[bighorn466e]

I realized that I never gave an update here!

I wound up getting 6th gear enabled and purchasing an Orion shortly after my last post.

I took the truck and Orion out to do some unloaded pulls and compare behavior, other than getting the brakes a bit warmer than I wanted everything went far better than expected. After running through some power from acceleration calcs I found that the factory 230 rating matched up with the Orion 190 with the difference that the problem described earlier was gone. I then moved to the 250 tune and my overly simplified calcs showed a 26% power increase with EGT's staying below 1250. Life seemed good.

Next time I towed with the camper and checked the datalog I noticed that my EOT was creeping quite high and I was getting the feeling of a bit of power loss. After the trip I pulled the thermostat element out of the oil cooler, did a change with t6 and got a clean bill of health on the old oil from blackstone.

The next trip was quite long (FL->DE) and there were significant ambient temp changes. I noticed that on the cooler days I was getting about a MPG better and didn't feel like I was losing any power on the top of long grades. This was a bit of an eureka moment as I was losing ~12% mpg and 12% of 250 is 30hp which happens to be about the power consumed by my mechanical fan according to some engineering spec sheets. EOT tracks almost perfectly with coolant temp and I'm not noticing any significant difference in warm up times although I've only had the truck down to 50ish degrees since pulling the thermostat.

Next planned step is to get drive, boost, outlet temp, intake temp, and egt datalogs to Bill from the factory turbo setup. I have a feeling that we are going to discover that we are quite far out of the ideal efficiency island of the factory turbo once we have the data in hand. If that's the case my WAG is that I'll wind up upgrading to an s364.5sxe turbo with a 0.91 housing. That may change once I have the numbers to better estimate what would be a good fit for the engine.