Mileage and Octane
11-18-2011, 10:17 AM
#41
in my second statement I should have said wouldn't, not would.
Yes sir, I think that comes with age. As a rule, I used to cut corners to save a buck here and there, sometimes out of necessity...but most of the time because I couldn't see the forest for the trees. As I get older, I have learned that an ounce of prevention is worth a pound of cure.
...fk...I'm turning into my mother/father.
Yes sir, I think that comes with age. As a rule, I used to cut corners to save a buck here and there, sometimes out of necessity...but most of the time because I couldn't see the forest for the trees. As I get older, I have learned that an ounce of prevention is worth a pound of cure.
...fk...I'm turning into my mother/father.
11-18-2011, 10:22 AM
#42
Team Owner
iTrader: (4)
in my second statement I should have said wouldn't, not would.
Yes sir, I think that comes with age. As a rule, I used to cut corners to save a buck here and there, sometimes out of necessity...but most of the time because I couldn't see the forest for the trees. As I get older, I have learned that an ounce of prevention is worth a pound of cure.
...fk...I'm turning into my mother/father.
Yes sir, I think that comes with age. As a rule, I used to cut corners to save a buck here and there, sometimes out of necessity...but most of the time because I couldn't see the forest for the trees. As I get older, I have learned that an ounce of prevention is worth a pound of cure.
...fk...I'm turning into my mother/father.
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rockstar143 (11-18-2011)
11-18-2011, 10:27 AM
#43
Instructor
I realize the horse is dead, beaten, and now exhumed, but I was posting because I think there's some justification to the other side of the discussion. The negative side-effects are being blown out of proportion and we're underestimating the efficiency of Japanese automakers.
Yes, the engines are designed for premium, but there are plenty of use-cases where people have been using 87 for 10+ years @ 150k-200k miles with no problems. Were they achieving optimal hp/torque/mpg? No. But if someone manages to save $$ over a decade because his/her specific driving habits don't yield measurable performance/mpg gains with premium, more power to them.
Personally? 91 octane all the way on my Lexus (RIP) and 91 on the Acura I'm picking up this weekend. I'm just saying people need to be more objective when looking at reasons why people do things. Bottom line: 91 octane on a TL is the best way to go, but if you want to go 87 because your driving conditions yield long-term savings, your engine will probably not blow up (though, it will not run optimally).
Yes, the engines are designed for premium, but there are plenty of use-cases where people have been using 87 for 10+ years @ 150k-200k miles with no problems. Were they achieving optimal hp/torque/mpg? No. But if someone manages to save $$ over a decade because his/her specific driving habits don't yield measurable performance/mpg gains with premium, more power to them.
Personally? 91 octane all the way on my Lexus (RIP) and 91 on the Acura I'm picking up this weekend. I'm just saying people need to be more objective when looking at reasons why people do things. Bottom line: 91 octane on a TL is the best way to go, but if you want to go 87 because your driving conditions yield long-term savings, your engine will probably not blow up (though, it will not run optimally).
11-18-2011, 11:23 AM
#44
Registered Member
I realize the horse is dead, beaten, and now exhumed, but I was posting because I think there's some justification to the other side of the discussion. The negative side-effects are being blown out of proportion and we're underestimating the efficiency of Japanese automakers.
Yes, the engines are designed for premium, but there are plenty of use-cases where people have been using 87 for 10+ years @ 150k-200k miles with no problems. Were they achieving optimal hp/torque/mpg? No. But if someone manages to save $$ over a decade because his/her specific driving habits don't yield measurable performance/mpg gains with premium, more power to them.
Personally? 91 octane all the way on my Lexus (RIP) and 91 on the Acura I'm picking up this weekend. I'm just saying people need to be more objective when looking at reasons why people do things. Bottom line: 91 octane on a TL is the best way to go, but if you want to go 87 because your driving conditions yield long-term savings, your engine will probably not blow up (though, it will not run optimally).
