99 Octane Fuels

[DCS_81]

I was being smug on Sunday by showing a friend that even by topping up with Tesco's Momentum fuel @ 122.9 per ltr was still cheap for me, but it got me thinking, does the IQ benefit from a higher octane fuel? Better mileage? Better performance. etc.?

[leebo]

im sure it would give some kind of performance, im not really clued up on iq's. but yeah its better for the engine. i only use 99ron in my rolla but thats only as toyota recommend 98ron or higher or risk knocking, :crybaby:and i hate the £1.22 pl price

[macabeus]

Not worth the extra money on a car with such a small engine. (in terms as more power)

[tonyishuk]

I was reading a well written letter in a Motorhome magazine by a reader in the petrochemical industry about fuels and to sum up the writer said that it was not the "Fuel" that could cause problems but the additives or more likely the lack of. The fuel out of the depot is the same, but differing additives are mixed during loading for various suppliers.

Edit : I cite premium fuels below, I mean non supermarket fuels, such as Esso, BP, Shell etc, not hi octane fuels.

Premium fuels have a number of sdditives, which are sometimes not added to super market fuel. This applied to both Diesel and petrol.

He had great reservations on running vehicles on supermarket fuel over long periods, suggesting that one supermarket to two premium fillups would suit him. For what it saved it was not worth the bother.

Obvviously differing octane values are different matter. Some cars need higher octanes to get the proformance. Modest motoring does not.

We run both the motorhome and car on premium fuel and there does seem to be a better performance in MPG and running generally when avoiding supermarket fuels. Maybe I am just kidding myself !!

Rgds

[APS]

I was being smug on Sunday by showing a friend that even by topping up with Tesco's Momentum fuel @ 122.9 per ltr was still cheap for me, but it got me thinking, does the IQ benefit from a higher octane fuel? Better mileage? Better performance. etc.?

Higher octane does not in itself give you more power. However, it allows for higher compression ratios as is normally found in highly tuned engines. In fact, higher octane fuel tends to have marginally lower energy content than lower.

The 1 litre engine in your car does have a fairly high compression ratio of 10.5:1 (the 1.33 litre has even higher, 11.5:1) so running it on a high octane fuel may allow the engine management to change ignition timing and get slightly more power out of it.

However, don't expect any dramatic changes. At best you may notice a better pull at low revs. At worst, it's wasted money. But your mileage may vary as they say.