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.
Don't want to tune it yourself?
Mail in your P01/P59 and get a VATS-deleted, swap-ready base tune for $100. Typical turnaround is 1-2 business days after the ECU is received.
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.
