How To Convert Your Carburetor for E85
Learning how to convert your carb for E85 is an excellent way to get more performance out of your engine while using cheaper fuel. E85 burns faster than gasoline. Therefore, more fuel must flow through the carburetor, which requires larger internal components to handle the increased volume. Making this transition allows your motor to run noticeably cooler and can unlock significant horsepower gains.
Removing Bowls And Accelerator Diaphragms
First, obtain a conversion kit from RobMix Services and E85carbs.com. Begin the teardown by removing the bowls and the metering blocks from your carburetor. If you have jet extensions on your secondary block, remove them carefully so they can be reused. If you do not have them, the entire block is history.
Next, remove the four screws that hold the accelerator pump in place. Carefully peel the old diaphragm off, but make sure to keep the spring. Look closely at your old part. Older style carburetors might have a black rubber diaphragm.
The alcohol in E85 will eat right through black rubber. You do not even have to take the pump apart to check this because you can simply look at the gasket overhang. Fortunately, the new diaphragm in your kit is made of GFLT alcohol resistant rubber. Make sure the mating surface is clean, then install the new diaphragm using the spring from your old pump and tighten the screws in a cross pattern.
Upgrading The Needle And Seat
Now you must upgrade the needle and seat. Although it is hard to tell by looking, the new needle and seat is slightly larger. Remove the rubber gasket and replace it with a nylon one. Reinstall the needle and seat into the fuel bowl.
Now secure the assembly with the lock down screw, which also gets a nylon gasket. After you follow these identical steps on the other fuel bowl, you are ready to move on. After following the same steps on the other fuel bowl, you are ready to convert the metering block over to E85.
Converting The Metering Block
Converting the metering block over to E85 only involves four simple steps. First, install the power valve. Next, install the new jets, which are visibly much larger than the stock versions.
Try to use a jet tool to install the jet. If you use a flat-blade screwdriver, you can actually damage the jet. Next, change the idle restrictors to the larger ones from the kit. Because the block was set up for gasoline, you must also change the position of the emulsion programming plugs.
Reassembling The Carburetor Body
Remove the stock shooters. Replace them with the higher flowing ones from the kit. Now, reinstall the metering blocks and the fuel bowl back onto the main body. As you install the fuel bowl, make sure the actuator arm is positioned above the pump lever.
Modifying The Fuel System
Your carburetor is done, but the vehicle is not. To complete this conversion, you may need to make some modifications to your fuel system. For example, you need a pump that is compatible with E85 and can flow up to 30% more fuel.
Additionally, your fuel lines must be updated. They need to be either stainless steel or rubber with a liner that is compatible with E85. After setting the floats, adjust your idle screws. They recommend setting the idle adjustment screws one and a half turns off the seated position.
Expected Tuning And Results
Once converted, you can fire up the engine. The motor should fire right up and run noticeably cooler than it did on gasoline. Surprisingly, you might require no tuning before your first full run. To maximize your performance, you can advance your timing.
For example, giving the motor a total of five degrees more timing can make a massive difference. This timing change can generate 12 foot pounds of torque and almost 18 horsepower more than gasoline. This timing change results in 477 horsepower over 459. Be prepared for higher fuel consumption. You will consume about 24% more fuel with E85.
Because E85 absorbs water quickly, it is only recommended for vehicles that are driven on a regular basis. Modifying a fuel injected engine is a little more difficult. That setup requires a few extra steps and you must get the computer recalibrated. With a carburetor, however, you can quickly begin enjoying the fuel that costs less per gallon.
