Issues with 89 Octane?
Originally Posted by hyukki
Do you know what the different octanes mean?
I hope you don't get a turbo car... I'm sure you'd end up putting regular in.
I hope you don't get a turbo car... I'm sure you'd end up putting regular in.
I'm aware of octane and detonation.
I don't think the manufacturers always recommend what's right, but with a 10.6:1 compression ratio it's obvious that this car needs premium.
On the contrary, my 2002 Acura MDX recommends premium, but I run regular in it. The reason for this is because the exact same engine is in the Honda Pilot which only requires regular. The consensus on the Acura rating is that Acura made a fleet wide premium requirement even though the MDX 3.5 liter engine doesn't require premium in any of its Honda counterparts.
However, it's a no brainer on this car with 10.6:1. Even if it retards timing safely, it will provide a SIGNIFICANT performance hit since regular gas will predet before it gets to 10.6:1 compression.
My bet is that 93 octane would even yield dyno proven increases over even 91. The 02 350Z put out 3 more WHP on 93 than 91 and that was a 10.3:1 engine.
On the contrary, my 2002 Acura MDX recommends premium, but I run regular in it. The reason for this is because the exact same engine is in the Honda Pilot which only requires regular. The consensus on the Acura rating is that Acura made a fleet wide premium requirement even though the MDX 3.5 liter engine doesn't require premium in any of its Honda counterparts.
However, it's a no brainer on this car with 10.6:1. Even if it retards timing safely, it will provide a SIGNIFICANT performance hit since regular gas will predet before it gets to 10.6:1 compression.
My bet is that 93 octane would even yield dyno proven increases over even 91. The 02 350Z put out 3 more WHP on 93 than 91 and that was a 10.3:1 engine.
Originally Posted by BrianV
I don't think the manufacturers always recommend what's right, but with a 10.6:1 compression ratio it's obvious that this car needs premium.
On the contrary, my 2002 Acura MDX recommends premium, but I run regular in it. The reason for this is because the exact same engine is in the Honda Pilot which only requires regular. The consensus on the Acura rating is that Acura made a fleet wide premium requirement even though the MDX 3.5 liter engine doesn't require premium in any of its Honda counterparts.
However, it's a no brainer on this car with 10.6:1. Even if it retards timing safely, it will provide a SIGNIFICANT performance hit since regular gas will predet before it gets to 10.6:1 compression.
My bet is that 93 octane would even yield dyno proven increases over even 91. The 02 350Z put out 3 more WHP on 93 than 91 and that was a 10.3:1 engine.
On the contrary, my 2002 Acura MDX recommends premium, but I run regular in it. The reason for this is because the exact same engine is in the Honda Pilot which only requires regular. The consensus on the Acura rating is that Acura made a fleet wide premium requirement even though the MDX 3.5 liter engine doesn't require premium in any of its Honda counterparts.
However, it's a no brainer on this car with 10.6:1. Even if it retards timing safely, it will provide a SIGNIFICANT performance hit since regular gas will predet before it gets to 10.6:1 compression.
My bet is that 93 octane would even yield dyno proven increases over even 91. The 02 350Z put out 3 more WHP on 93 than 91 and that was a 10.3:1 engine.
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Joined: Dec 2006
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From: Upstate, NY
Originally Posted by mkreddy
The doctor recommends you eat less fat and drink moderately also, but do you do that?
. I bet 99% of the people here treat their cars better than their bodies.
Originally Posted by mkreddy
I value my body much more than my car.
.
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Originally Posted by CarNutz
The engine is designed to use premium fuel. Knock sensors are there to protect the car from detonation, not so you can run regular fuel full time.
The knock sensor has to detect knock before it retards timing to control the knock. Knock has already occured and keeps occuring as the ECM looks to return timing to its DESIGNED point. So what you have is a knock being sensed then timing is pulled, then back to its pre-set state and it happens all over again. You can't always hear knock.. especially on a luxury car like the G where you have all kinds of engine sound damping.
Those links you provided are worthless.. written by journalists who need to write to live and will say anything.. It applies to those whos cars run on regular and whose owners think they are getting better performance by using premium.. not the other way around.
Don't you think Infiniti would like to have you use regular? It is a selling point for them... Pre-detonation is destructive.. knock sensors help but over time damage will occur.
The knock sensor has to detect knock before it retards timing to control the knock. Knock has already occured and keeps occuring as the ECM looks to return timing to its DESIGNED point. So what you have is a knock being sensed then timing is pulled, then back to its pre-set state and it happens all over again. You can't always hear knock.. especially on a luxury car like the G where you have all kinds of engine sound damping.
Those links you provided are worthless.. written by journalists who need to write to live and will say anything.. It applies to those whos cars run on regular and whose owners think they are getting better performance by using premium.. not the other way around.
