Help Needed - Arduino Water Meth Injection Controller

[L67PSI]

Hi all,

I'm looking for someone who is good with Arduino coding to help make a water meth injection controller.

What I've got in mind is a progressive system, that ramps up to full pressure. Yes, I know you can buy them off the shelf, but would like to learn more about coding and DIY stuff is always fun.

Planning on fitting to a VT L67, so was going to use a 2 bar map sensor and use the map 0-5 volt signal as input, then use PWM on the output, with a DC solid state relay to the injection pump.

I had in mind being able to set the start point. eg 5psi @ 20% flow then 10psi @ 100% max.

Does this sound feasible??

Thanks

[festy]

Yeah, that should be pretty straightforward to build.
Any reason why you wouldn't just use a FET instead of the SSR?

[L67PSI]

Would a Mosfet we able to handle the current of the water meth pump? I think it will draw approx 10 amps.

[festy]

Yeah, as long as you used something appropriate.
A 2n7002 isn't going to cut it here

Have a look at the IRL540 as an example, its a logic level FET (so can be driven directly from an arduino i/o pin) and is rated at 100V and 28A - and they're dirt cheap too.

[VL400]

Would a Mosfet we able to handle the current of the water meth pump? I think it will draw approx 10 amps.

A SSR normally uses a MOSFET, more than capable of the task and ideally suited as festy suggested

Dont bother with a cheap SSR found on ebay either. They are really poor when it comes to PWM switching speed and heat.

[L67PSI]

Thanks for the tip guys

[L67PSI]

Would the Mosfet need some form of cooling?

[festy]

Yes it will.
My quick (and probably very inaccurate) calc for the IRL540 says you'll need to dissipate up to 10w worst case.
With no heatsink the FET will increase in temp 62*C per watt, so would exceed its maximum operating temp of 175*C pretty quickly.

If you used a heatsink like this one - https://www.jaycar.com.au/heavy-duty-to ... e/p/HH8526 it should keep it from letting the smoke out, but a larger heatsink would be better.
What's the intended use though? If it's for 1/4 drags then you could get away with a smaller heatsink than if it was for everyday driving when it could be switching for hours on end.

[L67PSI]

Yes, would be on street car.

Thanks for the link to heatsink.