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ycr99

Grade Of Gas

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ive said it before and i'll say it again, run the octane that your engine needs. otherwise you're increasing the likely hood of excessive carbon buildup in the chambers, exhaust ports, and the egr valve.

Sure, but their gas mileage will be improved as they do.

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ive said it before and i'll say it again, run the octane that your engine needs. otherwise you're increasing the likely hood of excessive carbon buildup in the chambers, exhaust ports, and the egr valve.

Sure, but their gas mileage will be improved as they do.

and the $100 they save now they can spend in 2 years when the engine needs work for a stuck valve, stuck rings, bad egr valve, or excessive compression or dieseling due to carbon deposits.

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ive said it before and i'll say it again, run the octane that your engine needs. otherwise you're increasing the likely hood of excessive carbon buildup in the chambers, exhaust ports, and the egr valve.

Sure, but their gas mileage will be improved as they do.

and the $100 they save now they can spend in 2 years when the engine needs work for a stuck valve, stuck rings, bad egr valve, or excessive compression or dieseling due to carbon deposits.

Yes, providing they still have their car in two years.

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My last car was a 1986 Honda Civic, and as with my Corolla, I usually put in 89 octane.

 

In 15 yrs of owning my Honda I never had a ping or knock, nor did I ever have to have anything done to the engine for carbon deposits, stuck rings, etc - I never needed any fuel injector additive or anything else -

it ran great & the only problems were cosmetic (driver's seat splitting open, cracked windshield, etc)

 

I'm not saying these things can't happen to an engine, they just didn't happen to me -

 

I would agree that using 93 octane is probably a waste of money, but the 89 is what I prefer, as I said, I do get better gas mileage - I really like my Corolla - it's my second one...first one was a 1980 hatchback.

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ive said it before and i'll say it again, run the octane that your engine needs. otherwise you're increasing the likely hood of excessive carbon buildup in the chambers, exhaust ports, and the egr valve.

Sure, but their gas mileage will be improved as they do.

and the $100 they save now they can spend in 2 years when the engine needs work for a stuck valve, stuck rings, bad egr valve, or excessive compression or dieseling due to carbon deposits.

Yes, providing they still have their car in two years.

My owner's manual for my cars specify that I must use 87 Octane or higher. I have not seen anywhere that has any less than 87 Octane rating. If the owner's manual says that I can use higher, then how could it possibly be bad for my car?? I can see if it said only 87 Octane, but it does not. Like anything else, there are options to the owners.

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because higher octane fuels are meant to combust under higher compression and heat than your engine produces. they do not fully combust in the engine and lead to carbon buildup.

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because higher octane fuels are meant to combust under higher compression and heat than your engine produces. they do not fully combust in the engine and lead to carbon buildup.

 

 

That might be true of a car was tied down to a mechanical timming setting, but newer Corolla's have knock sensors and the ECU can control the timming based on knock counts, intake temps, ect.

 

I've yet to see any proof that a newer Corolla's ECU does or doesn't advance the timming based on knock counts, but I don't see why the car would have a knock sensor in the first place unless the ECU was going to always try and find a optimal fuel and timming curve. It's really cold out and I'm not going to find the page number on my owners manual about fuel, but I'm pretty sure it says 87 or higher. Being a economy car, I've made the choice to not run higher then 87, but in summer months when it's really hot out and the intake temps are already really hot, I feel better throwing in 89 to help fight against knock.

 

Carbon build up on engines are going to happen in time. It's part of a engine getting old and while having unburnt fuel due to running rich, or using too high of octane doesn't help, fuel is dirty and older cars still get carbon build up using the 87 octane.

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it doesnt advance timing based on knock counts, its not setup to do that. yes im talking about the 1ZZFE. it can not take advantage of higher octane fuels.

 

https://www.corolland.com/forums/index.php?...ndpost&p=123802

 

just because theres electronic ignition and a knock sensor does not mean that it can advance timing to take advantage of higher octane fuels. MOST cars (not just corollas) can only retard when knock is sensed.

