I've done a bunch of reading about DA in the past 36 hours after reading one of your previous posts. WOW, what a difference does your altitude make!
My take after reading up on this is that excessive DA makes a smaller turbo seem larger or larger turbo seem a lot larger. Personally, I'm not a fan of a GT45 because of the specs. but it might be a waaaay better option at your altitude. I'm thinking that the exhaust flow doesn't care about DA, but the compressor does. So the 'small-ish' compressor should be much more effective and not become the restriction because of the air flow. Maybe I'm thinking about this incorrectly - correct me if I'm wrong. But it seems that a larger compressor will be less effective due to the DA at your altitude.
Duke (Northernregal) you're going to need some tricks to light off the S488 at your elevation haha.
I've never thought about this. GroceryGetter83 is at 6' elevation in Bradenton, I'm at 900' elevation locally, and Duke and motorheadmike are at 2800' (like wtf - 2800????!). After doing some basic calcs, like wtf - is my thinking about this correct?
I used to live in a place that would get negative DA in the Fall. So yes, this is a rude awakening for me.
I found this to be an interesting take on the subject:
Boosting With Altitude - How Elevation Affects Turbochargers
Be sure and know what you're purchasing before you do. Find out the science of turbochargers and how they are affected by altitude and elevation.
www.dieselarmy.com
Turbocharging At Elevation
A naturally aspirated combustion engine will lose 3% of its power for every 1,000 ft of elevation gain. Add a Garrett turbocharger to minimize the loss
www.garrettmotion.com
Remember everything about this build is done around a budget and nothing else, and none of it is about a specific outcome other than having a moderately overpowered car that makes cool turbo noises. Nothing more. So it is very difficult me to rationalize a plan relative to the combo other than "I need: x, y, z components to avoid blowing it up".