On modified engines, modern fuel injection doesn’t always perform properly. So, many drivers can opt for a TBI carb swap and get rid of their TBI setup on their current engine.
However, you’ll need a complete TBI to carb swap parts list to do this, as it may not be a simple matter of nuts and bolts. Carburetors may operate more effectively on older or modified engines, and on a custom engine, it’s nearly always a positive. However, they use a different intake and distribute fuel in another way than a TBI carburetor.
You’ll need several components to make a carburetor function in your TBI vehicle. Get a carburetor, a prospective electric fuel pump, a distributor, and a transmission computer to start, followed by a potential intake manifold or TBI to carb adapter.
Besides all this, there are everyday items like air filters, etc. In our guide, you can learn more about the parts you’ll need compared to a carburetor; a fuel injection TBI system has some differences. (Learn How To Tell A 350 From A 305)
What’s the cost of a switch from carb to fuel injection?
Depending on your car’s model, a replacement fuel injection pressure regulator typically ranges in price from $40 to $200. A competent garage will charge $50 to $100 to install it. You have already saved roughly $200 just by doing the installation yourself.
Can you convert carb to fuel injection?
A fuel injection system is added in place of a carb during a fuel injection conversion. Fuel injection conversion kits exist that make the procedure quite simple.
Carburetors are still used in older cars, but electronic fuel injection (EFI) uses injectors to deliver better performance and greater fuel efficiency. The most basic things you’ll need to convert from a TBI to installing a carburetor are a carb and a matching manifold.
Although aftermarket aluminum manifolds make more power, are lighter, and cost about $60, you may try to run a used stock manifold.
What does TBI mean on a carburetor?
Throttle-body injection, or TBI, is often known as the carburetor with a brain. TBI systems use a throttle body with two injectors and a dual-plane aluminum intake manifold to supply fuel to the engine.
What is the fuel pump pressure for TBI?
The fuel pressure regulator is set at about 12 psi (30 psi on BBC vehicles from 1994- and 1995-year truck models).
What is a TBI 350 Throttle Body Engine?
What is a TBI 350? Fuel is injected into the throttle body in a fuel injection system known as TBI fuel injection. A single or a pair of injectors control the throttle body fuel injection system.
Are Parts In Stock?
The majority of TBI parts are available and in stock. On modified engines, modern fuel injection doesn’t always work well. So what parts are required to run a carburetor on your engine correctly?
On older or modified engines, carburetors may work more effectively. For a custom engine, it’s frequently a positive thing. You’ll need several parts to make a carburetor work in your TBI vehicle.
Get a carburetor, a suitable fuel pump, a distributor, and a transmission computer to start, followed by a potential intake manifold or adapter. You might also need an air filter or cleaner to keep junk out of your carburetor and cylinders.
In addition, to fix or switch your setup, you’ll need to replace some wiring and bolt on a few extra things. (Read Weak Alternator Cause Misfire)
What Parts Will I Need?
Intake manifold
An intake manifold transfers a lot of fresh air from the outside directly to the engine cylinders of a vehicle powered by a throttle body injection vehicle. When used with a vehicle powered by a carburetor, they have a somewhat different purpose and send the outside air to the carburetor for cleaning.
A TBI-powered vehicle’s intake manifold and a carbureted-powered vehicle’s intake manifold could differ. The connections are probably different when sending air to a carburetor instead of cylinders. An adapter may be available for this use that takes a different purpose.
Distributor
When switching to a carburetor, you’ll need a replacement distributor, partly because a computer controls your current distributor, and removing the TBI eliminates that computer.
A High Energy Ignition (HEI) distributor is what you need. A stronger spark is powerful with HEI, and wider spark plug spacing is used more effectively. As a result, combustion is more powerful and complete than with TBI, which is preferable for performance engines with modifications.
Adjustable Fuel Regulator
The two aren’t compatible because the throttle body system sends fuel at a higher pressure than a carburetor requires. To the fuel line, you should connect an adjustable fuel pressure regulator. (Run down the passenger side out of the way).