Edited by Bitter

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it doesnt advance timing based on knock counts, its not setup to do that. yes im talking about the 1ZZFE. it can not take advantage of higher octane fuels.

 

https://www.corolland.com/forums/index.php?...ndpost&p=123802

 

just because theres electronic ignition and a knock sensor does not mean that it can advance timing to take advantage of higher octane fuels. MOST cars (not just corollas) can only retard when knock is sensed.

 

Interesting read. It kind of makes me wonder why a Corolla even has a knock sensor at all. It would seem that most newer cars have knock sensors, but in the past, only performance cars and cars with forced induction hade a knock sensor.

 

I have a 92 turbo car and I have a logger for it. 0-3 counts of knock, my car advances timming, 3-7 counts of knock, the ECU leaves the timming alone. 7 plus counts of knock, the ECU starts to retard the timming. It's a DSMer stuff and while not related to Toyota at all, having a knock sensor and the ECU not tring to run optimal tunning is stupid to me. What's the point?

 

Why does my Toyota even have a knock seosor?

 

The only time I put 89 in our corolla instead of 87 is because the 89 was acually cheaper. While I'm not going to try and get more performance out of my Corolla by running higher octane because it's a economy car and I don't run WOT and redline it. I don't find that link above as 100% proof that the newer Corolla's don't take advantage of higher octane at all. The next time I'm in my car, I'll try and remember to read the owners manual. I don't know why toyota would even make mention of higher octane fuels if it was a complete wast.

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they have a knock sensor for gas mileage reasons. the leaner they can run they better mileage. BUT running too lean can cause knock, so they have a knock sensor to allow them to run as lean as possible with minimal knock. modern engines do knock, the AF bounces around between lean, stoich, and rich. an O2 sensor can only monitor combustion thats already happened, the sensor reports a rich condition, so the ecm takes away fuel, then the sensor reports a lean condition so the ecm adds some fuel. it bounces around like that in closed loop. the knock sensor is there to protect the engine incase the ecm leans it back too far and theres lean knock. the knock sensor is also there as an engine safe guard incase something weird happens and the engine starts knocking.

 

 

they mention higher octane fuels to cover their bases, so an owner doesnt spaz out they he/she cant find 87 octane fuel and doesnt have a mental breakdown because of it :lol:

 

its the same reason my lawnmower says 87 octane or better also, trust me...a flat head motor with 7.5 (or 8):1 compression doesnt need anything better than 87 octane.

Edited by Bitter

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it doesnt advance timing based on knock counts, its not setup to do that. yes im talking about the 1ZZFE. it can not take advantage of higher octane fuels.

 

https://www.corolland.com/forums/index.php?...ndpost&p=123802

 

just because theres electronic ignition and a knock sensor does not mean that it can advance timing to take advantage of higher octane fuels. MOST cars (not just corollas) can only retard when knock is sensed.

 

Interesting read. It kind of makes me wonder why a Corolla even has a knock sensor at all. It would seem that most newer cars have knock sensors, but in the past, only performance cars and cars with forced induction hade a knock sensor.

 

I have a 92 turbo car and I have a logger for it. 0-3 counts of knock, my car advances timming, 3-7 counts of knock, the ECU leaves the timming alone. 7 plus counts of knock, the ECU starts to retard the timming. It's a DSMer stuff and while not related to Toyota at all, having a knock sensor and the ECU not tring to run optimal tunning is stupid to me. What's the point?

 

Why does my Toyota even have a knock seosor?

 

The only time I put 89 in our corolla instead of 87 is because the 89 was acually cheaper. While I'm not going to try and get more performance out of my Corolla by running higher octane because it's a economy car and I don't run WOT and redline it. I don't find that link above as 100% proof that the newer Corolla's don't take advantage of higher octane at all. The next time I'm in my car, I'll try and remember to read the owners manual. I don't know why toyota would even make mention of higher octane fuels if it was a complete wast.

 

Your Toyota has a knock sensor because there can be variance in gasoline. I have bought gas before that said it was 87 octane and it caused my car to knock really badly, after a couple of minutes, the knock sensor did it's job and corrected my engine's operations to eliminate the knock. Also, even with good gas, the car can knock under certain conditions, and the knock sensor allows for ECU programming changes to eliminate the knock.

