dequardo
Autocross Newbie
- Location
- America’s Dairyland
- Car(s)
- ‘21 GLI Autobahn GLI
7% higher?
7
Gasoline grade in 2018 GTI
- Thread starter LDB
- Start date
RichardCranium
Ready to race!
- Location
- Arizona
Yeah, and this was exactly the point I was going to make in the last post but decided against it. Your little hypermiling run right there isn't indicative of anything. The better question is, what do you *average*? I know it isn't anywhere near 43 mpg, so then what was the point of posting this picture like you're some sort of savant?
You're making implications that people that don't put 93/91 in their car and cheap and can't afford it. I'm explaining to you that intelligent people that don't see the value in something don't spend money on it. That's the point, that once again, shocker, has flown right over your head.
Yeah, even you admit it's negligible. Is there a benefit? I'm sure. But it's small enough not to be noticed therefore spending money on it is a waste, as far as I'm concerned. I don't pay your credit card either, if you think buying premium for 3 extra hp is a worthy expenditure, who am I to tell you otherwise?
You still are.
I never said there was *no benefit*, I said I, personally, don't see the benefit.
My MFD consistently reads 3 mpg high vs hand calc. FWIW. 34 hand calculated always reads 37 on "since refuel page". Pretty much dead same mpg with 89 or 93. Every time.
That since start page is pretty useless I've found, it's always 7+ MPG high off the tank average for some reason. The "Since refuel" page is much better. Although still overly optimistic by 3 mpg in my car.
That since start page is pretty useless I've found, it's always 7+ MPG high off the tank average for some reason. The "Since refuel" page is much better. Although still overly optimistic by 3 mpg in my car.
greens
Ready to race!
- Location
- Republic of Texas
Intelligent people. I'm going to assume your Cranium has convinced itself that you fall in to that category?
Oh no it's clearly noticed hence why I use premium. Does that make me superior to "intelligent people"? Certainly not. Try harder though on downplaying the use of premium with your 3 hp number. VW clearly states 10 and neglect to mention the torque lost by using regular. People will spend $400+ for an intake that doesn't even provide 10 hp but skimp on the fuel that provides that. Makes sense?
And yet it still doesn't matter in the slightest if you choose to not see something that clearly exists.
ManInTheClouds
Ready to race!
- Location
- OK
inb4 the low octane, low quality fuel people run causes a stuck/clogged injector.
Tsi7
Ready to race!
- Location
- Ontario, Canada
You're joking right?
LDB
New member
- Location
- Houston suburb
My understanding is that octane is beneficial to a point. That point varies depending on specific engines and conditions. Once that point is reached any higher octane does nothing of value. That's what a Texaco engineer explained to me about 3 decades ago. I had a Lincoln MK VII. It didn't run well at full throttle. He said run 5 tanks of Texaco premium and then use Texaco regular, that it didn't need the premium octane long term, just for 5 tanks to clean the engine. He said Texaco and Chevron put the same amount of additives in every grade while other brands used less in lower grades. Worked like a charm.
Low quality fuel overall causes problems.
It's not the octane--octane rating is not a rating of quality. But there are junk fuels out there. I run Shell and Costco.
Here's a story: the local lawnmower shop stamps on every invoice, use Shell 89 only (their story is, octane rating goes down as the gas sits over a long period of time--which is typical for lawnmowers). If you use convenience/grocery store gas, or Speedway or Flying J or whatever, in the small engines, they stop working pretty quickly. Even BP, which is Top Tier, causes that problem.
I discovered this many many years ago, and it's true.
I have a ten year old snowblower--a good quality Toro. And every year starting on Dec. 1 I stage a fresh can of Shell 93 mixed with Echo brand two cycle oil. And every year, no matter what or even when I first use it, that blower starts right up with the first pull.
You can't argue with results. Junk gas is junk gas. I don't care what octane level you use, but the quality of the additive package absolutely makes a difference.
ManInTheClouds
Ready to race!
- Location
- OK
https://www.torquecars.com/bmw/nikasil-issue.php
Imagine if your nice BMW was bricked because you decided to use the cheapest gas Murphy USA/DiamondShamrock/Valero was pumping that day.
That is correct. Anything beyond that point is just burning money.
The problem is we don't know at what octane the GTI on that specific day/temp/atmospheric pressure will start pulling timing and reducing max power output due to the knock sensor triggering it to do so. Each day is different. Every location of people on this board is different, so they can have different results.
The only way to figure out even a close baseline estimate would be extensive dyno testing on the different fuel grades, which I don't think anyone has done. Or will do because it's expensive and time consuming.
I do know I can feel a pull back in 87 octane once I get into the boost. I can sometimes feel it with 89 if it's hot outside, 91 I feel nothing. 93 feel nothing and "I" feel the cost exceeds the point of any benefit on a stock tune for 93. Also see no difference between 89-93 for MPG. I do see a difference of "slightly" less efficient with 87. So my unofficial "guess" is somewhere around 90ish it needs for max efficiency and to not pull timing on a stock tune.. but that is just a guess based off my experiences with my stock tuned car. It may still be pulling timing with 91, just the difference is so small you can't feel it anymore.
89 is best bang for the buck for "commuting" in my opinion. Still gets optimal gas mileage and no real feel of power reduction. Or put in 91-93 if/when you plan to drive it hard just to guarantee you get what you paid for with the power output.
Last edited:
Wrath And Tears
Go Kart Champion
- Location
- Azusa, CA
- Car(s)
- 17 Sport, 99 E36
That has nothing to do with octane though...
robmarktoo
Ready to race!
- Location
- Oregon
I expected it to fuck up the car. My father didn't.
ManInTheClouds
Ready to race!
- Location
- OK
I doubt they're going out of their way to buy Shell or Exxon if they're content with 'any gas is fine'.
Tsi7
Ready to race!
- Location
- Ontario, Canada
Why are you presenting me an article about some old bmw engines and high sulfur content in supermarket gas in the UK? It's 2018, fuel quality regulations are a lot stricter now with the amount of sulfur being reduced significantly in both gas and diesel.
Also, why are we talking about fuel quality? Octane has nothing to do with fuel quality, there's a difference...
This thread isn't going anywhere and all we're going to do is keep flaming each other over something completely pointless... I've given my opinion, people can do or think what they want at the end of the day, but i'm done with this nonsense
ManInTheClouds
Ready to race!
- Location
- OK
The US has always had high-sulfur fuel compared to the EU markets.
This issue was also reported in US market BMWs.
I've shown you evidence that fuel choice matters, and that you should be intelligent as to what you put in your car.
Octane isn't quite as important as quality, yes. However, my point is that I doubt you're filling up with top tier Shell/Exxon/Chevron/etc.
Running garbage grade 87 in your direct injected VW is asking for trouble, and you deserve every ounce of trouble that comes your way as a result of that.