recommend fuel systems and fuel injectors
Thread Starter
Staging Lane
Joined: Feb 2023
Posts: 63
Likes: 6
recommend fuel systems and fuel injectors hey guys so i have an ls3 418 stroker N/A high compression that’s going into a c6 corvette, i don’t know much about fuel systems, and was curious as to what you guys recommend i get, i do plan on it being E-85, i just don’t know how much pounds the fuel injectors should me, and was hoping some of you guys with more experience would recommend , for both fuel systems, and injector CCs/pounds
thanks in advance!
thanks in advance!
There's a formula to give you an idea of what sized injectors you need. The two things you need to know is how much power the engine is going to make and the BFSC of the type of fuel you are going to use, number of injectors and the max duty cycle you want to run.
For example:
Engine is going to make 500hp.
BFSC for pump gas is .50
Number of injectors: 8
Max duty cycle: 80%
The BFSC for pump gas is .50. It takes roughly 1/2 a lb of fuel for make 1hp, so the math is pretty easy.
500hp x .50 = 250
8 x .80 = 6.4
250 / 6.4 = 39.06
In this example, 42 lb/hr injectors would work just fine.
Use your estimated HP level and BFSC for the fuel you are using and it should give you a good idea of what you need.
One thing to keep in mind is what fuel pressure the injectors are rated at and what your actual fuel pressure is going to be. Some injectors are rated at 3 bar(43.5psi) and others are 4 bar (58psi)
If you run an injector that is rated at 4 bar, at 3 bar pressure, that injector is not going to flow at it's advertised rate.
For example:
Engine is going to make 500hp.
BFSC for pump gas is .50
Number of injectors: 8
Max duty cycle: 80%
The BFSC for pump gas is .50. It takes roughly 1/2 a lb of fuel for make 1hp, so the math is pretty easy.
500hp x .50 = 250
8 x .80 = 6.4
250 / 6.4 = 39.06
In this example, 42 lb/hr injectors would work just fine.
Use your estimated HP level and BFSC for the fuel you are using and it should give you a good idea of what you need.
One thing to keep in mind is what fuel pressure the injectors are rated at and what your actual fuel pressure is going to be. Some injectors are rated at 3 bar(43.5psi) and others are 4 bar (58psi)
If you run an injector that is rated at 4 bar, at 3 bar pressure, that injector is not going to flow at it's advertised rate.
Thread Starter
Staging Lane
Joined: Feb 2023
Posts: 63
Likes: 6
There's a formula to give you an idea of what sized injectors you need. The two things you need to know is how much power the engine is going to make and the BFSC of the type of fuel you are going to use, number of injectors and the max duty cycle you want to run.
For example:
Engine is going to make 500hp.
BFSC for pump gas is .50
Number of injectors: 8
Max duty cycle: 80%
The BFSC for pump gas is .50. It takes roughly 1/2 a lb of fuel for make 1hp, so the math is pretty easy.
500hp x .50 = 250
8 x .80 = 6.4
250 / 6.4 = 39.06
In this example, 42 lb/hr injectors would work just fine.
Use your estimated HP level and BFSC for the fuel you are using and it should give you a good idea of what you need.
One thing to keep in mind is what fuel pressure the injectors are rated at and what your actual fuel pressure is going to be. Some injectors are rated at 3 bar(43.5psi) and others are 4 bar (58psi)
If you run an injector that is rated at 4 bar, at 3 bar pressure, that injector is not going to flow at it's advertised rate.
For example:
Engine is going to make 500hp.
BFSC for pump gas is .50
Number of injectors: 8
Max duty cycle: 80%
The BFSC for pump gas is .50. It takes roughly 1/2 a lb of fuel for make 1hp, so the math is pretty easy.
500hp x .50 = 250
8 x .80 = 6.4
250 / 6.4 = 39.06
In this example, 42 lb/hr injectors would work just fine.
Use your estimated HP level and BFSC for the fuel you are using and it should give you a good idea of what you need.
One thing to keep in mind is what fuel pressure the injectors are rated at and what your actual fuel pressure is going to be. Some injectors are rated at 3 bar(43.5psi) and others are 4 bar (58psi)
If you run an injector that is rated at 4 bar, at 3 bar pressure, that injector is not going to flow at it's advertised rate.
Pretty much every reputable fuel injector company has a fuel flow calculator on their website that asks those questions and does the math for you.
I normally use the Injector Dynamics calculator. I like how it shows the graph with different sized injectors and the duty cycle at any given RPM
https://injectordynamics.com/injector-selector/
I normally use the Injector Dynamics calculator. I like how it shows the graph with different sized injectors and the duty cycle at any given RPM
https://injectordynamics.com/injector-selector/
If I was any good at math, which I'm not. I'd reverse that formula to find out an estimate on how much power my car makes before I put it on the dyno to see how close it is.
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TECH Resident
Joined: Jun 2011
Posts: 936
Likes: 472
If the injector flow rating pressure is different than your expected operating pressure, you can use Bernoulli's Equation for In-compressible Fluid to figure out the effective flow rate in the vehicle: Q2 = Q1 x Sqrt(P2/P1) where Q = flow, P = Pressure
Remember, while flow goes up with pressure on the injector side, it has the inverse effect on the pump (if the pump has to create higher pressure it will lose flow, again using Bernoulli's but inverting the pressures).
Also, if you're planning on E85, add 30- 40% to calculated flow in gasoline.
Remember, while flow goes up with pressure on the injector side, it has the inverse effect on the pump (if the pump has to create higher pressure it will lose flow, again using Bernoulli's but inverting the pressures).
Also, if you're planning on E85, add 30- 40% to calculated flow in gasoline.
Last edited by 68Formula; Jun 19, 2025 at 05:53 PM.