Why?

[76 xlc]

Howdy, Binder Bench Bunch!

Why would I consider switching from a carb and Kettering on my 1976 Scout II xlc? What's the issues with a well-built two-barrel Holley?

Costs in 2010 dollars?

Thanks in advance!

[cj7ox]

More power, better fuel economy, and you won't stall at extreme angles.

[76 xlc]

Could you be more qualitative, please? I understand the general benefits of FI, but I'm looking for a cost/benefit analysis.

I have a 304/727 combo and do not expect to drive more than 3K miles per year.

What does a GM TBI conversion cost? What are the issues?

Thanks!

[guidolyons]

What Sean said. More power, better fuel economy, doesn't stall out on steep angles from fuel sloshing around in the carb bowl.

Read Bill USN-1 FAQ and if you scrounge the right stuff at a junkyard/ebay, it can be done pretty cheap. ~$200-300 depending on what deals you find on the parts.

TBI fuel injection is one of the easiest/cheapest ways to get EFI on an older rig. As far as EFI goes, it's pretty simple. Probably the only thing simpler than TBI to replace a carb would be propane.

[76 xlc]

I have a TBI on a SBC 350, I'm happy with its performance and mileage, but I don't believe it performs any better or produces any more power or mileage than a well-tuned spread-bore Quadrajet.

Was happy with my Holley on my 304 in a 64 C1200 I had from 74 to 87.

Haven't priced a carb since the eighties though. 2-bbl carb kits still are under $30.

TBI might be an option for when the carb is no longer rebuildable, but I don't see it ticketing out so long as the carb hangs on.

$300 plus the value of my labor for perhaps a slight mileage gain will take years to recoup at 300 gals a year. As per the fuel bowl sloshing, Holley does make an off-road kit to deal with that.

Thanks!

[WRENCH MAN]

More power?, you'll NEVER make me believe that one!
Better economy?, only if your carb is out of tune, My scout gets 18 with the Holley 2300!, TBI Chivys only do about that range!
EXTREME! angles, VERY extreme angles, but if your tank isn't FULL it'll still stall!

The guys praising the TBI conversions are more computer literate than screw driver literate, carbs can be made to RUN!!!

[guidolyons]

Originally Posted by WRENCH MAN

More power?, you'll NEVER make me believe that one!
Better economy?, only if your carb is out of tune, My scout gets 18 with the Holley 2300!, TBI Chivys only do about that range!
EXTREME! angles, VERY extreme angles, but if your tank isn't FULL it'll still stall!

The guys praising the TBI conversions are more computer literate than screw driver literate, carbs can be made to RUN!!!

More Power- I'll give you that, it's debatable. I was thinking along the lines of same engine, just swapping from carb to EFI. From just a pure Hp, yes a carb can make more Hp than a stock TBI. TBI usually has slightly better low end Tq. If you are looking purely for max Hp, TBI isn't for that.

Better economy- Yep. TBI will win, as it can make adjustments to the A/F ratio based on throttle position, air density, altitude, etc.

Carb has 2 adjustments, the size of the jet(s) (which you can't change while you're driving), so the one you can effect is how far you push the throttle open.

Your carb runs just as good at sea level as it does at the top of Pikes Peak (without changing the jets)? I doubt it. Starts on the first try in cold weather? Idles nice and smooth?

Even with a extended vent tube, offroad baffles, etc, a carb will stumble, flood, and stall when the fuel starts sloshing out of the bowl.
Really? You need a full tank of fuel to keep the EFI running? A carb will stall out from fuel starvation long before TBI will.

For EFI, TBI is about as simple as it gets. TBI can be be tuned with a few clicks of a mouse.

[Rick Westra]

Originally Posted by guidolyons

More Power- I'll give you that, it's debatable. I was thinking along the lines of same engine, just swapping from carb to EFI. From just a pure Hp, yes a carb can make more Hp than a stock TBI. TBI usually has slightly better low end Tq. If you are looking purely for max Hp, TBI isn't for that.

Better economy- Yep. TBI will win, as it can make adjustments to the A/F ratio based on throttle position, air density, altitude, etc.

Carb has 2 adjustments, the size of the jet(s) (which you can't change while you're driving), so the one you can effect is how far you push the throttle open.

Your carb runs just as good at sea level as it does at the top of Pikes Peak (without changing the jets)? I doubt it. Starts on the first try in cold weather? Idles nice and smooth?

Even with a extended vent tube, offroad baffles, etc, a carb will stumble, flood, and stall when the fuel starts sloshing out of the bowl.
Really? You need a full tank of fuel to keep the EFI running? A carb will stall out from fuel starvation long before TBI will.

For EFI, TBI is about as simple as it gets. TBI can be be tuned with a few clicks of a mouse.

x2 Well said.

[planes48]

I currently have the Holley 2300, but for quite a few years used a Motorcraft 2bbl carb, manual choke, seemed to do away with the steep climb problem. Had to make my own cable adapters and such, but it worked well.

[scoutingitout]

Installing anything as complex as a complete computer control system, in my opinion isn't worth it. Unless you're going to go all the way to port injection the mileage change wouldn't warrant the time and money to do all the work. If you're not trying to squeeze every bit of performance from the engine ( which again entails a huge amount of cost and work) I would just be happy with what I have.. After all, if I wanted top mileage and economy why do I own a 40 year old vehicle ?

