Devil’s Advocate

[rollingpinz]

I saw a video of a guy putting a Holley Sniper 1100 on a VW type-2 cargo truck and I thought why not me?
So, let’s go down that rabbit hole.
Let’s pretend I’ve got the intake manifold all fabbed up and I have a return line in my tank.
Now it’s just a matter of hooking it up?
I know it takes 12 volts. That’s just a converter. Right?
1. How many amps considering the sniper and pump?
2. Should I stick with 12 volt pump or go 24?
3. There’s a wire that goes to the + and one to the - on the coil. Isn’t that an insurmountable problem(24v)? Solutions?
4. The fuel tank is 17” tall. Is that too high a lift for the fuel pump? Solutions?
5. Is there anything else I’m missing?

[Hugues]

Interesting. I've been searching for ways to convert to EFI, don't remember bumping into this one. Got a link to the video you saw?
How does the ECU know when to trigger the injector?

[rollingpinz]

I googled Holley sniper vw. There was two. One was from Red-e Motorsport in Salt Lake City.
I believe the trigger input comes from the wires that connect to the coil, but I think our 24v system won’t be compatible and can’t envision a way to step that down to 12v. Admittedly, I am no expert.
Maybe the pinzssi system would be a better way to make that connection.

[rmel]

The Injector flowrate on these Holly's is way too high for the Pinz.
The 2 barrel version is 2 x 100 lb/hr. Pinz EFI conversions are in
the ballpark of 24 lb/hr. The problem with very high flowrate will
be a very low duty cycle giving poor control.

[rollingpinz]

The sniper 1100 is a single barrel with 1 injector. Holley’s info states that it will support up to 175hp.
I don’t present this as an argument. Just extra info to chew on. I do appreciate your input. This is the kind of stuff I’m looking for. Maybe it is a dead end.

[eric1355]

https://www.holley.com/products/fuel_sy ... ts/550-552

[rollingpinz]

Yes. That’s the one.

[rollingpinz]

I found a diagram that shows a crank sensor is possible. Would that eliminate the connections to the coil? And make the 12 volt requirement easier to deal with?

[rmel]

Again that's too high a flow rate, even if the intended application was a one barrel Holley
feeding a pair of cylinders. It would be a challenge for an adapter, which really would have
to be more of a vapor chamber to balance the flow.

[rollingpinz]

So when you say 24lb/hr, you mean combined total for all 4 injectors? Because 4 injectors at 24lb/hr would be real close to that 100. I’m not trying to frustrate/antagonize. I just want to understand.

[eric1355]

Hello
the injector can be replaced
by another with a greater or lesser flow rate
and I think that the injector opening time, i.e. the injection volume, can also be set.
to match the displacement and filling of our pinzgauer engines.
Eric

[rmel]

The vast majority of Pinz EFI conversions use 4 injectors typically in the range of 20 to 30 lb/hr.
So let's say 100 lb/hr total. Typically these are batch fired, although sequential has also been
implemented. I use 24 lb Delfi injectors with a 2.7L conversion and the duty cycle is ~20% under
normal driving conditions/load. This is a batch fired implementation.

The problem I see here is one of "impedance matching", that is establishing a uniform AFR
delivery to each cylinder and with good control. If the idea here is use one single barrel
Holly for all four cylinders it will be difficult to deliver uniformity to each cylinder without
having a relatively large vapor chamber that provides a reservoir of vapor AND not too large
that droplets condense out of the mist. The flip of this is a single barrel Holley/cylinder and
a very low duty cycle with poor control. If the injector can be changed to be <30 lb/hr that
may be a starting point. and a vapor chamber may still be required, all would depend upon
the draft and AFR balance/cylinder.

The AFR balance and volume delivery to each cylinder obviously needs to be nearly the same
or you will have power imbalance, lean and rich conditions between 1, 2, 3, and 4.

[Hugues]

...
Let’s pretend I’ve got the intake manifold all fabbed up ...
...

Indeed I think you cannot re-use the existing intake manifold, unless you use 2 of these Holley, but that's expensive
Having an intake manifold custom made for this is likely to be expensive.
But if you are going to pay that much for a custom manifold, you might as well have 4 injector ports added, closer to the combustion chamber.
But then you need to add an ECU to manage these, but they are not that expensive, i bought the Megasquirt 3 Pro mini.

As Rmel wrote, with only one injector for 4 cylinders, you might not get all the benefits of EFI, cylinder 1 and 4 will have a long path between the combustion chamber and the injector.

[rollingpinz]

So what I’m hearing is the plenum size is critical. Is there a “not crazy” calculation to determine the size of the plenum?

Speaking of that kind of thing, why is one carb higher than the other? Is it because the engine is tilted backwards and the carbs are “terraced” to make them more level?

Ok. So the sniper 1100 is off the table. I appreciate the input so much. Thank you.

There is a 48mm throttle body that has a single injection port. Guys have used a 66lb/hr injector to supports a 2100cc vw engine for 100hp at the flywheel.

Does this sound like the right direction?

Also, if I use a controller set to tbi and fuel only, it still needs a signal from the negative side of the coil. Would the controller get a 24v signal from that point? Is there a way to step that down?

[compunerdy]

I would love to inj my Pinz. I dont have the time to try and learn how fuel inj all works but I can design and machine a intake if that is needed.