I messaged VOHK today. He said their testing, tuning, and most validations are above 8k ft for boondocking/technical tree riding, and overall backcountry riding in the mountains. So the VTI allows them to tune the parameters in your ECU. The pump gas tune is a small increase in performance. They also have a higher octane tune that is a great increase in power. He mentioned it’s about a 20-30HP increase. (At their elevation, Colorado) Throttle response is better on the higher octane tuning, but it’s still a turbo at the end of the day. The throttle response on a N/A 850 is better. They will also have a high octane tune that will go with an intercooler to make even more boost and power. They have had the higher octane tune perform at low elevation with good results.
I know BMP using the Torque Link had a race sled Boost they ran at lower elevations, and obviously they have many others at higher elevations. They obviously did their dyno tuning at lower elevation as well.
