LS Injector Size Calculator
Use this calculator to estimate the correct injector size for your LS engine build. Enter your horsepower target, fuel type, injector count, and duty cycle to get a recommended injector size.
Calculate Your Injector Size
Fill in the fields below to get an estimated injector size for your build. Results are estimates — always verify with your tuner before purchasing injectors.
Recommended Injector Size
BSFC values used: gasoline 0.55, E85 0.65, E30/E40 blend 0.60, race gas 0.50.
Common LS Injector Size Reference
General starting points for gasoline at 80% duty cycle on a standard 8-injector LS V8. These are guidelines — your specific combination may differ.
| Horsepower Target | Recommended Injector Size | Common Applications |
|---|---|---|
| 300 hp | 28 lb/hr | Stock or mild cam, pump gas |
| 400 hp | 36 lb/hr | Cam/head build, pump gas |
| 500 hp | 50 lb/hr | Forced induction or big NA build |
| 600 hp | 60 lb/hr | Boosted LS, pump gas or race fuel |
| 700 hp | 72 lb/hr | High-boost turbo or supercharged LS |
| 800+ hp | 80–100 lb/hr | Race engine, E85 or race fuel |
Things That Affect Injector Size
- Fuel type — E85 requires roughly 30% more fuel than gasoline, which means larger injectors.
- Boost — Forced induction increases fuel demand significantly at peak load.
- Duty cycle — Running injectors above 85% continuously can cause tip wear and hot-start issues.
- Injector data — Once sized, correct dead-time and flow data must be entered in the ECU tune.
Need help setting up injectors in your ECU?
Midgard Industries provides LS ECU configuration and tuning services. Proper injector setup in the ECU — including dead times, flow rate, and offset data — is just as important as choosing the right injector size. Send your build details and get a quote.