Hi All
New owner of a 2018 3.5t RSport. So far, very happy with the purchase.

I do have one lingering question which I can't seem to get a straight answer on. I live in Denver (~5280 feet above sea level). How much power / boost am I theoretically losing?
I know on paper NA engines lose 3% per 1000 feet. And turbo engines generally don't lose anything as they just spool more / less goes out via the waste gate.
But what about our super chargers? Not knowing exactly what type we have, and if we have a bleed system like Audi's which can remain closed longer to achieve standard boost is making it difficult to work out based on what I am reading online.
Finally, if there is a loss, is this something that can be adjusted for via tuning or pulley change? I very rarely, if ever, drive to seal level.
Any info would be great.

Thanks guys

 

Yup, altitude will lower compression, all other things =. Same on a SC.

If you want to get the most from your engine, consider the Velocity AP tune, you'd get more like 415HP, without the pulley. He also offers a pulley that with the tune brings you up to 450 or so... Many people here are quite happy with just the tune, and if you search you'll find a forum discount here.

 

I suspect the supercharger bypass valve will try to compensate for the altitude. The stock ECU tune leaves a lot of boost on the table by keeping that valve open, even at WOT.