Carburetor vs. Throttle Body Injection

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billiardspintail

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Hey all, I've got an '89 Grand Wagoneer, and the engine is carbureted, but I've seen CARB approved kits for the AMC 360 to install Chevy 350 TBI kits. Is a TBI that much better than a stock carburetor?
 
A freshly rebuilt motorcraft 2bbl. It's been running just fine, but I've heard that TBI can net you some (5%) MPG gain.
 
I plan to do mountain exploring, but this is the best reason I've heard to switch.
Chevyman29 said:
Are you planning to travel through any big elevation changes ?
That's one big advantage to fuel injection vs Carb
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Does this kit allow you to do any tuning or does it self learn? Keep in mind the 350tbi setup is early to mid 80's tech. Is there another newer option out there?
My Memory of the old Chevy TBI engines were that they were reliable, but got no better mileage and had no tuning ability (OBD1)
 
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Chevyman29 said:
Are you planning to travel through any big elevation changes ?
That's one big advantage to fuel injection vs Carb
Click to expand...

It is an advantage but personally I don't think it's as big as most think. I've been driving vehicles with carbs over 50 years and if the carb os set up right they work fine. I grew up in CO at 8000-9000' feet and carbs worked fine. In todays world are they as good as fuel injecton? Absolutely not. But we're talking vehicles here that usually are going slow and easing along looking at the scenery and enjoying the outdoors.

Sure injection is good, will get better mileage (lmao), be easier to start but from all I've read and seen it will run $1000-$1500 before you done and it's working well. I have a 73 Wagoneer and looked into it for mine but decided for as much as I plan on doing it I'll stick with the carb.

I don't remember if anyone asked how many mines you plan on driving every year in it. Are you able to put it on and tune it or will it got to a shop?
 
You can run tbi on mega squirt and efilive instead of the stock ecu so yeah they can be tuned. If your having problems when your rig is at an up or down angle or off camber with the fuel bowl supply or the float working on the carb id say switch. If not stick with the carb. If your having problems with elevation the old way would be get a blow through carb and turbocharge it
 
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Two places EFI might be better, big elevation changes and driving off camber, like rock crawling but even in those 2 cases there are carbs which are designed to work well. My '78 F250 CrewCab was an old forestrytruck and had a carb which automatically adjusted for elevation changes, actually barometric pressure changes.

But if either of those affect your driving, I'd say EFI is a better solution.

Where I like a carb is low rpm luggiing. My TJ hates anything below 1000rpm but my '87 YJ would pull from 600rpm. 600rpm is a wonderful thing on ice or compact snow. I often started in second gear in the winter.
 
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Billiebob said:
Two places EFI might be better, big elevation changes and driving off camber, like rock crawling but even in those 2 cases there are carbs which are designed to work well. My '78 F250 CrewCab was an old forestrytruck and had a carb which automatically adjusted for elevation changes, actually barometric pressure changes.

But if either of those affect your driving, I'd say EFI is a better solution.

Where I like a carb is low rpm luggiing. My TJ hates anything below 1000rpm but my '87 YJ would pull from 600rpm. 600rpm is a wonderful thing on ice or compact snow. I often started in second gear in the winter.
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Any idea if an '89 Grand Waggy carb would have a barometric adjustment? I can't find any information either way.
 
64Trvlr said:
It is an advantage but personally I don't think it's as big as most think. I've been driving vehicles with carbs over 50 years and if the carb os set up right they work fine. I grew up in CO at 8000-9000' feet and carbs worked fine. In todays world are they as good as fuel injecton? Absolutely not. But we're talking vehicles here that usually are going slow and easing along looking at the scenery and enjoying the outdoors.

Sure injection is good, will get better mileage (lmao), be easier to start but from all I've read and seen it will run $1000-$1500 before you done and it's working well. I have a 73 Wagoneer and looked into it for mine but decided for as much as I plan on doing it I'll stick with the carb.

I don't remember if anyone asked how many mines you plan on driving every year in it. Are you able to put it on and tune it or will it got to a shop?
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I would have to do more research about how to install it. Most likely for these bigger things, I would send it to a shop. I just don't have the space in my apartment to do a lot myself :/
 
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64Trvlr said:
It is an advantage but personally I don't think it's as big as most think. I've been driving vehicles with carbs over 50 years and if the carb os set up right they work fine. I grew up in CO at 8000-9000' feet and carbs worked fine. In todays world are they as good as fuel injecton? Absolutely not. But we're talking vehicles here that usually are going slow and easing along looking at the scenery and enjoying the outdoors.

Sure injection is good, will get better mileage (lmao), be easier to start but from all I've read and seen it will run $1000-$1500 before you done and it's working well. I have a 73 Wagoneer and looked into it for mine but decided for as much as I plan on doing it I'll stick with the carb.

