E85 Carb Jet Size Calculator

E85 carburetor jet size varies depending on engine horsepower. For 300-500 HP, primary/main jet size is around 80-90, while secondary jet size is approximately 75-85. These are rough estimates, and tuning may be necessary for optimal performance. Consult a professional tuner for precise jet sizing for your specific engine.

Horsepower Range	Estimated E85 Carb Jet Size (Primary/Main)	Estimated E85 Carb Jet Size (Secondary)
150-300 HP	75-80	70-75
300-500 HP	80-90	75-85
500-700 HP	90-100	85-95
700-900 HP	100-110	95-105
900+ HP	110+	105+

FAQs

1. How much bigger jets for E85? Estimation: You may need jets that are around 20-30% larger than those used for gasoline. However, it depends on your engine’s specific requirements and tuning.

2. What happens if carb jets are too big? Estimation: If the carb jets are too big, it can result in a rich fuel mixture, leading to decreased power, poor fuel economy, fouled spark plugs, and potential engine damage.

3. What size carbs are available for E85? Estimation: Carburetors for E85 can vary in size, but popular sizes range from 650 to 850 CFM (cubic feet per minute) for most applications.

4. What fuel pressure for E85 carb? Estimation: Typically, a fuel pressure of around 6-8 psi is suitable for E85 carbureted engines.

5. Can I run E85 in my carbureted engine? Estimation: Yes, you can run E85 in a properly tuned carbureted engine with the right modifications and jetting changes.

6. Does E85 add more HP than 93 octane? Estimation: E85 can potentially provide more horsepower compared to 93-octane gasoline due to its higher octane rating and cooling properties, but the exact increase varies depending on the engine and tuning.

7. Will bigger jets in the carb make more power? Estimation: Increasing jet size in the carburetor can result in more power if it optimizes the air-fuel mixture for your engine. However, overly large jets can lead to rich conditions and reduced power.

8. How do I know what size jet I need? Estimation: You determine the right jet size through trial and error while monitoring the engine’s performance and monitoring spark plug color. A professional tuner’s assistance is often necessary.

9. What happens if a carburetor is running too rich? Estimation: Running too rich can lead to decreased power, poor fuel efficiency, fouled spark plugs, black smoke from the exhaust, and potential engine damage.

10. How can I make my E85 stronger? Estimation: To maximize performance with E85, consider upgrading components like the carburetor, intake manifold, and exhaust system, along with proper tuning.

11. Can you run 100% E85? Yes, you can run 100% E85 in vehicles specifically designed for it. Some engines may require modifications to handle E85’s characteristics fully.

12. What size injectors for 500hp E85? Estimation: For around 500 horsepower on E85, you might need injectors in the range of 50-60 lb/hr (pound per hour).

13. Do you need a high-pressure fuel pump to run E85? Estimation: A high-flow fuel pump may be required to meet the demands of E85, as it flows more fuel than gasoline.

14. How much fuel pump do I need for E85? Estimation: For E85, a fuel pump with a flow rate of around 450-600 liters per hour (LPH) should be sufficient for most applications.

15. Does E85 increase cylinder pressure? Estimation: E85’s higher octane rating can allow for higher compression ratios, potentially increasing cylinder pressure, which can contribute to improved power and efficiency.

16. How bad is ethanol for carburetors? Estimation: Ethanol can be corrosive to certain carburetor components, especially if the carburetor is not designed for ethanol use. Regular maintenance and using ethanol-compatible materials can mitigate this.

17. Will E85 ruin injectors? Estimation: E85 may not ruin injectors, but it can require injectors designed for ethanol to prevent potential damage or reduced lifespan due to its different properties.

18. Can you mix 100 octane with E85? Yes, you can mix 100-octane gasoline with E85 to adjust the octane rating and tune the engine accordingly.

19. Is it bad to mix E85 with premium? It’s not necessarily bad, but it requires careful tuning to maintain the desired air-fuel ratio and combustion characteristics.

20. Is E100 better than E85? E100 (pure ethanol) has a higher octane rating than E85 and can provide more power potential, but it may require significant engine modifications and specialized tuning.

21. How do I adjust my carburetor to get more power? Estimation: Adjusting the carburetor for more power involves tuning the air-fuel mixture, jet sizes, and ignition timing while considering engine characteristics.

22. Should I rejet my carb? Estimation: You may need to rejet your carburetor if switching to E85 or making other performance modifications to ensure the proper air-fuel ratio.

23. Can a carburetor get too much air? Yes, a carburetor can get too much air if it has vacuum leaks or is oversized for the engine’s needs.

