The "newbie" suggestions recommend using mid-grade 89 octane fuel even though 87 is normal. What do you use and why?
Bob Paris
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I use Top Tier 93. I have an ultra-gauge and I can see the difference in ignition timing between 87 and 93. On 93, I can accelerate in 6th gear going up a slight hill. With 87, I have to down shift. I've also noticed a difference of about 3mpg using premium.
Octane is an anti-knock rating. Fuel will detonate without a spark plug if there is enough heat and pressure. But you don't want an uncontrolled explosion, you want to ignite it at the perfect time for the circumstances. Most normally aspirated vehicles don't require premium because they do have enough compression to cause pinging/knocking (pre-detonation). Turbo-charged and supercharged vehicles are more susceptible to pre-detonation, especially in the summer when it's hot, because they pressurize the intake air. I've seen my intake temps reach as high as 147F in traffic with the AC on.
The Cruze has engine timing tables for different octane fuels. The computer monitors the knocking and changes the timing accordingly so the engine isn't harmed. If you don't use the full potential of the engine, you probably won't notice the difference in 87/93. If you like to work that tiny 1,364cc engine until the valves are popping out, then 93 will benefit you. You'll be able to use more of the engine's power and you'll get better economy. (The cost is a wash, it'll cost the same per mile no matter what fuel you're using, the cheaper stuff doesn't get you as far)
Octane is an anti-knock rating. Fuel will detonate without a spark plug if there is enough heat and pressure. But you don't want an uncontrolled explosion, you want to ignite it at the perfect time for the circumstances. Most normally aspirated vehicles don't require premium because they do have enough compression to cause pinging/knocking (pre-detonation). Turbo-charged and supercharged vehicles are more susceptible to pre-detonation, especially in the summer when it's hot, because they pressurize the intake air. I've seen my intake temps reach as high as 147F in traffic with the AC on.
The Cruze has engine timing tables for different octane fuels. The computer monitors the knocking and changes the timing accordingly so the engine isn't harmed. If you don't use the full potential of the engine, you probably won't notice the difference in 87/93. If you like to work that tiny 1,364cc engine until the valves are popping out, then 93 will benefit you. You'll be able to use more of the engine's power and you'll get better economy. (The cost is a wash, it'll cost the same per mile no matter what fuel you're using, the cheaper stuff doesn't get you as far)
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I use Top Tier 93 as well. I ran the regular in the winter and din't notice a difference in how it ran/accelerated, but when the outside temps started to warm up I noticed.
Been battling what I think is a misfire too. Only happens with A/C on and accelerating 65-80% on a freeway on-ramp. Bucks a few times but there is no CEL. Who knows.
Been battling what I think is a misfire too. Only happens with A/C on and accelerating 65-80% on a freeway on-ramp. Bucks a few times but there is no CEL. Who knows.
I'd have to say that just about any gasoline, even the regular and cheap ones (save for Chevron, which is known around here to be stuffed with crapanol), is better than the premium gasolines of the seventies and eighties.
The quality of fuel is top notch, and no longer lead filled!
The quality of fuel is top notch, and no longer lead filled!
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Even better now91+no ethanol, I get way better fuel economy!![Image]()
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Ironic but I'll tell ya Mr Sparkman you should check your spark lmao. I found mine did the same thing when the boot was holding up one of the springs. Ran fine otherwise except when nearing wot.
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I'll probably stick w/ 91oct now.☺Even better now![Image]()
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10,587 Posts
93 since new since my Eco didn't want to run 87. Even in the winter time 87 would stall the car if T/C or stabilitrac tried to step in and help me out. There was a ECU recall but it didn't count manuals. When I had my stock file from Trifecta, it pretty much was the file from a 2015 or so. If the guy who got my car reaches out to me again, I'll ask if he followed the premium fuel sticker or been running 87 flawlessly.
The thing with top tier and 93 is you have to buy from a station that's "selling it". There is some places here that are in the not so well off areas where they aren't near a freeway and have 87 only strings of stations nearby. Those 87 only strings are stealing fuel sales from the Shell and BP nearby so they lower 87 prices to compete and leave the 89 and 93 prices in an unreasonable price bracket. You ever see a station "Run out of 87" and start selling you 93 instead? chances are that gas been there forever and they trying to get rid of it.
