is higher octane fuel worth its price?

oscarloco · Post by **oscarloco** » 31 Jan 2005, 19:55

Here in my country, Shell sells it´s V power 98 octane fuel. Will my ZX take advantage of it's higher octane rating (advancing timing) or am I just wasting my money?

reffro · Post by **reffro** » 31 Jan 2005, 21:51

Worked well in my 2.0 8v Xantia, definitely better performance and economy, but it eventually got too pricey to justify the extra expense.

gardenpeas · Post by **gardenpeas** » 31 Jan 2005, 23:03

prob worth it in a 16 valve engine but less so in an 8 just use a fuel with a high detergent level the normal shell should have that sorted
cheap petrol will damage engines in the long run

Post by **cheesesliceking** » 31 Jan 2005, 23:18

load of bobbins, total waste of £'s
[B)]

Stempy · Post by **Stempy** » 01 Feb 2005, 03:26

If I have to fill my V6 with the cheap stuff I reckon it must lose about 10bhp as the knock sensor pull back the ignition timing, so I always use the dear stuff and make sure I've just been shopping before hand!

alan s · Post by **alan s** » 01 Feb 2005, 03:45

It seems to differ from car to car.
On my 16V BX there's little difference between the standard ULP and PULP and if I go to the extra high octaneabsolutely no difference between it and PULP. However, when I owned my series one CX and my BX Trs, they would run OK on LRP (Lead replacement) wouldn't run proper at all on ULP, went well on PULP and were absolutely unbelieveable on the extra high octane stuff. Fuel consumption improved by 10 - 12% (based on tankful to refill method) and overall running was so improved that passengers would comment on the improvement.
I'd suggest you give it a tankful as a trial and decide from there whether it's worth the effort.
Alan S

David Goddard · Post by **David Goddard** » 02 Feb 2005, 03:34

Makes a noticible difference on the V6 Xantia as the engine is optimised for 98. On regular, the knock sensor tells the ECU to back off a bit. The fuel economy is slightly better, but overall the extra fuel cost makes 98 a poor buy. I used to use it when I was going on quick cross country sort of runs. Absolutely no benefit on Mways.
Haven't tried 98 on my C5.

ninebob · Post by **ninebob** » 02 Feb 2005, 15:40

My journey to work is twisty A-road stuff (A52 Grantham to nottingham). Will using premium unleaded rather than regular make any difference to me (my car details in signature)? Any advice welcome...

oscarloco · Post by **oscarloco** » 03 Feb 2005, 23:37

I filled my tank with 98 octane and tried for a week. The difference:
NONE.
It was more expensive and didn't find any difference in response or economy.
I guess I will stick with the 95 octane.

dillosk8ter · Post by **dillosk8ter** » 03 Feb 2005, 23:52

Never really used the higher octane fuels but since I bought my ZX five years ago I've used Redex Injector Cleaner every time I've re-fueled it. Engine runs v. cleanly, queitly, pulls well and v.economical.

LeFrog · Post by **LeFrog** » 04 Feb 2005, 02:39

IMO: If you can't tell the difference, then is it's not worth it.