Yes, the engines are designed for premium, but there are plenty of use-cases where people have been using 87 for 10+ years @ 150k-200k miles with no problems. Were they achieving optimal hp/torque/mpg? No. But if someone manages to save $$ over a decade because his/her specific driving habits don't yield measurable performance/mpg gains with premium, more power to them.
Personally? 91 octane all the way on my Lexus (RIP) and 91 on the Acura I'm picking up this weekend. I'm just saying people need to be more objective when looking at reasons why people do things. Bottom line: 91 octane on a TL is the best way to go, but if you want to go 87 because your driving conditions yield long-term savings, your engine will probably not blow up (though, it will not run optimally).
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rockstar143 (11-18-2011)
11-18-2011, 12:05 PM
#46
Chapter Leader (Southern Region)
Use what works for you-130,000+ miles using regular gas-over 30MPG. Have all the service done by acura/honda dealers. Besides the regular dealer I have taken my tsx to other acura/honda dealers in Nevada, California, Utah, Kansas, and North Carolina. My regular dealer is in PA. They have all complimented me on how well maintained my car is and to keep up the excellent job. I do mostly highway driving.
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RaviNJCLs (11-18-2011)
11-18-2011, 01:19 PM
#48
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11-18-2011, 05:18 PM
#49
Racer
Yep ... I am pumping about $6,500 per year with the current prices. Worst of all, they are going to continue to climb. We are expecting some pretty bad stuff next year regarding crude prices.
11-18-2011, 06:11 PM
#50
Instructor
Being objective is recognizing facts and trying to remove personal biases where possible. And the incontrovertible truth of the matter is this: 1) these engines were design to burn premium fuel and, 2) the owner has both the right and the privilege to burn whatever grade of fuel he desires. It's really that simple in terms of facts and decisions. The vagueness enters not into the facts but into the decision part of these two sides. An owner can have any number of reasons for taking whatever decision he so wishes. But the facts are a constant.
While both of your statements 1 and 2 are indeed incontrovertible, there is still some ambiguity in the equation and it doesn't fall on the decision making. The ambiguity exists because of a third fact: engines have highly efficient knock sensors. Yes, the engine is designed to run optimally on 91 octane. No one is disputing that. The engine/ECU is also designed intelligently enough to retard timing to eliminate knock. This reduces performance. But will it kill the engine over time? There's risk of increased carbon build-up, but this can be cleaned. To answer the question definitively, does anyone here have any statistics, studies, or use-cases clearly demonstrating this particular engine (or even another high-compression engine with knock sensors) will inconsequentially fail by using 87 octane over its lifetime? I ask not because I am trying to prove a point; rather, I ask because I have not ever seen any definitive results on cars with modern ping sensors (aka everything in the last 15 years). I've seen enough rumors and stories to last me a lifetime, but the plural of anecdote is not data!
The question remains whether people with specific driving habits--who justify the octane downgrade financially (the number 1 driver)--are legitimately jeopardizing their car's longevity, or just the performance. I'm not talking about hypotheses put together based on what's in the manual and the compression ratios (both important details). I'm talking about real-world results.
And there's nothing wrong with reviving old threads to rekindle the debate! The only black and white portion of this discussion is that using octane below what the engine is rated for WILL lower your performance (but not vice versa). The unanswered questions are 1) will using lower-than-required octane gas actually affect the longevity of your engine given modern ECU compensation and 2) if not, can you justify the potential price differences (depending on driving habits)?
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d1sturb3d119 (10-19-2012)
11-18-2011, 06:32 PM
#52
Use what works for you-130,000+ miles using regular gas-over 30MPG. Have all the service done by acura/honda dealers. Besides the regular dealer I have taken my tsx to other acura/honda dealers in Nevada, California, Utah, Kansas, and North Carolina. My regular dealer is in PA. They have all complimented me on how well maintained my car is and to keep up the excellent job. I do mostly highway driving.
Dealers do not check your fuel pump, your injectors, or your engine.