The thing with top tier and 93 is you have to buy from a station that's "selling it". There is some places here that are in the not so well off areas where they aren't near a freeway and have 87 only strings of stations nearby. Those 87 only strings are stealing fuel sales from the Shell and BP nearby so they lower 87 prices to compete and leave the 89 and 93 prices in an unreasonable price bracket. You ever see a station "Run out of 87" and start selling you 93 instead? chances are that gas been there forever and they trying to get rid of it.
Lead was added to gas to reduce combustion chamber temperatures, without it, would be at 2,600*F, burn holes in pistons and eat exhaust valves. But its short fall was gets into lungs, with some can cross the brain blood barrier, make them very aggressive and stupid, kind of sounds like our politicians.
In WW II aircraft, without lead, water injection was used to cool things down, too complicated for the public so exhaust gas recirculation was used. First a valve for this, more crap in the engine, Cruze and others close the exhaust valves early to leave burnt gas in for the next cycle. EPA's major complaint was those high temperatures produced NOx's, smog because the air going inside of the engine is 80% nitrogen.
EGR can be as high as 30%, so in reality, that 1.4 L engine is more like a 1.1 L engine. 1972 was the year that the switch was made to unleaded gas. Had a 1970 Buick Riviera, 455 CID engine, that required leaded least 91 octane fuel, could still buy it, but the price jumped to $1.60 per gallon and was hard to find.
So I could still drive this thing, dropped the CR from 10.5:1 to 9:1 by installing Canadian fat head gaskets. Found a 72 455 at a wrecking yard, was able to buy the intake manifold with the EGR valve for ten bucks, installed that, now I could burn unleaded for 40 cents a gallon, until the so-called energy crisis hit, then 70 cents.
Had a venturi added to the carb, short hose to at water controlled thermostat, only opened at operating temperature directly to the EGR valve. Guy with 72 or newer vehicles found by disconnecting that hose, would suddenly have a rocket, but didn't last long, exhaust valves would burn out. On others that hose would fall off, paying 600 bucks for a valve job was very common back then. No such thing as a CEL to warn your EGR was not working.
Back then, only 87 octane unleaded was available, killed guys with muscle cars, ha muscle cars were extremely popular, but without knowledge were next to worthless, eventually 89, and 91 unleaded fuel became available, and you could add more spark advance by playing the the springs in the distributor. But if you couldn't find 91, would get pre-ignition, or knock, computer takes care of this today.
But at the same time studded snow tires were made illegal and road salt was introduced, so after a couple of years your pride and joy became a pile of rust. This takes this up to date.
Yeah those springs in the spark plug boots, this was day two on my Cruze, stretched them out about 3/8" so they would not hang up. Wanted to add dielectric grease, lots of it inside of the boots, or you will never get them off. Pulled the plugs at the same time, gaps were all over the place, manual said 28 mils, went down to 26 mils, tad better. Also want my center electrode insulator to be white, it starts get dark after about 15K miles, time to remove them and use my walnut shell spark plug cleaner.
Ran into some spark plugs with a very porous center electrode insulator, no amount of blasting would clean them, stay black, using my high voltage tester, that carbon was breaking down at only 2,200 volts, time to search for better plugs. Seem to get into trouble if I mention the brand.
PCV was very welcomed back in the late 50's, before using a breather pipe that would suck up road dust into an engine, needed a shovel to clean them out. But created a new problem, was returned to the base of the carb, with carbon build up on the intake valves, so started tossing a can of Seafoam in a full tank of gas about every 3K miles.
With FI, even worse, carbon builds up on the face of the fuel injectors, can get a misfire that burns up your cat, Is now returned to that turbo input because the air temperature has to be measured. At 40K miles, taking my foot off the gas keep the engine running at high speed, so had to clean the TB to stop this.
Carbon in fuels is a 120 year old problem and still is, also a chain reaction, builds up on piston rings augmenting blowby. Keeping your engine clean, on summer gas, don't even get me started on this winter gas crap, could average 50 mph with my 2LT with the cruise set at 60 mph. But this was not good either, could get rear ended by a semi, so when told to drive safe, your nuts, have to drive insane like everybody else. But had to live with more like 46 mpg.
In WW II aircraft, without lead, water injection was used to cool things down, too complicated for the public so exhaust gas recirculation was used. First a valve for this, more crap in the engine, Cruze and others close the exhaust valves early to leave burnt gas in for the next cycle. EPA's major complaint was those high temperatures produced NOx's, smog because the air going inside of the engine is 80% nitrogen.
