I've heard a lot of debate over what kind of fuel the 1.4L T should use (regular or premium) and hoping to get some opinions from you guys and gals. I've heard that premium causes less detonation (whatever the heck that means) and is easier on the engine, increasing service life. Also if I was to use premium gasoline which is more expensive, will the cost justify the means due to the fuel economy evening it out?
87
using a higher octane won't net you a better fuel mileage. at best you might gain some hp but its uncertain at this point. until someone gets one on a dyno we'll probably never know
you dont need a dyno to know if the premium fuel will make any difference. it will. its been discussed here before. i have a lot of experience with turbo cars and turbochargers in general and ive used regular on them before. never had any good results. car ran like crap, excessive knocking in the motor, and ridiculous amount of power loss. i wouldnt suggest trying it as i have lost one motor already to detonation. heres a really good explanation of what detonation is.
Detonation of Motor Fuels definition of Detonation of Motor Fuels in the Free Online Encyclopedia.
Detonation of Motor Fuels definition of Detonation of Motor Fuels in the Free Online Encyclopedia.
I understand what detonation is and how higher octanes work. GM is recommending 87 octane on all cruze's. I understand higher octane might be better, but if you engine blows under 100k GM replaces it for free..
Here is an email response I've received from their engineers:
Here is an email response I've received from their engineers:
You probably have more experience than I do so I'll deflect to you. Do you have a cruze yet? Did you notice any performance increase when switching to a higher octane? What did/do you use?
...interestingly, the USA manual states 87 octane, but, seemingly, some overseas models state 91 octane.
...anybody know *why* the difference--possibly, fuel grade or quality?
...anybody know *why* the difference--possibly, fuel grade or quality?
I've now gone through 2 tanks of 87 and 1 tank of 93. I did not really feel any difference?
If there is, it's minor. I need to see some numbers showing the higher octane actually helps this car at all. Until then I'm saving $5 and using 87...
If there is, it's minor. I need to see some numbers showing the higher octane actually helps this car at all. Until then I'm saving $5 and using 87...
...one has to wonder, however, *how* GM can warranty the engine on 89 octane, if, as you say, 91 octane is what *should* be used.
...sorry, I'm not buying it. Granted, using 91 octane might help you gain somewhat more HP when you're drag racing, pulling a heavy maximum capacity load, or climbing through mountains fully loaded, but it is probably not necessary for the 99.9% population who drive under "normal" conditions.
...if 91 octane was required, it would've been so stated in the Owners Manual, by the GM lawyers.
...sorry, I'm not buying it. Granted, using 91 octane might help you gain somewhat more HP when you're drag racing, pulling a heavy maximum capacity load, or climbing through mountains fully loaded, but it is probably not necessary for the 99.9% population who drive under "normal" conditions.
...if 91 octane was required, it would've been so stated in the Owners Manual, by the GM lawyers.
Based on the emails from Chevy and post by ChevyMgr I will stick with 87 octane in mine and keep some of that extra money in my pocket. It doesn't bug me at all knowing I could go to a higher level. If Chevy says 87 is perfectly safe and good, I will stick with that.
...my personnal policy: 87 octane for all 'normal' driving and 91 octane if/when driving under 'loaded' conditions, ie: heavy/full weight load, or climbing through mountains, etc.
Octane requirement is effected by lots of things. Boost certainly plays a big part, but so does ambient temps, coolant temp, oil temp, humidity, compression ratio....ect.
Worst case scenario...lots of boost, extremely low humidity, high air temperature, heavily loaded, coolant temps near boiling. All these things increase octane requirements, you might need an octane of 110 or more in those conditions. Cold humid weather. lightly loaded.....you might only really need 80 octane if it were availible.
The car manufacturers err on the side of caution. It would be interesting to know what they have the peak boost set at.
MHF
Worst case scenario...lots of boost, extremely low humidity, high air temperature, heavily loaded, coolant temps near boiling. All these things increase octane requirements, you might need an octane of 110 or more in those conditions. Cold humid weather. lightly loaded.....you might only really need 80 octane if it were availible.
The car manufacturers err on the side of caution. It would be interesting to know what they have the peak boost set at.
MHF
...regarding "peak boost" -- there are people now who are attempting to learn if that info can be read-out over the OBD-II port using one of the aftermarket gauges (such as ScanGauge or UltraGauge, etc.).
...first, we have to know if such info is "GM_Proprietary" and as such wouldn't be made available to the general public (ie: a general code).
...then, because we *still* want to know, it becomes a 'detective' game of literally searching through all the available engine control unit (ECU) codes to see if the data is available, but unlisted.
...finally, using the programability function of a ScanGauge, one could code it to search for and read the illusive info...and display it on the gauge readout.