Don't post a thread where your engine randomly fails and that Acura is not gonna help you with anything.
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d1sturb3d119 (10-19-2012)
11-18-2011, 07:50 PM
#53
Racer
A certain compression is required, depending on the octane rating, to cause detonation. Using an incorrect fuel will move away from the design specifications. If any engine on the market was to be considered "engine design intensive", it would be Honda/Acura.
Studies have been done within AHMC to determine the effects of operation with various fuels. End result ... it isn't recommended to use 91+, it is required. Furthermore, it is highly suggested to purchase from "Top Tier" manufacturers as well.
The good news ... it isn't my car you are mistreating.
Studies have been done within AHMC to determine the effects of operation with various fuels. End result ... it isn't recommended to use 91+, it is required. Furthermore, it is highly suggested to purchase from "Top Tier" manufacturers as well.
The good news ... it isn't my car you are mistreating.
11-18-2011, 11:13 PM
#54
Registered Member
I hate internet arguments, but I think it's important for me to clarify.
While both of your statements 1 and 2 are indeed incontrovertible, there is still some ambiguity in the equation and it doesn't fall on the decision making. The ambiguity exists because of a third fact: engines have highly efficient knock sensors. Yes, the engine is designed to run optimally on 91 octane. No one is disputing that. The engine/ECU is also designed intelligently enough to retard timing to eliminate knock. This reduces performance. But will it kill the engine over time? There's risk of increased carbon build-up, but this can be cleaned. To answer the question definitively, does anyone here have any statistics, studies, or use-cases clearly demonstrating this particular engine (or even another high-compression engine with knock sensors) will inconsequentially fail by using 87 octane over its lifetime? I ask not because I am trying to prove a point; rather, I ask because I have not ever seen any definitive results on cars with modern ping sensors (aka everything in the last 15 years). I've seen enough rumors and stories to last me a lifetime, but the plural of anecdote is not data!
The question remains whether people with specific driving habits--who justify the octane downgrade financially (the number 1 driver)--are legitimately jeopardizing their car's longevity, or just the performance. I'm not talking about hypotheses put together based on what's in the manual and the compression ratios (both important details). I'm talking about real-world results.
And there's nothing wrong with reviving old threads to rekindle the debate! The only black and white portion of this discussion is that using octane below what the engine is rated for WILL lower your performance (but not vice versa). The unanswered questions are 1) will using lower-than-required octane gas actually affect the longevity of your engine given modern ECU compensation and 2) if not, can you justify the potential price differences (depending on driving habits)?
While both of your statements 1 and 2 are indeed incontrovertible, there is still some ambiguity in the equation and it doesn't fall on the decision making. The ambiguity exists because of a third fact: engines have highly efficient knock sensors. Yes, the engine is designed to run optimally on 91 octane. No one is disputing that. The engine/ECU is also designed intelligently enough to retard timing to eliminate knock. This reduces performance. But will it kill the engine over time? There's risk of increased carbon build-up, but this can be cleaned. To answer the question definitively, does anyone here have any statistics, studies, or use-cases clearly demonstrating this particular engine (or even another high-compression engine with knock sensors) will inconsequentially fail by using 87 octane over its lifetime? I ask not because I am trying to prove a point; rather, I ask because I have not ever seen any definitive results on cars with modern ping sensors (aka everything in the last 15 years). I've seen enough rumors and stories to last me a lifetime, but the plural of anecdote is not data!
The question remains whether people with specific driving habits--who justify the octane downgrade financially (the number 1 driver)--are legitimately jeopardizing their car's longevity, or just the performance. I'm not talking about hypotheses put together based on what's in the manual and the compression ratios (both important details). I'm talking about real-world results.
And there's nothing wrong with reviving old threads to rekindle the debate! The only black and white portion of this discussion is that using octane below what the engine is rated for WILL lower your performance (but not vice versa). The unanswered questions are 1) will using lower-than-required octane gas actually affect the longevity of your engine given modern ECU compensation and 2) if not, can you justify the potential price differences (depending on driving habits)?
