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Old 12-21-2014, 09:34 PM   #1
rs74
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TBI vs. Carb?

Just wondering everyones thoughts on this subject. My 86 K30 is 454 carb powered but I have a TBI 454 also sitting in my garage. I think I have all the sensors, throttle body, computer but not the harness. The engine I am running now has an aluminum intake and holley carb now with headers. Not sure how much work it would be and what all I would need to convert to TBI. If it would even be worth it.

I like fuel injection as a whole but am thinking probably won't get the power that the carburetor will deliver. Any thoughts about any of this?
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Old 12-21-2014, 09:53 PM   #2
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Re: TBI vs. Carb?

I never saw much of an increase with TBI as opposed to the carb so my thingts are unless youre looking for a project to do , id just leave it be
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Old 12-22-2014, 12:04 AM   #3
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Re: TBI vs. Carb?

I've been driving these trucks for 32 years,had about 16 of them.1 EFI,the rest carbs & good luck with the carb.It's simple & reliable & when the carb is kept in good condition will give pretty decent performance.There are the ones that claim EFI starts better,but if the carb is set correctly will start just as good.
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Old 12-22-2014, 12:05 AM   #4
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Re: TBI vs. Carb?

Carb vs TBI if the cfm is ideal for the engine application may only slightly increase power if at all, but driving dynamics can be greatly increased. The power increase would likely come over time due to computer adjusting for incidentals a carb can not.

I have a bolt on 350 in my K20, and am playing with the idea of a TBI swap. My q-jet is having a couple of lite issues, but 95% fine. If I do the swap I will use mega squirt for computer controls, and the new version is user friendly.
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Old 12-22-2014, 12:11 AM   #5
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Re: TBI vs. Carb?

Would i have to swap out the complete engine bay harness or just part of it?
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Old 12-22-2014, 12:15 AM   #6
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Re: TBI vs. Carb?

I think Chevy seperates the harness from the chassis so it is only connected at a few places. This way a V6 or V8 truck does not need different chassis harnesses.
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Old 12-23-2014, 10:18 AM   #7
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Re: TBI vs. Carb?

Quote:
Originally Posted by Ziegelsteinfaust View Post
I think Chevy seperates the harness from the chassis so it is only connected at a few places. This way a V6 or V8 truck does not need different chassis harnesses.
That's what I thought. So wiring one in shouldn't be all that hard. Probably a power wire and ground somewhere.
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Old 12-24-2014, 10:35 PM   #8
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Re: TBI vs. Carb?

I went the other way. From tbi to carb on a 350. My feeling on the tbi is if it's working don't touch it. If it starts to have problems. It's an endless Pita of testing this and that. Then replacing this sensor and so on and on and on. As for power, I don't have any numbers to back this up. But I do feel like it has more mid to high end power with the carb (q-jet). Both ways it fires right up on the first try. And strangely my fuel mileage went up after swapping to a carb.

So Imho you won't gain anything going tbi. Other then having a project to work on.
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Old 12-25-2014, 09:36 AM   #9
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Re: TBI vs. Carb?

Fuel injection working properly is great. As reported, there are a lot more gizmos to go wrong - you are entering the computer zone which does not exist on carbureted vehicles. So, a new vehicle with fuel injection is mostly trouble free. An old vehicle with TBI will likely need a lot of trouble shooting and repair. Anybody can swap out a carburetor. Unless you drive a lot of miles, a TBI won't be worth the cost of modification/repair, IMO. If I went FI I would prefer a late model truck with less need for repair.
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