Why do people buy high octane petrol?

rossk26 said:
So a gain of 2-3hp is worth paying the extra? I'm not even sure on a normal day to day drive you would even use the extra performance it's giving you. Unless you drive everywhere like the stig.
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It's not just about total power.

Say your driving just in normal traffic an engine may run and pull better on super unleaded. This means you can change up slightly earlier (saving fuel). An example say your doing 30mph (in a 30mph) an engine may lumper on 95 RON and you really need to change to 4th. With the super unleaded it may make the difference you can stay in 5th gear.
 
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JasonM said:
It's not just about total power.

Say your driving just in normal traffic an engine may run and pull better on super unleaded. This means you can change up slightly earlier (saving fuel). An example say your doing 30mph (in a 30mph) an engine may lumper on 95 RON and you really need to change to 4th. With the super unleaded it may make the difference you can stay in 5th gear.
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Err....
 
JasonM said:
It's not just about total power.

Say your driving just in normal traffic an engine may run and pull better on super unleaded. This means you can change up slightly earlier (saving fuel). An example say your doing 30mph (in a 30mph) an engine may lumper on 95 RON and you really need to change to 4th. With the super unleaded it may make the difference you can stay in 5th gear.
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This baffles me,

Using super unleaded changes your gear ratio's now?
 
rossk26 said:
This baffles me,

Using super unleaded changes your gear ratio's now?
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He didn't say that.

He said that your engine may produce enough extra power than you can change to a higher gear at a lower speed (25mpg instead of 30mpg for example), therefore saving you petrol.

Simples.
 
A friend of mine only fills his Mini with V Power petrol. He would drive for miles out of the way just to go to a Shell Garage. It's only a Mini One. :/
 
rossk26 said:
This baffles me,

Using super unleaded changes your gear ratio's now?
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Its quite simple

He can change up a gear sooner since the car doesnt struggle so much at lower RPMS.

Unsure if it does do this but its certainly possible I could do this on a old car i had which could run either leaded or unleaded.
 
DAnDan said:
He didn't say that.

He said that your engine may produce enough extra power than you can change to a higher gear at a lower speed (25mpg instead of 30mpg for example), therefore saving you petrol.

Simples.
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Still confused, I personally find in my car being in the correct gear at the correct time is best for optimal economy driving i.e 3rd from 30-35 is better than 4th 30-35, as this requires less throttle action. Can see why a car with more torque will deliver better MPG. But saying a few more horses will give you 5mpg is a bit farfetched.
 
Muffin` said:
all your ep3's ukdm?
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Yes.

I ran the first two I had way back in 2004-2006 on a mix of V Power (German stuff, so 100 RON) when in Germany, Tesco 99 and Optimax when I was in the UK. This was where possible, if not 95 went in. I did it because back then it was less than a quid a litre, and in Germany even cheaper due to fuel coupons (think it worked out around 10p a litre so naturally I did 140 whenever I could on the autobahn :) ).

Every car since the fuel has shot up has been run on whatever it needs minimum. I noticed zero power drop running the EP3 on 95 so that got used.
 
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TheDome said:
Its quite simple

He can change up a gear sooner since the car doesnt struggle so much at lower RPMS.

Unsure if it does do this but its certainly possible I could do this on a old car i had which could run either leaded or unleaded.
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Surely if your that anal about MPG then why pay the premium for V Power? I'm getting a headache :mad:
 
rossk26 said:
Still confused, I personally find in my car being in the correct gear at the correct time is best for optimal economy driving i.e 3rd from 30-35 is better than 4th 30-35, as this requires less throttle action. Can see why a car with more torque will deliver better MPG. But saying a few more horses will give you 5mpg is a bit farfetched.
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The point he's making, is that an engine producing more HP (from using a better fuel) may have an optimal economy at a different (lower) RPM.
 
rossk26 said:
The big difference was made in the Subaru, which I have been stating all along, that if you have a high performance car, then high octane fuel is acceptable.
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...so your 2.5l turbocharged Focus ST is NOT a high performance car?
 
It isn't really. It's not a highly strung engine. It's a relatively large petrol with a turbo and it only makes 220bhp. That said I'm not dyning the benifits of 99ron, I'm sure it'll be felt and also have a cleaner engine.
 
rjkoneill said:
...so your 2.5l turbocharged Focus ST is not a high performance car?
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More a medium performance tbh in my opinion

Hyper - Bugatti Veyron, Koenigsegg ccx
Super - Gallardo, GTR
High - M3, RS4
Medium - ST, GTi

That's my ranking system anyway, not scientific just views
 
The engine has much more relevance than the car.

Put the ST engine into a truck, it's slow, put it in a radical, and it'll do laps round supercars.
 
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