My own personal opinions on the topic are this: 1) I have never and will never burn anything but premium grade fuel from one of the top suppliers in either of my TL's. 2) I could care less what anyone else does with their TL... not my property.
11-19-2011, 12:21 AM
#55
Team Owner
I hate internet arguments, but I think it's important for me to clarify.
While both of your statements 1 and 2 are indeed incontrovertible, there is still some ambiguity in the equation and it doesn't fall on the decision making. The ambiguity exists because of a third fact: engines have highly efficient knock sensors. Yes, the engine is designed to run optimally on 91 octane. No one is disputing that. The engine/ECU is also designed intelligently enough to retard timing to eliminate knock. This reduces performance. But will it kill the engine over time? There's risk of increased carbon build-up, but this can be cleaned. To answer the question definitively, does anyone here have any statistics, studies, or use-cases clearly demonstrating this particular engine (or even another high-compression engine with knock sensors) will inconsequentially fail by using 87 octane over its lifetime? I ask not because I am trying to prove a point; rather, I ask because I have not ever seen any definitive results on cars with modern ping sensors (aka everything in the last 15 years). I've seen enough rumors and stories to last me a lifetime, but the plural of anecdote is not data!
The question remains whether people with specific driving habits--who justify the octane downgrade financially (the number 1 driver)--are legitimately jeopardizing their car's longevity, or just the performance. I'm not talking about hypotheses put together based on what's in the manual and the compression ratios (both important details). I'm talking about real-world results.
And there's nothing wrong with reviving old threads to rekindle the debate! The only black and white portion of this discussion is that using octane below what the engine is rated for WILL lower your performance (but not vice versa). The unanswered questions are 1) will using lower-than-required octane gas actually affect the longevity of your engine given modern ECU compensation and 2) if not, can you justify the potential price differences (depending on driving habits)?
While both of your statements 1 and 2 are indeed incontrovertible, there is still some ambiguity in the equation and it doesn't fall on the decision making. The ambiguity exists because of a third fact: engines have highly efficient knock sensors. Yes, the engine is designed to run optimally on 91 octane. No one is disputing that. The engine/ECU is also designed intelligently enough to retard timing to eliminate knock. This reduces performance. But will it kill the engine over time? There's risk of increased carbon build-up, but this can be cleaned. To answer the question definitively, does anyone here have any statistics, studies, or use-cases clearly demonstrating this particular engine (or even another high-compression engine with knock sensors) will inconsequentially fail by using 87 octane over its lifetime? I ask not because I am trying to prove a point; rather, I ask because I have not ever seen any definitive results on cars with modern ping sensors (aka everything in the last 15 years). I've seen enough rumors and stories to last me a lifetime, but the plural of anecdote is not data!
The question remains whether people with specific driving habits--who justify the octane downgrade financially (the number 1 driver)--are legitimately jeopardizing their car's longevity, or just the performance. I'm not talking about hypotheses put together based on what's in the manual and the compression ratios (both important details). I'm talking about real-world results.
And there's nothing wrong with reviving old threads to rekindle the debate! The only black and white portion of this discussion is that using octane below what the engine is rated for WILL lower your performance (but not vice versa). The unanswered questions are 1) will using lower-than-required octane gas actually affect the longevity of your engine given modern ECU compensation and 2) if not, can you justify the potential price differences (depending on driving habits)?
Acura does not use exotic materials or heavy duty parts in the bottom end. In fact, the pistons, ring packs, and rods are geared toward efficiency meaning low friction and light weight, not robustness. This is fine as long as the engine is used within it's design parameters including a minimal amount of pinging using the correct octane.
Detonation will destroy any engine given enough time. A journal bearing is a journal bearing. Subject it to 4 times the stress it sees at full throttle without the pinging and you're going to wear it out quicker period. Same goes for the pistons and rings, nothing special. Couple that with Acura pushing 20wt oils in 100 degree summers and you will eventually have issues.
