A rant of sorts.

"Spanfeller is a twat" (theaspiringengineer)
02/26/2019 at 09:54 • Filed to: None

Today the local petrol station ran out of permium fuel. When I went to another station I realized why.

Everyone is buying 92 octane. As I waited in line at the other station I saw hoards of Nissan Versas and Tsurus being fed 92 octane. WHY? The whole point of naturally aspirated engines at high altitude is that you could feed it like -10 octane and not even worry about knock. Regular gas is 87 octane here BTW.

Admitedly, the 12-14 PSI of boost my car has is not a lot, but being a twin turbo setup I don’t wanna risk triggering the knock sensors and suffering from worse fuel economy, so I’ve always fed Premium to it, and most turbocharged cars demand premium fuel.

The other day I saw an Audi A4 owner getting regular and it's quite strange considering that, according to Motortrend, it runs at 21PSI!

DISCUSSION (28)

Ash78, voting early and often > Spanfeller is a twat
02/26/2019 at 09:58

Most current turbos engines are pretty good about detuning themselves to accommodate 87 (or 85 at high altitude). Astute owners might willingly accept that slight power reduction, especially if 92+ octane is priced like it where I live: 50% higher than 87 (eg $3 vs $2). For most people that’s not worth it.

Weirdest part is that just a few years ago, those same stations were only charging 30-40 cents’ premium for high octane. What the hell?

OTOH, putting high-test in a small, low-compression NA engine? Throwing money away.

Nick- Professional Car Destroyer > Spanfeller is a twat
02/26/2019 at 10:01

Depending how modern that Audi was it can run 87 just fine in a pinch, I had torun 87 a couple times when I was in small towns with my big turbo car, and as long as I wasn’t going wide open or building insane boost the computer would correct for it.

As for normal cars running high octane, I’ve seen that around too, its some mentality of “it’s better so It will help my car run better” not understanding the reason why it exists and that some cars run fine on the normal fuel and don’t see any improvement at all over high test.

facw > Ash78, voting early and often
02/26/2019 at 10:02

That’s a big spread. It’s about a 50 cent premium here, and I definitely see people saying it’s only 20-30 cents higher for them. Some of that growing spread is surely just inflation, but I tend to think a lot of it is the fact that most gas stations only advertise their regular price these days, so there’s a bit less competition in terms of the price of premium. Probably we (or at least I) should be using apps to check pricing more?

Spanfeller is a twat > Ash78, voting early and often
02/26/2019 at 10:03

I always used regular on my jeep cus it’s what the manual said it needed, the Kia’s manual asked that I use premium.

one day I might get a fillup with regular (87 isn’t really that bad), and the price difference is 7 0 cents of a dollar per gallon , so I don’t mind it that much

facw > Spanfeller is a twat
02/26/2019 at 10:04

I mean the gas station certainly wants you to buy premium even if you don’t need it, so they try hard to create the idea that you are “treating” your car, and/or getting essential detergents to keep your engine clean, even though there’s little to no practical benefit to premium for a car that doesn’t need it. So on one side you have a lot of advertising money, and on the other you have very little education about how cars work (at least in the US, but I’m assuming the situation isn’t much better in Mexico).

Spanfeller is a twat > Nick- Professional Car Destroyer
02/26/2019 at 10:05

In turbo cars higher octane increases fuel economy because the computer doesn't have to detune... on an NA car with regular compression, at 7500 feet there wouldn't be any knock even running very low octane, so it is truly not something I understand.

Long_Voyager, Now With More Caravanny Goodness > Spanfeller is a twat
02/26/2019 at 10:06

Eh, I see up to a 5 mpg improvement in my vehicles running 91 instead of 87, not because of the octane rating, but because our 91 octane is ethanol free.

Older vehicles do not like ethanol.

Ash78, voting early and often > facw
02/26/2019 at 10:08

Agreed -- the rare times I step inside a station, I try to mention to the staff that if they’d advertise premium again, they’d get a lot more business. A ton of new cars still do better on premium fuel and I’d gladly pay +30-40 cents for that. It would also change my car shopping behavior because, as it stands, neither of us could justify a car that requires premium because of the spread.

Nick- Professional Car Destroyer > Spanfeller is a twat
02/26/2019 at 10:08

Yeah, people are weird. I had a friend in highschool who would put 93 in his ranger because he thought it made it run better, or something.

I get the whole decreased fuel economy, I was only getting a max of 16 with this car anyways, so I wasn’t worried about it, I just wanted to get the car home, or to a better gas station,so 87, and nothing more than quarter throttle was safe.

Spanfeller is a twat > facw
02/26/2019 at 10:09

Fuel (specially diesel) used to be really freaking bad many years ago, but nowadays petrol stations are tightly regulated, all stations in Mexico City have vapour recovery systems, they purge their tanks very often, and they’re generally good at maintenece.