EGR can be as high as 30%, so in reality, that 1.4 L engine is more like a 1.1 L engine. 1972 was the year that the switch was made to unleaded gas. Had a 1970 Buick Riviera, 455 CID engine, that required leaded least 91 octane fuel, could still buy it, but the price jumped to $1.60 per gallon and was hard to find.
So I could still drive this thing, dropped the CR from 10.5:1 to 9:1 by installing Canadian fat head gaskets. Found a 72 455 at a wrecking yard, was able to buy the intake manifold with the EGR valve for ten bucks, installed that, now I could burn unleaded for 40 cents a gallon, until the so-called energy crisis hit, then 70 cents.
Had a venturi added to the carb, short hose to at water controlled thermostat, only opened at operating temperature directly to the EGR valve. Guy with 72 or newer vehicles found by disconnecting that hose, would suddenly have a rocket, but didn't last long, exhaust valves would burn out. On others that hose would fall off, paying 600 bucks for a valve job was very common back then. No such thing as a CEL to warn your EGR was not working.
Back then, only 87 octane unleaded was available, killed guys with muscle cars, ha muscle cars were extremely popular, but without knowledge were next to worthless, eventually 89, and 91 unleaded fuel became available, and you could add more spark advance by playing the the springs in the distributor. But if you couldn't find 91, would get pre-ignition, or knock, computer takes care of this today.
But at the same time studded snow tires were made illegal and road salt was introduced, so after a couple of years your pride and joy became a pile of rust. This takes this up to date.
Yeah those springs in the spark plug boots, this was day two on my Cruze, stretched them out about 3/8" so they would not hang up. Wanted to add dielectric grease, lots of it inside of the boots, or you will never get them off. Pulled the plugs at the same time, gaps were all over the place, manual said 28 mils, went down to 26 mils, tad better. Also want my center electrode insulator to be white, it starts get dark after about 15K miles, time to remove them and use my walnut shell spark plug cleaner.
Ran into some spark plugs with a very porous center electrode insulator, no amount of blasting would clean them, stay black, using my high voltage tester, that carbon was breaking down at only 2,200 volts, time to search for better plugs. Seem to get into trouble if I mention the brand.
PCV was very welcomed back in the late 50's, before using a breather pipe that would suck up road dust into an engine, needed a shovel to clean them out. But created a new problem, was returned to the base of the carb, with carbon build up on the intake valves, so started tossing a can of Seafoam in a full tank of gas about every 3K miles.
With FI, even worse, carbon builds up on the face of the fuel injectors, can get a misfire that burns up your cat, Is now returned to that turbo input because the air temperature has to be measured. At 40K miles, taking my foot off the gas keep the engine running at high speed, so had to clean the TB to stop this.
Carbon in fuels is a 120 year old problem and still is, also a chain reaction, builds up on piston rings augmenting blowby. Keeping your engine clean, on summer gas, don't even get me started on this winter gas crap, could average 50 mph with my 2LT with the cruise set at 60 mph. But this was not good either, could get rear ended by a semi, so when told to drive safe, your nuts, have to drive insane like everybody else. But had to live with more like 46 mpg.
Was part of the group back in the 70's attempting to eliminate carbon from our fuels, methane would even be better and have a 12,000 year supply of this stuff, but we were pushing H2.
Now after some odd 42 years, seeing a new interest in hydrogen, GM is pushing toward burning the stuff in an ICE, Honda is pushing toward fuel cells, claim it has twice the efficiency as an internal combustion engine, but their vehicles would cost over three times as much, Mazda is pushing their Wankel, no results on this. While others are pushing battery operated vehicles.
Other proponents say whether battery or H2, still need electricity to either charge the batteries or electrolysis to make hydrogen. But their claim is that either hydrogen if burned or fuel cells, both have 80% nitrogen in the air with impurities, NOx's with burning, degradation with the platinum used in fuel cells. Fuels cells may have to replaced after 80K miles as will batteries, both would cost both arms and legs to replace, but for all three, still have to burn coal or natural gas to get that electrical power.
One answer is nuclear fusion, did learn how to harness fission after six short years, but first H bomb is already 62 years old, very little has been done in this area.
