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Relative to motoring norms in the United States.
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Dec 29, 2022 06:50
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Dec 29, 2022 07:31
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If you put 93 in your 87 octane rated engine and its newer than 2000, basically nothing except you given shell slightly more money than what you would've spent otherwise. If you do the reverse, put 87 in car that normally needs 93, you'll get slightly worse fuel economy and if you keep doing it, wear out the engine faster. Generally speaking, most cars have internal computers that can compensate for the effects of slightly worse or slightly higher octane than normal gas. You get no benefit from putting more expensive gas in your car, but you do spend slightly more money for it. If, let's say, you put race car fuel in your car (because I've seen this at a gas station in the South before), it will gently caress up your engine because your engine isn't rated to try to compress that kind of fuel. Similarly speaking, if you found some weird 40 octane stuff somewhere and put it in your car, it would similarly gently caress it up pretty quickly. so basically 
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Dec 29, 2022 07:32
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I think they sometimes have fancy detergents that's supposed to keep the engine "cleaner" but will gently caress up your lawnmower.
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Dec 29, 2022 16:08
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Octane is resistance to burn. High compression and forced induction engines, using lower octane fuels, can detonate early ("pre-detonation") and this is very bad as you can imagine. Using a higher octane fuel will allow you to run higher compression in your engine and thus create more power. It's why your average car is built for non-premium fuels: it plain doesn't need it. It also can clog up your engine and exhaust with the extra unburnt fuel.
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Dec 29, 2022 18:50
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A Festivus Miracle posted:If you put 93 in your 87 octane rated engine Under what conditions does someone own a car that can't take normal fuel?
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Dec 30, 2022 03:44
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The sort of someone who is into modifying their cars with performance upgrades, or someone who owns a dedicated racing car.
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Dec 30, 2022 11:41
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Baron Porkface posted:Under what conditions does someone own a car that can't take normal fuel? My parents 1998 Mazda 626 doesn't run properly on 95E10 fuel which is the normal here, but it works fine on 98E5. European octane ratings, 95 octane E10 = 10% ethanol. Equivalent to US 87 and 98 is equivalent to 93. 98 octane is a little bit more expensive, but the car runs better on it and the car is despite it's age reliable and uses very little fuel (like 4.5l/100km). They bought it new in 98.
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Dec 30, 2022 19:09
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When you compress gasses, like air, it creates heat. Heat can cause gasoline to ignite before its supposed to. Thus a car with a higher compression ratio will ignite gasoline easier. 93 octane gas needs more heat to ignite it than 87 octane. If you use 87 octane gas in a car that the manufacturer specifies needs "premium" (higher octane) gas, the gas will ignite before its supposed to which will cause severe engine damage. *Potentially* voiding any warranty that may be in effect. Thus costing the owner thousands of dollars to replace the engine. Or not and then they have a car with an engine that doesn't work and a worthless car. Many street going cars use premium gas, not just race cars and/or modified cars. Mainly high performance poo poo. Corvettes, Ferraris, Lamborghinis etc.... Even some "less prestigious cars" like certain Hyundais that are the "N Line" performance spec cars I'm pretty sure need it. Various others as well, but those are the ones I can think of offhand.
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Dec 31, 2022 05:33
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Baron Porkface posted:Under what conditions does someone own a car that can't take normal fuel? Lots of cars with factory turbos want higher octane fuel.
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Dec 31, 2022 07:13
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Baron Porkface posted:Under what conditions does someone own a car that can't take normal fuel? Define normal. The whole of western Europe has RON 95 gasoline as standard, i have never seen a car's user manual that states you can run anything lower than 95 (although most cars have knock sensors to avoid damaging the engine if you do put it in there). To USA standards, RON 95 is already a premium (depending on the exact measurement method 91 or 92 on USA's octane rating scale), while in western europe it's the lowest you can get. My father traveled through the whole of europe in an Opel Kadett in the early 1970s. The rental agency specifically told them to get the 'better gasoline' in southern europe (in the early 70s, you could still get lower than 95 in many places). He didn't, being a not-too-rich teenager, and got severe knocking climbing hills in a little Kadett with mayyyybe 50hp, hauling 3 people and their full camping equipment up those hills. The kadett survived but it was slow, noisy progress. Most european cars have and had small, relatively high compression high RPM engines compared to traditional USA cars. That makes them inherently more sensitive to knocking. Lower octane fuel kinda works in them, but primarily on low engine load, on cool days. Once you start climbing a gradient, hauling a car full of stuff, or sit on the highway on a hot summer's day, things can start going wrong. In an older car you'd get knocking with potential damage, in a newer car your ignition and injection timing will be retarded automatically, and you'll have less power. Putting more than 95 octane in a conventional eurocar won't get you more power unless you go the chip tuning way and set it up with very aggressive timing and higher boost. RON 98 specifications i've only seen for the most high strung turbocharged cars out there. There also was 102 up until about 3 years ago - i occasionally put it in my carbureted bikes becuase it just smelled better than the other stuff. If you have a catalytic converter you don't notice it, but Shell's euro 95 smelled nasty and sour, Competition 102 smelled pleasantly sweet when running it in my carbureted bikes without catalytic converter. AFAIK that stuff really only makes sense in race cars specifically set up to run it. Right now i put 98 in my bikes, not because of the knocking stuff, but because the RON 95 stuff here has 10% ethanol and my bikes are running with 20 and 30 year old fuel systems. Not all rubber parts agree with ethanol, and it also attracts moisture from the air rusting out the tanks. The 98 has betwen 0 and 5% ethanol, reducing that impact. But that's a whole different can of worms. In Germany i just get 95 without ethanol and i don't think i've ever had knocking, not even up a mountain in 30 degree weather with the engine absolutely blistering hot. LimaBiker fucked around with this message at 21:05 on Jan 2, 2023 |
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Jan 2, 2023 20:58
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taqueso posted:Lots of cars with factory turbos want higher octane fuel. A turbocharger can frequently reduce fuel consumption and emissions as part of the initial design. A factory turbocharged engine can often have lower operating costs despite requiring higher octane fuel due to the lower fuel consumption. There's a bunch of math and design tradeoffs involved but this type of design decision is becoming more common as fuel emissions regulations tighten.
