|
Octane Overkill
Hello,
Not being an engine expert, I figured I'd throw this question out to this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade (89 octane) or premium (92 or 93 octane) in it because I heard that doing so will keep your injectors clean. (Is that true?) Once I really splurged and put 100 octane fuel in it (only 5 gallons) and it did run pretty good. One thing I noticed, is that if I run premium (93) in it several tanks in a row, it will actually not run quite as good. It's a very minuscule difference, but I can tell there is a slight decrease in performance. If I drop it back down to mid-grade or even back to regular on the next tank, it seems to go back to running better. Is this all in my head, or is it possible to have an "octane overkill" on such a small 4-cylinder engine? Thanx in advance, Jonathan |
Re: Octane Overkill
"K-town" <jdu52580@carolina.stopspam.rr.com> wrote in message news:D6cqd.7794$Mu3.802926@twister.southeast.rr.co m... > Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade > (89 octane) or premium (92 or 93 octane) in it because I heard that doing so > will keep your injectors clean. (Is that true?) Once I really splurged and > put 100 octane fuel in it (only 5 gallons) and it did run pretty good. One > thing I noticed, is that if I run premium (93) in it several tanks in a row, > it will actually not run quite as good. It's a very minuscule difference, > but I can tell there is a slight decrease in performance. If I drop it back > down to mid-grade or even back to regular on the next tank, it seems to go > back to running better. Is this all in my head, or is it possible to have > an "octane overkill" on such a small 4-cylinder engine? The vehicle was designed to run on regular fuel. Using any other grade is just throwing your money away. Brian |
Re: Octane Overkill
"K-town" <jdu52580@carolina.stopspam.rr.com> wrote in message news:D6cqd.7794$Mu3.802926@twister.southeast.rr.co m... > Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade > (89 octane) or premium (92 or 93 octane) in it because I heard that doing so > will keep your injectors clean. (Is that true?) Once I really splurged and > put 100 octane fuel in it (only 5 gallons) and it did run pretty good. One > thing I noticed, is that if I run premium (93) in it several tanks in a row, > it will actually not run quite as good. It's a very minuscule difference, > but I can tell there is a slight decrease in performance. If I drop it back > down to mid-grade or even back to regular on the next tank, it seems to go > back to running better. Is this all in my head, or is it possible to have > an "octane overkill" on such a small 4-cylinder engine? The vehicle was designed to run on regular fuel. Using any other grade is just throwing your money away. Brian |
Re: Octane Overkill
"K-town" <jdu52580@carolina.stopspam.rr.com> wrote in message
news:D6cqd.7794$Mu3.802926@twister.southeast.rr.co m... > Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put > mid-grade (89 octane) or premium (92 or 93 octane) in it because I heard > that doing so will keep your injectors clean. (Is that true?) Once I > really splurged and put 100 octane fuel in it (only 5 gallons) and it did > run pretty good. One thing I noticed, is that if I run premium (93) in it > several tanks in a row, it will actually not run quite as good. It's a > very minuscule difference, but I can tell there is a slight decrease in > performance. If I drop it back down to mid-grade or even back to regular > on the next tank, it seems to go back to running better. Is this all in > my head, or is it possible to have an "octane overkill" on such a small > 4-cylinder engine? > > Thanx in advance, > > Jonathan > High octane fuel is for high compression engines, to prevent detonation (ping). Your owner's manual will tell you what grade to use - probably 87 octane. Rather than going to a premium grade (which, it's true, often has higher detergency), stick with the recommended octane. Some brands have more detergents than others, and they advertise that. (I like Shell/Texaco and Chevron.) I had a Nissan 300ZX that would get balky - the clutch would start to feel grabby - if I ran 76 in it for a couple months but would straighten right out about halfway through a tank of Texaco. My other cars never seem to care. We also have a Toyota Prius, and on the Prius newsgroup others have warned me it won't run right and will even set the "check engine" light if premium grades are used. (The Prius has what Toyota calls a "modified Atkinson/Miller cycle" engine - it uses valve timing to tame the 13:1 expansion ratio to a variable compression ratio.) Mike |
Re: Octane Overkill
"K-town" <jdu52580@carolina.stopspam.rr.com> wrote in message