Fuel Pump
You do have the choice to install a fuel pump rather than a variable fuel regulator. A fuel pump is simpler than a regulator, and there is a possibility that the fuel pump you now have as part of your fuel system is old. You’ll need to hardwire as the computer will search for a tach signal to keep the pump running. (Read Does The Brake Pad Wear Indicator Go On The Inside Or Outside)
Note: A stock fuel line won’t use a return line.
Transmission
Sensing sensors in your TBI-equipped transmission instruct the vehicle when to shift by providing this information. However, you have a few choices: You could install a different transmission that doesn’t require electronics or purchase a transmission controller computer from a dealership or online.
With a non-electronic transmission, you could also require a throttle kick-down cable for the same purpose.
Air Cleaner or Filter
Although it’s not necessary for every installation, you could additionally need an air cleaner or filter. Your intake manifold may use something to prevent debris from being clogged since it sends high-pressure air into the carb like a vacuum and could use it.
A Carburetor
We held off on this till last because it’s arguably the most obvious. A carburetor with the proper hoses is required. While they aren’t that different in reality, we advise doing some study to determine which one will provide you with the setup and durability you desire. Other elements, like the intake manifold’s capabilities, have a role.
Why Switch from TBI to Carburetor?
Changing to a carburetor is advantageous for a few reasons because TBI is computer controlled and not explicitly built up for a more powerful engine that takes fuel differently. Some individuals who modify vintage Chevrolets and Ford find that TBI messes with modified engines and results in error codes and performance issues.
Others enjoy the sound a carburetor makes, perhaps out of nostalgia. You are currently listening to the sound of older fuel systems at work, which sound cool compared to today’s relatively quiet vehicle. On older cars, carburetors are regarded as original equipment.
What Are The Disadvantages Of A Carburetor?
Fuel injector systems virtually require cleaning up after fuel buildup in carburetors, which can happen. Carburetors may require some warm-up time in cold temperatures and may experience issues.
Contrary to popular belief, carburetors were phased out by newer technology and the EPA. While capable of powerful performance, carburetors cannot continuously operate at their highest efficiency since they are not computer controlled.
While a carburetor is a continuous – sometimes needless fuel flow, a fuel injector-powered vehicle has a computer capable of delivering varied quantities of fuel at different times, including while idling.
Are Carburetors Now Illegal?
More regulations than before applying to carburetors. Inefficient carburetors were made substantially worse and more challenging to operate. In many aspects, fuel injection replaced carburetors instead of carburetors since fuel injection systems are simpler to maintain, better for fuel economy, and more environmentally friendly.
California prohibits the promotion, sale, and use of performance components for legally operating vehicles unless those components adhere to the CARB Executive Order. Vortec heads and Performer RPM manifolds can be included with engine modifications.
The same executive order gradually limits the use of carburetors in engines with lesser displacements, such as those seen in lawnmowers and weed eaters. (Learn How To Clean Aluminum Intake Manifold)
Other Conversions To Consider
Carb to EFI:
There are times when a carb will not perform as you want. So, you may switch to fuel injection. You can get a “donor” truck from a friend or a junkyard and swap its components onto your carbureted truck.
You must use one truck as a donor because many parts aren’t interchangeable between years. If you start grabbing components from other trucks, you may have issues down the line. The last thing you want is to go to all this trouble and find mismatched parts and have to start over.
Ensure you grab the full engine harness from the “donor truck,” including the ECU. Then get all the vacuum lines, switches, MAP sensors, solenoids, sensors, etc. Without these components, your truck won’t run. Run the factory EFI distributor and ignition switch. Don’t forget the “donor” truck’s high-pressure fuel pump.
EFI to Carb Conversion:
For anyone wanting to convert from fuel injection to a carb. Start by removing the factory ECU, harness, sensors, vacuum lines, etc. The key components for this conversion are a manifold and carburetor or carburetor.
You can run a DUI distributor or LC Pro distributor with an aftermarket ignition box or a stock igniter for the ignition system. You can run a carbureted distributor with a stock or aftermarket ignition. Because the EFI distributor has no advance, you’ll need the above distributor when switching to a carburetor.
A new fuel delivery system is required (you can install a pressure regulator, or you can get a new low-pressure pump). This is practically all you need to convert your factory fuel injection to carburetion.