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Jan 4, 2023 05:09
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LimaBiker posted:RON 98 specifications i've only seen for the most high strung turbocharged cars out there. There also was 102 up until about 3 years ago - i occasionally put it in my carbureted bikes becuase it just smelled better than the other stuff. If you have a catalytic converter you don't notice it, but Shell's euro 95 smelled nasty and sour, Competition 102 smelled pleasantly sweet when running it in my carbureted bikes without catalytic converter. AFAIK that stuff really only makes sense in race cars specifically set up to run it. Is the 102 leaded? That would explain the smell. Another thing to keep in mind OP is that you can't just make all the fuel in any arbitrary octane, because various crude oils break down in the refinery into different proportions of hydrocarbons, with premium gasoline using among the lightest distillation fractions (the heaviest being poo poo like asphalt). Even without higher grade fuels would still be relatively scarce and would have to be rationed in some way.
Woolie Wool fucked around with this message at 16:26 on Jan 4, 2023 |
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Jan 4, 2023 16:21
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Leviathan Song posted:A turbocharger can frequently reduce fuel consumption and emissions as part of the initial design. A factory turbocharged engine can often have lower operating costs despite requiring higher octane fuel due to the lower fuel consumption. There's a bunch of math and design tradeoffs involved but this type of design decision is becoming more common as fuel emissions regulations tighten. modern factory turbos in non-performance vehicles are preferable because they allow a 1.4L 4cyl to put out the power of something like a 3.0L NA inline 6 on demand, while being a 1.4L 4cyl in terms of fuel consumption when they aren't in their powerband. Assuming those two hypothetical dngines have identical peak power, when it's actually *using* the turbo to reach the power output of the higher displacement engine, it's going to use about the same amount of fuel at the same rate, because it's simply compressing air and burning more fuel in a smaller space to accomplish the same thing from a cost and fuel efficiency standpoint a naturally aspirated 1.4 l would be ideal, but then it would be gutless and take you 18 seconds to get up to 60. It'll use less fuel, however, because turbochargers suffer parasitic loss when they're running in vacuum, causing your engine to generate less power than it would without the turbo. It's a tiny amount nowadays with how rapidly they spool now, but still there. Meanwhile, the output equivalent inline 6 would probably be preferable to the 1.6L I4T (at sea level) for if you're hauling rear end due to a wider powerband across the rev range of the motor, particularly with low-end torque, and probably also still better from a (manufacturing) cost standpoint than a 1.4T - no intercooler, turbine, or complicated exhaust routing - but it would get Much worse mileage when doing regular day-to-day driving due to the added parasitic friction loss from the larger surface area of the engines internals moving against each other, and added cylinders, weight, etc So the compromise is a tiny engine with a turbo that allows it to do big engine stuff when necessary and get the gas mileage of a tiny engine when it isn't, since most of the time people don't need to accelerate super fast, and don't The main point I'm trying to make is that fuel consumption of a turbocharged engine will always be higher across the board than that same engine without a turbocharger (except at high altitude - Live in CO? Get a turbocharged car every time) but the nuance is that they're not competing with NA engines of the same size, because the turbo allows tiny motors to punch up and compete in a higher weight class so you compare mileage between engines of similar power output as opposed to displacement, and that's where the cost savings are, in not needing the larger engine that runs less efficiently in regular driving conditions to achieve the desired performance
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Jan 5, 2023 03:13
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FirstnameLastname posted:modern factory turbos in non-performance vehicles are preferable because they allow a 1.4L 4cyl to put out the power of something like a 3.0L NA inline 6 on demand, while being a 1.4L 4cyl in terms of fuel consumption when they aren't in their powerband. I don't disagree with any of that. My statement that, "A factory turbocharged engine can often have lower operating costs despite requiring higher octane fuel due to the lower fuel consumption," might seem simplistic but for a lot of drivers it fits 100% with your more detailed explanation. Most real world scenarios involve a combination of critical, short, high power segments; and long, sustained, low power segments.