The knock sensor is reactive, not proactive. It has to hear knock before retarding timing. The ECU will constantly try and put timing back in so it doesn't just ping once on low octane and never again, it's still constantly pinging but not quite as much as if it had no knock sensor. Once the pinging starts, a much greater amount of timing has to be pulled to stop it and sometimes it can't be stopped. The correct way of controlling this is using enough octane to prevent pinging from happening in the first place and let the knock sensor take care of things under short term high load conditions such as shifts. This sensor is there to prevent damage in the event you use the wrong octane once or twice, not to rely on for the life of the car.
So now you're running retarded timing all the time. You've lost torque, hp, and mpg. You're also running much higher EGTs now, making the exhaust valves and everything downstream run hotter.
But all of this engine damage aside, from a purely monetary standpoint, why would you run regular? The only way running regular could ever benefit you financially would be to fill the car up, run it to empty and never refuel it again.
It's so easy, save a few bucks at the pump right now only to have to fill it more often or spend a few more bucks at the pump and go longer between fill ups.
What's so hard to understand, it's cheaper to run premium, there is not a single benefit to running regular but there are many disadvantages.
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11-19-2011, 07:06 AM
#56
Registered Member
There are literally hundreds of studies on the negative effects of pre-ignition and detonation on engines. But let's get one thing out of the way first. This whole thing about additional carbon buildup due to pre-ignition is entirely false.
Acura does not use exotic materials or heavy duty parts in the bottom end. In fact, the pistons, ring packs, and rods are geared toward efficiency meaning low friction and light weight, not robustness. This is fine as long as the engine is used within it's design parameters including a minimal amount of pinging using the correct octane.
Detonation will destroy any engine given enough time. A journal bearing is a journal bearing. Subject it to 4 times the stress it sees at full throttle without the pinging and you're going to wear it out quicker period. Same goes for the pistons and rings, nothing special. Couple that with Acura pushing 20wt oils in 100 degree summers and you will eventually have issues.
The knock sensor is reactive, not proactive. It has to hear knock before retarding timing. The ECU will constantly try and put timing back in so it doesn't just ping once on low octane and never again, it's still constantly pinging but not quite as much as if it had no knock sensor. Once the pinging starts, a much greater amount of timing has to be pulled to stop it and sometimes it can't be stopped. The correct way of controlling this is using enough octane to prevent pinging from happening in the first place and let the knock sensor take care of things under short term high load conditions such as shifts. This sensor is there to prevent damage in the event you use the wrong octane once or twice, not to rely on for the life of the car.
So now you're running retarded timing all the time. You've lost torque, hp, and mpg. You're also running much higher EGTs now, making the exhaust valves and everything downstream run hotter.
But all of this engine damage aside, from a purely monetary standpoint, why would you run regular? The only way running regular could ever benefit you financially would be to fill the car up, run it to empty and never refuel it again.
It's so easy, save a few bucks at the pump right now only to have to fill it more often or spend a few more bucks at the pump and go longer between fill ups.
What's so hard to understand, it's cheaper to run premium, there is not a single benefit to running regular but there are many disadvantages.
Acura does not use exotic materials or heavy duty parts in the bottom end. In fact, the pistons, ring packs, and rods are geared toward efficiency meaning low friction and light weight, not robustness. This is fine as long as the engine is used within it's design parameters including a minimal amount of pinging using the correct octane.
Detonation will destroy any engine given enough time. A journal bearing is a journal bearing. Subject it to 4 times the stress it sees at full throttle without the pinging and you're going to wear it out quicker period. Same goes for the pistons and rings, nothing special. Couple that with Acura pushing 20wt oils in 100 degree summers and you will eventually have issues.
