90 octane real gas vs. 93 octane Frankenfuel
08-14-2013, 10:42 AM
#21
AudiWorld Super User
Ooh, no sir! Octane is not Octane!
Your fuel (USA) is measured as an average of two Octane Measures
RON is measured in an engine under no load and basically gives a figure of how well the fuel burns.
MON is measured in an engine under load and basically gives a figure of how much work the fuel can do - or how well it performs.
10% ethanol blends give a poor MON figure - you do not get as much work out of them.
They do raise RON though, which can help reduce knocking, but mainly they're used to reduce emissions.
Your fuel (USA) is measured as an average of two Octane Measures
RON is measured in an engine under no load and basically gives a figure of how well the fuel burns.
MON is measured in an engine under load and basically gives a figure of how much work the fuel can do - or how well it performs.
10% ethanol blends give a poor MON figure - you do not get as much work out of them.
They do raise RON though, which can help reduce knocking, but mainly they're used to reduce emissions.
They can increase RON and decrease MON but the ratings on the pump will stay the same ..
the only real diffeerence you will feel is if your engine have the capacity to burn this extra octane on higher octane fuels .. if not it just comes out as emmisions anyway ..
an aside -->My 911 is rated at requiring 87 gas as it is a relatively low compresion ratio engine .. I run Shell 93 , there is no real power gain but the shell 93 in Canada containes no ethanol. Ethanol atracts water and water in a CIS fuel system is very bad and parts are getting hard to get ...
08-14-2013, 12:25 PM
#22
AudiWorld Super User
Eh. I don't discount the us corn ethanol lobby, but I note that Brazil uses E100 and the automotive industry adapted quite well. In point of fact, E100 works quite well for power..13+:1 compression ratios possible, high supercharger pressure ratios, etc. range and economy maybe nt so much...
08-15-2013, 05:32 AM
#23
AudiWorld Super User
wow thats amazing, i wonder if there is some technology in the DFI engines that prevents pre-ignition, / even my old 944 ( albeit 80s technology ) with a 10.9 comp ratio required at least 91 or the anti knock sensors would start retarding the timing.
08-15-2013, 06:12 AM
#24
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wow thats amazing, i wonder if there is some technology in the DFI engines that prevents pre-ignition, / even my old 944 ( albeit 80s technology ) with a 10.9 comp ratio required at least 91 or the anti knock sensors would start retarding the timing.
You time your injection and ignition very precisely - no pre-detonation then.
I'm actually surprised other manufacturers haven't started increasing compression.
But then I suppose all the Euro's, Subaru and Nissan are going turbo, Toyota is busy convincing the world that hybrid is the future, and Honda insists on seeing how fast they can spin their engines! And the old 'big 3' are always a bit slow off the mark...
The irony with Mazda's 'Sky Active' engines is that their Diesels run a relatively low compression using 14:1 as well.
(The cynic in me says its a cost cutting exercise to allow usage of engines-in-common with their petrol 'cousins')
Last edited by twentysevenlitres; 08-15-2013 at 06:18 AM.
08-16-2013, 04:12 AM
#25
AudiWorld Super User
The technology is the Direct Injection!
You time your injection and ignition very precisely - no pre-detonation then.
I'm actually surprised other manufacturers haven't started increasing compression.
But then I suppose all the Euro's, Subaru and Nissan are going turbo, Toyota is busy convincing the world that hybrid is the future, and Honda insists on seeing how fast they can spin their engines! And the old 'big 3' are always a bit slow off the mark...
The irony with Mazda's 'Sky Active' engines is that their Diesels run a relatively low compression using 14:1 as well.
(The cynic in me says its a cost cutting exercise to allow usage of engines-in-common with their petrol 'cousins')
You time your injection and ignition very precisely - no pre-detonation then.
I'm actually surprised other manufacturers haven't started increasing compression.
But then I suppose all the Euro's, Subaru and Nissan are going turbo, Toyota is busy convincing the world that hybrid is the future, and Honda insists on seeing how fast they can spin their engines! And the old 'big 3' are always a bit slow off the mark...
The irony with Mazda's 'Sky Active' engines is that their Diesels run a relatively low compression using 14:1 as well.
(The cynic in me says its a cost cutting exercise to allow usage of engines-in-common with their petrol 'cousins')
Scew it all .. Im buying a tesla
10-08-2013, 03:21 AM
#26
AudiWorld Super User
E-85
Last week I visited my repair shop and they were working for many days on a truck which everybody suspected had had its tank sugared. After completing the repairs and thousands of dollars later the real culprit was determined to have been E-85. The truck owner had left the truck sitting for several months and the E-85 had reacted in his tank and separated into its sugar components.
Anyway, shop said that vehicles with E-85 should not sit for more than a week business trip. Anymore than that, think about filling or at least topping the tank with real gasoline.
Anyway, shop said that vehicles with E-85 should not sit for more than a week business trip. Anymore than that, think about filling or at least topping the tank with real gasoline.
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