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Jan 5, 2023 05:09
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Do older SUVs typically require premium? My stepdad had a Navigator made around 2003 or so and he insisted on premium whenever he filled up. He refused to explain exactly why. Was he just being weird or was he on to something?
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Jan 5, 2023 20:17
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ProperGanderPusher posted:Do older SUVs typically require premium? My stepdad had a Navigator made around 2003 or so and he insisted on premium whenever he filled up. He refused to explain exactly why. Was he just being weird or was he on to something? It looks very much like Navigators made around that era required premium fuel.
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Jan 5, 2023 21:15
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Leviathan Song posted:I don't disagree with any of that. My statement that, "A factory turbocharged engine can often have lower operating costs despite requiring higher octane fuel due to the lower fuel consumption," might seem simplistic but for a lot of drivers it fits 100% with your more detailed explanation. Most real world scenarios involve a combination of critical, short, high power segments; and long, sustained, low power segments. oh i wasn't disputing or countering anything you were saying, just kinda expanding on it in case anyone was wondering how what you saying worked out w/r/t tiny turbo motors being in the sweet spot between efficiency/performance and overall cost to operate
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Jan 6, 2023 01:48
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ProperGanderPusher posted:Do older SUVs typically require premium? My stepdad had a Navigator made around 2003 or so and he insisted on premium whenever he filled up. He refused to explain exactly why. Was he just being weird or was he on to something? dads require premium
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Feb 7, 2023 02:06
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LimaBiker posted:
I think even the "95 without ethanol" is 5% ethanol nowadays, though.
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Feb 8, 2023 09:14
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My brother tested fuel economy in college on his trips to and from home. 6 hour drive. Tested gas mileage for low and high octanes the highway and around each town. Low octane was the same on the highway, each way, and around town. Made no difference in mpg in any case. High octane was the same in each town, but noticeably better on the long trips. I don't remember the numbers but it was something like 20 mpg on the low octane but it something an extra 5 mpg on the highway. We figured the difference in cost vs extra mileage was worth it. It saved something like $20-25 bucks. I did the same tests when I went to college, a four hour drive, and had the similar results. We figured the high octane was good for road trips, but just more expensive for driving around town. Internetjack fucked around with this message at 02:29 on Mar 9, 2023 |
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Mar 9, 2023 02:21
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On the turbocharged cars I drive, if you put lower octane fuel in them they will knock under load, but the engine management will reduce the timing advance to compensate and protect the engine from damage. This results in lower power output and also worse gas mileage. I get measurably better mileage with premium, like 3-4 mpg but it's not enough to offset the cost difference. I still use premium and consider it paying extra for the peak power output. I like the power. And one of my cars is modified to make more power than stock so running regular would actually be wasting the effort I spent on the upgrades.
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Mar 13, 2023 18:46
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LloydDobler posted:On the turbocharged cars I drive, if you put lower octane fuel in them they will knock under load, but the engine management will reduce the timing advance to compensate and protect the engine from damage. This results in lower power output and also worse gas mileage. I get measurably better mileage with premium, like 3-4 mpg but it's not enough to offset the cost difference. I still use premium and consider it paying extra for the peak power output. I like the power. And one of my cars is modified to make more power than stock so running regular would actually be wasting the effort I spent on the upgrades. You are almost certainly damaging your engine if you don't run premium in those cars. Timing adjustments can only compensate so far. Maybe if the car asks for midgrade and you use standard because somehow it's all you can get and you're gentle, but I wouldn't trust a car that demands premium to run on standard.
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Mar 14, 2023 00:01
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Rorac posted:You are almost certainly damaging your engine if you don't run premium in those cars. Timing adjustments can only compensate so far. Maybe if the car asks for midgrade and you use standard because somehow it's all you can get and you're gentle, but I wouldn't trust a car that demands premium to run on standard. Nah, people run regular in them all the time to save money, nothing happens.
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Mar 14, 2023 17:03
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Sounds like a bunch of nerds should get some American muscle v8s
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Mar 14, 2023 17:10
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Rorac posted:You are almost certainly damaging your engine if you don't run premium in those cars. Timing adjustments can only compensate so far. Maybe if the car asks for midgrade and you use standard because somehow it's all you can get and you're gentle, but I wouldn't trust a car that demands premium to run on standard. It depends on the engine management. Something made in the last 10 years will fare better than something much older.
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Mar 14, 2023 22:24
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