The knock sensor is reactive, not proactive. It has to hear knock before retarding timing. The ECU will constantly try and put timing back in so it doesn't just ping once on low octane and never again, it's still constantly pinging but not quite as much as if it had no knock sensor. Once the pinging starts, a much greater amount of timing has to be pulled to stop it and sometimes it can't be stopped. The correct way of controlling this is using enough octane to prevent pinging from happening in the first place and let the knock sensor take care of things under short term high load conditions such as shifts. This sensor is there to prevent damage in the event you use the wrong octane once or twice, not to rely on for the life of the car.
So now you're running retarded timing all the time. You've lost torque, hp, and mpg. You're also running much higher EGTs now, making the exhaust valves and everything downstream run hotter.
But all of this engine damage aside, from a purely monetary standpoint, why would you run regular? The only way running regular could ever benefit you financially would be to fill the car up, run it to empty and never refuel it again.
It's so easy, save a few bucks at the pump right now only to have to fill it more often or spend a few more bucks at the pump and go longer between fill ups.
What's so hard to understand, it's cheaper to run premium, there is not a single benefit to running regular but there are many disadvantages.
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Acura_Dude (11-20-2011)
11-19-2011, 08:34 AM
#57
3G TL/2G MDX Owner
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to the topic on hand, the TL's manual states that it's required that we run premium (as you and other's have said) otherwise we risk damaging the engine which for any TL owner that loves their car will know. IHC and SB have made very good statements regarding the consequences of using anything lower than 91 octane. if any body chooses NOT to follow Acura's recommendations...well....i hope not to ever buy a used car from you.
11-19-2011, 10:03 PM
#58
Instructor
There are literally hundreds of studies on the negative effects of pre-ignition and detonation on engines. But let's get one thing out of the way first. This whole thing about additional carbon buildup due to pre-ignition is entirely false.
Acura does not use exotic materials or heavy duty parts in the bottom end. In fact, the pistons, ring packs, and rods are geared toward efficiency meaning low friction and light weight, not robustness. This is fine as long as the engine is used within it's design parameters including a minimal amount of pinging using the correct octane.
Detonation will destroy any engine given enough time. A journal bearing is a journal bearing. Subject it to 4 times the stress it sees at full throttle without the pinging and you're going to wear it out quicker period. Same goes for the pistons and rings, nothing special. Couple that with Acura pushing 20wt oils in 100 degree summers and you will eventually have issues.
The knock sensor is reactive, not proactive. It has to hear knock before retarding timing. The ECU will constantly try and put timing back in so it doesn't just ping once on low octane and never again, it's still constantly pinging but not quite as much as if it had no knock sensor. Once the pinging starts, a much greater amount of timing has to be pulled to stop it and sometimes it can't be stopped. The correct way of controlling this is using enough octane to prevent pinging from happening in the first place and let the knock sensor take care of things under short term high load conditions such as shifts. This sensor is there to prevent damage in the event you use the wrong octane once or twice, not to rely on for the life of the car.
So now you're running retarded timing all the time. You've lost torque, hp, and mpg. You're also running much higher EGTs now, making the exhaust valves and everything downstream run hotter.
But all of this engine damage aside, from a purely monetary standpoint, why would you run regular? The only way running regular could ever benefit you financially would be to fill the car up, run it to empty and never refuel it again.
It's so easy, save a few bucks at the pump right now only to have to fill it more often or spend a few more bucks at the pump and go longer between fill ups.
What's so hard to understand, it's cheaper to run premium, there is not a single benefit to running regular but there are many disadvantages.
Acura does not use exotic materials or heavy duty parts in the bottom end. In fact, the pistons, ring packs, and rods are geared toward efficiency meaning low friction and light weight, not robustness. This is fine as long as the engine is used within it's design parameters including a minimal amount of pinging using the correct octane.
Detonation will destroy any engine given enough time. A journal bearing is a journal bearing. Subject it to 4 times the stress it sees at full throttle without the pinging and you're going to wear it out quicker period. Same goes for the pistons and rings, nothing special. Couple that with Acura pushing 20wt oils in 100 degree summers and you will eventually have issues.
