92 octane vs. 87/89
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92 octane vs. 87/89
i've been spending lot more money on 92's (sometime 91/93 depends where i am and whats available)...anyways am i gaining anything or waste of money?
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Re: 92 octane vs. 87/89 (dniedacess)
Well you ARE driving a turbocharged car, right? Higher octane also helps by burning slower than lower octane fuel. This means that it'll combust somewhere ATDC unless you've adjusted your timing. Hmm, I don't think I'm making any sense.
#3
Re: 92 octane vs. 87/89 (dniedacess)
what are you running?
the octane rating is just how ignitable it is
i was running 91 in my car and i tried running 89 and it made no difference in gas millage or performance
the only thing it made a difference is that i was payin 11 cents more
the octane rating is just how ignitable it is
i was running 91 in my car and i tried running 89 and it made no difference in gas millage or performance
the only thing it made a difference is that i was payin 11 cents more
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Re: 92 octane vs. 87/89 (dom93hatch)
Well you ARE driving a turbocharged car, right? Higher octane also helps by burning slower than lower octane fuel. This means that it'll combust somewhere ATDC unless you've adjusted your timing. Hmm, I don't think I'm making any sense.
https://honda-tech.com/zerothread?id=221040
http://www.howstuffworks.com/question90.htm
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Re: 92 octane vs. 87/89 (WRCivicsSiandEX)
not if you have a LS since it has a lower compression compared to all the other b series engines..well **** even in the b17a u don't have to run 91 either
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Re: 92 octane vs. 87/89 (WR93EG)
If you have a B series you NEED to run 91+
btw, so fla has good octanes!
[Modified by DarkKnight[DMD], 11:35 AM 9/11/2002]
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Re: 92 octane vs. 87/89 (99MR_SiR)
from another message board
You might notice a difference in the way your engine runs on premium unleaded, but I assure you that if the motor is a mostly stock Honda mill then you are not gaining any performance with the expensive juice.
What does octane do? It raises the temperature at which the fuel ignites thereby delaying the full combustion of the a/f mixture. This is something desirable in a high compression or force inducted motor (a law of physics is that when you compress a gas the temperature increases, so in both the preceding cases the a/f mixture will be at a higher temperature and prone to igniting too quickly unless you run a higher octane fuel). In a car capable of running without pre-detonation on mid- or low-grade fuel you will not see any benefit and may actually see a drop in power as a result of running high octane fuel. Why? Because you end up pushing back the point at which the a/f mixture combusts past the point where the piston is just barely past top dead center...as a result you do not get the full benefit of the combusting gasses pushing against the piston top.
What about cars with knock sensors that advance timing as far as possible before encountering knock? Well, higher octane and advanced ignition timing result in the same thing as lower octane and retarded ignition timing. The goal is to obtain the optimal timing of the full combustion of the a/f mixture relative to the position of the piston. Increasing octane pushes that point back, and advancing the ignition timing pushes that point forward. In the end it equals out. Also most of these systems have a finite range of adjustment and if you exceed the computer's ability to advance the timing, then you lose power.
Why did your car behave differently on higher octane? Because the full combustion was occuring after the optimal point relative to the position of the piston (probably). You may see lower EGT's (although the opposite is also likely) and head temps, but these are just further indications that you are not getting the most out of the fuel's energy store.
So if you don't mind paying $.30 more per gallon for less power, then go for it. You will not be hurting your injectors or anything. But if you are more interested in getting the most power out of you motor, then don't use a higher octane fuel than you need. Don't believe the hype.
What does octane do? It raises the temperature at which the fuel ignites thereby delaying the full combustion of the a/f mixture. This is something desirable in a high compression or force inducted motor (a law of physics is that when you compress a gas the temperature increases, so in both the preceding cases the a/f mixture will be at a higher temperature and prone to igniting too quickly unless you run a higher octane fuel). In a car capable of running without pre-detonation on mid- or low-grade fuel you will not see any benefit and may actually see a drop in power as a result of running high octane fuel. Why? Because you end up pushing back the point at which the a/f mixture combusts past the point where the piston is just barely past top dead center...as a result you do not get the full benefit of the combusting gasses pushing against the piston top.
