Has anyone on this forum replaced their carburetor with the Holley throttle body fuel injection system? If so I was wondering what problems they encountered installing it and if they are happy with the results. Thanks.
Original Post
Replies sorted oldest to newest
Yes, i have used the Holley TBI.
The ones i have used are the old analogue systems that have a fuel controller rather than a computer.
After having used these systems i would never buy a carburettor ever again.
Even on the ancient system i use the ability to tune the engine while sitting in the driver's seat and in fact while actually driving is phenomenal.
So is the ease at which flat spots can be eliminated and starting improved immeasurably. Power is substantially improved.
You will need the 900cfm unit even on a completely stock engine. I have tried both the 700cfm and 900cfm throttle bodies and the improvement with just the change to 900cfm was significant.
With injection the fact that you are not relying on venturies to draw in the fuel and that it is pushed in by a pump means you can go much larger on the cfm rating and have no problems with bog down on accelleration and have superior airflow for higher rpm.
If a 1200 cfm throttle body was available i would get one for my car.
You need to be good with wiring, not a genius or rocket scientist but neat and logical with placement of wires/fuses/switches and other electrical items away from heat and sources of abrasion. Good quality electrical connections are a must also.(read the instructions) If your wiring is like a dogs breakfast you are asking for trouble.
You will need to add a 3/8" fuel return line back to the tank, i advise this should be done in stainless steel not rubber hose and the fuel line itself should be upgraded to 3/8" also. You will need to re-engineer the fuel lines in some way no matter what as the lines will need to go to different places than stock.
Take the suction strainer out of the tank if you have one and use a external suction filter between the tank and the injector pump. Use a filter after the pump as well (high pressure). Pressure is about 22psi on the Holley system.
If you are using a dual plane manifold you will need a 2" or 3" high open spacer under the throttle body, this will improve airflow incredibly and if you have a single plane manifold that will be better but you still may need a spacer to get the throttle body to the correct height to connect up cables hoses ect.
If you use the old analogue controller that i use the control nobs (potentiometers) will need to be removed from the circuit board and replaced with a quality substitute as the stock ones are crap. (simple task) If you are using one of the more modern digital controllers or computers this is not required.
Overall it is well worth the effort, once you get your head around the system it is far simpler than any carburettor. I have used one for 20 Years or more and it has been totally reliable. Once you have it set up you need not ever to think of it again.
The ones i have used are the old analogue systems that have a fuel controller rather than a computer.
After having used these systems i would never buy a carburettor ever again.
Even on the ancient system i use the ability to tune the engine while sitting in the driver's seat and in fact while actually driving is phenomenal.
So is the ease at which flat spots can be eliminated and starting improved immeasurably. Power is substantially improved.
You will need the 900cfm unit even on a completely stock engine. I have tried both the 700cfm and 900cfm throttle bodies and the improvement with just the change to 900cfm was significant.
With injection the fact that you are not relying on venturies to draw in the fuel and that it is pushed in by a pump means you can go much larger on the cfm rating and have no problems with bog down on accelleration and have superior airflow for higher rpm.
If a 1200 cfm throttle body was available i would get one for my car.
You need to be good with wiring, not a genius or rocket scientist but neat and logical with placement of wires/fuses/switches and other electrical items away from heat and sources of abrasion. Good quality electrical connections are a must also.(read the instructions) If your wiring is like a dogs breakfast you are asking for trouble.
You will need to add a 3/8" fuel return line back to the tank, i advise this should be done in stainless steel not rubber hose and the fuel line itself should be upgraded to 3/8" also. You will need to re-engineer the fuel lines in some way no matter what as the lines will need to go to different places than stock.
Take the suction strainer out of the tank if you have one and use a external suction filter between the tank and the injector pump. Use a filter after the pump as well (high pressure). Pressure is about 22psi on the Holley system.
If you are using a dual plane manifold you will need a 2" or 3" high open spacer under the throttle body, this will improve airflow incredibly and if you have a single plane manifold that will be better but you still may need a spacer to get the throttle body to the correct height to connect up cables hoses ect.
If you use the old analogue controller that i use the control nobs (potentiometers) will need to be removed from the circuit board and replaced with a quality substitute as the stock ones are crap. (simple task) If you are using one of the more modern digital controllers or computers this is not required.
Overall it is well worth the effort, once you get your head around the system it is far simpler than any carburettor. I have used one for 20 Years or more and it has been totally reliable. Once you have it set up you need not ever to think of it again.
Ps: do not use the holley injector pump, they fail. Use a Bosch injector pump, part number 044.
FAST EZ-EFI 2.0 has 8 injectors in the throttle body and supports up to 1200 hp. This system works great.
I have a 900cfm Holley Avenger system. I agree with Aus Ford I would not go back to a carb. I had issues early on due to my unit being an early serial number with software issues and a failing injector. The injector was easy to diagnose as you could see it spray intermittently. I did send the computer to Holley for a software upgrade and all has been good since.
Steve
Steve
I have the FAST EZ EFI and love it. There are a bunch of throttle body EFI systems out there that utilize a wide band O2 sensor and self learning algorithms. Huge improvement over a carb if you can sort out the technical aspects.
Also, your intake manifold and exhaust system must be absolutely sealed and leak free. If a small air leak gets to the O2 sensor, the system goes haywire. My formula for success is the Remflex header gaskets & Percy's dead soft aluminum collector gaskets. Accept no substitutes.
Get it right and will have brilliant throttle response and instant starting.
Also, your intake manifold and exhaust system must be absolutely sealed and leak free. If a small air leak gets to the O2 sensor, the system goes haywire. My formula for success is the Remflex header gaskets & Percy's dead soft aluminum collector gaskets. Accept no substitutes.
Get it right and will have brilliant throttle response and instant starting.