The knock sensor is reactive, not proactive. It has to hear knock before retarding timing. The ECU will constantly try and put timing back in so it doesn't just ping once on low octane and never again, it's still constantly pinging but not quite as much as if it had no knock sensor. Once the pinging starts, a much greater amount of timing has to be pulled to stop it and sometimes it can't be stopped. The correct way of controlling this is using enough octane to prevent pinging from happening in the first place and let the knock sensor take care of things under short term high load conditions such as shifts. This sensor is there to prevent damage in the event you use the wrong octane once or twice, not to rely on for the life of the car.
So now you're running retarded timing all the time. You've lost torque, hp, and mpg. You're also running much higher EGTs now, making the exhaust valves and everything downstream run hotter.
But all of this engine damage aside, from a purely monetary standpoint, why would you run regular? The only way running regular could ever benefit you financially would be to fill the car up, run it to empty and never refuel it again.
It's so easy, save a few bucks at the pump right now only to have to fill it more often or spend a few more bucks at the pump and go longer between fill ups.
What's so hard to understand, it's cheaper to run premium, there is not a single benefit to running regular but there are many disadvantages.
I don't know why everyone is attacking those who don't run premium. The groupthink here is oddly strong for a car forum. The reason why we're discussing this is because there are plenty of people who have run sub-optimal octane levels in their premium-only cars and have not experienced measurable engine damage[1]. I know SEVERAL people who have run their premium-only cars for 200k+ on 87 and still have solid engines.
IHC, I agree with 99% of your post. There should be plenty of studies showing pre-ignition and detonation are bad--this is pure mechanics and cannot be refuted. The 1% creating a question among the car community is, when you put the whole picture of ECU, KS, and 87 octane together, how much measurable damage will a premium-only engine experience? Those are the studies I'm after. Something like a Consumer Reports, perhaps. Personally? It's a non issue and I don't really care since I run 91+, but I don't like seeing people dismiss discussions without empirical analysis and by jumping on bandwagons.
[1] for some premium-only cars, the mpg difference between 91 and 87 is marginal enough where it's actually cheaper to use 87. This doesn't appear to be the case for the TL, so I apologize if it seems I'm making a big stink about nothing.
11-20-2011, 12:09 AM
#59
Team Owner
First, thank you for making a well-reasoned post! It's refreshing to know there are some gearheads in the Acura community.
I don't know why everyone is attacking those who don't run premium. The groupthink here is oddly strong for a car forum. The reason why we're discussing this is because there are plenty of people who have run sub-optimal octane levels in their premium-only cars and have not experienced measurable engine damage[1]. I know SEVERAL people who have run their premium-only cars for 200k+ on 87 and still have solid engines.
IHC, I agree with 99% of your post. There should be plenty of studies showing pre-ignition and detonation are bad--this is pure mechanics and cannot be refuted. The 1% creating a question among the car community is, when you put the whole picture of ECU, KS, and 87 octane together, how much measurable damage will a premium-only engine experience? Those are the studies I'm after. Something like a Consumer Reports, perhaps. Personally? It's a non issue and I don't really care since I run 91+, but I don't like seeing people dismiss discussions without empirical analysis and by jumping on bandwagons.
[1] for some premium-only cars, the mpg difference between 91 and 87 is marginal enough where it's actually cheaper to use 87. This doesn't appear to be the case for the TL, so I apologize if it seems I'm making a big stink about nothing.
I don't know why everyone is attacking those who don't run premium. The groupthink here is oddly strong for a car forum. The reason why we're discussing this is because there are plenty of people who have run sub-optimal octane levels in their premium-only cars and have not experienced measurable engine damage[1]. I know SEVERAL people who have run their premium-only cars for 200k+ on 87 and still have solid engines.
