Solenoid controls on mechanical devices

[callard]

I've got mechanical fuel injection on my engine and am wondering if I can activate some of the external controls (barometric, temp and cold start) via computer controlled solenoids instead of heated tubes,temp sensors and timers. Any comments?

[JeffYoung]

Pretty much a "no" on that one unless you can find a rule that allows it and I'm pretty sure there isn't one.

Sorry on that. See other thread on REM treatments for IIDSYCYC. Probably the most critical concept to understand about the IT ruleset.

I've got mechanical fuel injection on my engine and am wondering if I can activate some of the external controls (barometric, temp and cold start) via computer controlled solenoids instead of heated tubes,temp sensors and timers. Any comments?

[lateapex911]

Well, now, not so fast.
That is a fuel pump. Fuel pumps are free. Some common fuel pumps have the ability to govern themselves and so on. I can control my fuel pump with a switch, or even a rheostat.....

(I credit that definition to a couple CRB guys, who, when we were classing a Porsche 911, on an ITAC con call, told me that it could make oodles of power, when I was telling them that it was pretty much maxed from the factory (headers, port sizes, air cooling mechanical fuel injection with s largely unadjustable space cam). They insisted it is a fuel pump and you can 'do anything you want with it'.)'

So, ......

[JeffYoung]

Wow, that is a good one -- I don't remember that one Jake....did that one really get put out there?

I guess under that theory a fuel injector would be a fuel pump too???

[lateapex911]

Not sure if you're familiar with the MFi system in a 911, Jeff. it's like a little inline 6 cylinder engine. There's a low pressure pump that feeds a main galley, then the pistons pump up and down, pressurizing the fuel down 6 lines to the ports.

Where the EFi systems use a crank trigger and electronics to trigger the solenoid injectors, this uses a belt off the cam to drive it, and adjusts with internal widgets for rpm, load, temperature, baro pressure, etc.

But, fundamentally, it's a pump. And it pumps fuel to the cylinders in a 911.

Yes, the members of the CRB (at the time) who said it were quite impassioned. I certainly see the logic.
The injectors are the injectors in either car, and can not be changed.

But the pump itself is free by todays ITCS, and it's common for people to add supplementary switches, and i'd opine, legal as well.

[callard]

As Jake points out, the rack under the MFI pistons has multiple control inputs and we'd like to smooth out the fule flow at the lower RPMs. On EFI this is easily doable with a MegaSquirt system. We're working on a MechaniSquirt (TM ) way to achieve the same results from the pump.

[Greg Amy]

But, fundamentally, it's a pump. And it pumps fuel to the cylinders in a 911.

Can't speak to the CRB thing, but yup, MFI is the same general technology as a diesel injection pump: in the end, it's the fuel pump.

I guess under that theory a fuel injector would be a fuel pump too???

Negative. A fuel injector is typically a solenoid valve; it does not pump fuel, it meters and atomizes it. In the case of MFI, it's just a pop-off valve.

[JeffYoung]

Interesting. Well, I learned something today and will defer to you guys who know far more about mechanical injection than me.

Thanks for the explanations.

[joeg]

Yeah..carbs and a dizzy (w/points) for me too.

[callard]

Fear not, the area we are working on helps us get the car in and out of the trailer and around the paddock. I just wanted to get some clarification so that the other mid-pack IT-S drivers won't panic and run to the stewards when they see wires going to my mechanical fuel injection.

[tom91ita]

Fear not, the area we are working on helps us get the car in and out of the trailer and around the paddock. I just wanted to get some clarification so that the other mid-pack IT-S drivers won't panic and run to the stewards when they see wires going to my mechanical fuel injection.

i'd run the wires anyways just to give them something to worry about.....