Using higher octane fuel

[niceboyjohn]

Hi All,

 

Is there any advantage in using v-power/momentum in my sigma engined 1.6 2009 caterham? Particularly interested if it makes any difference on track.

 

Thanks

[Jonathan Kay]

There's no particular reason for thinking that for an engine with a given compression ratio use of a fuel with a higher octane rating will increase the power output. (But a higher compression ratio which requires higher rated fuel to avoid premature detonation will increase power output. And some engines adjust themselves if they detect knocking.)

But the archives contain several anecdotal reports of detectable effects. TTBOMK none of them involved blind testing or objective measurement.

Previous discussions: https://duckduckgo.com/?q=site:caterhamlotus7.club+octane+power

Jonathan

[StevehS3]

I cannot notice any difference in my 310 Sigma. I use higher octane but that is only because it comes with the E5 petrol.

[TomB]

The other element of the VPower type fuels is they have additional additives and are reputed to keep the valves and stems cleaner with reduced carbon build up, and they have less bioethanol in too if your worried about rubber components. 

[Mechanical Moz]

https://www.bbc.co.uk/sounds/play/m001hfqq?partner=uk.co.bbc&origin=share-mobile

Recent episode of the BBC show Sliced Bread about this very question. 

[Geoff Brown]

Since the change to E10 I have been using SHELL V-Power E5 98 in my 2013 R400.

I have not noticed any particular change in the cars performance. But have noticed a marked improvement in cold starting, tick over when hot & improved pick up to throttle input which was good any way.

From what I know of most if not all ECUs it is just controlling the engine characteristics to prevent detonation so regardless of fuel quality/octane/Ethanol there will not be much of a perceived change in 'performance'. Unless one goes off piste with 100+ octane then I fear engine damage could result.

Of course being a Caterham I may be totally wrong!

[MattB]

When my Mk3 MX-5 (2l Duratec with VVT) was being tuned on a rolling road I told the tuner that it had always been run on V-Power. He said that it wouldn't make any difference. A few hours later he expressed his surprise at how much ignition advance he'd been able to programme in safely, getting higher bhp readings than he'd ever managed before on cars that ran 'normal' fuel.

It does make a difference in a NA engine, but you need to reprogramme the ecu to see that difference.

MattB

[Jonathan Kay]

Have any factory-engined Sevens had knock detection?

Thanks

Jonathan

[MattB]

The knock sensor on a Duratec is usually on the left side of the block directly under no.2 intake runner.

It's an empty space with just the threaded hole for the securing bolt on my 420 (note - photo's upside down).

MattB

[StevehS3]

Whenever I dip into this topic there always seems to be a lack of hard evidence that there are quantifiable benefits of premium fuel over standard for cars that don't require it. Personally I am not convinced that long term use of fuels with more additives is better for the engine. I accept it may keep an engine cleaner but does having more detergents increase wear elsewhere? Maybe it depends on the particular engine and how it is used (eg long journeys vs city start/stop etc). 

[niceboyjohn]

Thanks for the insight all.

Makes sense that an ecu remap (as I used to have in my imprezas) would be needed.

 

John

[Simon420R]

I remember digging out some lab studies on this subject a few years ago. Unfortunately I don't have the references anymore but there was some evidence of a slight increase in throttle response but no significant difference in over-all power output. I still use V Power simply for the cleaning additives though. 

[Jonathan Kay]

BTTT because of recent question about properties of fuel.

Jonathan

[Ant2]

I read some studies in 2001 about different companies fuels, octane, cleaners, additives etc. 

Off the back of that i have always filled my cars with shell unleaded or diesel.

I would then fill with vpower about every 5-10 fills or if it was my second 'fun' / performance car, always with vpower.

I always get better mpg with vpower, but not enough to offset the cost as such, but for it's cleaning properties.

 

Needless to say I've never had any issues of bad dpf's, deposits, gunk build up or premature wear in any of my cars, so continue that way for the next 20 years too.

Incidentally shell has never been more expensive than any other competitor,  not including supermarket stuff, which isn't im the same ball park

[john milner]

Three benefits to a regular engine without that has not been tuned up in some way such as increased compression.

1/ Less likely to rot old fuel hoses.

2/ Some cleaning although probably not enough to warrant frequent use.

3/ Shareholders of oil companies become richer.