[LastActionHero]

I was reading an article on America's biggest rip-off's and chanced upon this gem

If you're filling up your tank with super gasoline, chances are your wallet will soon be running on empty.

The special stuff costs up to 20-40 cents more per gallon than regular gasoline, even though it doesn't do anything to improve the performance of most cars. With regular gas averaging about $2.72 a gallon, that translates to a 15% premium.

It's like feeding your dog more expensive food and expecting it to jump higher," says Gabriel Shenhar, senior auto test engineer at Consumer Reports.

When Shenhar tests cars, he doesn't put much stock in the manufacturer's "recommendations for optimal performance" -- instead, he uses the fuel grade that's explicitly required. You can find the requirement printed on the inside flap of your car's gas tank.

The bottom line: Read your owner's manual. While some high-performance or luxury cars may need super gas, your average Celica doesn't.

Does this mean tha Premium fuel does not give additional performance for your car? Personally I have noticed better engine performance in my car(Chevy UVA) when I put in the premium fuel. But it could also be just a figment of my imagination.

Article Link

Any comments?

[piyush78]

Even i used to tank up HP premium in my petrol swift for a long time.On one occasion had to fill the normal petrol from IOCL, from then on never did miss the premium as there was absolutely NO difference in performance or economy.I suppose if at all there is some difference, it is not easily perceptible.

[vikramk]

Its all in the compression ratio of engine used in a car. If a manufacturer recommends higher octane fuel, that's because some engines will end up knocking with regular fuel.

In India I guess its a marketing stunt meant to sell a higher octane fuel to a customer in the name of better mileage and thus recover some of the money lost on regular fuels on account of government subsidies.

[scorpio_fan]

For my Zen (old model, 2002) the M.A.S.S. advised to use the normal fuel as they say the engine does not require high octane fuel. From that day, I never filled high octane fuel in my Zen.

[Shan2nu]

Same case with IOC. Have been filling regular fuel since Sept 2009 and haven't noticed any drop in performance or knocking/pinging of any sort.

Shan2nu

[Mayavi]

That is true, high octane fuel is not equivalent to high performance. Some cars are tuned to deliver their rated horsepower only with the premium fuel but they do run on regular fuel.

Infiniti cars, for example, generate their rated hp only with premium fuel. Using recommended premium helps, but not required.

Honda's on the other hand are tuned to generate max hp using regular fuel. Using premium only burns a hole in the wallet.

BMW and Mercedes are tuned to run on high octane only. With low octane fuel, the engine will knock. Premium is required.

[Sudan_NFS]

i have used both normal and Premium (speed) petrol ,believe me i would easily find the difference in performance and mileage the car gives.
I think this might differ for other cars.

[bottle]

I found that the car was slightly more drivable in traffic conditions while using premium as in it felt slightly more torquey and less prone to knocking while regular fuel seemed to give me a better top speed and top end performance

[WDM007]

But I guess that it will definitely make difference if you feel "normal petrol" of "premium companies" like SHELL instead of "premium petrol" of "normal companies" like IOC,BP etc.

As I believe whatever quality issues [like adulteration etc] are there with IOC,BP will not be there with Shell.

[SPARKled]

I am yet to see any benefits of premium fuel in any of my cars but I have to admit that using Shell petrol in my Honda Eterno scooter improved mileage by atleast 2-3 kms. Have not been using it for the past 6 months now as the Shell bunk is far away from my new home. So does Shell provide better quality fuel than our local IOCs and HPs?

[Gansan]

The octane rating of both premium and normal fuels are the same. The only difference lies in the additives for cleaning the engine. I have never used any fuel other than Shell super unleaded in my car, so can't say anything about performance with normal fuel. But I have tested my bike with both fuels, and there definitely is a difference in smoothness as well as mileage while using the premium fuel. It is more easily measurable in bikes IMO.

[gpa]

Originally Posted by Gansan

there definitely is a difference in smoothness as well as mileage while using the premium fuel.

You are right about the smoothness. The engine does feel a tad bit smoother especially when trundling along at low speed. However, the increase in FE is negligible and not enough to justify the higher premium paid. I have used Shell's Super in my Alto (2-3 tank-fills) to validate the higher FE theory and the difference was just marginal, hence I switched over to their normal brew.

Besides, the FE of 20.43 km/l that I once achieved in 100% city driving (no use of a/c) was with the normal Shell petrol.

[Delta Wing]

Octane rating (measured against a mix of iso octane mixed with heptane e.g. 90% iso octane and 10% heptane matching with sample makes sample octane 90)has to do only with the knocking properties of a fuel so more octane number means lesser knocking. What would that do to performance, economy? The super fuel in those countries is a high octane fuel. In India, it's only additives with same octane number. The value of this kind of premium fuel is debatable at best. Bharat Petroleum site gives this:
"Speed" is a blend of petrol and world-class multi-functional additives, sourced from Chevron Oronite Company LLC, a ChevronTexaco company, which complies with EPA 97 (Environment Protection Agency, USA) requirements. "Speed" contains unique deposit control additives that effectively remove harmful deposits from all fuel metering systems and components resulting in enhanced overall engine performance - easy starting / smooth idling, maximum power and acceleration, reduced emission, and no engine knocking - improved mileage and reduced maintenance costs.
---
If your car needs high octane fuel, the manufacturer will tell you so. Additives for any cars? Take your pick as per your experience. I stick to plain unleaded after not much difference in economy/performance as compared to extra dough coughed up.

[shadow]

I have been using Speed in my Pulsar 180 (2005) and the engine feels smoother than occasions when I have had to use regular fuel. Maybe the octane helps the fuel burn better. Any thoughts?

[vrprabhu]

Originally Posted by Gansan

It is more easily measurable in bikes IMO.

+1 to that.

In my Palio I found not much difference between BP Speed / HP Premium vis-a-vis normal petrol. I felt normal + IFTEK is a better bet - because I am sure of what I a mixing!

However, in my Gladiator the difference between normal and premium is clearly apparent - the exhaust sounds smoother and at 90 kmph (as per odo) the bike is eager - with normal petrol, at this speed, the engine feels throttled

BTW, does the compression ratio has anything to do with this? As per user manual the compression ratio of the Palio is 9:1 and Gladiator is 9.5:1.