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well I don't really have a choice when it comes to what gas i use, they say I can only use 91 octane(premium) being that its the 2zz engine, sometimes I wish I did have a choice being that gas isnt cheap here, but hey, what else can you do

Edited by BabyBird200

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they have a knock sensor for gas mileage reasons. the leaner they can run they better mileage. BUT running too lean can cause knock, so they have a knock sensor to allow them to run as lean as possible with minimal knock. modern engines do knock, the AF bounces around between lean, stoich, and rich. an O2 sensor can only monitor combustion thats already happened, the sensor reports a rich condition, so the ecm takes away fuel, then the sensor reports a lean condition so the ecm adds some fuel. it bounces around like that in closed loop. the knock sensor is there to protect the engine incase the ecm leans it back too far and theres lean knock. the knock sensor is also there as an engine safe guard incase something weird happens and the engine starts knocking.

 

 

they mention higher octane fuels to cover their bases, so an owner doesnt spaz out they he/she cant find 87 octane fuel and doesnt have a mental breakdown because of it :lol:

 

its the same reason my lawnmower says 87 octane or better also, trust me...a flat head motor with 7.5 (or 8):1 compression doesnt need anything better than 87 octane.

 

I know what a ECU does. Do you know for a fact about what you are saying? You are talking about the ECU controling fuel only, not timming. Modern cars still need a correct base mechanical timming set and the ECU assumes that the timming is set correctly, but ECUs can also adjust how the spark plugs fire, and how the long or short the injectors squirt fuel. Any car with a coil pack and knock sensor is going to have a ECU that can control timming and have injector squirt time control based in o2 readings and all the other sensors in the car.

 

You are correct in most of what you said, but everything you discribed is a ECU and knock sensor setup that can take advantage of higher octane fuels. Others have reported knocking, so higher octane fuel might be a better choice for some people.

 

I've still yet to see any hard core proof either way to prove or disprove that are engines can take advantage of higher octane fuels. While 91 and up is going to be a wast, 89 might acually have some advantages over 87.

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they have a knock sensor for gas mileage reasons. the leaner they can run they better mileage. BUT running too lean can cause knock, so they have a knock sensor to allow them to run as lean as possible with minimal knock. modern engines do knock, the AF bounces around between lean, stoich, and rich. an O2 sensor can only monitor combustion thats already happened, the sensor reports a rich condition, so the ecm takes away fuel, then the sensor reports a lean condition so the ecm adds some fuel. it bounces around like that in closed loop. the knock sensor is there to protect the engine incase the ecm leans it back too far and theres lean knock. the knock sensor is also there as an engine safe guard incase something weird happens and the engine starts knocking.

 

 

they mention higher octane fuels to cover their bases, so an owner doesnt spaz out they he/she cant find 87 octane fuel and doesnt have a mental breakdown because of it :lol:

 

its the same reason my lawnmower says 87 octane or better also, trust me...a flat head motor with 7.5 (or 8):1 compression doesnt need anything better than 87 octane.

 

I know what a ECU does. Do you know for a fact about what you are saying? You are talking about the ECU controling fuel only, not timming. Modern cars still need a correct base mechanical timming set and the ECU assumes that the timming is set correctly, but ECUs can also adjust how the spark plugs fire, and how the long or short the injectors squirt fuel. Any car with a coil pack and knock sensor is going to have a ECU that can control timming and have injector squirt time control based in o2 readings and all the other sensors in the car.

 

You are correct in most of what you said, but everything you discribed is a ECU and knock sensor setup that can take advantage of higher octane fuels. Others have reported knocking, so higher octane fuel might be a better choice for some people.

 

I've still yet to see any hard core proof either way to prove or disprove that are engines can take advantage of higher octane fuels. While 91 and up is going to be a wast, 89 might acually have some advantages over 87.

i know that they control timing as well, but in MOST cases only retard. probably so that its harder to in and monkey with it and ruin your emissions compliance.

