Octane: what it actually means and does
05-05-2010, 05:43 PM
#27
One Shot One Kill
I would like to add that the main danger of knocking is not from bending or breaking of any part, but rather then the transition of the flow in the combustion chamber from laminar flow to turbulent flow. This significantly reduce the ability for the air in the chamber to spread the temperature/heat evenly and carry it out of the combustion chamber. This causes hot spots in the combustion chamber and eventually fails it.
05-07-2010, 09:32 AM
#30
Metatron
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.........the way the different grades are determined is by the concentration of iso-octane within the gasoline. 87 AKI will contain less iso-octane than 91 AKI. From what I have been told and found in research, this is the way it is done. Racing fuels and E85 type fuels are done slightly differently I believe. If I am wrong please correct me.
Iso-octane and heptane are just the reference fuels - there may not be ANY actual iso-octane in a particular fuel, depends on the crude's components and how the refinery makes it.
Lately the lab just buys drums of 'standard reference fuel' from Ethyl Corp and compare their results to that.
Some of the components our refinery uses have an actual octane number in the 20-to-30 range, so we use a blend of toluene and xylene to bump up the octane of the final blends.
S
Iso-octane and heptane are just the reference fuels - there may not be ANY actual iso-octane in a particular fuel, depends on the crude's components and how the refinery makes it.
Lately the lab just buys drums of 'standard reference fuel' from Ethyl Corp and compare their results to that.
Some of the components our refinery uses have an actual octane number in the 20-to-30 range, so we use a blend of toluene and xylene to bump up the octane of the final blends.
S
07-25-2010, 03:08 PM
#31
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So, since I am not a chemistry major and all these numbers are a bit confusing let me just ask the simplest question possible.
Do we have to put 91/93 Premium (US) in the RX-8 or can 87 work ok?
Do we have to put 91/93 Premium (US) in the RX-8 or can 87 work ok?
10-28-2010, 06:07 AM
#35
10-31-2010, 06:59 PM
#37
Nature vs. Nurture
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My reasons for no ethanol - I understand ethanol attracts water - don't need that in my system unless I go FI and need something to cool things off. I think it degenerates faster. More energy per gallon.
03-01-2011, 06:39 PM
#38
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So i'm used to put Mobil1 full synthetic and 93 octane in my car, now I buy a RX8 and I have to put the cheapest oil in the market (money wise is good), but what about the gas. Which octane do I use??
03-01-2011, 08:54 PM
#39
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What I have read here is the the RX-8 knock sensors are not able to detect knocking until it is too bad. Also, I have read elsewhere that 2 stroke oil in the fuel reduces knock resistance (I don't know if its all 2Ts and I don't know if it is the injected oil) Regardless, multiple reasons to be sure you have plenty of octane.
if you have a good ear and have some way to learn what knocking in a rotary sounds like, i am sure you can run less than 91 (maybe when it is cooler or you are not hammering it). With all the strange knocking noises the rotary makes - i couldn't tell you what knocking sounds like!
if you have a good ear and have some way to learn what knocking in a rotary sounds like, i am sure you can run less than 91 (maybe when it is cooler or you are not hammering it). With all the strange knocking noises the rotary makes - i couldn't tell you what knocking sounds like!
03-02-2011, 12:33 AM
#40
I HATE SPEEDBUMPS!
I use 91 octane on my RX8. No pings and knocks. No problem so far.
Owner's Manual prefer the highest grade (93 octane). You don't really have to unless you car is over 50,000 miles or higher.
03-02-2011, 01:30 AM
#44
Registered
the reason why rotary engine is less affected by pinging is the rotary always move in one direction unlike the piston engine up and down. pinging is when the mixed gas starts to ignite before the piston reaches the highest part (still moving up). so you have two forces on the piston which can damage many things.
on a rotary the rotor always move in one direction so its less harmful.
on a rotary the rotor always move in one direction so its less harmful.
03-02-2011, 02:02 AM
#45
the reason why rotary engine is less affected by pinging is the rotary always move in one direction unlike the piston engine up and down. pinging is when the mixed gas starts to ignite before the piston reaches the highest part (still moving up). so you have two forces on the piston which can damage many things.
on a rotary the rotor always move in one direction so its less harmful.
on a rotary the rotor always move in one direction so its less harmful.
03-03-2011, 12:53 PM
#48
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I will admit it, Most of that is way above my head. I do know that in my car if I use regular gas, I get about 2.5 to 3.5 mpg better than using super unleaded. I do get a little less vibration by using super unleaded though.
03-06-2011, 12:34 PM
#50
A recent UTube showed a guy putting 1/4 cup of pure Acetone to 10 gallons of gas and claims an impressive increase in fuel economy in a piston car. He did warn against spilling any on the paint!!
Any thoughts on the reality of doing that? Anyone on this board tried it in their Renesis?
Any thoughts on the reality of doing that? Anyone on this board tried it in their Renesis?