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Tbi vs carb

Discussion in 'Engine & Performance' started by Jawzjeep, Jun 10, 2021.

  1. Jawzjeep

    Jawzjeep Full Access Member

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    Without starting a fuss, I know opinions vary.

    Is there I consensus here on this? Are more people swapping from tbi to carb or carb to tbi (or another form of injection)? Say on a basic stock engine with a 4 barrel already or stock tbi.
    Does this opinion differ between a big or small block?

    Asking for a friend...

    If this is covered then point me in the right direction. Thanks.
     
  2. dusterdude

    dusterdude Full Access Member

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    I'm in the planning stages of installing an aftermarket(based on the gm system)tbi setup.it will be a few weeks before the actual install.

    Sent from my LM-X420 using Tapatalk
     
  3. Corvette Ed

    Corvette Ed Full Access Member

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    I’d keep whatever I had,but fuel injection is best.
     
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  4. RecklessWOT

    RecklessWOT Full Access Member

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    The TBI obviously wasn't the best fuel injection system ever designed, but still better than a carb. Fuel injection is generally better at everything- more reliable starting (and staying running), consistent running regardless of temperature/elevation changes, slightly better fuel economy, a little more HP. Just a lot easier to live with. Only real downside is that now the truck isn't purely mechanical so if you ever get stuck out in the woods you might not be able to just fix it with a screwdriver and a hammer. With all that being said, if your carburetor isn't giving you any trouble I personally wouldn't mess with it, it's not quite as easy as plug and play.

    There are only two reasons I can imagine someone swapping backwards to a carb. Either someone is having major issues with the TBI system and says screw it, or if someone has some crazy crate motor they're building up and wants to throw a big ass carb on there to make tons of power as factory TBI has its limitations. They make aftermarket standalone TBI systems that are good for making plenty of power, but they cost WAY more than a big fat carb that will make the same power.
     
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  5. SquareRoot

    SquareRoot Full Access Member

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    If your going to spend time & money swapping from a carb to EFI, DONT half-ass it and settle for TBI. Speaking for a friend.
     
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  6. Jawzjeep

    Jawzjeep Full Access Member

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    Ok thanks for the replies. I currently have tbi both on my 350, and the 454 I'll be swapping in later. Just looking for opinions. Ive seen a lot of people just toss the tbi in favor of building more power. Im about fixing it in the woods so I was a little iffy on running TBI at first but I figured since it's the first fuel injection it would be the easiest to work out a problem. Can't be too hard to carry a voltmeter and a few extra sensors. Thanks guys.
     
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  7. Bextreme04

    Bextreme04 Full Access Member

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    My opinion is that you should stay with what you have, there is ZERO benefit to changing a TBI to carb or vice versa on an old truck like these. Get what you have working right. If you want to make a carbureted vehicle run better by adding fuel injection... going TBI is about the WORST way I can think to do that. You'd be way farther ahead by getting a donor 96-99 GMT-400 and swapping in the whole engine/trans/fuel system from that or just LS swap it with a basic 01-03 5.3/6.0.
     
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  8. Jawzjeep

    Jawzjeep Full Access Member

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    Thanks bextreme04.

    Im into wheeling and tipping my rig so there is a benefit sometimes to swap from a carb to tbi when power is about stock. But that is admittedly partial to off-road only. A street princess won't be the same.
     
  9. Bextreme04

    Bextreme04 Full Access Member

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    I still hold that it is not worthwhile to go TBI if you are swapping. If you want fuel injection so that you aren't sloshing around the fuel in the carb bowl, you upgrade to a GOOD fuel injection for the same price. TBI is going to be no cheaper and is a pain in the butt to troubleshoot if it starts running poorly.
     
  10. Jawzjeep

    Jawzjeep Full Access Member

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    Im putting a little more info here to help.

    Im happy with my current setup and it works fine with tbi. I dont like computers in the boonies. so if it came with a carb I'd be fine with it and probably wouldn't change it. I'm just asking to kind of get the feeling of the crowd here. I do have a 454 tbi/5 speed setup im looking to swap in and may consider a change. I will never, ever go to a newer injection system than tbi. To many of those truck with problems for me. I had to pull out the stupid spider injection system that was under recall in another truck. Eff that system. And a LS is not in my future for this suburban.
     
