.
I'd suggest using the low current ones, check the table near the bottom of the UserGuide
Thanks guys, it's making more sense now, I initially thought they would be dedicated terminals rather than flexible.
Alex
The whole thing is flexable and configurable, its a blessing and curse in equal measure :)
I've added the configuration and wiring of a shiftlight to the UserGuide
http://www.vems.hu/wiki/index.php?page=MembersPage%2FPhatBob%2FUserGuide
Simple when you know how ;)
Trying to get my tacho to work, I've set the output to pin 3 from within megatune (unsure about divider as well?), the tacho I have allows me to select input settings, will any of the following work without needing to use a pull up diode?
Signal input settings:
Contact breaker ignition
Hall effect
ECU (open collector output)
ECU
Alternator
Signal generator
What was driving it on the previously?
Rob
the previous output came from my alpha ecu (currently on ebay :D ) and the tacho was set to hall effect, i've tried this but didn't get a response, either I need to change the divider, the tacho input or most likely both?
The tacho should be set to ECU (open collector) IIRC. The divider can be set when you get some kind of reading on the tacho...
VEMS doesnt put out any voltages (apart from the stepper pins), as it switches to zero.
What hall voltage is it expecting?
What I did the Nissans was to connect a 330ohm resistor between EC36pin28 5V out, and EC36pin3 (P259 ch.4), and EC36pin3 to the tacho. When the VEMS switches pin3 to ground, the voltage drops to zero, at other times you get +5v.
This could just as easily be a +12v supply if thats what the tacho is wanting.
Thanks guys, I'll give the ECU ope collector a go first, if it doesn't work I'll try the resistor option.
re: hall sensor, it can use the positive signal from the hall sensor, I can do this easily but after all the comments about avoiding noise in the system it seems a daft thing to do, I could be wrong though.
<<<What I did the Nissans was to connect a 330ohm resistor between EC36pin28 5V out, and EC36pin3 (P259 ch.4), and EC36pin3 to the tacho. When the VEMS switches pin3 to ground, the voltage drops to zero, at other times you get +5v.
This could just as easily be a +12v supply if thats what the tacho is wanting.>>>
- Could you show me how to do this? Is the resistor value the same 330 ohm? And does this make the 5v supply un-usable to power other functions(launch control switch, fuel pressure sensor)?
Here is my OEM tach info:
Tach +10.8v, 66% DC "on", 3 tach signals per rev.
Thanks!
Kevin
Theres plenty of current available with the 5v supply maybe I'd need to up the resistor value if I wanted to use the ALS,Shiftcut and what have you.
Just wire 12v via say a 1K resistor to the channel rather than the 5v.
Wow I really need to go to sleep before 6 am and not post, I made myself look stupid haha.
I was intending on using a 12v supply for the tach, but I somehow lumped that thought in with wondering if the 5v supply can be used for more than one other pullup input channel at a time.
Can you recommend a resistor setup for using the launch control and the shift cut with the 5v supply?
Thanks,
Kevin
Here you go:
(http://www.vems.co.uk/VEMSUserManual/ConnectingAnalogInput.png)
The configuration details are found in the Using Spare Analog Inputs section of the User Guide:
http://www.vems.hu/wiki/index.php?page=MembersPage%2FPhatBob%2FUserGuide
I did see that and I will say here thanks for the User Guide, it is a life saver!
I was wondering if the Launch Control and the Shift Cut can both be poweed by the Pin 28 +5v supply, and what resistor(s) would be needed. Come to think of it the Launch and Shift would not ever be used at the same time, so that seems a non issue.
Can Launch and ALS both select one channel as an Input? (I think I will be fine with launch only)
For those interested, my Launch and Shift setup would be as follows, I have 2 possible setups:
Setup 1:
Launch Control and Shift Cut on a clutch switch, use the handbrake handle switch to disable Shift Cut while using Launch Control. FWD drag guys use the handbrake to hold the car still at the starting line and to allow pre-loading the clutch to reduce breakage.
- possible issue, driver could release the handbrake first, which would cause the shift cut to enable and shut the engine down. Two possible solutions:
1) A diode(?) on the Launch Control Relay to hold it open for a fraction of a second, in case of early handbrake release (can this be done?, like how OEM ecus hold open injectors after engine shutdown)
2) Use a Misc. Output to allow the shift cut to only occur at high rpm (~1000 short of redline) which would be higher than the startline RPM to avoid conflict.
Setup 2:
Use ALS for Shift Cut, more flexable on/off with better turbo respool using retarded timing and spark cutting. Need to read up on the ALS.
Yes you will need seperate 2k7 resistors to limit the current draw so that you can connect up multiple switches to the various inputs.
You will need two seperate inputs for the Launch control and ALS functions.
I have never used the Launch control, Shift cut or anti-lag as I tend to do NA stuff and those with turbos are not keen on using these due to turbo life expectancy, gearbox issues and what have you.