Discussion
Yes. Optimax like superplus has more calorific energy per gallon than plain old unleaded.
I found years ago that my old audi would go approximately 4 miles further for the same fuel quantity of super as opposed to ordinary unleaded.
Presumably, the fuel burns more efficiently/ hotter maybe, so giving that extra mileage and power they always promise us.
But i could be wrong!
>> Edited by deltaf on Tuesday 8th April 14:38
>> Edited by deltaf on Tuesday 8th April 14:38
I found years ago that my old audi would go approximately 4 miles further for the same fuel quantity of super as opposed to ordinary unleaded.
Presumably, the fuel burns more efficiently/ hotter maybe, so giving that extra mileage and power they always promise us.
But i could be wrong!
>> Edited by deltaf on Tuesday 8th April 14:38
>> Edited by deltaf on Tuesday 8th April 14:38
I've also done a little anorak type calculation - based on 78p per litre vs 83p per litre (normal v optimax) I get 11.6p per mile Optimax v 11.8p per mile normal....just needed the figures to justify to 'er indoors why I'm buying expensive juice...'look luv, it's cheaper in the long run'
Evo did a test with optimax a while back, ran a variety of cars on normal unleaded (either super or not depending on manufacturer recc.) for 1500 miles then on optimax for 1500 miles, they tested MPG, acceleration thru gears etc, and used some kind of endoscipic camera to test the claims that it cleaned valves etc. It was a very positive report, concluding that it did what it said on the tin. frim memory I thnk they used a Civic Tyoe R, M Coupe, I think there was a Jag in there of some descrption too...
I'm, not convinced that Optimax has a higher calorific value, does it say this anywhere on the Shell web site?
Having a higher ocatne rating than any other readily available pump petrol will give a small power/mileage gain to those engines that can use it (mainly turbo's and Jap imports that are designed to run on 100RON anyway).
However, higher octane petrols generaly burn more slowly, so if an engine is specificaly design to use a low octane fuel, then it may well see a slight power loss without ignition adjustment.
Having a higher ocatne rating than any other readily available pump petrol will give a small power/mileage gain to those engines that can use it (mainly turbo's and Jap imports that are designed to run on 100RON anyway).
However, higher octane petrols generaly burn more slowly, so if an engine is specificaly design to use a low octane fuel, then it may well see a slight power loss without ignition adjustment.
Been running the Escort on it for a few days now.
It definately has more torque, there's a steep hill near me that I can now climb in 3rd wheras 2nd was the limit on normal petrol. The car is MUCH smoother at low revs in any gear, has stronger engine breaking, better low end pull and sounds nicer to boot.
Needless to say I'm impressed. It's also on target to match unleaded fuel consumption, possibly even beat it. I'll keep you posted.
It definately has more torque, there's a steep hill near me that I can now climb in 3rd wheras 2nd was the limit on normal petrol. The car is MUCH smoother at low revs in any gear, has stronger engine breaking, better low end pull and sounds nicer to boot.
Needless to say I'm impressed. It's also on target to match unleaded fuel consumption, possibly even beat it. I'll keep you posted.
Alan420 said:
has stronger engine breaking
I'd love to know how this is when the engine is using virtualy no fuel on the overrun (in fact no fuel on modern injection engines that cut fuel to reduce emmsions).
[Edit] Perhaps it's gumming your engine up and making it more difficult to turn
>> Edited by Mr2Mike on Friday 11th April 13:03
Mr2Mike said:
Alan420 said:
has stronger engine breaking
I'd love to know how this is when the engine is using virtualy no fuel on the overrun (in fact no fuel on modern injection engines that cut fuel to reduce emmsions).
[Edit] Perhaps it's gumming your engine up and making it more difficult to turn
>> Edited by Mr2Mike on Friday 11th April 13:03
Don't ask me, I'm only an engineer...
Seriously, it may be my imagination, but it certainly seems to keep to a certain speed better down hills.
Is that how overrun works then? I never knew... Could it be cleaning the insides of the engine so it seals better or something? It is a bit knackered...
TVR suggets that the Griff 500 is run on 98RON unleaded petrol. The super-unleaded fuels are marked as 97RON. On teh SHELL website they say OPTIMAX is 98RON and is "octane boosted". The fuel is supposed to give better engine response and performance when under high load conditions. OTIMAX is also supposed to "clean" the engine (probably not a good thing on an old engine!).
In conclusion, I have tried a number of different brands of super unleaded and found that OPTIMAX provides the best performance (no pinking, smooth running and stable idle) and does marginally improve fuel consumption. I am in absolute no doubt about the benefits of using OPTIMAX in the Griff 500.
In conclusion, I have tried a number of different brands of super unleaded and found that OPTIMAX provides the best performance (no pinking, smooth running and stable idle) and does marginally improve fuel consumption. I am in absolute no doubt about the benefits of using OPTIMAX in the Griff 500.
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