So I doubt anyone would have performance issues related to octane rating on NA cars. I need to research more about my Kia because the internet is not certain on what the hell is going on. Some say it could run on regular, some say it's boosted to 17PSI, some say the compression is super low and some say it's super high. If I can run on regular because of the altitude I just might half of the time.

OmerCarrothers333 > Spanfeller is a twat
02/26/2019 at 10:11

When I moved from California to Utah, I couldn’t figure out what the deal was with 85 octane; thanks for clearing that up.

Is there a Costco with a gas station near you? Might be worth it to get a membership so you can get gas at a lower price. Especially, since you use premium.

Spanfeller is a twat > Long_Voyager, Now With More Caravanny Goodness
02/26/2019 at 10:14

I don’t know how it’s mixed in the US, but here in Mexico it’s illegal to serve fuel with more than 5.8 % ethanol content.

facw > Spanfeller is a twat
02/26/2019 at 10:14

I mean on a modern car, it should be ok (and even with a turbo, I’d imagine the altitude has a positive impact). If it were me, I’d probably just give it a quarter tank of regular and hope to grab some of that delicious octane next time it was available. That would minimize the amount of time it’s running on the cheap gas.

Long_Voyager, Now With More Caravanny Goodness > Spanfeller is a twat
02/26/2019 at 10:16

It’s 10% here.

That mix is enough to knock about 5 mpg off my economy. Used to be a local station with 87 no ethanol, that was my best/cheapest bet, but if we’re taking long trips, I dump in 91 because 5 mpg makes a huge difference on a 200+ mile road trip.

Spanfeller is a twat > OmerCarrothers333
02/26/2019 at 10:17

Costco doesn’t sell gasoline here... I think gasoline prices are freely floated where I live, but most stations usually charge the same. I'm not willing to drive 40mins to save 10% on gasoline costs, so even if it's 4.15$/gallon at the station 5km away from my house I don't mind.

Spanfeller is a twat > Long_Voyager, Now With More Caravanny Goodness
02/26/2019 at 10:18

We were about to switch to 10%, but the Supreme Court ruled againts it when a group of enviromentalists sued the government. Not sure how long it’s gonna last because they say that by mixing with ethanol they might be able to cut prices by 25%

Spanfeller is a twat > facw
02/26/2019 at 10:22

I need to research it more. Some say that power goes down a lot with altitude, but when a local tuner shop tested the Jeep Trackhawk it produced similar very power than at a shop at lower altitude.

Forced induction certainly helps, and intercoolers help making the air more dense, which is good given that there's a quarter less oxigen at this altitude compared to sea level.

Dash-doorhandle-6 cyl none the richer > Long_Voyager, Now With More Caravanny Goodness
02/26/2019 at 10:30

Carbs dislike corn.

OmerCarrothers333 > Spanfeller is a twat
02/26/2019 at 10:37

There’s always the GasBuddy app that you can use as well. I used that in California before I moved to Utah, and discovered Costco gas stations.

OmerCarrothers333 > Spanfeller is a twat
02/26/2019 at 10:39

I’m sorry, I forgot you did not live in the USA until you used metric distance and a greater than $3 per gallon price for fuel.

Spanfeller is a twat > OmerCarrothers333
02/26/2019 at 11:00

#Mexico.

Today in particular I paid 4.2$ a gallon, but that’s the most expensive gasoline in the country (Mexico City and Premium). In Mexicali where gas is price controlled, it’s at 3.74, in Reynosa(border city with Texas) its at 3.20.

As the Mexican Peso gains ground compared to international currencies and gasoline production costs go up, I think we’re gonna see very high prices.

Long_Voyager, Now With More Caravanny Goodness > Spanfeller is a twat
02/26/2019 at 12:01

We heard how much cheaper gas would be once it was ethanol blend. It’s been over a decade, I’m still waiting on this cheaper gas.

Long_Voyager, Now With More Caravanny Goodness > Dash-doorhandle-6 cyl none the richer
02/26/2019 at 12:02

*Cars dislike corn.

*fify.

Dash-doorhandle-6 cyl none the richer > Long_Voyager, Now With More Caravanny Goodness
02/26/2019 at 12:50

Dual carbs double dislike corn.

Decay buys too many beaters > Spanfeller is a twat
02/26/2019 at 13:21

People look at me like I’m crazy when I put 87 in my bikes.

Spanfeller is a twat > Decay buys too many beaters
02/26/2019 at 13:25

I thought bikes needed premium

Decay buys too many beaters > Spanfeller is a twat
02/26/2019 at 13:41

One of 6 require premium for me. Oversquare engines are far less prone to knock. Case in point, my Triumph makes 106hp out of 675cc, revs to 13.5K, and has a static compression ratio of 12.6:1, and still only needs 87 according to the manual.

FSI > Spanfeller is a twat
02/26/2019 at 13:45

My 1.6 FSI requires at least 95 octane but 98 is recommended lol. The early version even required 98 Octane. VAG was quick to drop FSI engines after 2008.