TBI to carburetor...how hard is it?

[dazada]

I want to put a Weiland intake manifold and Holley Street Avenger on my 1500, but how difficult would that be? I have no clue about the workings of throttle body injection, and what problems would I encounter if I were to just install a new manifold and carb?

[dazada]

I don't know if it's a Street Avenger, but this is what Summit Racing has.

http://store.summitracing.com/partde...5&autoview=sku

It seems like a pretty good deal, but then again it could be too good to be true.

[rhandwor]

If you do a search on superchargers they cover this. Basically you have to buy a kit to handle the electronics. The valves on these engines collapse at 5850rpm so you will need a new camshaft and valve springs. Probable cost close to $4000.00 but it can be done. I don't know how far you want to go.
Just the electronics will probably be at least $1000.00. I was hunting for an aluminum intake manifold appx.$500.00 plus I not sure what extras I will need.

[gouldie1903]

you'll need a fuel presure regulator, carbs function at a much lower pressure. and you will need to change the fuel lines at the engine.

the rest i'm not so sure about but you may need to reprogram the computer. you may run into some problems with the vacuum lines tps and other sensors.

good luck and let us know how it turns out

[maxwedge]

No electronics with a carb, the entire fuel management system is gone once the carb is installed, or did I miss something here!? Dazad what you looked at at Summit is a carb and manifold, again no computer hook up or controls to the pcm, not emissions legal either.

[rhandwor]

I was of understanding he was putting this on a 1999 5.3L silverado. He could get a older 350 and use the dist. with electronics enclosed and get it running. I was talking about using the computer and other engine controls to fire the plugs and ect. It depends on what he wants to do.
Cost wise he would be better off rebuilding a 350 with a new dist or rebuilding a junk yard unit. He would probably need to change the trans also.

[maxwedge]

rhandwor. Good point, but when he said tbi, that eliminated any chance of it being a late model truck, so again the lack of info throws us all "under the bus".

[rhandwor]

I think I clicked on silverado 1999 and newer but it might have been listed wrong.

[dazada]

It's a 1994 Silverado.

Someone said ealier that it would cost around $4,000. That's what I was afraid of. This is my "fun" truck, so if it's gonna cost $4k to convert my exsisting 350 with 200k miles to a carbureted setup, I might as well just buy a 350 crate and a 400 trans for closer to $3k.

Jegs has an upgraded TBI/manifold package for $900, but I'd rather pass on that and save for the new motor/trans.

http://www.jegs.com/webapp/wcs/store...08231_-1_11261

(Thanks everybody for your responses too!)

[Elbert]

Originally Posted by dazada

It's a 1994 Silverado.

Someone said ealier that it would cost around $4,000. That's what I was afraid of. This is my "fun" truck, so if it's gonna cost $4k to convert my exsisting 350 with 200k miles to a carbureted setup, I might as well just buy a 350 crate and a 400 trans for closer to $3k.

Jegs has an upgraded TBI/manifold package for $900, but I'd rather pass on that and save for the new motor/trans.

http://www.jegs.com/webapp/wcs/store...08231_-1_11261

(Thanks everybody for your responses too!)

What year type truck are you talking about?

its not going to cost $4k to convert to a carb if thats what you are trying to do. Personally if you just talking about swapping the intake over to a carb style and installing a carb... I think you would be better served to stay with the OEM TBI setup.

[rhandwor]

The $4000.00 I was talking about was using the carb on a supercharger with electronics to use the existing computer. Prices have went up since close a $1000.00.
I think his idea of using a 350 engine with a dist. with complete electronics to run the engine is the way to go.

[zario]

I would not recommended converting to carb I was thinking of doing the same but the problem is that if you have the original engine and cam it won't unless you put an external fuel pump for carburetor or you will need to replace the cam since it does not have the lobe for the fuel pump push rod

in my opinion the best you could do is go with MULTI-PORT injection I have done it and it runs great I went from TBI to TPI

[Elbert]

if you wanted to do this why couldn't you run a regulator between the carb and the OEM electric fuel pump?

In general my advice would be to stay with the TBI setup.

[jackpot5283]

tbi is a great setup as long as youre not goin extreme otherwise im pretty sure you can bolt a quadrajet directly in place of the tbi and an adjustable inline fuel regulator isnt gonna require a second mortgage.... simple job still not worth it ill take my tbi anyday

[silicon212]

Originally Posted by jackpot5283

tbi is a great setup as long as youre not goin extreme otherwise im pretty sure you can bolt a quadrajet directly in place of the tbi and an adjustable inline fuel regulator isnt gonna require a second mortgage.... simple job still not worth it ill take my tbi anyday

TBI = two barrels and 3 bolts. A Q-jet won't bolt up in any sort of way, short of hiring Red Green or Tim - the toolman - Taylor to do it. Then, it has to work. You need an intake along with the carb, and you need an intake with 72-degree center bolts.

Which begs the question, why? Why do you want to do this? The computer is much more efficient at spark curves and fuel delivery than what the best mechanical setup has to offer.

You lose the aggressiveness of the ESC timing advance (running the timing to the edge of detonation, such as the ESC system does, not only cleans the tailpipe contents but also makes for a snappier-feeling engine), the precision of fuel delivery that EFI offers (welcome back to cold-morning engine starts and stalling until everything warms up), and the performance that actually comes with these.