I don't remember if anyone asked how many mines you plan on driving every year in it. Are you able to put it on and tune it or will it got to a shop?
Click to expand...
Better mileage would be one of my sticking points. The ~11-12 I get now hurts a lot.
 
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Having wheeled with both over the years, here is what I have found:
With a carburetor the positives are - less cost, simplicity and ease of trail side repairs, Even if something does go wrong, you can usually limp it home.
The negative is the potential need for tuning due to extreme elevation, temperature and humidity changes if you're driving in different parts of the country and types of terrain. Also if you plan to do some serious offroading ie: steep hillclimbs or fast over rough terrain, carburetors tend to not perform as well as FI although they still work decently.
My desert car has an Edelbrock carb with offroad needles. With some tweaking it has performed very well here in the high desert and not left me stranded.

FI is less hassle to maintain and potentially a little better fuel mileage. But this comes with the installation cost and electrical upgrades required to run it, especially on a vehicle that did not come equipped with FI. A 5% increase in fuel mileage at 14 MPG is only .65 miles per gallon. That's a total of 14.2 miles on your 20.3 gallon gas tank or 1 gallon of gas. It would take a while to recoup your investment.

In my opinion, if it runs good and you're not getting crazy, that Motorcraft 2 brl is pretty bulletproof, just carry some extra fuel for long trips.
 
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billiardspintail said:
Better mileage would be one of my sticking points. The ~11-12 I get now hurts a lot.
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If you're lucky the "increase" will get you from 11-12 to 12-13. What gears and tires are you running?

You have to remember you're driving a brick through the air, there is nothing aerodynamic about a Wagoneer. I've had a lot of them over that years, best I ever got with locking hubs, tall skinny tires, good gearing was 13-15 on flat ground, in the mountains 10 was good.

If you just want FI because you want FI then get it but don't think you're mileage is going to improve 4-5 MPG when you do.
 
472HemiGTX said:
In my opinion, if it runs good and you're not getting crazy, that Motorcraft 2 brl is pretty bulletproof, just carry some extra fuel for long trips.
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I agree with Hemi!

My advice for what it's worth is to have a good tune-up done with quality parts.By that I mean new coil, rotor and cap (Blue Streak), plug wires, quality plugs (Autolite or NGK), Wix filters (gas, oil, air), synthetic oil, then have someone that really knows carbs set your up. Make sure the brakes are adjusted and the parking brake isn't dragging a little. Also check the front end for bad bearings on the axle shafts, repack your wheel bearings and make sure your tires are inflated properly. All this will probably get you a 1-2 MPG increase in mileage.

You should be able to get in punch the gas pedal once, turn the key, have it roll over and fire right up on hi-idle. A quick warm up and punch the gas pedal again and low-idle and you drive away.

Unless you're overloading or camping keep the roof rack empty.

After you do this shut the hood, go someplace and have fun with your Jeep.
 
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billiardspintail said:
Any idea if an '89 Grand Waggy carb would have a barometric adjustment? I can't find any information either way.
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I'm thinking not. They were pretty rare and only sold in mountainous regions. Mostly on commercial vehicles.

I think they are actually called variable venturi carbs or pressure carbs. My experience says they compromise fuel economy and power for the ability to work well at any elevation. EFI is popular on snowmobiles since it eliminates the need to rejet a carb for different elevations.

And I agree with the others, if what you have is working, keep it.
 
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Thanks everyone, sounds like I'm sticking with the Carburetor! This is my first non-FI truck, so I wanted to make sure I was doing the right stuff.
 
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billiardspintail said:
Any idea if an '89 Grand Waggy carb would have a barometric adjustment? I can't find any information either way.
Click to expand...
AMC used 2 different 2 barrel carbs, the Motocraft 2100 and 2150. The difference is the 2150 had the anaroid bellows for altitude adjustment. It is simply a port on the back of the carb that is opened to let in extra air or closed depending on the air pressure on the bellows. Maybe this weekend I can snap a picture if you like. Easy to tell, if there is a blank port on the back of the carb, you have a 2100, if there is a cylindrical device attached and sticks out about an inch and a half, you have the 2150. Not sure if Chrysler carried this into the 80's, but AMC did on V8s headed to dealerships above 4000 ft elevation. If the carb works well, and no emissions testing issues, keep it. But.... the TBI will do much better with elevation changes, temperature changes, inclines, rough trails, and allow you to take a number of your smog devices off (for my 76 that includes removing EGR valve, air injection, and thermal air cleaner system). With emission parts hard to find and no longer made, I'm getting close to ditching my carb for the TBI simply because my EGR delay valve is off time and no longer available. It all depends on the smog guys mood if he lets it pass. You gotta love California... and it is hard to find any one with the old sniffer smog check system and the willingness to bother. Its all plug in the computer now and let the software do the work. The TBI will make the smog guys smile. I would not consider MPG in your decision, there is no meaningful change if your carb is working correctly
 
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