merc 2.5 injectors

[patchesII]

That's interesting why a pre-mix gas/oil spray would scuff like that. My ECU has an adjustment for injector timing but I have noticed nothing power wise using it but I'm still injecting into the crankcase right now.

-BL

Think about spraying water from a water hose nozzle down on your concrete driveway. Notice how there’s basically no water right where it’s hitting. It blows the water away from the point it’s hitting. Just my theory

There’s almost no power in injector phasing in the crankcase. You’d have to really screw it up to notice any difference

[BLisBack!]

Interesting. Does it scuff right at that point or around it? Maybe the cooling effect from the injection charge is changing the shape of the skirt? -BL

[PanRonnie]

This might give a better understanding why they did it this way

[BLisBack!]

Thats cool! The original patent of sequential EFI? In all those figures they are still suggesting one "squirt" every 360 degrees. Its just the timing of it that they vary. I (and others here) have never noticed any diff from varying the crankcase injection timing (its all one huge mixing bowl IMO). The flow charts and names of some of the objects are quite amusing (circa 1981)

i.e one mixing bowl per cyl since there are rings on the crank separating the cyls

[BLisBack!]

I see now after reading a little more. The purpose of the patent was "simplification of fuel-lnjection control circuitry" (why they batch fired cyls). I can see where that would've been an issue back in 1980 when most embedded electronics was all TTL circuitry. Nowadays with the advent of CMOS and high end Microcontrollers and CPUs that simply not an issue at all. -BL

[25two.stroke]

15% is way out.

Do you know what this injector is? I bought a blown motor from a guy and he said these injectors were a direct replacement for the bosch that he purchased at a Mercedes dealer years ago. I immediately figured they were the reason he blew his motor and I set them on the shelf. Thinking about it again, I pulled them down and a basic flow test shows they flow actually a little more than the original bosch...you ever mess with these Blake?

[InjectorService]

To me those look like every other generic replacement I have seen. It is sort of interesteing that they would have come right from the Mercedes dealer though, you would think they wouldn't be selling ebay injectors. Do they flow match? hows the spray pattern?

[CI STV]

I’m just thinking it would be really cool if someone could figure out what needs to be done to the ECU/tune to run a set of high-quality, modem injectors, like the ID1300Xs… Just dreamin…

[BLisBack!]

Back to reality

Factory systems were never designed to accommodate that due to warranty and liability issues. Go with an aftermarket ECU and individual cyl EGTs, start rich and work up to your temp max slowly.

-BL

[PanRonnie]

If you think you need more fuel or shorter pulsewiths
But 1300cc is a bit overkill don't you think

[CI STV]

If you think you need more fuel or shorter pulsewiths
But 1300cc is a bit overkill don't you think

Yep, 1300s would definitely be overkill, unless you want to run ethanol or methanol. Not that I want to do that.
The big advantage of the ID injectors would be that they have all stainless internals, are a far better quality, etc. and even the 1300s are cheaper than those old circa-1974 Volvo/Mercedes’ hose feed injectors that we use.
BTW: the smallest injector tor ID makes is a 1050, which is what I run in my Vette with E85. But I would bet good money that they meter better at idle than those old hose feeds.

[PanRonnie]

This is my current collection
Chances are that even with brand new injectors they will deviate close more than 1%
So in order to get a proper set together you would still need to buy more than you actually need
I like to do that as cheap as possible after getting literly burned by aftermarket injectors
Even with the original mercury injectors you see quite a deviation
I would wurry more about flow mid to top rpm rahter than idle
A racing two stroke eninge is never going to idle like a stock engine

just build my set up again to see if i can get some proper dead times at 40,50 and 60 psi with the megasquirt only focused on equal flow before

[BLisBack!]

This is my current collection

Is that a homemade injector test station? I like that! That’s very cool. I need to take the time to set something like that up.

Does the Megasquirt allow you to alter idle timing dynamically? With my ECU (BLmicro VSFI) it’s adjustable from the touchscreen in the boat and I can get the motor to start and pur like a kitten in under one crank Rev because it’s all brought out on the touchscreen.

It’s amazing what it teaches you, when the timing goes up you can lean out the period, when the timing goes down in order to get a slower idle you need to bump up the period a bit. It’s a combustion efficiency/scavenging thing. In or out of the water has similar effects. I did a cold start the other day at 30deg ambient and was able to have it start and idle just as smooth, down to 800rpm. Now, granted, your port timing is much higher but the principle is the same, timing control is the key.

-BL

[PanRonnie]

By idle timing you mean ignition time BTDC or injection angle?
i have a raspberry pi4 in the boat which runs a full version of tunerstudio connected to a touchscreen
now the letters are a bit small 10 inch might have been better but with an industrial keyboard everything is accessable
https://www.xenarcdirect.com/892GFC.html

[BLisBack!]

Yes, ignition timing. Use it interactively to control idle if Megasquirt brings it out in a way that is easy to adjust. I'll post an example of mine. Once you get the hang of it you'd think it was a 4 stroke around the docks its so smooth.

-BL