Quote:
Originally Posted by Megahurtz
no PID for that, I mean the exhaust valve temp being cooled by ethanol evaporation by spraying when the exhaust valve is still partially open. I'm not suggesting this is correct or good or accurate. It's just a thought I had about I wonder if it actually does anything or is beneficial. I also wondered if it cooled the cats a little too. I have NO working theory or proof of this thought.
SOI at 400-440 is VERY bad on DI. You're literally dumping raw fuel into the exhaust stroke and probably at some point at WOT you will have a continuous flame from the exhaust tips as the hot exhaust mixed with raw fuel hit oxygen rich air.
360-380 SOI is fine. 160-180 EOI is fine. Fit the spray window in where you minimize spraying fuel out of the exhaust port and minimize spraying too far into the compression stroke.
|
I'm sure you've seen this but the factory tune definitely dumps fuel into exhaust, up to I think around 385* SOI when COT engages. A few different sources recommend SOI around exhaust valve closing like you're saying. Usually pushing SOI further before EVC to keep EOI around 180*, my tuner says above 150* is ok. Interested in your theory about exhaust valve cooling, possibly why factory tune does it, but usually I've seen it correlate with COT turning on. Completely agree with the statement the dyno tells the tale, just like with a few aspects of tuning. It's all about what makes the engine happy and each one will have small variances at a minimum.
JSH, Get that bad boy on a dyno with a competent tuner so you can document your testing for us