news:D6cqd.7794$Mu3.802926@twister.southeast.rr.co m... > Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put > mid-grade (89 octane) or premium (92 or 93 octane) in it because I heard > that doing so will keep your injectors clean. (Is that true?) Once I > really splurged and put 100 octane fuel in it (only 5 gallons) and it did > run pretty good. One thing I noticed, is that if I run premium (93) in it > several tanks in a row, it will actually not run quite as good. It's a > very minuscule difference, but I can tell there is a slight decrease in > performance. If I drop it back down to mid-grade or even back to regular > on the next tank, it seems to go back to running better. Is this all in > my head, or is it possible to have an "octane overkill" on such a small > 4-cylinder engine? > > Thanx in advance, > > Jonathan > High octane fuel is for high compression engines, to prevent detonation (ping). Your owner's manual will tell you what grade to use - probably 87 octane. Rather than going to a premium grade (which, it's true, often has higher detergency), stick with the recommended octane. Some brands have more detergents than others, and they advertise that. (I like Shell/Texaco and Chevron.) I had a Nissan 300ZX that would get balky - the clutch would start to feel grabby - if I ran 76 in it for a couple months but would straighten right out about halfway through a tank of Texaco. My other cars never seem to care. We also have a Toyota Prius, and on the Prius newsgroup others have warned me it won't run right and will even set the "check engine" light if premium grades are used. (The Prius has what Toyota calls a "modified Atkinson/Miller cycle" engine - it uses valve timing to tame the 13:1 expansion ratio to a variable compression ratio.) Mike |
Re: Octane Overkill
In article <D6cqd.7794$Mu3.802926@twister.southeast.rr.com> ,
"K-town" <jdu52580@carolina.stopspam.rr.com> wrote: > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade > (89 octane) or premium (92 or 93 octane) in it because I heard that doing so > will keep your injectors clean. (Is that true?) Prior to 1995, it may have been truer than not. The oil companies used to put detergents into only their higher octane fuels, as an incentive to get you to pay the price. Around 1995, though, the feds defined a minimum level of detergency to be put into ALL fuels. This dried up the oil companies' ability to claim that "buy our expensive stuff, and your car will be cleaner and run better". Shell is back into that game now, though, with their V-Power. They simply add MORE detergents to their 92 octane gas than is specified by law. This all being said, you can add a can of Chevron Techron to your fuel every now and then and get the same results or better. And it's MUCH cheaper than using Shell V-Power on an ongoing basis. > Once I really splurged and > put 100 octane fuel in it (only 5 gallons) and it did run pretty good. Not as good as you think. You wasted your money, AND you wasted fuel on top of that. > One > thing I noticed, is that if I run premium (93) in it several tanks in a row, > it will actually not run quite as good. It's a very minuscule difference, > but I can tell there is a slight decrease in performance. That's right. The higher octane fuel won't give your engine as much power as the lower octane fuel, believe it or not. http://www.faqs.org/faqs/autos/gasoline-faq/part1/ |
Re: Octane Overkill
In article <D6cqd.7794$Mu3.802926@twister.southeast.rr.com> ,
"K-town" <jdu52580@carolina.stopspam.rr.com> wrote: > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade > (89 octane) or premium (92 or 93 octane) in it because I heard that doing so > will keep your injectors clean. (Is that true?) Prior to 1995, it may have been truer than not. The oil companies used to put detergents into only their higher octane fuels, as an incentive to get you to pay the price. Around 1995, though, the feds defined a minimum level of detergency to be put into ALL fuels. This dried up the oil companies' ability to claim that "buy our expensive stuff, and your car will be cleaner and run better". Shell is back into that game now, though, with their V-Power. They simply add MORE detergents to their 92 octane gas than is specified by law. This all being said, you can add a can of Chevron Techron to your fuel every now and then and get the same results or better. And it's MUCH cheaper than using Shell V-Power on an ongoing basis. > Once I really splurged and > put 100 octane fuel in it (only 5 gallons) and it did run pretty good. Not as good as you think. You wasted your money, AND you wasted fuel on top of that. > One > thing I noticed, is that if I run premium (93) in it several tanks in a row, > it will actually not run quite as good. It's a very minuscule difference, > but I can tell there is a slight decrease in performance. That's right. The higher octane fuel won't give your engine as much power as the lower octane fuel, believe it or not. http://www.faqs.org/faqs/autos/gasoline-faq/part1/ |
Re: Octane Overkill
On Sun, 28 Nov 2004 04:03:47 GMT, "K-town"
