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I've become intrigued recently with Denso's 12 hole shooters. Yes, you read that right, instead of having a single holed pintle type mechanism, these have little discs with 12 tiny little holes in them, which assures better atomisation of fuel. These little plastic bodied wonders (similar to Bosch's EV6's or EV14's) are all the rage in Europe for ULEV. Denso were the first to bring 12 hole injectors on the market, and I think they're still the only manufacturers that have them.

Apparently they're available between 240cc/min and 380cc/min, which hits us perfectly for our naturally aspirated 12 cylinders, and with their lightweight internal componentry, their responses are very quick.

Ducati uses or at least used marelli IWP-189 12 hole injectors.....shoot I can't remember but it came after the 999 I got my TB from. This is a shower injection setup and the 12 hole injectors smoothed off idle transitions,

I had a set on the help but ebayed them when I decided to go low injection with ID-1000 injectors which with only about a 5-10 degree spray cone are just about the opposite of the 12 hole injectors. Injector dnamics is the hot ticket if for no other reason then the mixture in all your cylinders will match but they are also being used for very shot pulse injection (under 38% duty cycle) which when done correctly adds 3-5% more hp.....probably by getting the fuel to cool the air instead of mostly cooling the port walls.

I think the though with low mount 12 hole injectors would be just the opposite. The goal would be to completely vaporize the fuel to ensure even mixing and also to take up the maximum space in the cylinder, effectively reducing displacement and increasing mileage...that would be my thought anyway.

Mark, I think you're right about the goal with these being getting the fuel as completely vaporised/atomised as possible, but that should be good for overall engine efficiency as well, not just emissions & mileage. At least that's my (perhaps flawed) logic. I have a set of pink ones here (P/N: 23250-20030) which are 64mm o-ring to o-ring, which is just a tad shorter than the Bosch's that came in the Ferrari, but I think with a shim plate on the manifold, they should work OK. There doesn't seem to be much technical data available out on the 'net about them, however. Here's what I've been able to gather so far, but it's incomplete:



Here's a pic of the pink versions:

I'm sure that's true.....but I think they'll have a slightly negative effect on hp due to reduced charge cooling and you may see something in the enrichment/derichment as liquid volume on the port/runner walls will probably change.

Luckily your new ECU will let you change all that

These injectors are as low as possible in the manifold without actually being part of the head, so other than wetting of the ports, hopefully there won't be much wetting of anything else. Just hope the spray splits evenly between the 2 intake valves. I'll have to get some pics/videos of these as they're spraying to ensure I get them clocked right.

Not following you on the reduced charge cooling? I'd have thought more finely atomised spray would offer better and more even cooling? Or are you referring to them not being used in a shower arrangement?

The ECU sounds very encouraging - I have some questions that I'll ask in the other thread.

The thinking is anything that touched a wall will cool the wall not the charge and with long dutycycle even though you're spraying at the valve the whole port.runner ends up wet. You may get exactly what you're after with slightly improved mileage and good hp, but my money is on a slight reduction in hp because I think the mist is more likely to travel back up the port than bigger droplets from a standard injector.

We have two different Denso (I believe) 12-hole injectors.

The first ones are stock in the Yamaha WR450F bike (and I assume the YFZ450F quad which shares the same architecture) and I believe have a flow rate of 387 cc/min at 3 bar. These particular injectors have a very short body length (O ring to O ring) but the tip is standard length.

The second ones are stock in the Yamaha Raptor 700 quad, and I believe their flow rate is 450 cc/min at 3 bar. These have almost identical features to the WR450F injectors but a longer body length. Connector is the same. We use two of these operating at 4 bar for our turbo WR450 engine. Based on the pictures I'd guess these are similar length to the pink ones earlier in the thread, maybe slightly shorter.

I'll see if I can get pictures of mine. I'm working on organizing a full characterization on our injector rig (to get flow rate vs pressure and dead times vs voltage and pressure). Maybe in a month or two I'll have it.

We tested a single Raptor 700 injector on our NA powertrains, both high and low mount, we found higher peak power with the high mount injector (facing into the runner from the other side of the manifold), but far better fuel consumption and transient performance at part throttle and off the power peak with low mount injector (normal position at the port). We suspected the fuel was being blown all around the manifold and we had to run richer to prevent occasional misfire. The intake had very strong acoustic tuning and this did not help off-tune. With the turbo setup we run two, one at the port and one 8" up from the port in the pipe (there is no runner and plenum ball, just a pipe).

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Old thread but it made me recall something. I did a bunch of dynamic flow modeling with injector spray patterns and droplet size and velocity. Long story short, it's nearly impossible to get a perfect mist or cloud of fuel mixed with the airflow due to a number of things, one the air never flows in a continuous direction, the pulsing creates all kinds of eddies and low pressure zones. Second at a certain point of pressure to droplet size one runs into electrostatic flow problems, i.e. the droplet becomes charged and will 'clump' or attract other droplets or pull out of the air to the wall, recall the block is also part of the ground loop to the battery. DI is especially prone to this but given that it's mixed in the chamber the distance to the wall or charged surface is greater then in the port. Best results are obtained with extensive testing or modeling in virtual space. However no matter what spraying in the port will always result in wetting as the valve is in the way of an air pulse.

What duty cycle were you at?...or I guess the real question is how many crank degrees were you spraying fuel and when was the pusle starting/ending?

Interesting... that's getting closer to what I'd need to run Psuedo DI on my Northstar.