sort of OT but yet not - High Octane Petrol

[Shaun Cook]

i got a 1.6 16v, and when the engine is cold, it shutters alot when i drive, normally does it at about 1800 revvs, but when its warm it doesnt do it as much, its just a little flat spot in my fuel apparently.

but anyway back to the topic, i normally try and put fuel in at Total, but sometimes its at Esso (cuz its closest to my house), and i found that Esso makes my car shutter really bad and the performance lacks a little. but one day i went to tesco and i dont really like tesco fuel so i put some High Octane fuel in, and my car drove like a dream, it performed better and the ride was just really smooth. and then i saw Total do a High Octane petrol aswell.

I did a search for previous posts but there was no direct answer to this, but in what way is High Octane better for my car?

PS - You can tell im bored at work lol this is what happens if ur a graphic designer working infront of a computer all day.....

Sorry couldnt hear you??

 

[Ozric-Al]

Tesco 99RON gets very good write ups it has to be said. Use Tesco fuel day in day out in Shabash! and it's never done her any harm.
As for the question, no idea.

"Doctor said to give up Keee-Babs. I said 'No, no-no'"

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[donnylad]

i use shell optimax in my mate never put anything else in it as after a while they seme to run crap on normal petrol but i must say optimax for me has been better than others especialy on long runs but each engine will react differently so trial and error i think mate.

 

[donny lad]

sos there wasnt an answer there was there lol

it helps keep ure engine clean and varius other stuff but on cars like imprezza's can give an increase in bhp that is noticeble

 

[Tom]

How old are your plugs?

I stick to Shell or BP cheap fuel, my worn out 1.6 runs fine on it.

BTW Oz, your email bounces.

 

[Carroll]

Any engine will like and run better on higher octane fuel, especialy if the engine's compression ratio is high enough to be able to take full advantage of it, (and modern car engines are.)

Most engine management systems will compensate by advancing the ignition timing to suit it.

In the days,(upto mid 1970's) when 101 octane '5-star' petrol was available, many high-performance engines would gain around 5% in extra power (and economy) compared to using 97 octane 4-star.

 

[Tom]

My 1.6 bravo has the same CR as my 1972 MGB....

An engine will only really take advantage of a higher octane fuel if the manufacturer mapped the ECU such that it can advance the timing enough. And before people mention knock sensors and adaptive ECUs, the knock sensor is there primarily to retard the timing in cases of poor fuel or during very hot weather.

 

[Ozric-Al]

Works fine for me Tom. Try "yeahandsowhat at hotmail dot com" instead chap.

"Doctor said to give up Keee-Babs. I said 'No, no-no'"

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[Carroll]

So we're agreed then Tom My point about modern car engines is that they nearly all have higher compression ratios nowadays,(whereas many of the older cars did'nt) and that most engine management systems are able to deal with higher octane fuel.