24. How do I know if my main jet is too small? Estimation: If your engine experiences poor performance, hesitation, or runs lean at high RPMs, your main jet might be too small.

25. What does the slow jet do in a carburetor? The slow jet controls the fuel mixture at low engine speeds and idle, ensuring smooth and stable operation.

26. Do carb jets wear out? Estimation: Carburetor jets can wear out over time, but it’s not common. They may get clogged or corroded, affecting their performance.

27. Is it better to run rich or lean? Neither is ideal. It’s best to run an engine with the correct air-fuel ratio for optimal performance, which typically varies depending on the engine and application.

28. How do you tell if a carburetor is rich or lean? Estimation: Spark plug color, exhaust smoke, and engine performance can provide clues. A rich mixture may result in black smoke and fouled plugs, while a lean mixture may cause hesitation and overheating.

29. Does rich or lean cause backfire? Both rich and lean mixtures can potentially cause backfire, but it often happens more with a lean mixture.

30. Why do you need bigger injectors for E85? E85 requires larger injectors because it needs a greater volume of fuel to maintain the correct air-fuel ratio compared to gasoline.

31. What modifications are needed to run E85? Estimation: To run E85, you may need modifications such as larger injectors, a higher-flow fuel pump, an E85-compatible carburetor or fuel injection system, and engine tuning adjustments.

32. Is E85 hard on engines? E85 is not inherently hard on engines, but it does require proper preparation, modifications, and tuning to ensure optimal performance and reliability.

33. At what point is E85 worth it? Estimation: E85 may be worth it if you’re seeking increased power and can source it at a competitive price, considering the modifications required for your specific application.

34. Is 105 the same as E85? No, 105 is not the same as E85. 105 typically refers to a high-octane racing fuel, while E85 is an ethanol-based fuel.

35. Is E85 the same as flex fuel? No, E85 and flex fuel are not the same. E85 is a specific blend of 85% ethanol and 15% gasoline, while flex fuel vehicles can run on a range of ethanol-gasoline blends, including E85.

36. What size fuel line for 1000 hp E85? Estimation: A fuel line with a minimum diameter of 3/8 inch is recommended for a 1000 hp E85 setup, but larger sizes may be necessary for some applications.

37. How many HP is 30 over injectors? Injectors rated as “30 over” usually imply they flow 30% more fuel than stock injectors. However, the exact horsepower increase depends on other factors like fuel pressure and engine tuning.

38. Can you have too big of injectors? Yes, having injectors that are too large can result in poor idle quality, drivability issues, and decreased fuel efficiency. It’s essential to match injector size to your engine’s needs.

39. What color pump is E85? E85 pumps are typically yellow in color to distinguish them from standard gasoline pumps.

40. Can I run E85 without a flex fuel kit? Yes, you can run E85 without a flex fuel kit, but you’ll need proper modifications and tuning to accommodate E85’s characteristics effectively.

41. How much HP does full E85 add? Estimation: On average, E85 can add around 5-10% more horsepower compared to running on regular gasoline, but the actual gain depends on the engine and tuning.

42. What is the best air-fuel ratio for power E85? Estimation: The optimal air-fuel ratio for power with E85 is typically around 12.5:1 to 13.2:1, but it may vary based on engine and setup.

43. Does E85 add more HP than 93 octane? Estimation: Yes, E85 often adds more horsepower than 93-octane gasoline due to its higher octane rating and cooling properties.

44. Does E85 make more power than 93 octane? Estimation: E85 can potentially make more power than 93-octane gasoline when properly tuned, but the actual increase varies depending on the engine and setup.

45. Does E85 damage piston rings? Estimation: E85 itself is unlikely to damage piston rings, but aggressive tuning or improper combustion could potentially lead to increased wear over time.

46. What is the best gas for a carbureted engine? Estimation: The best gas for a carbureted engine depends on the engine’s requirements and its intended use, but high-octane gasoline or E85 may be suitable options.

47. What is the best fuel additive for carbureted engines? Estimation: The best fuel additive for carbureted engines depends on your specific needs, but options for cleaning carburetors and improving fuel stability are available.

48. What is the best fuel treatment for carbureted engines? Estimation: The best fuel treatment for carbureted engines should address your specific concerns, such as carburetor cleaning, corrosion prevention, or fuel stabilization.

49. What are the downsides of E85? Estimation: Downsides of E85 include lower energy content (reduced fuel mileage), availability, potential corrosion of non-compatible components, and the need for engine modifications.

50. Can I run E85 in my carbureted engine? Estimation: Yes, you can run E85 in a carbureted engine with the appropriate modifications and tuning to accommodate its characteristics.