<jdu52580@carolina.stopspam.rr.com> wrote: >Hello, > > Not being an engine expert, I figured I'd throw this question out to >this NG. What makes you think we are experts? We just have computers and internet connections. > I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put >regular unleaded (87 octane) in it. It is my understanding that using a higher octane than is called for in the owner's manual is a waste of money. Modern engines are designed to adjust the spark advance so as to avoid the "octane ping" that was common with older engines. On the other hand, it is true that some manufacturers claim the higher octane gasoline ("premium grades") contains additives that may help clean your injectors. You have to treat these claims the way you treat all marketing claims. Elliot Richmond Freelance Science Writer and Editor |
Re: Octane Overkill
On Sun, 28 Nov 2004 04:03:47 GMT, "K-town"
<jdu52580@carolina.stopspam.rr.com> wrote: >Hello, > > Not being an engine expert, I figured I'd throw this question out to >this NG. What makes you think we are experts? We just have computers and internet connections. > I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put >regular unleaded (87 octane) in it. It is my understanding that using a higher octane than is called for in the owner's manual is a waste of money. Modern engines are designed to adjust the spark advance so as to avoid the "octane ping" that was common with older engines. On the other hand, it is true that some manufacturers claim the higher octane gasoline ("premium grades") contains additives that may help clean your injectors. You have to treat these claims the way you treat all marketing claims. Elliot Richmond Freelance Science Writer and Editor |
Re: Octane Overkill
K-town wrote: > > Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade > (89 octane) or premium (92 or 93 octane) in it because I heard that doing so > will keep your injectors clean. (Is that true?) Once I really splurged and > put 100 octane fuel in it (only 5 gallons) and it did run pretty good. One > thing I noticed, is that if I run premium (93) in it several tanks in a row, > it will actually not run quite as good. It's a very minuscule difference, > but I can tell there is a slight decrease in performance. If I drop it back > down to mid-grade or even back to regular on the next tank, it seems to go > back to running better. Is this all in my head, or is it possible to have > an "octane overkill" on such a small 4-cylinder engine? > > Thanx in advance, > > Jonathan Waste of money. All modern gasolines regardless of grade have additives to prevent injector problems... -- JT Just tooling through cyberspace in my ancient G4 |
Re: Octane Overkill
K-town wrote: > > Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade > (89 octane) or premium (92 or 93 octane) in it because I heard that doing so > will keep your injectors clean. (Is that true?) Once I really splurged and > put 100 octane fuel in it (only 5 gallons) and it did run pretty good. One > thing I noticed, is that if I run premium (93) in it several tanks in a row, > it will actually not run quite as good. It's a very minuscule difference, > but I can tell there is a slight decrease in performance. If I drop it back > down to mid-grade or even back to regular on the next tank, it seems to go > back to running better. Is this all in my head, or is it possible to have > an "octane overkill" on such a small 4-cylinder engine? > > Thanx in advance, > > Jonathan Waste of money. All modern gasolines regardless of grade have additives to prevent injector problems... -- JT Just tooling through cyberspace in my ancient G4 |
Re: Octane Overkill
K-town wrote:
> Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade > (89 octane) or premium (92 or 93 octane) in it because I heard that doing so > will keep your injectors clean. (Is that true?) Once I really splurged and > put 100 octane fuel in it (only 5 gallons) and it did run pretty good. One > thing I noticed, is that if I run premium (93) in it several tanks in a row, > it will actually not run quite as good. It's a very minuscule difference, > but I can tell there is a slight decrease in performance. If I drop it back > down to mid-grade or even back to regular on the next tank, it seems to go > back to running better. Is this all in my head, or is it possible to have > an "octane overkill" on such a small 4-cylinder engine? > > Thanx in advance, > > Jonathan increasing octane effectively = slower flame front propagation speed. that reduces detonation in combustion chambers with poor flow/mixing configurations, sharp angles & extended reach. good mechanical design addresses these problems pretty much completely, therefore low octane can be used without detonation and with ignition timing matched accordingly. using a high octane fuel in a low octane timed engine puts too much of the combustion energy out of the exhaust because it's still burning on the down stroke, not expanding and providing push for the pistons. that said, you may notice a slight increase in power for a mid grade fuel in that motor without a detonation sensor. partly because, in the absense of a sensor, the engine timing used has to be a "compromise" range designed to be safe and partly because of fuel chemistry. here's an interesting post that touches on the subject: http://www.digest.net/bmw/archive/v9/msg04942.html it seems to assume that ignition timing is optimal for each different combustion characteristic of the different blends described. you can be assured that gas companies use all the cheap options for their lowest grade of gas. |
