Santa Pod it is then chaps ?

Tell you what though, in all seriousness, the result would be interesting

Not really, the result would be obvious.

Tony

isnt the estate more aerodynamic anyways?

anyways those 3 or 4 extra horses he has means id need at least a 15 sec head start wouldnt i

its turning into a my cokc's bigger than your cokc comp

isnt the estate more aerodynamic anyways?

Yes. And lighter.

I always find these discussions interesting.

Because a car will run on what it gets.

It's only if you use the better fuel a lot that the car will adjust to run on it. Why do people ignore posts saying that and then say they stuck a tankful of expensive stuff in and saw no difference? :wonder:

In the real world, there is probably not much difference and even 5mpg can easily be explained by the way it's driven with nothing to do with the RON.

At the end of the day, the car will run fine on either, so just stick the same type of stuff in all the time.

A question on power/torque curves: are they maximum output at each rpm - i.e. usually full throttle? What improvements does one get for, say, half throttle? And what throttle position, on average, relates to normal usage?

From my old days in the early 80's with my Golf GTIs (K Jetronic automatically adjusted to octane), I noticed an improvement with high octane fuel at full throttle. With my foot on the floor, I could compare like for like. How does one measure, or subjectively assess, the difference (if any) at in-between throttle settings?

My experience was that it was more 'fun' when flooring it, but no real difference otherwise. It seems to me that the high octane rating hardly makes a difference unless the fuel is pushed to its limits. And any difference to the engine life is only due to the times when the high octane kicks-in. What percentage of the car's overall life is that?

I'm free the next few weekends

All a bit of fun, but it would be interesting! However, the Estate is lighter and more aerodynamic as you say so maybe we should find another hatch... :p

Maybe a dyno run or something

The only reason I put in 99 is so the engine can be fed on stuff that it was intended to be fed on.

Having had turbos / high compression engines in the past, running the higher RON value allowed me to run normal or even more boost (do they still sell 105 RON in Portsmouth?). Of course temperature and air pressure played a large part.

In the old days the car's ECU would detect the detonations on compression and then reduce the boost available. Running a high RON eliminates the knocks (ok other things effect this too), but this results in more power.

I'm not so sure about running high RON on non-turbo'd / supercharged engines, the fuel does have other cleaning elements in it and perhaps the power gains on non-charged engines is down to the running gear getting a bit cleaner?

I would like to point out though that Thorney Motorsport is sponsored by Momentum 99. Read into that what you will.

Unless they bring lead back in I'll be on the 99

I put a tank full of Momentum 99 in when I was in Barrow in Furness this morning. The car really likes it !

Very interesting original post and subsequent debate! This is what forums are for.

I happen to use Sainsburys 97 or Tesco 99 (the extra cost doesn't bother me) and both of those do feel a little livlier and maybe 1-2mpg more.

For what its worth tho none of the "tests" performed can really be held up as "scientific evidence" or proof that superfuels are better. You'd need to assemble a very large (and therefore expensive!) number of mechanically identical vehicles and test them all for the study to have enough power to identify a statistically significant difference between the two fuels. None of what was mentioned at the begining would stand up to a proper statistical analysis but it sure does make an interesting read!

Maybe a bit off topic for you MK2 owners; but I'd love to see the same test done on cetane content on diesel fuels for a TDi engined car such as the MK1 vRS. I've heard that, don't quote me, above a certain cetane level (50 or something? not sure) the cetane number becomes obsolete as the engines can't take advantage of a cetane number above this. Would just love to see a test on DERVs!

I can't comment about the 2 ratings (or however many) but my car is mapped and is VERY noticeably different.

It's high octane for me for sure in future. Now I know.

the mad monk, would you class the Polo GTI or Ibiza Cupra as an hot hatch - if so why not the Fabia vRS, after all they both use the same engine and gearbox

the mad monk, would you class the Polo GTI or Ibiza Cupra as an hot hatch - if so why not the Fabia vRS, after all they both use the same engine and gearbox

where did i say the vrs wasnt anything? honestly some folk are just out to argue, get a grip

infact for the record, i never said 98 wasnt better i just asked if youd notice it, people please read before putting your size twelves into it!!!!

