Flow Racers is a reader-supported site. Purchases made through links may earn a commission.

What Type Of Fuel Do Indycars Use?

Different motorsports vary in many different ways. From the vehicles used to the tracks they race on; some are more alike than others. However, IndyCar is a truly unique motorsport, and this extends from the racing itself to the fuel used by Indy cars as well.

Indycars use an 85% mix of ethanol and gasoline, or E85 mix. The series originally used pure methanol but changed to ethanol in 2007. Ethanol is much safer than methanol, and it gives better mileage. It is mixed with a small amount of gasoline so that it has visible flames in case of a fire.

There is a fair bit of history to consider when thinking about the fuel used in IndyCar racing, which we will go through in more detail below. We will also consider the advantages of the series using ethanol over normal gasoline as well.

The Early Years Of IndyCar

The Indy Racing League (IRL) had used methanol for IndyCar racing since its formation in 1994, and methanol was the fuel of choice for all open wheel racing in the United States. This was in part due to a crash that occurred at the Indianapolis 500 in 1964, which killed two drivers, Dave Macdonald and Eddie Sachs.

Safer To Use

The fuel was chosen over gasoline due to the fiery blaze that was to blame for the deaths, at least in part. Methanol has a higher flash point than gasoline, meaning it ignites at higher ambient temperatures than gasoline. It also allows for a lot of compression, and thus can be used in a smaller fuel tank, which helps to minimize any fire or explosion risks.

The key thing about methanol however is the fact that it can be easily extinguished with water. This is due to the fact that it can essentially be diluted down with enough water to the point that there is not enough alcohol left to burn, much in the same way that alcohol or liquor that you buy needs to be above a certain percentage proof in order to be set alight.

Easier Cleanup

This proved very important in IndyCar, as pit stops with refueling was a constant occurrence in the sometimes 3-hour-long races. This meant that there were plenty of occasions for things to go wrong, and if there were to be spillages or at worst ignition in the pit lane, the situation could be fairly easily diffused without the need for messy foam fire extinguishers.

However, the issue with methanol is that it burns with an almost invisible flame. This phenomenon was first seen at scale in 1997 when IndyCar first began to race at night. At night, when there was a fiery crash, the fuel would burn with a light blue flame. However, during the day you would not be able to see it.

Renewable Fuels

This is why additives were then introduced to cause the fuel to have a color when it burned. This is because it posed a risk, with the potential of fires being invisible until it was too late. Methanol can also be produced from renewable sources, though ethanol is a far easier one to do that with. That is part of the reason that ethanol came to replace methanol in IndyCar.

Ethanol And IndyCar

While ethanol and methanol are somewhat similar in both their physical appearance and chemical properties, there are a few key differences that makes the former much safer than the latter. However, ethanol had undergone a lot of criticism in the past about its potentially damaging effects when used as a fuel on vital components of the car, including the engine.

EPIC Changes

But this was simply not the case, and though many believed that ethanol dramatically limited the performance of cars, a group called the Ethanol Promotion and Information Council, or EPIC, sponsored IndyCar driver Paul Dana in 2005 in the hopes of proving the critics wrong by encouraging the use of ethanol as a fuel in IndyCar.

Unfortunately, Paul Dana died in a crash the following year, but by then the Indy Racing League had realized the potential gains of adopting ethanol as a fuel source instead of methanol. They used a 90% methanol and 10% ethanol mixture in 2006, but in 2007 this had changed to 98% ethanol and 2% gasoline.

Smaller Tanks

The fact that gasoline was added met a rule that prevented the fuel from being deemed as fit for human consumption, and it added the visible color to the flame should there be a fire. The switch from methanol also took advantage of better mileage, which allowed the fuel tanks to be decreased from 114 liters to just 83 liters.

Less Harmful

Ethanol is also much less harmful than methanol, with the latter causing irritation and even burns when exposure is to large enough quantities. However, current Indy cars use an 85% ethanol/gasoline blend as this is what can often be used in road cars, with motorsport across the world trying to remain relevant to the everyday world as much as possible.

There have been various different fuel suppliers in IndyCar over the years, with the current being Speedway LLC. They took over from the previous supplier Sunoco in 2019, with Sunoco being the official fuel supplier for all three major NASCAR series since 2004. They had been suppliers of the fuel to IndyCar since 2012.

What About Other Motorsports?

Ethanol proves to be a very popular fuel across the world, mainly due to its fuel economy and its renewability. It can be made from crops like corn, making it a far more environmentally friendly option than fuels like regular gasoline, or even leaded gasoline which was still used in the NASCAR Cup Series until 2008.

NASCAR vs F1

NASCAR now uses a 15% ethanol blend from Sunoco called Green E15, which has been in use since 2011. This fuel is relatively high octane, coming in at 98.  F1 on the other hand uses a relatively low octane fuel, at minimum 87, in order for the sport to remain as relevant to the everyday world as possible, with the fuel used in F1 cars not too dissimilar to that used in road cars.

Drag Racing

Perhaps the most unusual fuel used in motorsport is that of a drag racer, which is nitromethane. This fuel is designed to burn hard and fast, with up to 15 gallons being used in their sub-5-second runs along the strip. When it comes to fuel economy and fuel safety, IndyCar is definitely one of the best, with drag racing definitely coming in at the opposite end of the scale.

Final Thoughts

IndyCar uses an 85% ethanol fuel blend for its cars, and this has been the case since 2018. Before that, it used a 98% blend, and before that it used methanol instead. The switch was made for several reasons, namely safety and fuel economy. This is in contrast to most other motorsports, which use more gasoline-heavy fuels.