A recent survey of petrol vehicle owners in India found that about half of drivers with pre-2022 petrol cars reported a noticeable drop in fuel efficiency after filling up with E20 petrol (petrol blended with up to 20% ethanol).
Key findings from the survey include:
📉 Mileage Drop in Older Cars
- Around 50% of owners of petrol cars made before 2022 said their mileage (km per litre) dropped after using E20 petrol.
- Of those reporting a drop, many said the decrease was 10–20% or more compared with before.
🛠️ Wear and Tear Issues
- Some owners also reported higher wear and tear on parts like fuel pumps, injectors, seals and gaskets — components that may not have been designed for higher ethanol fuels.
📊 What the Numbers Show
In one part of the survey:
- ~25% reported more than 20% drop in efficiency.
- ~7% reported a 15–20% drop.
- ~13% reported a 10–15% drop.
- Around a quarter saw no noticeable change.
This mix of responses suggests that while many older cars are affected, not all vehicles show the same level of efficiency loss — it depends on the model and how well their fuel system tolerates ethanol blends.
⚠️ Why This Happens
Ethanol contains less energy per litre than pure petrol, so cars not designed or calibrated for higher ethanol blends like E20 may get slightly fewer kilometres per litre of fuel. This is a known technical effect of ethanol’s lower energy content compared with petrol.
Older vehicles in particular may also have fuel components (like seals, hoses or injectors) that aren’t built for higher ethanol content, which could lead to both mileage changes and maintenance concerns.
🔍 Broader Context — Government Begins E20 Rollout
From April 1, 2026, India made E20 petrol with a minimum 95 RON rating mandatory nationwide to reduce fuel imports and emissions.
While newer cars (especially those manufactured after 2023) are typically designed or calibrated to run on E20 fuel without major issues, many older models were originally tuned for fuels with less ethanol, making them more sensitive to the blend change.
🧠 What Owners Should Know
✔ Mileage loss isn’t universal — some cars adapt better than others.
✔ A drop in fuel efficiency doesn’t automatically mean engine damage, but some older components may wear faster.
✔ Servicing fuel system parts regularly and checking compatibility with E20 can help maintain performance.
