As a moderator, you wouldnt be allowed to use your ignore list anyways.
Yeah I know :tear: but it’s fun to think about it sometimes, makes me all warm and fuzzy inside.
Yeah I know :tear: but it’s fun to think about it sometimes, makes me all warm and fuzzy inside.[/quote]Me too. :tear:
It would just be me and you.
91 is fine in a stock SR…
I hope you know that you are waisting your money by buying that octane boost crap from CT. Most all of those products claim to raise your octane 2-3 points but what they are not telling you is that in 1 octane raiting there is 10 points.
So if you buy some NOS octane boost and add it to you 94 octane gas you get 94.3 octane. Is that really worth the $11 you just spent?
I run 91 octane on my KA-t at 10psi all the time but I am carefull not to step on the gas too much. If I am really driving then its 94.
Chris
Ok 2 more questions about gas.
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A buddy of mine has a 92’ 5L and he told me that he gets better gas miliage running higher octaine rather then lower. I personally think it’s bs but can anyone see any truth in that?
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Is there any particular gas station you guys prefer getting gas at? If so why.
uhm well if your car is programmed to take higher octane, it can be tuned to get better milage, but you’re still paying for more expensive gas, however, its a give and take. With higher octane you can make more power and have better gas milage when properly tuned. That’s the point…
The stock cars with KAs are meant to run on 89 recommended but can run on 87…
Mind you, the engines in Japan, well cars in general in japan run on very high octane quality fuel… I forget what their octane ratings are but I think they are like 100 or something… someone correct me… The Japanese have much stricter standards…
better gas mileage AND power pretty much never go hand in hand… :?
how do you figure? more powerful gas would take less to accomplish the same work of less powerful gas.
consider it,
Octane rateing how much compression gas can take before it detonates ands nothing else.
Pump Feul is made up of mostly “Octane” which the name for the hydrocarbon that has a length of 8 molicules and handles compression well.
Heptane has a length of 7 and does not handles compression well.
If you have a 94 octane you have 94% octane and 6% heptane or some other cheap not so usefull hydrocarbon.
If you had 100 octane then it is straight octane.
If you have over 100 octain then it is no longer and octane rateing as a percent but the compression rateing. Anything over 100 actane has ssomething added to it to help it handle compression but you can not have more then 100 octane.
You can buy airplane gas with a rateing of 130 which contains 100% octain fuel with lead which raise the compression level of the fuel.
(Airplane are the only vehicles which still use leaded gas)
So as far as better mileage! In my opion it goesa like this, the higher the octane rateing the slower the burn, the slower the burn the less heat you get, colder combustion temps could give you more power and better gas milage. Is it noticable? Maybe not on a NA car but it is on a turbo car where combustion temps are high.
I am sure its could be more scientific then that but this post is long enough already.
I have notice a dif in fuel consumption between 94 and 91 …94 seems to last longer .
a sr has a knock sensor for a reason.
at standard boost levels, ie 7psi you can run it all day without hurting it…You’ll be in knock map.
I once saw a canadian car show dyno a 911. Once on 94, once on 87. It lost 9hp woah omg.
If you’re that cheap rock 89 whatever. Point is if you drive it like a normal person you could run 89 in that car for it’s entire life and it would be fine.
Start beating the piss out of it an dyou’ll have problems down the line.
Higher octane will only make power because the motor is designed to use it, and not lower octane. There is nothing in the gas itself that gives the motor more power, or fuel efficiency.
So stock 240’s with KA’s were designed to run with 89 octane? Because doesnt it say somewhere on the dash (i think in the cluster) that it runs 91 octane normally?
whatever the car is stated to run is best to RUN IT, the ecu is optimized for that fuel.
Running a better fuel will net nothing other than carbon build up do to the slower burning fuel. To take advantage of a higher octane fuel you ave to adjust your timing and timing maps.
If you run a LOWER octane fuel, the ecu will dentect ANY knock values and if a certain value is reached, the ecu kicks into “bad gas fuel map” or knock fuel. The timing is adjusted and it runs in a “safe mode”
this is why, like i said before, if you drive a sr20det on 87-89 like a normal person and not beating the piss ou of it all the time, you coudl run it, it’s entire life on it and be absolutley fine.
How is a motor designed to to use higher octane?
Higher octane fuel is only required if an engine is built with higher compression or if it has forced induction.
If you are trying to say an engine that dose have forced induction or high compression does not need high octane you are correct.
However in theory high octane does not give you better performance in any apllication it only lets you build an engine with greater performance with out causeing preignition/knock.
In reality if the colder the compestion temp the more dence the air is, if the air is dence then you get a bigger bang for the same volume of air. If high octain fuel burns slower/later then combustion temp will drop and your “bang” is more efficient, wich would give you more power and better fuel econemy. Maybe???
I could be talking out my ass here, but thisb is what I have concluded of studying fuels in school and what I have experienced on my own.
Some one correct me if I am way out of line here.
You could run 89-87 and you are right the knock sensor would detect knock and cut timeing and that is why you would have a lack of power and fuel econemy would be crap.
So what you are saying then is 94 would give you better fuel econemy and more power in an sr20det over 87-89.
Sounds right to me.
Chris
How is a motor designed to to use higher octane?
Higher octane fuel is only required if an engine is built with higher compression or if it has forced induction.
If you are trying to say an engine that dose have forced induction or high compression does not need high octane you are correct.
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like others have said timing, this also relates to power, think of it like a stroker motor, it has a longer than normal stroke allowing a lot of burn time, the longer the burn (and therefore expansion) time, the more energy is put into motion and the less is wasted to heat out the exhaust
in a turbo motor the burn time is significantly reduced due to higher compression, which makes the fuel/air more volatile and like a diesel is more prone to detonation
also to go back to the fuel octane post, the octane/heptane thing is partly right, except that in the real world your gas is about 60-70% octane at best, the rest is like 15% heptane (low knock index), toluene and methylethylketoneperoxide afaik (high knock index), as well as a few other toxic compounds including mtbe, and lastly other gas derivatives and alcohols like ethanol to raise the overall knock index of the fuel… this is all then measured on paper and measured in a lab, and averaged… and voila you get a number on the pump
Chris, I meant just what you just said… an SR is designed to run on fuel that doesn’t detonate at the wrong time, like 87 or 89 does. You don’t gain power by running 91+, you potentailly lose it by running less. We’re saying the same thing; I’m responding to those people who think that running 94 in their KA will give them more power.
And Osad, it says on the fuel door “Premium Fuel Recommended,” but I have never noticed a difference between 87 or 94 octane in my KA.
I have. Not between 91 and 94, but definitely between 87 and 91. I’ve only put 87 once, since people on this forum said it doesn’t make a difference, but it did. Car was a lot more sluggish, so I topped off with 94 for awhile to balance it out and then went back to 91.
My FSM says 89 and that’s what I use.