Don't you think Infiniti would like to have you use regular? It is a selling point for them... Pre-detonation is destructive.. knock sensors help but over time damage will occur.
glad to see logical and informed posts like this one. thanks carnutz. you clearly have a good head on your shoulders
just one nitty gritty though, there's no "pre-detonation"... it's just detonation. the mechanism by which engines *normally* work is called combustion. detonation automatically implies pre-ignition (which is what I think you meant in the first place anyway!)
also, as for how the ECU retards timing... i actually don't know the answer to this so i'm curious: does the engine constantly evaluate the ping sensor, or does it do a one-check each time the engine ie activated (that is, if it pings, it retards timing permanently until the car is switched off and back on again)? i thought it was the latter but i guess it could be the former as well. just seems like more work for the ECU.
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From: Carolinas USA
Altersys.. I use the term pre-detonation to make it clear I am talking about un-intended detonation.. but you are correct..
The ECM monitors the knock sensors listening for knock.. when it is found, timing is immediatley pulled to prevent any further knocking. The ECM will then try to resume using the optimal fuel trim and timing. If the knock continues another fuel trim and timing parameters are selected. It depends on the ECM programming, but the goal is to return to optimal factory settings. An engine runs most efficiently just before the threshold of knock. The ECM programming is designed to get it back to optimal ASAP.
The ECM monitors the knock sensors listening for knock.. when it is found, timing is immediatley pulled to prevent any further knocking. The ECM will then try to resume using the optimal fuel trim and timing. If the knock continues another fuel trim and timing parameters are selected. It depends on the ECM programming, but the goal is to return to optimal factory settings. An engine runs most efficiently just before the threshold of knock. The ECM programming is designed to get it back to optimal ASAP.
Originally Posted by Altersys
re-visiting this thread to see where it ended up.
glad to see logical and informed posts like this one. thanks carnutz. you clearly have a good head on your shoulders
just one nitty gritty though, there's no "pre-detonation"... it's just detonation. the mechanism by which engines *normally* work is called combustion. detonation automatically implies pre-ignition (which is what I think you meant in the first place anyway!)
also, as for how the ECU retards timing... i actually don't know the answer to this so i'm curious: does the engine constantly evaluate the ping sensor, or does it do a one-check each time the engine ie activated (that is, if it pings, it retards timing permanently until the car is switched off and back on again)? i thought it was the latter but i guess it could be the former as well. just seems like more work for the ECU.
glad to see logical and informed posts like this one. thanks carnutz. you clearly have a good head on your shoulders
just one nitty gritty though, there's no "pre-detonation"... it's just detonation. the mechanism by which engines *normally* work is called combustion. detonation automatically implies pre-ignition (which is what I think you meant in the first place anyway!)
also, as for how the ECU retards timing... i actually don't know the answer to this so i'm curious: does the engine constantly evaluate the ping sensor, or does it do a one-check each time the engine ie activated (that is, if it pings, it retards timing permanently until the car is switched off and back on again)? i thought it was the latter but i guess it could be the former as well. just seems like more work for the ECU.
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From: Toronto
Originally Posted by mkreddy
but the manual does not say you HAVE to use 91. It says recommend, not require but recommend. So again to each his/her own. The doctor recommends you eat less fat and drink moderately also, but do you do that? I know I don't and I value my body much more than my car.
I have a question for people that bought a G35 that was a rental car or other cars that "require" premium gas that was a rental car. Do you think the renters used premium gas when they filled up? Did the rental car companies require it? Because of those reasons Infiniti if they want to sell (and they do BTW) sell their cars to rental car companies who then sell them to people through dealers and the like, cannot design a car that would have long term damage due to using a lower grade gas. Sure performance decrease... fine but not long term damage... because of the knock sensors.
The knock sensors detect and compensate for the gas and life goes on. Sure some performance decrease... but if you don't care, you don't care again no big deal, its your car. The people that care about the 10 or 15 more horsepower they potentially could get using a higher grade gas, drive their car to the max and then complain that they get 13 MPG. I have tons of fun driving my car and I like it. It is plenty fast for me. I use 87 and I don't hear a knock in my car or notice anything weird with it. I had a VW Passat 1.8T, which was a turbo engine and it said 91 again for it, because it was a turbo engine. I used it for 6 years no problems, VW said everything was fine as far as oxygen sensors and everything else in the car. Engine was in great condition when I sold it. Again to each his own. If someone wants to use a lower grade gas... so be it. It won't damage your car, and whoever says it will , really does not know what they are talking about...
http://www.msnbc.msn.com/id/7924659/
http://www.usatoday.com/money/autos/...emiumgas_x.htm
http://www.myhonestmechanic.com/arti...ium-fuel.shtml
http://www.edmunds.com/advice/fuelec...3/article.html
I have a question for people that bought a G35 that was a rental car or other cars that "require" premium gas that was a rental car. Do you think the renters used premium gas when they filled up? Did the rental car companies require it? Because of those reasons Infiniti if they want to sell (and they do BTW) sell their cars to rental car companies who then sell them to people through dealers and the like, cannot design a car that would have long term damage due to using a lower grade gas. Sure performance decrease... fine but not long term damage... because of the knock sensors.
