THE reason so many manufacturers are moving to smaller-capacity turbo engines is economic rather than for economy. A lower emissions rating means higher sales in many countries due to tax breaks.
Starting with a clean slate as Peugeot Starting with a clean slate as Peugeot did with the T9 308 means the engineers were able to create a lighter and more aerodynamic car around the terrific 1.2-litre three-pot turbo, maximising the downsizing potential. And, as regular readers know, we’ve revelled in the performance, agility, control and ride comfort of the 96kW e-THP 1.2-litre turbo-equipped Active.
However, for some people, one downside of downsizing is the need to fill them with premium unleaded petrol, due to their higher octane diet demands. While our 308’s triple can run on the standard 91 RON brew, it isn’t recommended.
But what about at the other end of the petrol price scale? Which of the two premium unleaded fuels is better – 95 RON or 98 RON?
We normally fill the Pug with the more expensive stuff because that’s what we’ve long believed to be the best for efficiency. To find out for sure, though, we switched to the lower-octane premium bowser for three fills, lower-octane premium bowser for three fills, before returning back to the top-shelf stuff for three more.
We attempted to control the variables as much as possible, visiting the same service station brand, keeping consistent driving techniques and sticking with the same general commuting routes. That’s about as scientific as this exercise got. And the results are interesting.
The trio of runs on 95 RON saw CWY-07A average 7.4L/100km, with 7.0 achieved on a country cruise and 7.8 during regular innerurban schlepping. Back on 98 RON, the average was 6.6L/km, the best was 6.3 and the worst was 6.9. That’s 0.8L/100km better on the richer brew. So, even at 147.9 cents versus 155.9 cents per litre, spending more for 98 RON literally makes cents, because the five percent premium is covered twice-over by an 11 percent consumption decrease. All up, for every 500km driven, we saved $3.25 using the more expensive stuff. Over 20,000km, that’d be about $130.
Obviously prices and gaps fluctuate almost daily, but in our experiment the outcome is a victory for 98 RON – at least as far as our 308 is concerned, and a win-win when you factor in the slightly stronger performance that the premium promises. Yet even on 95 RON, it’s an outstanding result for the tiny turbo triple, as well as a big thumbs up for downsizing.
EDUCATING readers is always a noble endeavour, but the true instigator for our premium fuel fight-out came about when I recently queried CWY-07A’s unusually listless performance. My partner replied: “Oh yes, I filled it up with 95 RON for a change” — the first time he’d done so — thus prompting the experiment.
As a scientist, Jim needed convincing about the merit of the full brew, which the result duly delivered. Now he’s a 98 RON convert. And now the 308’s vigour is back.
34 44 3 3 0 0 6 4 7 0 WEEK 21 Date acquired: March 2015 Price as tested: $26,890 This month: 1528km @ 6.9L/100km Overall: 6460km @ 6.7L/100km Da Pri Th Ove
Peugeot has chopped 308 prices, with the Active auto dropping $1450 to $26,890 (plus on-roads, of course)