Discussion
Everytime I fill up with Super - I do wonder if what I'm actually putting in the car is any better than the garage next door ?!
What's the deal with Optimax ? Why's it cheaper than normal Super unleaded ?
Fuels vary, that I know, I've used 76 fuel in the race car at 105p a ltr ! But what do you guys think ?
Just an open question !
What's the deal with Optimax ? Why's it cheaper than normal Super unleaded ?
Fuels vary, that I know, I've used 76 fuel in the race car at 105p a ltr ! But what do you guys think ?
Just an open question !
I was talking to a guy from Millers Lubricants last year. He was saying that all petrol loses its octane value after a while, and because Super Unleaded is used far less than premium the petrol stays in the storage tank longer, so it maybe lower in octane than the premium thats just been refreshed. Of course he might have been saying this to sell me some CVL octane booster....
Optimax is supposed to 98.4, but you will only get more power from this if your engine's timing is advanced to make use of it. I'm not sure if a modern ECU can do this?
I took my race car (Golf GTi) to a rolling road last week and despite trying everything I was 10BHP down on last years figure (identical engine rebuild). Then someone suggested my petrol as stale (it was Optimax from Oct last year). We bunged in a bottle of Millers CVL and on a back to back power run gained all 10BHP back. We were amazed and impressed.
So the moral is - if you engine has the timing advanced enough to make use of high octane petrol, then it is definitely worth using - as long as you know the petrol itself is fresh.
Optimax is supposed to 98.4, but you will only get more power from this if your engine's timing is advanced to make use of it. I'm not sure if a modern ECU can do this?
I took my race car (Golf GTi) to a rolling road last week and despite trying everything I was 10BHP down on last years figure (identical engine rebuild). Then someone suggested my petrol as stale (it was Optimax from Oct last year). We bunged in a bottle of Millers CVL and on a back to back power run gained all 10BHP back. We were amazed and impressed.
So the moral is - if you engine has the timing advanced enough to make use of high octane petrol, then it is definitely worth using - as long as you know the petrol itself is fresh.
quote:
Everytime I fill up with Super - I do wonder if what I'm actually putting in the car is any better than the garage next door ?!
Most 'super' is 97ron. This is compared to 95ron for normal unleaded. It is better fuel, but not all cars will be able to benefit from it - it depends on the engine management system of the car.
quote:
What's the deal with Optimax ? Why's it cheaper than normal Super unleaded ?
thats marketing for you ;-) they just want you to try it out. I think you'll find that once its established then it'll cost MORE than other fuels.
My V8 esprit has an ecu that will self adjust to different fuels - definitely a positive difference when using optimax. And yes - it is 98.4 ron.
Some cars are actually designed for super - e.g Tuscan (i think?)
Rob
quote:
Optimax is supposed to 98.4, but you will only get more power from this if your engine's timing is advanced to make use of it. I'm not sure if a modern ECU can do this?
Don't most cars with ecus have a "knock sensor" which enables them to advance the timing just up to the point of "pinking" therefore getting the most out of the fuel? I don't mind being corrected here.
Interesting story for everyone... Back in the dark ages (1981) when I was still in high school (here in the States) a mechanic friend of mine told me to talk to a friend of his that worked at the local airport and to try running a tank of aviation fuel (I think 105 or 107 octane). The car I had at the time ran the best ever and there was a noticable difference... (or maybe it was the NOS that we hooked up to it?) Never went back because it was also the most expensive tank of gas (petrol) that I ever bought... ErnestM
"ladies and gentlemen please take your seats, the landcraft will be departing shortly..."
quote:
Don't most cars with ecus have a "knock sensor" which enables them to advance the timing just up to the point of "pinking" therefore getting the most out of the fuel? I don't mind being corrected here.
My Mondeo definitely has a knock sensor - but I thought this was there to retard the timing if reduced octane petrol was used for any reason, so that the engine wouldn't pink. I'm not sure if it works the other way round on ordinary cars, though obviously it can do like on the Esprit. I don't mind being corrected either.
But if I'm right there's no point in putting Optimax in a Mondeo.
My knowledge (probably not complete)about knock detection:
Most new european vehicles are calibrated using reference 95 fuel. The spark tables will assume that is what is being used. If the knock detector senses knock it will retard the spark (from the setting in the table) to a safe level to eliminate the risk of pre ignition failure.
Therefore I don't believe that a vehicle calibrated for 95 will benefit from running 98 without some recalibration work.
I also know that not all knock detection systems are effective (particularly at high revs), consequently you'll find that it no longer appears on 3.0 V6 in Mondeo (i.e. ST220)
My it's warm in this anorak...
Dave
Most new european vehicles are calibrated using reference 95 fuel. The spark tables will assume that is what is being used. If the knock detector senses knock it will retard the spark (from the setting in the table) to a safe level to eliminate the risk of pre ignition failure.
Therefore I don't believe that a vehicle calibrated for 95 will benefit from running 98 without some recalibration work.
I also know that not all knock detection systems are effective (particularly at high revs), consequently you'll find that it no longer appears on 3.0 V6 in Mondeo (i.e. ST220)
My it's warm in this anorak...
Dave
Sounds about right.
On a completely separate note just looked at your profile.
I ran a 1976 Alfa Romeo GT Junior for about 4 years, it was indeed wonderful but I hope yours is less rusty than mine turned out to be!
www.geocities.com/peter.nixon/alfa.htm
On a completely separate note just looked at your profile.
I ran a 1976 Alfa Romeo GT Junior for about 4 years, it was indeed wonderful but I hope yours is less rusty than mine turned out to be!
www.geocities.com/peter.nixon/alfa.htm
quote:
a mechanic friend of mine told me to talk to a friend of his that worked at the local airport and to try running a tank of aviation fuel (I think 105 or 107 octane).
I notice that gas stations near race tracks often sell 110 octane racing fuel. I guess that is 110 octane US AKI which will be close to 120 RON octane. The pumps state that phosphorus is used to replace the lead. I'm not sure if you could use that in your everyday vehicle but would probably go down well in something like a Lingenfelter Corvette, assuming the cats weren't affected...
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