What are implications of using Unleaded 95 octane
Discussion
I can't speak for the early car 4.2s but on ones like mine ('99 4.5) there's no need to use 98 RON. The ignition timing is very conservative and is absolutely fine with 95. In fact, aside from any additional detergents in fuels like Optimax, there's no real benefit in using it. It's not like you've got a knock sensor advancing the timing to within an inch of the engines life to take advantage of the higher octane. Optimax users might cite benefits in other areas but as far as any increased power is concerned, there's a large element of emperor's new clothes.
As far as I'm aware, on the 4.5's only the factory Red Rose cars with the dual maps and the 95 - 98 dashboard switch actually *need* 98 (with the switch in the appropriate position).
As far as I'm aware, on the 4.5's only the factory Red Rose cars with the dual maps and the 95 - 98 dashboard switch actually *need* 98 (with the switch in the appropriate position).
I use 95 almost all the time. When I first got the car I used 98, but really not much difference between the two unless you are are a road mapping warrior.
Interesting thing I got in a cerb about two weeks ago (not someone who comes on PH), and couldn't believe how he was driving the car. High throttle and low revs with a fair amount of load on the engine at slow revs. The car was pinking like a bastard, and he didn't bat an eyelid. It was difficult to comment on his driving because he was doing me a favour and I didn't know him that well, but I nearly threw up after getting out of the car.
I think it doesn't really matter whether you use 95 98 or nitrous in your car, I think what matters is your sensitivity to what the engines telling you when you drive.
Interesting thing I got in a cerb about two weeks ago (not someone who comes on PH), and couldn't believe how he was driving the car. High throttle and low revs with a fair amount of load on the engine at slow revs. The car was pinking like a bastard, and he didn't bat an eyelid. It was difficult to comment on his driving because he was doing me a favour and I didn't know him that well, but I nearly threw up after getting out of the car.
I think it doesn't really matter whether you use 95 98 or nitrous in your car, I think what matters is your sensitivity to what the engines telling you when you drive.
Wiggyfella said:
Whereas mine has a sticker recommending me to use 95 RON unleaded. It doesn't say 'at least 95 RON unleaded either'. John at David Gerald also said that 95 is fine.
I've not noticed any difference between 95 and 98, having used both so far.
Mine's a 99 Speed Six.
Cheers.
Right, i am going to start using 95, its cheaper!!! You cant be far from me Wiggyfella, using David Gerald?
You have a hand-built, thoroughbred car then run it on the cheap stuff? Mine has a "Use 98 RON only" sticker on it and I've only ever used Optimax or (more recently) Tesco 99RON Super.
I used to use Optimax when I was doing 30k miles/year in a Scoob -- it's better for the engine as it cleans the valves (I saw the report in Evo where they used a borescope) and it gave about 10% better MPG.
What next, Halfords oil because it's cheaper?
I used to use Optimax when I was doing 30k miles/year in a Scoob -- it's better for the engine as it cleans the valves (I saw the report in Evo where they used a borescope) and it gave about 10% better MPG.
What next, Halfords oil because it's cheaper?
I use 98 Premium on our SAAB Turbo , and 95 unleaded (E10 10% ethanol blend ) for the Mitsu V6 , I do about 100,000 Miles Per year , The 95 E10 gives better economy , performance (yes I know it shouldn't) and no pinking (got that with the 91 , and even sometimes if I use 95 straight) It seems to be subjective to the vehicle though .Have been working this way for a number of years.
carl_w said:
You have a hand-built, thoroughbred car then run it on the cheap stuff? Mine has a "Use 98 RON only" sticker on it and I've only ever used Optimax or (more recently) Tesco 99RON Super.
I used to use Optimax when I was doing 30k miles/year in a Scoob -- it's better for the engine as it cleans the valves (I saw the report in Evo where they used a borescope) and it gave about 10% better MPG.
What next, Halfords oil because it's cheaper?
Correct me i f i am wrong but wasn't the conclusion here that it didn't make any noticable difference? I am only going on experiences listed here...
Halfords Oil is a different story.
carl_w said:
You have a hand-built, thoroughbred car then run it on the cheap stuff? ...What next, Halfords oil because it's cheaper?
No, Millers CFS because there *is* benefit to be derived from a quality lubricant.
If there's no benefit to be gained from a higher RON fuel it doesn't still represent a better choice just because it's more expensive.
What do you use in your washer bottle - Evian?
purpleheadedcerb said:
It was mentioned that EVO or someone was doing back to back in depth tests of 95, 97, 98 and 99 ron (incidentally, what happened to 96 RON??). I think its more scientific than the, "My car pops and bangs better on Sainsbury's 97" type tests that have been reported so far on PH!
Is that on a Cerb?
I don't think so. I'll see if I can find the thread. I'm sure it will include cars that are designed to run the higher octane fuel by the manufacturer.
BTW, I'm not saying you are wrong running yours on 95. It probably can run Ok on it just like most classics designed to run on 4 star leaded run fine on unleaded. All they tend to need is the timing retarded slightly to avoid pinking. Although, I am aware of someone in our club who ran a Sprint engine on unleaded and did alot of motorway mileage. It completely mullered his engine over 20k miles. Short, lower revving journeys seem to be fine though with unleaded.
Scott
BTW, I'm not saying you are wrong running yours on 95. It probably can run Ok on it just like most classics designed to run on 4 star leaded run fine on unleaded. All they tend to need is the timing retarded slightly to avoid pinking. Although, I am aware of someone in our club who ran a Sprint engine on unleaded and did alot of motorway mileage. It completely mullered his engine over 20k miles. Short, lower revving journeys seem to be fine though with unleaded.
Scott
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