Anyway, to each his own and we all have a vision of how we want our vehicles to be. I buy old cars because I like the simplicity, I hate trying to figure out if some sensor is causing a no start problem. You are all great people, willing to help without thought of reward. Mostly giving of your time, the most precious thing we have. ( it is after all, all we can truely say is ours)

[Eric]

Yes TBI isn't as efficient as MPFI, which isn't as good as SEFI, but still it is not uncommon to increase the MPG 10% or more. The other big thing that it provides is a timing "curve" that doesn't have to be a curve. With mechanical advance you are stuck with a somewhat linear advance, vacuum advance is pretty linear as well. With the computer controlling it you can put it anywhere, that is where the TBI can increase power as well as MPG, since you don't have to compromise the mid-range to prevent detonation under high load/high rpm.

[Drew Merrick]

Fuel injection on an IH engine is pretty damn cool I think. However, I don't run with EFI, I seem to enjoy natural, simple, aspiration. But the EFI component sounds really damn cool to me.

Not because I may or may not feel a power increase. Not because I may or may not find a few more miles out of my tank of gas. And not because I can or can't keep my engine running while cliffhanging off the sheer face of some Denali mtn. But because programatically controlling every facet of fuel to air ratios in any circumstance fits my nature as a programmer and taking something old and making it work with something new fits my nature as an engineer.

It's cool not because of dollars and sense.. but because it's another challenge concerning a hobby I love.

If you like your carb then keep it. Your overall net financial situation won't benefit in any meaningful way by switching to EFI (your tax bracket will remain the same). Just an overall feeling of accomplishment... or maybe not.

[jeffs_62]

While I won't argue that a carb can get good mileage and as much HP as a TBI injection system. Providing you know how to tune your carb.

Both inductions have their merits. I personally am swapping to TBI to eliminate problems that I have while out on the trail. Going from sealevel to the top of some of the mountains I climb requires adjustment on the fly.

I have never got over 16 MPG with my carb, but I have gotten 22 MPG with my 350 TBI Suburban. Granted that isn't a constant number. I average 17MPG because of my lead foot.

Putting this system in a rig that weighs a good ton less, I have faith that it will produce gains that I will be happy with.

I plan on putting several thousand miles on my rig a year. The ultimate goal is to be able to drive it to the trails, wheel it all day or two and drive it home.

So to sum it up, for me the ultimate goal is reliability and functionality.

Jeff

[76 xlc]

I would just like to say thanks to all who replied. I really appreciate your experiences, analysis and opinions!

So long as we keep 'em running and enjoy the camaraderie that comes from marching to the sound of IHC's different drum, it's all good to me!

Thanks for the great welcome to the "club," after a twenty year absence from the ranks of IHC owners.

[badscout74]

i love my carb-600cfm edelbrok.but i have been concidering the new aluminum intake and drilling for multi point injection.has ayone else done this yet?

[Eagle-Mark]

The new aluminum intake can come with injectors pre-drilled and the fuel rail to boot.

[madmonkmort]

Originally Posted by guidolyons

More Power- I'll give you that, it's debatable. I was thinking along the lines of same engine, just swapping from carb to EFI. From just a pure Hp, yes a carb can make more Hp than a stock TBI. TBI usually has slightly better low end Tq. If you are looking purely for max Hp, TBI isn't for that.

Better economy- Yep. TBI will win, as it can make adjustments to the A/F ratio based on throttle position, air density, altitude, etc.

--propane: yep, got a 50% increase in mileage over gasoline as well as noticeably massive low range grunt. It will peel off my 33's in reverse without playing the clutch. I would not expect such a large gain in efficiency if I did not have 4.11s in the axles.

Originally Posted by guidolyons

Carb has 2 adjustments, the size of the jet(s) (which you can't change while you're driving), so the one you can effect is how far you push the throttle open.

--propane: Has two adjustments, Power and idle, which I only had to adjust to go on a V8 engine once, when I installed it.

Originally Posted by guidolyons

Your carb runs just as good at sea level as it does at the top of Pikes Peak (without changing the jets)? I doubt it. Starts on the first try in cold weather? Idles nice and smooth?

--propane: yep, it sure does! I've taken my Scout from Lewiston, ID (elevation: 745 feet) to McCall, ID (elevation 5013 ft) and then into the mountains with no problems. I know this isn't Pikes Peak or some other high elevation, but I've heard that you don't need to worry as they self adjust. Also, it's starts first time, every time, and idles almost immediately, even in the dead of winter.

Originally Posted by guidolyons

Even with a extended vent tube, offroad baffles, etc, a carb will stumble, flood, and stall when the fuel starts sloshing out of the bowl.
Really? You need a full tank of fuel to keep the EFI running? A carb will stall out from fuel starvation long before TBI will.

--propane: the fuel is pressurized, so it runs until it's gone, at ANY angle that won't starve my engine of oil, and I can shake the holy bejeezus out of it and never slosh a drop.

Originally Posted by guidolyons

For EFI, TBI is about as simple as it gets. TBI can be be tuned with a few clicks of a mouse.

--Propane: compared with propane, a couple mouse clicks seems labor intensive.

additional upsides: Propane is usually cheaper to begin with, AND most vendors don't charge you road tax on it. Because it has a very complete burn due to it's a vapor and not an atomized liquid, it's environmentally much friendlier than gasoline, with much fewer unburned hydrocarbons. Additionally, because the fuel is so clean, I only have to change my oil about every ten thousand miles, and it STILL comes out really clean. You should see the inside of my engine...spotless, no caked grime, no deposits, nothing! Also, since I still have my gasoline carburetor, I have the option of running either fuel, or can massively extend my range. Compared with the cost of installing a MPFI or even a TBI kit, LPG is much cheaper AND much easier: I only spent about $500 for everything, and it all bolts on.
propane's downside: not every place sells it.

Really I'm just ribbing you guys.