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Supercharged111

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I brought an Edelbrock carb'd car to Colorado Springs (6500' at my house) from MI and it ran like ass. It was so rich when it warmed up it rolled black smoke. I'm far from convinced that any carb will tolerate such altitude swings. OP my 1500 in my sig does pretty good up here and I only hit 110kpa with the Whipple. Back in MI, I saw a high of 139kpa IIRC. I modded it to be able to pull my ~8500# enclosed car hauler. If it's low end and midrange you want, the LS isn't it. I'd lean toward boost, but it's up to you to define what that looks like in terms of engine management, fueling, engine config, etc. You could also do a 383 that breathes better. It all comes down to what you're willing to spend and how much asspain you can stomach.
 

Turbo4whl

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GM when doing high altitude emissions certification wasnt just a carburetor adjustment, its carburetor parts, emissions components(all depending) and also different specs relative to eachother than at sea level. as in, you dont just scale everything up a set amount(or down) its all done together. Im sure any deviation from that is just pissing in the wind so to say

Yeah if you are trying to make emissions legal, I'm sure it will be hard to cover a 4000 foot difference.

The OP asked about the best option for altitude and I am still pushing option 4. Just increase the boost pressure as needed going up. The waste gate I installed is variable and could be adjusted from the cab with a turn of the knob of the regulator. I kept it at 7 PSI but the turbo would build 13 PSI unregulated.

Never ran mine at that altitude so maybe the carb would go too rich. These guys get it done:

Turbocharging at Elevation.

Hey @Eargesplitten check the link ^^^
 

AuroraGirl

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Yeah if you are trying to make emissions legal, I'm sure it will be hard to cover a 4000 foot difference.

The OP asked about the best option for altitude and I am still pushing option 4. Just increase the boost pressure as needed going up. The waste gate I installed is variable and could be adjusted from the cab with a turn of the knob of the regulator. I kept it at 7 PSI but the turbo would build 13 PSI unregulated.

Never ran mine at that altitude so maybe the carb would go too rich. These guys get it done:

Turbocharging at Elevation.

Hey @Eargesplitten check the link ^^^
I wasnt actually following that part of the convo, i see what you mean. using boost to overcome a lower pressure atmosphere wise. I feel like the most mild supercharger setup put on an engine would probably work better since it doesnt need to spool and its on the front end of the whole hting. but If you drive smart I could see how yours works
 

AuroraGirl

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I brought an Edelbrock carb'd car to Colorado Springs (6500' at my house) from MI and it ran like ass. It was so rich when it warmed up it rolled black smoke. I'm far from convinced that any carb will tolerate such altitude swings. OP my 1500 in my sig does pretty good up here and I only hit 110kpa with the Whipple. Back in MI, I saw a high of 139kpa IIRC. I modded it to be able to pull my ~8500# enclosed car hauler. If it's low end and midrange you want, the LS isn't it. I'd lean toward boost, but it's up to you to define what that looks like in terms of engine management, fueling, engine config, etc. You could also do a 383 that breathes better. It all comes down to what you're willing to spend and how much asspain you can stomach.
theres a high altitude set of parts needed for the edelbrock
 

JeremyNH

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I had thought the biggest hurdle to doing anything with TBI is tuning it. Regardless, as a seasoned engineer I place greatest stock with things that are guaranteed to work and many of your options seem complicated, uncertain of success, expensive, and will take a great deal of time to accomplish leading to an ever-common abandoned project/went a different way posting for parts-for-sale. I would whittle down to three:
(1) Head replacement. Either after-market TBI or vortec heads with a carb manifold and TBI adapter. Unsure which would produce better results but vortec heads are cheap (more than $300/pair and you are overpaying) as are carb manifolds and TBI adapters for them. Much cheaper than a TBI vortec manifold. And compare to after-market TBI heads. Either would give an immediate noticeable boost for moderate cost over a weekend of work. See if you can live with the truck then. If not:
(2) Gather funds for an LS swap then sell your truck and buy a Gen 3 with a 6.0 already in it and see if you can live with it. If not:
(3) Supercharge (2) with not hard-to-find kits and see if you can live with it. If not mortgage your house, sell your wife and children into slavery, borrow money from the mob, and then, maybe, you'll have enough to buy a gen 6 truck.
I understand the allure of GMT400s. I have a 1998 Z71 k1500 that I have put more work into than most would deem rational (marine intake and cam, cpc, 4L80e, shorties with HD exhaust upgrade, plus a few lessers) but I was starting from a better platform than you have. Honestly swapping a TBI to an LS vice just swapping trucks isn't something that is sensible unless you are doing it for the sake of doing it (which I can understand).
 
