# European Car - Proven



## halbwissen (Jul 20, 2001)

I was flipping through an old European Car at work and found this Tech Article on the performance differences between 87 and 91 octane in a 2010 Jetta 2.5l.
European Car is nice enough to have all these Tech Articles hosted on their website. 


European Car Proven




*sorry if rozap


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## thygreyt (Jun 7, 2009)

thanks for sharing! 

so 93 is better all across the board.. lol. 

i guess haters are going to have a harder time "denying" this "mod"


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## TylerO28 (Jul 7, 2008)

You know for those of us that have run 91 or higher in our cars since day one. And us that have had the 2.5 for a while. This is old news!

But anyone who is picking up lease returns, or buying used 2.5s should really read this and see the significance of using better/premium petrol


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## tay272 (Aug 22, 2007)

Ever since I got my SRI Ive had to run premium so I never really noticed the difference. I believe thats true tho that its better for our engines and this proves it. One thing I dont quite get tho is how the dyno with the Pflo on the car made more hp to the wheels then it did torque. Thought short rams give you more torque and less hp, cold air is the opposite?


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## jaja123 (Jan 17, 2011)

Yea I put down 163whp on a dyno dynamics with just intake and exhaust and 93oct. I heard that the older 2.5's do not respond as well to 93oct.


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## thygreyt (Jun 7, 2009)

TylerO28 said:


> You know for those of us that have run 91 or higher in our cars since day one. And us that have had the 2.5 for a while. This is old news!
> 
> But anyone who is picking up lease returns, or buying used 2.5s should really read this and see the significance of using better/premium petrol


i agree. i too have ran 93 almost since the day i got the car... but its always good to have unbiased info and supporting proof of how good 93 is with the 5 cyl


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## Vash350z (Jun 25, 2007)

I bet this only applies to 170hp motors.


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## Tacoma750 (Sep 16, 2004)

SOB....my next tank will be 91 or better.


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## tchilds (Nov 21, 2008)

It really depends on the time of year. They actually flush the fuel lines w/the winter gas several months before winter. The fines are something like $50,000 a day if you're selling the wrong gas so they don't risk it, since it takes literally months to pump the summer gas out w/the winter gas. THERE'S A LOT OF GAS IN THEM THOUSANDS MILES OF LINES. Don't equate the season to the gas because it actually changes to the winter or summer formula in spring and fall at different times every year.

93 octane or 94 octane are kind of a waste around here. I prefer to run mid grade 91 or 89 typically. When it is over 70 degrees or the wrong time of year I do run 93+ octane though.

My dad worked in air quality control and was a program manager for the city. Trust me I know what I'm talking about. The car will run fine on 89 most of the year, just not always. If you want to run mid grade to save a few bucks then that is fine. If you log your gas mileage the changes will be apparent and you'll know when to switch up or down on octane. We are talking about 30 miles a tank difference after all.

All in all I probably save enough $$ a year on gas to cover one oil change. Its not that big of a difference so if you want to, run 93 year round. Its just not necessary or always a value as some think around here.


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## TylerO28 (Jul 7, 2008)

Well the car will run perfectly fine on low knock petrol... But this is more for us who want a touch more from our alredy excellent motor


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## tchilds (Nov 21, 2008)

TylerO28 said:


> Well the car will run perfectly fine on low knock petrol... But this is more for us who want a touch more from our alredy excellent motor


it really won't just run the same on low octane all the time. you're talking +/- 20hp if you're running 87 octane the wrong time of year. again, if you guys log your gas mileage it will tell you what the gas is doing. it will also increase resale value of car, etc etc. there's million reasons to do it so why not. just like checking your oil level every time you fill up, nobody does it but me :screwy:


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## thygreyt (Jun 7, 2009)

tchilds said:


> , nobody does it but me :screwy:


i do so too... lol.

i wanted to point something out, here in florida gas suks!
89 (mid grade) is almost as bad a 87...
but 87 is absolute crap....

when i drove to h2o, and fueled up there, i noticed that each tank was some good 30-50 miles "longer" than normal...

i had better fuel economy on the down trip, than on the up..


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