If you own a car produced after 2015 and it’s fuel-injected, there is nothing to worry about
BHPian V0rtex recently shared this with other enthusiasts:
I read an Instagram post by Harmonixx Tuning a couple of hours ago. This is the content from that post. According to Harmonixx, they started to take an interest in ethanol blends in October 2020, because American tuners recommended it to increase HP and torque. They ordered their first flex fuel kit for one of their customers’ Skoda Octavia vRS and ethanol testing bottles to monitor the progress of ethanol blending in India.
They did extensive testing over the next few months. Back then, all fuels had 0% ethanol in them. And they tested this on several fuels available back then like Shell Regular, Shell V-Power, HP Power 99 and found that all fuels contained zero ethanol. Back then it was very difficult to source ethanol (E100) because there were strict government regulations over production and distribution of ethyl alcohol.
In the last 5 years, they’ve used ethanol blends ranging from E30-E85 in their builds. Hence they have collected a vast amount of data and experience with ethanol over the past few years. Petrol sold in India prior to 2021 was just petrol combined with other additives (like injector cleaners, octane boosters, dye to help identify the fuel, detergents, etc.). Although the government’s proposal to blend ethanol had begun back in September 2002, serious blending began only post Covid-19.
When they had tested the fuels in late 2020, almost all available fuels had zero ethanol in them. Slowly the petrol companies started blending small amounts of ethanol or ethyl alcohol (C2H5OH) into petrol.
- 5% Ethanol + 95% Petrol blend is called E05
- 10% Ethanol + 90% Petrol blend is called E10
- 20% Ethanol + 80% Petrol blend is called E20
- 85% Ethanol + 15% Petrol blend is called E85
In countries like the US and Brazil, you can drive into most gas stations and fill up E85 straight out of the dispenser.
The earliest ethanol blend they saw in India was with Power 99 which had E07-E08 in late 2022, and XP95 which had E05 in April 2023.
The advantages of blending petrol with ethanol
- Ethanol has a much higher RON rating compared to petrol
- Because of the added RON, ethanol has a higher knock resistance than regular petrol
- Ethanol also helps reduce charge temperature
- Ethanol helps reduce CO & HC emissions
- Ethanol helps reduce soot formation
- Ethanol helps reduce India’s dependency on imported crude oil
- Ethanol helps reduce the cost of the fuel
The disadvantages of blending petrol with ethanol
- Ethanol has a much lower energy density compared to regular petrol, so you need to burn nearly 33% more fuel to achieve the same results.
- That’s why you see a drop in fuel economy by around 3–4% with E10 blends, and up to 6–8% with E20 blends — which is actually normal.
- In older cars (mostly non–fuel-injected vehicles manufactured prior to 2005), the materials used for rubber hoses, gaskets, seals, etc., might not be as durable as those in modern-day manufacturing and may need replacement. However, as vehicles age, you’ll have to replace these parts anyway, as they become brittle over time — regardless of whether the petrol is blended with ethanol or not.
- Ethanol is hygroscopic, meaning it can absorb moisture or water. If ethanol-blended fuel comes in contact with water, ethanol and water mix completely, and you wouldn’t be able to tell the difference visually. If water enters the engine, the pistons can compress ethanol but cannot compress water. This is how a hydrolock can occur. However, such cases are extremely rare.
- Running very high ethanol blends (in excess of E50) can cause engine starting issues in very cold climates. These problems are unlikely in India, where such high blends are not common and single-digit or sub-zero temperatures occur only in certain parts of the North and North-East.
Should you be worried about E20 blends?
If you own a car produced after 2015 and it’s fuel-injected, there is nothing to worry about. Your ECU is smart enough to adjust the fuel trims accordingly, and will maintain the air–fuel ratio (AFR) it’s programmed to target. They’ve extensively tested very high ethanol levels (up to E85) on engines like the EA888, B58, S58, and EA839, because they show impressive performance gains. They’ve been running much higher ethanol blends on cars launched as early as 2017 and have not seen any issues in over five years.
In the US, you can simply drive to a petrol station and fill up with E85 directly into your tank provided your ECU is tuned for such high ethanol content (commonly called Flex Fuel). 
Social media hype is exactly that – hype. Many content creators thrive on fearmongering to get more views, which is causing unnecessary panic among car owners in India. Another reason for the spread of misinformation is the lack of expertise in internal combustion engine technology. At E20, your engine cannot die. The only real downside is a small drop in fuel economy. Globally, ethanol blended fuels are cheaper than regular petrol.
But, since this is India, when has any government reduced prices to benefit taxpayers? That’s our only gripe with E20 blending. The reality is: it improves the performance of modern engines, reduces charge temperatures, and if priced fairly could be a win–win for everyone. If ethanol blending can do all of this while also reducing emissions, we should welcome the change.
What engines can run safely on E20 petrol?
- All 1.0 TSI, 1.2 TSI, 1.8 TSI, 2.0 TSI, 2.9 TT, 3.0 T, and 4.0 TT engines from the VW Group (post-2012).
- Hyundai 1.0 TGDi and 1.5 TGDi engines.
- All BMW B48, B58, and S58 engines.
- Almost all Mercedes-Benz petrol engines (post-2015).
- Almost all naturally aspirated petrol engines (post-2018).
If you own a car older than 2015, it’s already a decade old, so you should be doing preventive maintenance anyway — such as injector replacement, fuel filter and pump changes, and replacing hoses, gaskets, and seals, which will naturally wear out over time.
So stop panicking, fill up with the fuel available at your nearest petrol station, and enjoy driving! Always remember: your car will only be as good as the maintenance you put into it. Don’t wait for parts to fail and then scramble for repairs, practice preventive maintenance.
Recommended preventive maintenance intervals:
- Engine oil: every 4,000 km if using mineral oil, or every 7,500–8,000 km if using synthetic oil.
- Spark plugs: every 15,000–20,000 km.
Harmonixx has been running blends far higher than E20 since 2021 and has yet to see a single issue apart from a drop in fuel economy. We’re talking about cars worth over a crore and making more than 500 hp. If ethanol is safe for these engines, it’s safe for smaller, lower-horsepower engines too.
What are the current ethanol levels in the fuels they’ve tested as on August 2025?
- XP100 – E8-E12
- XP95 – E18-E22
- Power 95 – E15-E18
- Shell V-Power – E12-E15
- IOCL 91 RON – E18-E2
Why do we love ethanol?
Here’s a dyno chart of a Stage 2 G82 M4.
On XP100 with an E10 blend, the car made 586 HP. Raising the blend to E50, the car picked up an insane +88 HP.
This gain came from increasing boost slightly and adding about 4° of ignition timing over the 100 RON map.
Check out BHPian comments for more insights and information.