Re: Octane Overkill
K-town wrote:
> Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put mid-grade > (89 octane) or premium (92 or 93 octane) in it because I heard that doing so > will keep your injectors clean. (Is that true?) Once I really splurged and > put 100 octane fuel in it (only 5 gallons) and it did run pretty good. One > thing I noticed, is that if I run premium (93) in it several tanks in a row, > it will actually not run quite as good. It's a very minuscule difference, > but I can tell there is a slight decrease in performance. If I drop it back > down to mid-grade or even back to regular on the next tank, it seems to go > back to running better. Is this all in my head, or is it possible to have > an "octane overkill" on such a small 4-cylinder engine? > > Thanx in advance, > > Jonathan increasing octane effectively = slower flame front propagation speed. that reduces detonation in combustion chambers with poor flow/mixing configurations, sharp angles & extended reach. good mechanical design addresses these problems pretty much completely, therefore low octane can be used without detonation and with ignition timing matched accordingly. using a high octane fuel in a low octane timed engine puts too much of the combustion energy out of the exhaust because it's still burning on the down stroke, not expanding and providing push for the pistons. that said, you may notice a slight increase in power for a mid grade fuel in that motor without a detonation sensor. partly because, in the absense of a sensor, the engine timing used has to be a "compromise" range designed to be safe and partly because of fuel chemistry. here's an interesting post that touches on the subject: http://www.digest.net/bmw/archive/v9/msg04942.html it seems to assume that ignition timing is optimal for each different combustion characteristic of the different blends described. you can be assured that gas companies use all the cheap options for their lowest grade of gas. |
Re: Octane Overkill
ive been using amoco ultimate in my 04 accord should i switch to regular??
"K-town" <jdu52580@carolina.stopspam.rr.com> wrote in message news:D6cqd.7794$Mu3.802926@twister.southeast.rr.co m... > Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put > mid-grade (89 octane) or premium (92 or 93 octane) in it because I heard > that doing so will keep your injectors clean. (Is that true?) Once I > really splurged and put 100 octane fuel in it (only 5 gallons) and it did > run pretty good. One thing I noticed, is that if I run premium (93) in it > several tanks in a row, it will actually not run quite as good. It's a > very minuscule difference, but I can tell there is a slight decrease in > performance. If I drop it back down to mid-grade or even back to regular > on the next tank, it seems to go back to running better. Is this all in > my head, or is it possible to have an "octane overkill" on such a small > 4-cylinder engine? > > Thanx in advance, > > Jonathan > |
Re: Octane Overkill
ive been using amoco ultimate in my 04 accord should i switch to regular??
"K-town" <jdu52580@carolina.stopspam.rr.com> wrote in message news:D6cqd.7794$Mu3.802926@twister.southeast.rr.co m... > Hello, > > Not being an engine expert, I figured I'd throw this question out to > this NG. I have a 1990 Civic LX, 1.5L DPFI 5-speed, and usually I put > regular unleaded (87 octane) in it. Every once in awhile I'll put > mid-grade (89 octane) or premium (92 or 93 octane) in it because I heard > that doing so will keep your injectors clean. (Is that true?) Once I > really splurged and put 100 octane fuel in it (only 5 gallons) and it did > run pretty good. One thing I noticed, is that if I run premium (93) in it > several tanks in a row, it will actually not run quite as good. It's a > very minuscule difference, but I can tell there is a slight decrease in > performance. If I drop it back down to mid-grade or even back to regular > on the next tank, it seems to go back to running better. Is this all in > my head, or is it possible to have an "octane overkill" on such a small > 4-cylinder engine? > > Thanx in advance, > > Jonathan > |
| All times are GMT -4. The time now is 02:35 AM. |
© 2024 MH Sub I, LLC dba Internet Brands