Another system proposed in around 1899 was a monorail system, goodbye intersections, only a simple electric motor, even battery powered with small retractable wheels to get to your neighborhood. Small shroud over that rail would eliminate ice and snow, goodby road salt. 300+ mph hour light weight vehicles would be possible for cross country, goodbye airports and long lines. Well except for oceans. Should put together our best minds to solve these problems.
Now after some odd 42 years, seeing a new interest in hydrogen, GM is pushing toward burning the stuff in an ICE, Honda is pushing toward fuel cells, claim it has twice the efficiency as an internal combustion engine, but their vehicles would cost over three times as much, Mazda is pushing their Wankel, no results on this. While others are pushing battery operated vehicles.
Other proponents say whether battery or H2, still need electricity to either charge the batteries or electrolysis to make hydrogen. But their claim is that either hydrogen if burned or fuel cells, both have 80% nitrogen in the air with impurities, NOx's with burning, degradation with the platinum used in fuel cells. Fuels cells may have to replaced after 80K miles as will batteries, both would cost both arms and legs to replace, but for all three, still have to burn coal or natural gas to get that electrical power.
One answer is nuclear fusion, did learn how to harness fission after six short years, but first H bomb is already 62 years old, very little has been done in this area.
Another system proposed in around 1899 was a monorail system, goodbye intersections, only a simple electric motor, even battery powered with small retractable wheels to get to your neighborhood. Small shroud over that rail would eliminate ice and snow, goodby road salt. 300+ mph hour light weight vehicles would be possible for cross country, goodbye airports and long lines. Well except for oceans. Should put together our best minds to solve these problems.
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I use 87, unless it's really hot. Then I begrudgingly use 89 or 91 because the Cruze runs like garbage in the heat on 87. This is probably one of the biggest issues with the Cruze, how poorly it runs in the heat.
In my area, the jump from 87 to 89 or 91 is big. I've tested it, and I don't get nearly enough mileage increase with higher octane fuels to offset the additional cost. So running 89 or 91 actually costs me more per mile than 87, even though the mileage does go up slightly.
I bought the Eco model for mileage on my commute, so minimizing my cost per mile is a goal.
In my area, the jump from 87 to 89 or 91 is big. I've tested it, and I don't get nearly enough mileage increase with higher octane fuels to offset the additional cost. So running 89 or 91 actually costs me more per mile than 87, even though the mileage does go up slightly.
I bought the Eco model for mileage on my commute, so minimizing my cost per mile is a goal.
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93 when it gets above 65-70F, so spring, summer, fall. Then back to 87 when it is cooler and dryer air. I found that Conoco/Phillips fuel is best/most consistent MPG in my car. The gap from 87 to 93 is .40/gal in MO, most places. My car runs much better in the warmer temps on 93 and in the winter it does not seem to care. I get better MPG on 93 only with the summer blend of fuel. Seems it costs me about $2/tank to run 93 vs 87. The increased performance is worth that.
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Curious what the difference is for you. I'm running into the same thing. The increased cost of premium grossly undermines the increase in fuel economy. 2.38 for reg 87 and 2.99 for premium 91 what's that a bit over 20% increase in cost...Under best circumstances I see max improvement of 6-8% in fuel economy going to premium. So can't really make up for that 12%
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I haven't done it in a while, but I remember getting only around 10% better economy. My cost increase for fuel was similar to you, around 20% higher.
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10,587 Posts
Which eco did you have, have you changed, gapped plugs, and how many back to back tanks have you used?
*Manual and auto make a difference. Manual eco on 87 in the heat was horrible compared to the auto Eco. you also had less gas to fill than auto when it comes to the 3rd point below.
*Plug gaps and quality also play a factor as earlier years or higher miles make the eco suck more in heat and in 6th gear. Regapping or swapping to the NGK in the 1st post of http://www.cruzetalk.com/forum/34-gen1-1-4l-turbo/21850-hesitation-gone.html usually helps out a bunch.
*The car will not just switch to 91 fuel map and stay on 1 tank of 91/93 gas. It needs a constant 3 tank minimum to kinda hold the 91 fuel map. It almost "feels like" the brand new gas no matter what grade had more energy than what was already in the tank when you get gas. You get the 91 fuel map every time you refuel giving you this illusion. Then the 87 gas doesn't do well eventually and the 87 map comes back a few blocks later.
For me and my Eco manual I accepted the higher price even when I wasn't tuned for months at a time. I also have a 91 only octane car that runs 17 city and 22 highway so that price of 93 with 31 city and 40 highway wasn't a huge deal.
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