IHC, I agree with 99% of your post. There should be plenty of studies showing pre-ignition and detonation are bad--this is pure mechanics and cannot be refuted. The 1% creating a question among the car community is, when you put the whole picture of ECU, KS, and 87 octane together, how much measurable damage will a premium-only engine experience? Those are the studies I'm after. Something like a Consumer Reports, perhaps. Personally? It's a non issue and I don't really care since I run 91+, but I don't like seeing people dismiss discussions without empirical analysis and by jumping on bandwagons.
[1] for some premium-only cars, the mpg difference between 91 and 87 is marginal enough where it's actually cheaper to use 87. This doesn't appear to be the case for the TL, so I apologize if it seems I'm making a big stink about nothing.
Many will disagree with me but I believe 11:1 compression should be direct injection territory for a street car that's expected to run on pump gas. I'm not saying compression is the only factor, throw a large cam in there and you can probably get away with the higher compression and that brings me to another point. It's only a guess but I'm ASSuming that these vtec engines use a fairly small cam profile when not in vtec which will increase cylinder pressure at part throttle and lower rpms making it more likely to ping.
One thing I believe is linked to the pinging is all of the spark plugs that keep loosening up and being blown out of the head. It's always the front middle plug. I would guess that's the cylinder that's most prone to pinging and pinging will loosen spark plugs occasionally.
You might not see catastrophic engine failure from a life on 87 octane but what you will likely see is more frequent exhaust valve adjustments, more rod bearing wear which you would be unaware of until you run into rod knock or idle oil pressure issues or ring lands that get hammered that might only show up in a leak down test. It's basically "loosening up" your engine slowly, increasing blowby and losing compression which of course permanently lowers power and mpg.
We all want our cars to last so you have to think of what happens when pre-ignition or detonation occurs. The piston is still traveling up, the charge gets ignited before the spark plug fires or it detonates. It's trying to push the piston back down the opposite way essentially trying to stop the engine and turn it backwards while spinning 1000-7,000rpm. You can see cylinder pressures spike up anywhere from 4-10x what you would see under full throttle without the pinging. Or it would be like the equivalent stress of 800hp on the internals for a moment. With the TL's modest hp it's usually a cumulative effect. It will still be running at 100,000 miles on 87 but I believe a leakdown test will show the engine run on premium to be healthier at the same mileage.
The following 2 users liked this post by I hate cars:
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Acura_Dude (11-20-2011)
11-20-2011, 08:38 AM
#61
Racer
There is always a degree of detonation even with premium fuel, but the knock sensor can handle it. When you start to run regular fuel, the sensor just can't keep up in proper fashion and, as noted, things start to become stressed.
Three things should never be done to an Acura engine ... 1) improper oil viscosity OR a junk grade of oil; 2) Not changing the oil at the proper interval and; 3) Cheap gas - not "Top Tier".
The reason for #3 is simple ... cheaper fuels tend to be those with minimal detergency, just meeting the Federal guidelines. They don't keep the engine clean enough, carbon deposits are formed and the end result can be the addition of pre-ignition to the already existent detonation issues.
IMO, it isn't rocket science ... follow the instructions. AHMC wouldn't tell you to put premium "Top Tier" fuels into the vehicle if it didn't matter. They realize that it adds to the ownership costs AND that it does drive away a few buyers - potential first time and repeat. It really does matter, it is just that simple.
Three things should never be done to an Acura engine ... 1) improper oil viscosity OR a junk grade of oil; 2) Not changing the oil at the proper interval and; 3) Cheap gas - not "Top Tier".
The reason for #3 is simple ... cheaper fuels tend to be those with minimal detergency, just meeting the Federal guidelines. They don't keep the engine clean enough, carbon deposits are formed and the end result can be the addition of pre-ignition to the already existent detonation issues.
IMO, it isn't rocket science ... follow the instructions. AHMC wouldn't tell you to put premium "Top Tier" fuels into the vehicle if it didn't matter. They realize that it adds to the ownership costs AND that it does drive away a few buyers - potential first time and repeat. It really does matter, it is just that simple.
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