I'm running into some misfires on the upper end, and I'm somewhat sure it's due to injection angle. It might be spark gap, but I really think i'm doing bad DI math because of not-good DI experience. It's like a weird misfire, and changing injection angle definitely does something to it. Any ideas?
BTW These engines at about 21ish PSI make 220whp so 177whp without being able to rev out is pretty nice!
that means EOI is 20 deg before bottom dead center (a little early)
4.8ms is 181 degrees injection angle
SOI is then 381 degrees BTDC combustion, aka 21 degrees BTDC intake (injecting for the last 20 degrees of the exhaust stroke). This is dangerously early.
I suspect you're getting piston impingement and/or lighting the fuel with the leaving exhaust charge.
1. Slide your EOI later at high RPM. I wouldn't go any later than maybe -160 degrees. Try -180 and see if that improves it.
2. Add fuel pressure. This will reduce injection duration. I would try to set fuel pressure such that the injection ANGLE stays relatively constant at the same engine load as RPM changes.
Thanks a ton for the input, it fried my brain for a few minutes lol
While moving EOI later did make it behave better, power took a very noticeable nosedive. I'm trying to wrap my head around this but I don't really get it, maybe I was missing fuel orrrrrrr idk I need to play with it some more. I'm still nervous cause this is all too new for me lol
I had a slight thought of raising fuel pressure, but i saw 100 bar as my target and started pooping my pants. I guess stock DI goes to to 150 but my brain still thinks in psi for some things.
The thing about adding fuel pressure I had literally no concept that it would work like that but it makes perfect sense, thanks again! I'll update with more news. If I can get stock power out of it I will cry tears of joy.
I THINK I can get a log of stock ECU EOI/SOI which would help me greatly.
Yeah, you can log stock soi/eoi, just copy that. Also try to log stock fuel pressure, then copy that too. That should help a lot, as those tables are optimized for "don't explode the engine or have bad emissions" above all else from Hyundai.
edit: for reference, my focus ST would target 145-150 bar at full load
On my street tune I had ignition timing at about 16 degrees at about 11psi. On the dyno, I kept pulling timing on the dyno until about 6 degrees, after which power finally started dropping. How tf did it not knock itself apart with 10 degrees of unnecessary timing???
Was it actually knocking? Modern DI engines have a pretty high knock threshold, well past MBT usually
That's what I asked lol; how the f did it not blow up???? I can see exactly what you mean because it WAS running way past MBT. Most engines with 10 degrees over MBT at 12psi knock so loud you can hear it a few blocks away lol