[Totoro11]

Ethanol blending is a harsh reality that we cannot escape in today's climate conscious times and the govt. seems to be fully committed to increase the spread. There have also been a lot of queries and discussions on the effects of ethanol on life of parts and fuel efficiency on the forum.

This coupled with the reducing mileage of my car (from 15kmpl to 13kmpl in one year, which i suspect could be partly due to fuel composition) prompted me to consider completely moving to the premium fuels on offer. My running in Delhi NCR is around 60km per week with a 700-1000km long trip per quarter, the car is 2 yrs old with1.5L NA engine and CVT automatic.

Can BHPians please share their thoughts on:
1. Does the low running justify going for premium fuels? What is the cost benefit analysis?

2. Which brand gives better results (IOCL/HPCL/BPCL or any other)?

3. Another option is to get normal petrol from Reliance/Essar/Nayara if they are not blending?

4. Should i just wait for the fuel level to drop low and then refill with premium petrol or get the normal petrol completely drained from tank first and then refill?

[Shreyans_Jain]

There is no benefit to be had from premium fuels in a car like yours. Your engine is tuned for 91 octane, and that is the minimum octane rating sold anywhere in India. Any advantage of using higher octane is purely placebo.

The loss of fuel efficiency over the past year can in part be justified by the increased amount of ethanol that is now being blended. Ethanol’s caloric value is 30% less than normal petrol, using blends leads to loss of both performance and efficiency. All petrol sold in India is ethanol blended, irrespective of the brand. 12% is the current minimum.

In fact, premium fuel like IOCL’s XP100 is E15.

[dmplog]

I had used premium petrol ( and diesel) in the past, mainly Speed and Power. But didn't observe much difference in performance or mileage with my previous cars.

But my perception changed completely when I used XP95 on my Kushaq. The refinement, performance and fuel efficiency is noticeably better.

[Shreyans_Jain]

Originally Posted by dmplog

But my perception changed completely when I used XP95 on my Kushaq. The refinement, performance and fuel efficiency is noticeably better.

Kushaq is different. The engine is optimised for 95 octane, with 91 octane being the minimum allowed. The same is mentioned in bold and capitals in the owner’s manual as well as on a sticker at the back of the fuel filler. That is why it performs better on XP95.

[Totoro11]

Originally Posted by Shreyans_Jain

There is no benefit to be had from premium fuels in a car like yours. Your engine is tuned for 91 octane, and that is the minimum octane rating sold anywhere in India.

Ethanol’s caloric value is 30% less than normal petrol, using blends leads to loss of both performance and efficiency. All petrol sold in India is ethanol blended, irrespective of the brand. 12% is the current minimum.

In fact, premium fuel like IOCL’s XP100 is E15.

Thanks, I was looking to go for premium in the hope that it will not be blended. However, your last sentence put paid to those hopes.

[Sufficient_shop]

Originally Posted by Shreyans_Jain

Kushaq is different. The engine is optimised for 95 octane, with 91 octane being the minimum allowed. The same is mentioned in bold and capitals in the owner’s manual as well as on a sticker at the back of the fuel filler. That is why it performs better on XP95.

Any idea what Kia Seltos 2023 Turbo DCT is optimised for? I suspect it's still 91 octane, but not sure.

[cranberry1864]

Originally Posted by Sufficient_shop

Any idea what Kia Seltos 2023 Turbo DCT is optimised for? I suspect it's still 91 octane, but not sure.

Per the manual:

Your new vehicle is designed to use only unleaded fuel having an Octane Rating of RON (Research Octane Number) 91 / AKI (Antiknock Index) 87 or higher. (Do not use methanol blended fuels)

They don’t mention the 'optimized' octane value but do state it's 'designed to use 91 or higher'.

[Samarth 619]

I've recently tried Speed 95 on my Duke 390, and I can't say the performance has gone up because I hardly rev that hard but I do feel something has improved, could be response, vibrations or the combustion feel. My bike being a high compression engine, may use the extra octane well.

I have a feeling this could be due to lower ethanol blending as compared to normal fuel, but I don't know for sure. I've heard somewhere that Rajasthan's ethanol blending is 10%, but this could be an older figure.


PS: There's a whole lot of confusion between octane, ethanol and premium fuel. From what I know, let me summarize the important points:
1. Premium fuel may be of the normal 91 octane as well, with additives. Pay attention to its branding.
2. Higher octane fuel isn't more explosive or combustible scientifically, in fact it's the opposite.
3. Ethanol blending increases the octane number of fuel. In short because ethanol can compress more without pre-igniting. This is why most people get confused when normal fuel is of a higher octane and premium fuel is lesser- it's ethanol working here.
4. High compression ratio engines may make the best use of higher octane fuel to the best of my knowledge.

[shankar.balan]

XP 95 makes the best sense for my beloved little racing rabbit. Plus the Octane Boost additive.

Once in a while I treat it to a good long drink of that delicious super-juice - XP100, but that is an expensive game. Without doubt there is a palpable difference in performance and even the growl.

I do at times go for HP Power which is also good juice.

I cannot find BPCL Speed 97 as well dsitributed as the above two, at least in Bangalore, but if I saw it I would use it based on need.

[ssjr0498]

Somehow, the packaged octane boosters never could impress me. Always made me feel, if the effects were placebo!
Have tried these with multiple options of fuel, but never noticed any difference.

However, using premium fuel from IOCL (XP95/100), BPCL and HP did make some difference. The best being IOCL followed by BPCL and HP (references are from fuel used from COCO outlets).

The old school mix of toluene, naptha etc with fuel turns out to be the best, however, if running a stock pgm-fi with knock sensors will make the car feel more dull than stock. Need to have a programmable ecu and relative tune to best utilize these 110 plus octane concoctions.