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  11. Bextreme04

    Bextreme04 Full Access Member

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    Like you said, everyone has a different opinion. To me TBI is more reliable than carb, but is the least reliable fuel injection system. They work great as long as they are working, but are a bear to troubleshoot and can have horrible drivability issues without the system even realizing it is having a problem. There's a whole lot of 2-300,000 mile fuel injected trucks running around that have never had a single fuel injection component serviced or adjusted. Carbs not so much, but they are simple and easy to work on and repair with minimal knowledge or tools.

    I bought a donor 97 K2500 Suburban with the 454/4L80E to swap into my '80 K25. Converted the 454 to the 0411 computer and individual coil packs. The motor and trans had been untouched and still drove well at 288,000 original miles.

    If you can get a donor 454 TBi/5speed that you KNOW runs good and had no issues... and you can get it for dirt cheap, it would probably be worth it. Especially for you since you are already TBI, its a stupid simple swap. If you were carb... maybe still worth it if its a known good runner before the swap and its DIRT CHEAP. any thing over about $1000 and its cutting into what an LS swap would cost. $1500-2000 and its completely not worth it(except for maybe the 5-speed.. that's probably worth another $1k all on its own)

    I guess bottom line for me is I'm not a fan of TBI... its too much of a half measure fuel injection and its too hard to program/tune/datalog.
     
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  12. bucket

    bucket Super Moderator Staff Member

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    It's just going to vary widely. Personally, I've had quite a few TBI engines and they have all been incredibly reliable. The couple issues that I have had troubleshooting was simply me overthinking things and I overlooked something basic and simple.

    If there is off-roading going on and the current TBI is working well, personally I would run TBI when the 454 goes in.
     
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  13. SirRobyn0

    SirRobyn0 Full Access Member

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    I see a lot of great opinions and thoughts in this thread I'd love to quote and add my two cents to, but there's just to many to quote them all. So I'll go at it like this. I completely agree that it is a better idea to keep what you have vs swapping one way or another, there aren't enough good benefits to make a swap like that worth while.

    That being said I've worked on a ton of carb'ed GM engines, and TBI, more so back in the day. The biggest issue we saw with TBI was lack of understanding them and I think that to some degree still holds true. In a carb'ed vehicle for people use to carburetors it is generally easy to understand what problem causes what symptom, with modern fuel injection the slightest thing out of parameter and the system sets a code. But with TBI the computer systems were not so sensitive, so you could have a rig run like crap with no check engine light and the mechanic not knowing what direction to go in, but in reality the TBI system is very simple and reliable. To me the biggest benefit in the TBI system is consistency and less maintenance, which might not matter for all but in a daily not having to tweak the carb, or change the plugs as often is a benefit.

    I'm rockin' an 84 C20 with 305 edelbrock the former owner put on. It runs right and good. Would I rather have a Q-jet yes I would, but will I remove a perfectly good carb to do it. No. And although I would prefer TBI to my carb, I'll never convert, not enough benefits given the work involved to do it right.

    I would encourage the OP to consider selling his truck to someone that would like TBI and buying one that is carbed already. If you insist on the conversion please do it the right way. Get a carbed parts truck and put make it as close to factory conversion as you can unless you plan for a custom fuel system. Please do not be the guy that tries to regulate down the TBI pump pressure for the carburetor and don't use some sort of adaptor to adapt a 4 barrel carb to the TBI manifold. That will only lead to heart ache and pain.
     
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  14. SquareRoot

    SquareRoot Full Access Member

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    Well put. My point was that either stay carb or go full efi. That means port efi, i:e. Factory LS style or aftermarket like Edelbrock PF-4. I tried the TBI (Sniper) and QUICKLY regretted it so I tossed it and went PF-4. Truck runs like a new vehicle every time I turn the key. As for cost? It comes out close to the same after the dust settles.
     
  15. Jawzjeep

    Jawzjeep Full Access Member

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    Thanks bextreme04 for your insight. I already own a running driving 454/5speed/4x4 with 160,xxx miles. Its the one in my post in 'other rigs'. I got it for the purpose of using the engine tranny in the future for my burb. And I was trying to make it a easy as I can on myself by getting a 454 tbi so that it'll slide in with minimal cussing. Thanks again. A strong opinion like your is usually due to experience. I'd prefer that.
     

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