MicroSquirt.com read only forum (Jan.15,2018)

Hi,

Recently purchased a microsquirt V3 and was not able to procure a relay board, as I was told B&G aren't manufacturing them at present. What options does this leave me for things such as fan control, water injection etc. Of course, these require relay operation. Is it as simple as buying a standard automotive relay, and wiring it up?

Thanks.

anonymous.shyster wrote:...Is it as simple as buying a standard automotive relay, and wiring it up?

I think this is covered in documentation, but for fan control a relay works for me.

In some of the documentation, it looks like they've got resistors wired in with the relays. Can't find it now. I'm assuming it's as simple as running a wire from the MS to a fuse that ends up on the solenoid end of the relay?

I'm going to prototype for a weather-tight relay board that includes 2 or 4 relays, and Type-II circuit breakers (self-reset after power is removed). Would you like to be a tester?

Product info - http://www.ttrignition.com/rugged-efi.html

Thanks for the offer, I'll consider it. Do you have photos? I just need to know how many relays I need. Need a main relay (+1)
I'd like to have fan control (+1)
Water injection control (+1)
Intercooler water pump (+1) so it isn't always running

That's four. I can probably get away without wiring the fuel pump up to the MS, since I'm using carburettors. So four may do, if I haven't forgot anything. :/

I've attached a pic (shamelessly stolen from Jean Belanger's site - http://www.jbperf.com) of the enclosure in his hand to give a sense of size, and I've uploaded a basic wiring diagram on the site (attached below). The -B model has the 4 relays - main, fuel pump, Spare1 and Spare2. The only issue I see is that the two 'spare' relays are powered by the 'fuel' relay; while each relay can be turned on or off independently, cutting the 'fuel' relay chops the other two. In an EFI situation, that's probably a good thing; in your situation, it might be annoying.
Hmmm ... I might wire a jumper to the 'main' output; that way the spares would be ... Nope. That would bypass the 'fuel' relay, and everything downstream of it would be powered when the 'main' relay comes on. Hmph.

Ok, that was easier than I thought. Presenting - the 'C' (carburetor) model, with the two 'spare' relays activated independently of the 'fuel pump' relay. The PWM option is also deleted.

Looks promising, so can it fit inside the Microsquirt enclosure? I'm guessing not since it has a huge connector on it?

There's no room for just about ANYTHING in a uS enclosure - they are VERY tight. No, this is a stand-alone (beside?) unit. The relay board you were contemplating earlier was also a stand-alone. Actually, it was almost big enough to fit the uS inside itself!

Not trying to hijack my own thread, but I am just going over what current things draw to see if it's suitable and I got to thinking about how things can be triggered etc. Here's a scenario, can someone tell me if this is possible?

Intercooler fan and pump is turned on and off depending on the intercooler (water to air) coolant temperature. If the coolant (non-glycol) gets to a temperature 7C above ambient the fan and pump are running OR if the throttle exceeds a threshold (1/2) it will also come on. The fan and pump are turned off again after another threshold has been reached, i.e temperature is now 5C above ambient. I'd like to able to do this, it does sound efficient, doesn't it?