 

remember that automakers are trying to do only 3 things with their cars

1. make money

2. meet emissions

3. meet fuel milage requirments (which sometimes goes back to #1)

 

the government only cares about #2 and #3, automakers want to make it difficult for you to fail emissions while under their emissions warranty period (back to #1). its gonna be harder for you to fail emissions if you have to get a $500 box to play with your timing and fuel curves rather than just poking around in the ECU's programming, which is probably why Toyotas ecu's are more difficult (what ive heard) than most other imports because toyota doesnt want anyone seeing what they're doing to meet emissions and fuel mileage requirments and they dont want anyone messing with how the vehicle operates. bad for the performance guys but good for the average consumer and for the company.

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they have a knock sensor for gas mileage reasons. the leaner they can run they better mileage. BUT running too lean can cause knock, so they have a knock sensor to allow them to run as lean as possible with minimal knock. modern engines do knock, the AF bounces around between lean, stoich, and rich. an O2 sensor can only monitor combustion thats already happened, the sensor reports a rich condition, so the ecm takes away fuel, then the sensor reports a lean condition so the ecm adds some fuel. it bounces around like that in closed loop. the knock sensor is there to protect the engine incase the ecm leans it back too far and theres lean knock. the knock sensor is also there as an engine safe guard incase something weird happens and the engine starts knocking.

 

 

they mention higher octane fuels to cover their bases, so an owner doesnt spaz out they he/she cant find 87 octane fuel and doesnt have a mental breakdown because of it :lol:

 

its the same reason my lawnmower says 87 octane or better also, trust me...a flat head motor with 7.5 (or 8):1 compression doesnt need anything better than 87 octane.

 

I know what a ECU does. Do you know for a fact about what you are saying? You are talking about the ECU controling fuel only, not timming. Modern cars still need a correct base mechanical timming set and the ECU assumes that the timming is set correctly, but ECUs can also adjust how the spark plugs fire, and how the long or short the injectors squirt fuel. Any car with a coil pack and knock sensor is going to have a ECU that can control timming and have injector squirt time control based in o2 readings and all the other sensors in the car.

 

You are correct in most of what you said, but everything you discribed is a ECU and knock sensor setup that can take advantage of higher octane fuels. Others have reported knocking, so higher octane fuel might be a better choice for some people.

 

I've still yet to see any hard core proof either way to prove or disprove that are engines can take advantage of higher octane fuels. While 91 and up is going to be a wast, 89 might acually have some advantages over 87.

i know that they control timing as well, but in MOST cases only retard. probably so that its harder to in and monkey with it and ruin your emissions compliance.

 

remember that automakers are trying to do only 3 things with their cars

1. make money

2. meet emissions

3. meet fuel milage requirments (which sometimes goes back to #1)

 

the government only cares about #2 and #3, automakers want to make it difficult for you to fail emissions while under their emissions warranty period (back to #1). its gonna be harder for you to fail emissions if you have to get a $500 box to play with your timing and fuel curves rather than just poking around in the ECU's programming, which is probably why Toyotas ecu's are more difficult (what ive heard) than most other imports because toyota doesnt want anyone seeing what they're doing to meet emissions and fuel mileage requirments and they dont want anyone messing with how the vehicle operates. bad for the performance guys but good for the average consumer and for the company.

 

 

How do you KNOW in most cases? What are you basing that off of? The ECU is going to have a target timming advance that it can run. I know my mitsu ECU is always tring to advance the timming as much as possible. I have a logger, I can look at it. I just upgraded my injectors on my car and my ECU is advancing my timming at WOT more aggressive then it was before the injectors. While I do have a different ECU chip, the only main changes were to account for larger injectors and a different MAF that I'm running. The programers goal of the software is to make the car run near as stock as possible. He does a awsome job at it.

 

The new Corolla's are pretty damn zippy for a 1.8l econobox and they get great fuel economy. They are not going to be able to do this without some pretty aggressive ECU programing. Our record is 43MPG on a tank. While that's not normal, I don't know of any gasoline Honda's that can do that. They have some California only cars that I can't buy, and the CRX HF was a great economy car, but it was also slow as could be.

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