...nothing is impossible, just sometimes it's rather improbable (ha,ha).
...first, we have to know if such info is "GM_Proprietary" and as such wouldn't be made available to the general public (ie: a general code).
...then, because we *still* want to know, it becomes a 'detective' game of literally searching through all the available engine control unit (ECU) codes to see if the data is available, but unlisted.
...finally, using the programability function of a ScanGauge, one could code it to search for and read the illusive info...and display it on the gauge readout.
...nothing is impossible, just sometimes it's rather improbable (ha,ha).
it is really rich, and the turbo is fairly maxed out i believe. i can see a bigger turbo upgrade coming soon aftermarket
Car engines are built for a specific octane. Lower octane is more flamible (contrary to what most people think). Years ago, the reason people would use higher octane in an older car to prevent knocks is for this reason: build up (some times lead) in the cylinders causing a smaller compression space meaning the piston was firing too early before the spark, thus causing a knock. Higher octane is less flamible meaning it would allow the piston to fully compress and not explode prematurely. Using 91 in a brand new Cruze means you are putting less flamible gas in the engine for which its designed. There is no mechanical reason for a knock, nor a reason to supress a knock.
Quesion for those claiming 89 is causing less hessitation: Are you driving 1.4 or 1.8?
Quesion for those claiming 89 is causing less hessitation: Are you driving 1.4 or 1.8?
Well and thats the thing, I wrote to GM and they said the car CAN run 87, but do not run anything higher than 89. They would not give me a direct answer on what I SHOULD be running. It was very odd.
I'm no sure how European octanes differ from US but in Europe they recommend 89...
I'm no sure how European octanes differ from US but in Europe they recommend 89...
Honestly I don't know what they are thinking telling everyone to use 87 with this much boost. Maybe they wrote the instructions for the LS normally aspirated engine and forgot about the 1.4 turbo or something.
You know what would be great? An indicator that tells you when or how often the knock sensor goes off. Or tell us the timing advance setting so we can see what the engine is doing at different octane ratings, loads and weather conditions.
You know what would be great? An indicator that tells you when or how often the knock sensor goes off. Or tell us the timing advance setting so we can see what the engine is doing at different octane ratings, loads and weather conditions.
i had a long talk with vince from trifecta last week. very smart knowledgeable guy. really enjoyed our conversation.
here is the deal, chevy tuned the car to run on 87 for reason previously stated and its why its so **** slow for an FI car. so in its stock form without any sort of tune, 87 OCT is just fine to run. you might notice its runs better with 89 OCT since it is a FI car.
if you were to get some sort of tune like the one Vince from trifecta offers it will have to run on 91 OCT or it will knock regardless of knock sensors or anything else.
cruise control is right about running 91 in FI cars, but that's is for a car tuned to run on it. like with the hondas and aftermarket turbos which are tuned for big horsepower number and have very high air to fuel ratios so u have to run 91 to avoid knocking also known as detonation. that is not the case with the cruze in its stock form it was not tuned for performance not power. it was tuned for 36 mpg on the high way bottom line
here is the deal, chevy tuned the car to run on 87 for reason previously stated and its why its so **** slow for an FI car. so in its stock form without any sort of tune, 87 OCT is just fine to run. you might notice its runs better with 89 OCT since it is a FI car.
if you were to get some sort of tune like the one Vince from trifecta offers it will have to run on 91 OCT or it will knock regardless of knock sensors or anything else.
cruise control is right about running 91 in FI cars, but that's is for a car tuned to run on it. like with the hondas and aftermarket turbos which are tuned for big horsepower number and have very high air to fuel ratios so u have to run 91 to avoid knocking also known as detonation. that is not the case with the cruze in its stock form it was not tuned for performance not power. it was tuned for 36 mpg on the high way bottom line
Maybe the tankful of fuel from the dealership was old fuel, or contaminated with condensation, because it hesitated a lot upon acceleration until I put a new tank of fuel in. And I put in 91. Next fill up I'll put in 87 and see if it goes back to hesitating again or not.
BTW it is "slow" for an FI car because of the small displacement. 1.4 liters is a small engine. It is designed to be fuel efficient not a hot rod. I understand it may be designed to run on 87 but keep in mind the engine thermostat is set to 220 deg. F. unlike other cars that are set to 195 deg. F. That might cause the fuel to ignite a bit faster.
BTW it is "slow" for an FI car because of the small displacement. 1.4 liters is a small engine. It is designed to be fuel efficient not a hot rod. I understand it may be designed to run on 87 but keep in mind the engine thermostat is set to 220 deg. F. unlike other cars that are set to 195 deg. F. That might cause the fuel to ignite a bit faster.
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