The knock sensors detect and compensate for the gas and life goes on. Sure some performance decrease... but if you don't care, you don't care again no big deal, its your car. The people that care about the 10 or 15 more horsepower they potentially could get using a higher grade gas, drive their car to the max and then complain that they get 13 MPG. I have tons of fun driving my car and I like it. It is plenty fast for me. I use 87 and I don't hear a knock in my car or notice anything weird with it. I had a VW Passat 1.8T, which was a turbo engine and it said 91 again for it, because it was a turbo engine. I used it for 6 years no problems, VW said everything was fine as far as oxygen sensors and everything else in the car. Engine was in great condition when I sold it. Again to each his own. If someone wants to use a lower grade gas... so be it. It won't damage your car, and whoever says it will , really does not know what they are talking about...
http://www.msnbc.msn.com/id/7924659/
http://www.usatoday.com/money/autos/...emiumgas_x.htm
http://www.myhonestmechanic.com/arti...ium-fuel.shtml
http://www.edmunds.com/advice/fuelec...3/article.html
NUCLEI-G
Joined: Dec 2006
Posts: 268
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Bottom line is, if you can't afford a Premium gas. Don't buy a luxury car.. Go buy a KIA or Hyundai and put what ever gas you like. You can eve put vegetable oil in some cars......
Ignore your DR recommendation then you will have major illness when you get older. You can see that for yourself....
Ignore your DR recommendation then you will have major illness when you get older. You can see that for yourself....
Originally Posted by mkreddy
but the manual does not say you HAVE to use 91. It says recommend, not require but recommend. So again to each his/her own. The doctor recommends you eat less fat and drink moderately also, but do you do that? I know I don't and I value my body much more than my car.
I have a question for people that bought a G35 that was a rental car or other cars that "require" premium gas that was a rental car. Do you think the renters used premium gas when they filled up? Did the rental car companies require it? Because of those reasons Infiniti if they want to sell (and they do BTW) sell their cars to rental car companies who then sell them to people through dealers and the like, cannot design a car that would have long term damage due to using a lower grade gas. Sure performance decrease... fine but not long term damage... because of the knock sensors.
The knock sensors detect and compensate for the gas and life goes on. Sure some performance decrease... but if you don't care, you don't care again no big deal, its your car. The people that care about the 10 or 15 more horsepower they potentially could get using a higher grade gas, drive their car to the max and then complain that they get 13 MPG. I have tons of fun driving my car and I like it. It is plenty fast for me. I use 87 and I don't hear a knock in my car or notice anything weird with it. I had a VW Passat 1.8T, which was a turbo engine and it said 91 again for it, because it was a turbo engine. I used it for 6 years no problems, VW said everything was fine as far as oxygen sensors and everything else in the car. Engine was in great condition when I sold it. Again to each his own. If someone wants to use a lower grade gas... so be it. It won't damage your car, and whoever says it will , really does not know what they are talking about...
http://www.msnbc.msn.com/id/7924659/
http://www.usatoday.com/money/autos/...emiumgas_x.htm
http://www.myhonestmechanic.com/arti...ium-fuel.shtml
http://www.edmunds.com/advice/fuelec...3/article.html
I have a question for people that bought a G35 that was a rental car or other cars that "require" premium gas that was a rental car. Do you think the renters used premium gas when they filled up? Did the rental car companies require it? Because of those reasons Infiniti if they want to sell (and they do BTW) sell their cars to rental car companies who then sell them to people through dealers and the like, cannot design a car that would have long term damage due to using a lower grade gas. Sure performance decrease... fine but not long term damage... because of the knock sensors.
The knock sensors detect and compensate for the gas and life goes on. Sure some performance decrease... but if you don't care, you don't care again no big deal, its your car. The people that care about the 10 or 15 more horsepower they potentially could get using a higher grade gas, drive their car to the max and then complain that they get 13 MPG. I have tons of fun driving my car and I like it. It is plenty fast for me. I use 87 and I don't hear a knock in my car or notice anything weird with it. I had a VW Passat 1.8T, which was a turbo engine and it said 91 again for it, because it was a turbo engine. I used it for 6 years no problems, VW said everything was fine as far as oxygen sensors and everything else in the car. Engine was in great condition when I sold it. Again to each his own. If someone wants to use a lower grade gas... so be it. It won't damage your car, and whoever says it will , really does not know what they are talking about...
http://www.msnbc.msn.com/id/7924659/
http://www.usatoday.com/money/autos/...emiumgas_x.htm
http://www.myhonestmechanic.com/arti...ium-fuel.shtml
http://www.edmunds.com/advice/fuelec...3/article.html
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Joined: Jan 2007
Posts: 435
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From: Carolinas USA
Originally Posted by Altersys
actually what i meant was, detonation is *never* intended. when an engine is running correctly it is not detonating, it is combusting. they are two fundamentally different mechanisms of fuel ignition.