Injector duty cycle

[98GTI]

So i have a 1.8t 20v running a hybrid Ko3 turbo from frakenturbo. Im runnnig 386cc (Audi TT 225) injectors at 4 bar which comes to around 450cc injectors. From "calculations" and "hear-say" this turbo makes ~no more than 250 whp, these injectors should handle it. My data log says im running ~124% duty cycle, which i didnt think was possible. Maybe i have a setting wrong.

When its just getting up to temp its fine. But when i've been running it for a while it will cut out at 5-5500 rpm as you can see from the log. I wanted to get it dyno tuned but i dont want to spend the money have have it cutting out when its on my wallet.

I was gonna go BT and larger injectors but i've decided to dump funds into a Turbo 6.0 build (like everyone else) and just keep this car as is until this new project is done. So if i just have to run less boost until i upgrade, so be it.

If someone with more experience could look it over and give me their opinion, that would be great

[98GTI]

And the MSQ. Took me a minute to figure out i had to change the name from "current tune"

[Matt Cramer]

Looks like you're either out of injector or fuel pump - you have the injectors locked open and the AFR still isn't where I would like it to be. Check to be sure the fuel pressure isn't dropping.

Weirdly, the cutout appears to be the boost dropping abruptly, even at the same boost control output.

[grom_e30]

i was under the assumption if you have the injector staging+squirts per cycle set wrong it reports the incorrect duty cycle. i may be wrong though.

[Paul_VR6]

You are right a k03 won't make much more than mid 200s on a good day and usually a bit less. Definitely double check fuel pressure, and the injector part number.

[98GTI]

Looks like you're either out of injector or fuel pump - you have the injectors locked open and the AFR still isn't where I would like it to be. Check to be sure the fuel pressure isn't dropping.

Weirdly, the cutout appears to be the boost dropping abruptly, even at the same boost control output.

Yeah it only happens when its been running a while, hot day, or after some aggressive pulls. I assume its spark/ fuel cut making the boost dive off and momentum/ boost leaving the intake through the throttle body and motor making the rpm rise the slightest before it dies off

i was under the assumption if you have the injector staging+squirts per cycle set wrong it reports the incorrect duty cycle. i may be wrong though.

Im no professional, but i believe they are correct, could anyone chime in? i do find it weird that it shows over 100% duty cycle anyone know why?

You are right a k03 won't make much more than mid 200s on a good day and usually a bit less. Definitely double check fuel pressure, and the injector part number.

I have confirmed they are legitimate audi tt225 386cc injectors. I bought an intank Bosch 044 fuel pump setup in preparation to go BT, ill install it this weekend. maybe ill buy a fuel pressure sender and data log fuel pressure from now on


Thanks for the help guys

[lotus23C]

Check out boost duty table 2, where it should be 6000rpm, it is 0.
Might cause a few issues

[kaeman]

when the duty cycle is calculated isn't it duty cycle = required fuel pw/fuel pw x 100. if you have your enrichment curves or your boost ve table values high then wouldn't this show a high duty cycle.
After checking into this further....I take back my previous thoughts...
I am revising my thoughts on duty cycle.. it is the time the injector is open pw... divided by the total time it takes for the engine to make one engine cycle at a given rpm.

added note after looking at my recent data log I know that rpm is part of the duty cycle equation. I have a data log that during a rapid acceleration my pw went to 12.5..ms which at 2500 rpm was a duty cycle of about 30... and that when the engine got to 7000 rpm that same 12.5..ms pw was a 72% duty cycle... I am now convinced that the duty cycle has a relationship to rpm and the total time allowed for an engine cycle. I was getting pw of 16.4..ms and it was showing a duty cycle of only 20% but that was an Accel pulse at about 1500 rpm...
I know that a duty cycle of 100% means that the injector is being held open for the total time the engine cycle takes to occur.

[grom_e30]

Sets injector staging in non-sequential modes. For Sequential set 2 Squirts/Alternating or 1 Squirt/Simultaneous.

your msq is set to 2 simultaneous. i think this does not affect the fueling but i believe it does have an effect on the calculated injector duty cycle you will see in the log.