The "self learning" EFI starts with a too rich base map for safety and leans itself out through time. The FiTech computer allows for fine tuning for most parameters - I suspect most TBI retrofit systems offer the same.
Anyone who is unclear on why EFI trumps a carb on ANY engine needs only to drive their vehicle from sea level to 8000' of elevation without opening the hood.
So whats the problem with carbs at altitude? Jet change? Power valve change? Your statement is simply untrue. No hood needs to be lifted with a carb equipped car to correct for altitude. I have made countless trips over Tioga Pass, Ca. [alt. 9945'] in 3 different carb equipped cars and not once did I need to lift the hood to adjust for altitude. All 3 cars have 3310/780 Holleys and ran just fine. No puking black smoke, no loading up, no stumbling or flat spots, all ran fine. A carb will respond in kind to atmosphere or lack of as fuel delivery is directly related to the amount of air flowing thru the carb. Less air...less fuel, its that simple.
RJP is correct, carbs are not ham-fisted nor do they not sense the environment. Changes in air mass change the the amount of fuel they provide, they do fine at higher elevations and any other changes in atmospheric pressure. I have a buddy that tries to chase jets around for all kinds of things, and we finally put an O2 sensor and logged it for him. Every time he changed jets, the a/f did what he did. Bigger jets it got richer, smaller it got leaner, but he expected daily jet changes to MAINTAIN the proper a/f and it just didn't change based on weather or elevation LOL Now we just hammer the car down the tracks and verify the a/f, nearly never a jet change.
Additionally, try not to go crazy about self learning being bad. Hand held systems take your inputs and set up the base maps. Then after that, within the limits of what the human program writers allow, the system does little samples and determines how to get it to a pre-determined a/f mixture for the calculated load, temp and other inputs. The program writers are smart enough to limit how much the system can correct, and more advanced EFI systems let you pick all kinds of things for a starting point as well as limit how far it learns, however, if you get to know your hand held, to some extent, you can manipulate your inputs to tweak the base maps.
That being said, the shortfall with most hand held tuners is you just don't know what the guy did inside the program, so you don't know the starting point or limits. An example, what if you changed your setup input from 482 cid to 382 cid on the initial setup? It would likely change the injector curve on the base map a lot, might help for a certain build, or maybe instead of 482 cid you put 476 cid, or lie about what the cam duration is, each would change the base tune, as well as correction capabilities, and might get you closer or may screw you up. The issue is, you don't really know what is in there to start, with advanced systems you can see it on your laptop, and equally important, share base tunes by email with guys who have had success with similar combos
As a guy with 10 years of street EFI experience on a 489 FE, EFI vehicle repair since the 80s, and more to come. My opinion is the benefits of EFI are VERY significant but not elevation related in and of itself: (and should be compared against cost)
1 - Cold start performance (both what you enjoy in the seat AND fuel mileage/a/f mixture) It is night and day over the hatchet-like response of a choke or accel pump dousing a cold or cool motor, less so when hot.
2 - Fuel under continuous pressure from source to injector, avoiding vapor lock and boiling of essentially the same fuel feed technology of your toilet
3 - The ability to readily link timing control to measured engine parameters
4 - Adjusting for temp and load changes
5 - Being able to modify/experiment without getting dirty or wearing out parts
6 - (likely lower than 6, just spitballing here) Tweaking for atmospheric pressure.
The truth is 1-3 completely change how your car feels to you
on the street and is why guys dig EFI so much, the others are far less important as a reason to change
Now TB vs port injection....NASCAR has gone to a port injection where the injectors are way up high near the TB and it works great for atomization. That is very TB-like in the distance from the valve, so it isn't bad, although NASCAR still aims at a runner, not the plenum and injectors fire independently, what is more important than TB vs port is user interface. Like I said, if I could adjust a TB like I can my SEFI, it would be awesome. Sure, I cannot adjust injector timing at idle based on cam events with a batch fire TB system, and never can if it batch fires into a plenum, but that is only used at idle and likely not needed in 99% of the vehicles.
However, if I can see what I am starting with and what the computer is adjusting, AND control it, then I can do some good stuff.
The question lies how far from "normal" your build is, in most cases a wideband off the shelf TB works real well, but generally as guys learn, they want more control.
