Megasquirt users thread to discuss all things Squirty

[TTV8RA23]

Thankyou very much! Can anyone offer any info on dwell times for distributor ignition using a IGN1A coil off DIYautotune? They say 2.5ms for coil per plug application and "a bit less" for my style of system. Doesnt really help as i dont know what a bit less is. For a (low compression factory) old 18rgeu i should be able to get away with 1.5ms and still have a very healthy spark yes?
Cheers guys sorry for the noob questions.
Simon

[The Witzl]

dude.. when you get my MSQ files tomorrow, you can see all my configurations and go from there, including dwell, and everything else.
I was using a single bosch MEC712 coil (iirc), and it worked very well, i dare say your coil you are using will work well too.

Also, i was using the on-baord VB921 iGBt ignition driver as the ignitor for the coil. Have you got the on board ignition driver installed on your MS pcb, otherwise youll need an external ignitor of some kind.

I'll put more detail up tomorrow bro, and more in my email to you.

[TTV8RA23]

Oh yep sweet as Witzl i look forward to pouring over it. The coil i have has the built in ignitor doowacky, so the folks at DIYAUTOTUNE tell me so i didnt need to do that mod.
Cheers
Simon

[stidnam]

Quick question on trigger wheels. I am working on the trigger wheel on my crank pulley and want to know if there will be issues with interference with the wheel size I have. The diameter of the wheel (top of of teeth to top of teeth) is 130mm, the diameter of the valley to valley is 119mm, and the crank pulley is 121mm diameter.

This give me a 1mm overlap of the crank pulley. The teeth are 5.5mm high so that leaves 4.5mm free of the crank pulley for the teeth. Is this sufficient or will I likely get interference issues? I will be using a hall sensor with this setup.

I am thinking not but don't want to fit this wheel and the find out that I need a larger one.

The angle of the pic makes the overlap look larger than it really is btw.

[The Witzl]

get the extra 1mm machined down - problem solved?

Still, i think a 4.5mm difference is enough for the sensor to pick it up.


BTW - how can you be using a hall sensor? They are designed to detect a break in the magnetic field between the hall sensor and a permanent magnet

This is how a hall effect sensor normally works:




I think you mean a VR sensor, such as this:




Does your sensor have 2 or 3 wires?

[The Witzl]

just to add some info....

if your sensor has 3 wires - it is most likely a hall effect sensor, with the 3 wires being:
- POWER (+)
- EARTH (-)
- Signal (pulse)

there are some sensors that use some internal trickery to do the same thing as a hall effect sensor, without needing a vane to pass through the magnetic field per-se.
These sensors might otherwise look like a VR sensor....

So yeah, it can be confusing.

[stidnam]

Nope its a 3 wire hall effect gear tooth sensor like below



These have a magnet inside the body and the flux density of the permanent magnet alters when approached by ferrous metal (ie teeth on tigger wheel).

Taking the 1mm off is not a desired approach so I'll avoid that.

[The Witzl]

Nice little sensor.... where did you pick it up from, and how much for?
I currently have a VR sensor for my 36-1 trigger wheel, but wouldnt mind keeping the option open for hall effect like yours.


WRT to machining down the 1mm on the crank puller.... whats the problem with doing that? I had two complete belt ribs removed from mine so that I could add the 36-1 trigger wheel.
I kinda went the oposite way to you - mine ended up too big (i didnt measure so good when i ordered from http://www.trigger-wheels.com/store/ )


Here's my 36-1 crank trigger setup.
Note to others..... measure twice, fuckup less.

There is a very handy spot on the 18RG timing case to make up a bracket for mounting the crank sensor.... see below.




... and here's what JMR did to the 18RG crank pulley and the trigger wheel to make them fit together so well.
- machined out the inside of the trigger wheel on laithe, and added a "Step"
- machined off the outer two belt grooves from the crank pulley, and made a matching shoulder for the trigger wheel to mate with
- drilled and tapped locating bolts to secure

[o_man_ra23]

I see you didn't make your bracket adjustable. Was this from your aforementioned learned lesson?? IE, you measured twice this time?? Or did you simply fuck up a few brackets to get to this one?

[The Witzl]

I fucked up measuring the diameter of the crank pulley, and as such ordered a trigger wheel with a larger diameter than what i needed.

The non-adjustable bracket means no chance of sensor moving over time and fucking up the signal.
This is a lesson from the experience of others - both JMR and Silverwater Auto recommended making a non-adjustable bracket for the sensor, because they have seen many people have signal issues dues to their adjustable brackets adjusting themselves over time (due to engine vibrations).

I got JMR to make the sensor bracket at the same time as putting the trigger wheel on the crank pulley, to ensure it was all perfect.

[stidnam]

The sensor you can get from diyautotune.com for $34 USD + postage. There is also a honeywell sensor (1GT101DC) that looks identical that you can use. It was linked to on this thread for a local source of the honeywell sensor but they may even be the same thing.

The trigger wheel was purchased as I was going to remove the front pulley grove and heat fit it on but I now want to run air-conditioning so the groove stays and will not be modified.

[thechuckster]

fwiw: you can shim up the gap between sensor and mount to provide some level of adjustability.

[TTV8RA23]

Still havent got my MS talking to my laptop, What sort of cords is everyone using to link them up? Can the MS be setup not in the car with no 12v feed to it?
Cheers
Simon

[thechuckster]

Simon: get a stim kit so you can drive the ECU on the bench.

Also, what are you using to connect to it (assuming you have one of the earlier models with serial-only port) - some USB to serial adaptors are shite.

[TTV8RA23]

Thanks for your reply.
Its an MS2.2 with 3.57pcb so i didnt think it was that old. It has two plugs on the one side one serial and another wider one. Yea this is just a wee plug with serial on one end and you plug ya usb into the back of it then the other end into ya laptop.

I will google what a stim kit is. I have a guys number who is a bit of a whizz with these im contemplating just sending it to him and say make it work for my motor so all ill have to do is set base timing and go. Im such an ammeture with this shit. I can build a whole car on the mechanical side and wire the basic stuff but ECUs etc just fuck me up. I do need to learn a bit more about them though as i have alot of life ahead of me and im fucked if ill ever be putting a carby on any of my projects.
Simon