Edited 28 December, 201114 yr by the mad monk

I say run whatever you want to run in YOUR car as it is YOUR car! It's exactly the same as modifications, some people will like them and some will hate them but at the end of the day it's what you like that counts as it's your taste and money.

I say run whatever you want to run in YOUR car as it is YOUR car! It's exactly the same as modifications, some people will like them and some will hate them but at the end of the day it's what you like that counts as it's your taste and money.

Thats right. I work with the mad monk and he will run his car on what he wants. In fact when he had his diesel VRS people use to say when he whet past the exhaust had a strong smell of burning fish and chips.

And before anybody takes that literally and reposts about it, it is a joke but working with him isn’t lol

Edited 28 December, 201114 yr by harryweld

Thats right. I work with the mad monk and he will run his car on what he wants. In fact when he had his diesel VRS people use to say when he whet past the exhaust had a strong smell of burning fish and chips.

And before anybody takes that literally and reposts about it, it is a joke but working with him isn’t lol

now now HARRY, no more special mayo for your chip butties if this carries on!!!! and work is such a strong word

Glad to see the old petrol debate comes round again. Some good points and factual information in this thread this time round.

My feeling is that if the car is desgined to run correctly/better/to obtain the maximum out of it, by using 98 RON Petrol, then for me thats what I will (and have fed it) to date.

As a side note 2 cars ago I had a Focus ST2 2.5 turbo and I always ran that on 98 ron and it never missed a beat.

My tuppence worth....

Glad to see the old petrol debate comes round again. Some good points and factual information in this thread this time round.

My feeling is that if the car is desgined to run correctly/better/to obtain the maximum out of it, by using 98 RON Petrol, then for me thats what I will (and have fed it) to date.

As a side note 2 cars ago I had a Focus ST2 2.5 turbo and I always ran that on 98 ron and it never missed a beat.

My tuppence worth....

And well worth the tuppence , done to death now though, mostly by me LOL

And well worth the tuppence , done to death now though, mostly by me LOL

Cheers !

Happy New Year

My feeling is that if the car is designed to run correctly/better/to obtain the maximum out of it, by using 98 RON Petrol, then for me that's what I will (and have fed it) to date.

Designs are always a compromise. It is subjective opinion on 'the maximum out of it' that causes the debate. e.g.

• If you want maximum power at full throttle, go for a higher RON.
  
• If you want maximum miles per pound at low throttle, go for a lower (cheaper) RON.
  

All choices will be a mix of these in different proportions. Furthermore, if you really want maximum life from the engine, don't thrash it - whatever RON you use.

Well after 200 miles on 97/99 (Texaco High Octane & Momentum) here's my findings -

1) The first 450 miles of my car was run on a mixture of Shell V Power / 95 RON Morrisons 'best' - Lumpy idle was obvious. Knew no difference as I've mentioned here before.

2) The next 250 miles have been driven on Momentum 99 / Texaco High Octane only. No idle issues.

* During the first 450 miles (mostly normal driving, speed limits observed, I achieved no more than 31mpg.

* During the 200 miles of 99 RON, I have achieved 37mpg, same driving style.

Don't forget, my car has a Revo Stage 1 map and upgraded filter only.

There's absolutely NO doubt and no scientific studies needed for a mapped car. High Octane fuel is essential.

I'm delighted by the results and the invaluable info offered on here. Cheers chaps.

If I went to buy any performance car second hand, be it a VRS or a Porsche, if the owner told me he always used 95RON I would not touch it!

I've been reading up on this a fair bit the last week or so, by my understanding the efficiency improvement is derived from avoiding retardation of ignition under load for high comrpession operation.

So just trundling along say 60mph there won't be any efficiency difference since the engine is operating with very little compression (near closed throttle), but when driving more 'enthusiastically' there should be quite a difference.

If I went to buy any performance car second hand, be it a VRS or a Porsche, if the owner told me he always used 95RON I would not touch it!

so you wouldnt mind how it had been run in or if the oil had been changed?? very odd imho

Defintley care, but if I went to look at a car and based on first opinion if I asked "what petrol do you use?" and you replied "95". I would presume that the car hadn't been "ran in" well. They may look after there car as much as physically possible but....

so you wouldnt mind how it had been run in or if the oil had been changed?? very odd imho

Lets be realist, what seller would admit to running it on lower grade fuel??? Not many id bet, the answer straightaway would be 98 Ron minimum