What about cars with knock sensors that advance timing as far as possible before encountering knock? Well, higher octane and advanced ignition timing result in the same thing as lower octane and retarded ignition timing. The goal is to obtain the optimal timing of the full combustion of the a/f mixture relative to the position of the piston. Increasing octane pushes that point back, and advancing the ignition timing pushes that point forward. In the end it equals out. Also most of these systems have a finite range of adjustment and if you exceed the computer's ability to advance the timing, then you lose power.
Why did your car behave differently on higher octane? Because the full combustion was occuring after the optimal point relative to the position of the piston (probably). You may see lower EGT's (although the opposite is also likely) and head temps, but these are just further indications that you are not getting the most out of the fuel's energy store.
So if you don't mind paying $.30 more per gallon for less power, then go for it. You will not be hurting your injectors or anything. But if you are more interested in getting the most power out of you motor, then don't use a higher octane fuel than you need. Don't believe the hype.
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Re: 92 octane vs. 87/89 (DarkKnight[DMD])
If you have a B series you NEED to run 91+
Not necessarily, I have run 89 and 93 octanes in a b16a1 and they both gave me the same whp numbers. 142 whp.
btw, so fla has good octanes!
[Modified by DarkKnight[DMD], 11:35 AM 9/11/2002]
Not necessarily, I have run 89 and 93 octanes in a b16a1 and they both gave me the same whp numbers. 142 whp.
btw, so fla has good octanes!
[Modified by DarkKnight[DMD], 11:35 AM 9/11/2002]
also do you mean B16A? I wasnt aware there was an A1, only A2 and A3.
[Modified by WR93EG, 2:31 PM 9/11/2002]
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Re: 92 octane vs. 87/89 (FifthGearOnline.com)
Higher octane raises the PRESSURE at which the a/f mix will spontaneously ignite. That's why you need 91+ in a high compression motor.
Strangely my 02 Escape has a 10.2:1 comp ratio and recommends NOT using premium. WTF??
Steve
Strangely my 02 Escape has a 10.2:1 comp ratio and recommends NOT using premium. WTF??
Steve
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Re: 92 octane vs. 87/89 (WR93EG)
Higher octane = slower buring w/a loger burn= better for high performance engines/airplanes with high compression (ie. longer power stroke)
Lower octane = quick burn = good for low compression engines = detonation in High Performance/compression engines.
High octane in a "stock engine" can decrease performance or waste your money.
[Modified by Maverick, 11:19 PM 9/11/2002]
[Modified by Maverick, 11:21 PM 9/11/2002]
Lower octane = quick burn = good for low compression engines = detonation in High Performance/compression engines.
High octane in a "stock engine" can decrease performance or waste your money.
[Modified by Maverick, 11:19 PM 9/11/2002]
[Modified by Maverick, 11:21 PM 9/11/2002]
#16
Re: 92 octane vs. 87/89 (WR93EG)
well in the manual for my 99 Si/SiR and 02 Type S it says use 91+...using a lower octane will result in lowered performance and/or detationation engine pinging
Edit: There's no such thing as "ocrane." Except maybe on "Frasier" dubbed for the Irish market.
[Modified by mph6563, 4:14 PM 9/11/2002]
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Re: 92 octane vs. 87/89 (WR93EG)
also do you mean B16A? I wasnt aware there was an A1, only A2 and A3.
[Modified by WR93EG, 2:31 PM 9/11/2002]
[Modified by WR93EG, 2:31 PM 9/11/2002]
[Modified by DarkKnight[DMD], 1:52 PM 9/19/2002]
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Re: 92 octane vs. 87/89 (DarkKnight[DMD])
some of u dont understand
say. when i drop $6 for a gallon of race gas at the track, i am NOT doing it for 'horsepower numbers' im doing it for safety. When u are running high compression or high boost, detonation is your worst enemy and its good to have that extra security while boostin.
say. when i drop $6 for a gallon of race gas at the track, i am NOT doing it for 'horsepower numbers' im doing it for safety. When u are running high compression or high boost, detonation is your worst enemy and its good to have that extra security while boostin.
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