[Joshinator99]

Originally Posted by Evansa22

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 EVO 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

Factory tune richens the mixture during COT to get the exhaust temps down, which in turn protects the cats. That’s all.