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The GM LS engine is arguably the most versatile V8 ever made. From naturally aspirated street cruisers to twin-turbo drag cars, the LS handles power with ease. However, when it's time to upgrade the fuel system, many owners get stuck before they even start.
With different intake manifolds, three different injector lengths, and various electrical connectors, choosing the right set can be a minefield. Here is the breakdown of how to choose the perfect injectors for your LS build.
1. Understanding "The Three Lengths"
Unlike many engines that use a standard size, LS injectors come in three distinct physical lengths. If you buy the wrong ones, they won't seat in the fuel rail or the intake manifold correctly.
- Short (38mm - "LS3 / LS7 Style"): Found on the LS3, LS7, and many late-model L98 engines. These are the most compact and are common in modern performance applications.
- Medium (53mm - "LS2 Style"): Primarily found in the LS2 and some truck engines (L76/L77).
- Long (60mm - "LS1 Style"): The classic length found in the early LS1 (VT-VZ Commodore/C5 Corvette).
Pro Tip: If you change your intake manifold (e.g., swapping an LS1 intake for a FAST or an LS3 manifold), your injector length requirement will change too!
2. Connectors: EV1 vs. EV6 vs. Multec
It’s not just the length; the "plug" matters too.
- EV1 (Jetronic): Found on early LS1 harnesses.
- EV6/USCAR: The modern standard for LS2, LS3, and LS7.
- Multec: Common on LS-based truck engines.
At Excess Injectors, we take the guesswork out of this. Our LS-specific kits come with the correct Plug & Play adapters, so you don't have to cut your factory wiring harness to get your new high-flow injectors to work.
3. Sizing for the LS: How Much Flow is Enough?
The LS is a thirsty engine, especially when you add a cam or a supercharger.
- Naturally Aspirated (Cam/Heads): A set of 710cc injectors is usually more than enough for a high-performance NA build, providing plenty of headroom and a crisp throttle response.
- Boosted (LSA/Turbo/ProCharger): If you are running a forced induction setup, you should look at 1100cc injectors as your baseline. This allows for safe duty cycles even when the boost is turned up.
- The E85 LS: Because the LS is a large-displacement engine, it consumes a massive volume of E85. For a boosted LS on E85, the 1500cc or 2000cc kits are the go-to choice for those chasing four-digit horsepower.
4. The "LSA" Supercharger Trap
A very common upgrade is "top-swapping" an LSA supercharger onto a standard LS engine. The LSA uses specific short-style injectors. If you are doing this swap, ensure you buy injectors specifically labeled for the LSA/LS3 height to ensure they seal perfectly under boost. A fuel leak on top of a supercharger is a recipe for disaster.
5. Why Tuning Data is Your Best Friend
The GM E38 and E40 ECUs are incredibly powerful, but they are very sensitive to injector data. If the "Short Pulse Width Adder" or "Offset" tables are wrong, your LS will suffer from a surging idle and "bucking" at low RPMs.
By using Excess Injectors’ Exact Match Data, your tuner can calibrate the ECU perfectly in minutes. This results in a car that makes 800hp but still drives smoothly enough to take to the grocery store.
Don’t Play a Guessing Game
Upgrading your LS injectors doesn't have to be a guessing game. By matching the correct physical length (Short, Medium, or Long) with the right flow rate and professional tuning data, you can ensure your V8 gets the fuel it needs to perform.