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Eargesplitten

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I had thought the biggest hurdle to doing anything with TBI is tuning it. Regardless, as a seasoned engineer I place greatest stock with things that are guaranteed to work and many of your options seem complicated, uncertain of success, expensive, and will take a great deal of time to accomplish leading to an ever-common abandoned project/went a different way posting for parts-for-sale. I would whittle down to three:
(1) Head replacement. Either after-market TBI or vortec heads with a carb manifold and TBI adapter. Unsure which would produce better results but vortec heads are cheap (more than $300/pair and you are overpaying) as are carb manifolds and TBI adapters for them. Much cheaper than a TBI vortec manifold. And compare to after-market TBI heads. Either would give an immediate noticeable boost for moderate cost over a weekend of work. See if you can live with the truck then. If not:
(2) Gather funds for an LS swap then sell your truck and buy a Gen 3 with a 6.0 already in it and see if you can live with it. If not:
(3) Supercharge (2) with not hard-to-find kits and see if you can live with it. If not mortgage your house, sell your wife and children into slavery, borrow money from the mob, and then, maybe, you'll have enough to buy a gen 6 truck.
I understand the allure of GMT400s. I have a 1998 Z71 k1500 that I have put more work into than most would deem rational (marine intake and cam, cpc, 4L80e, shorties with HD exhaust upgrade, plus a few lessers) but I was starting from a better platform than you have. Honestly swapping a TBI to an LS vice just swapping trucks isn't something that is sensible unless you are doing it for the sake of doing it (which I can understand).
The first option does seem like the most practical in that it's a simple, relatively cheap modification that as I understand it should function standalone assuming I'm not messing with compression on the heads, just letting them flow better. Whereas a turbo or cam or supercharger or LS swap involves new wiring or new exhaust plumbing or a new ECU or all of the above. And as you mentioned, once that's done, I can see if that's livable.

Which, at this point, I think it might very well be, I got the truck up here last night and it handled the elevation and mountain passes much better than expected. I got the truck for $750 from my dad, who has owned it since 2001, because I know it was taken care of well before the issues that caused it to become a farm truck popped up. It's in much better mechanical shape than I anticipated, I brought a new set of spark plug wires, spark plugs, air filter, oil change supplies, and a new battery, and all it needed was the tires filled up, battery replaced (I have never seen a battery sitting at under 1 volt), and oil filter adapter gasket replaced to be humming. It still needs work, but nothing that stopped me from driving it about 200 miles. Pleasantly surprised by everything but the amount of places that mice found to poop.
 

RichLo

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I bet there's a way to control boost to compensate for altitude changes by controlling the wastegate with a barometric sensor while using a blow through carb so the carb sees the same pressure when under boost. But by then your creating a new computer to control that and you could just as easily (well way easier) use a stand alone throttle body like FiTech and let that computer learn and adjust for altitude real time.
 

Eargesplitten

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Yeah, combining a carburetor and forced induction could make up for the shortcomings somewhat, at least I think so (I repeat, I don't know fluid dynamics), but then you're looking at a manual boost controller adjusted every time you gain/lose a couple thousand feet of elevation or using some kind of ECU-controlled boost solenoid, which frequently run off of a MAP sensor on cars that have them, and if you're intimidated by managing fuel injection but not by ECU tuning then I am confused.
 
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