[Nick1979]

I am confused as to what is the proper octane rating for the 2.0 turbo Atlas. The official advertisement from VW states that the engine makes 235HP but the small print states that the 235hp is achieved using premium fuel. Now, my dealer says to use it regularly. According to VW.com specs of the engine, it also says regular unleaded. Now, what sort of miss advertising is that? 235hp, but use regular, which would obviously reduce the engine’s power down from 235. I always knew that the GTI’s 2.0 turbo engines needed premium, even when I test-drove one in the past, the dealer said it needed premium. The Atlas 2.0 is the GTI’s engine.

I looked at the current specs on the current GTI model and according to VW.com GTI uses regular gas! Since when does the GTI’s 2.0 use regular gas? Is this in error?
I am totally confused as to what is proper fuel for the 2.0 atlas is. It seems none of the current VW cars needs premium!??! But they advertise HP using premium fuel.

 

[Xbnch001]

Same

I too noticed the difference in the use of fuel. I guess they wanted to show the highest HP so they tested it with premium fuel. My salesman said he never noticed that, so he said.
I use regular fuel as I will give up a little HP for fuel that is around 50 cents per gallon cheaper. But that is just me, saving $9 per fill up is Ok with me.

 

[gregmirich]

If you do mods to the 2.0L you should use Premium. I have mods on my 2.0L and use Premium and on the highway get between 20 and 21 MPG at 70 to 75MPH. Around town about 18MPG.

 

[WestB87]

I see your point! What does your gas door say? What about the owner's manual? I've got the VR6 and mine recommends regular, though I'm unfortunately not boosted. Some folks with the VR6 were thinking they should use premium, but the gas door expressly states 87 octane.

 

[Scottie]

I agree, look at the fuel door and see what it says. I think (without going to look) that the 3.6 says either regular or premium fuel. The 235hp is (I'm sure) with premium.
But the engine will probably realize the octane that you put in and change the engine's tune to use it. You will get less hp with regular though.
Unless you really need a couple extra HP for towing or racing or something, and the car allows it (I'm sure it does), then go with the regular fuel.

Scott

 

[VNeBLOB42]

I agree, look at the fuel door and see what it says. I think (without going to look) that the 3.6 says either regular or premium fuel. The 235hp is (I'm sure) with premium.
But the engine will probably realize the octane that you put in and change the engine's tune to use it. You will get less hp with regular though.
Unless you really need a couple extra HP for towing or racing or something, and the car allows it (I'm sure it does), then go with the regular fuel.

Scott

It says 87 octane R+M/2 or 91 RON. This is for the V6 engine. Based on that we should be using 87 Octane in the US

 

[Nick1979]

Here’s the thing - I bought a car that makes 235hp per advertisement (238hp per the manual). VW adds a small print saying *235hp achieved with premium fuel. My gas door stickers says use unleaded regular 87. So if one is supposed to use 87 regular gas, will one be getting the 235hp advertised? No! If this is the intended fuel for the engine, what are the real HP for the car? I understand for marketing purposes VW used this bait and switch tactics. I also understand that this engine is made to work with both 87 and 93, and while it won’t get damaged with 87, it won’t produce the advertised 235hp. What would be the actual real world HP with the intended 87 - those are the numbers VW should have disclosed. Do you see my point?
Here’s another thing - I also have some slight suspicion that these stickers go on the cars before the actual engine type gets installed on the car. Case in point - the tire pressure sticker on my door says 35psi on all tires. My manual says 35psi for the v6, and 30psi (!) fr the 2.0 liter engine. Or the manuals could be written before final technical decisions are made. Go figure...

 

[Nick1979]

Just to add to the confusion: I read the entire information in the manual regarding engine HP "the maximum 238HP were achieved using REGULAR grade gasoline". So much for clarity, transparency, and technical accuracy from VW.

 

[KarstGeo]

Here’s the thing - I bought a car that makes 235hp per advertisement (238hp per the manual). VW adds a small print saying *235hp achieved with premium fuel. My gas door stickers says use unleaded regular 87. So if one is supposed to use 87 regular gas, will one be getting the 235hp advertised? No! If this is the intended fuel for the engine, what are the real HP for the car? I understand for marketing purposes VW used this bait and switch tactics. I also understand that this engine is made to work with both 87 and 93, and while it won’t get damaged with 87, it won’t produce the advertised 235hp. What would be the actual real world HP with the intended 87 - those are the numbers VW should have disclosed. Do you see my point?
Here’s another thing - I also have some slight suspicion that these stickers go on the cars before the actual engine type gets installed on the car. Case in point - the tire pressure sticker on my door says 35psi on all tires. My manual says 35psi for the v6, and 30psi (!) fr the 2.0 liter engine. Or the manuals could be written before final technical decisions are made. Go figure...

Because the 2.0 weighs less and that's why the pressure is different.

 

[KarstGeo]

Both motors are tuned to run on 87 regular gas (Top Tier is recommended). The VR6 says it makes 280hp on reg fuel and the 2.0 238hp on reg fuel in the back of the manual in the engine data section. This seems to contradict the info on the VW site showing slightly lower numbers for the VR (275) and slightly less for the 2.0 (235 noting premium fuel). Bottom line for me...it isn't enough hps to make f all difference and just run regular and don't worry about performance minutia that nobody will be able to feel in a huge family hauler. They have tuned the vehicles to run on regular and running premium is throwing cash out the window.

 

[KarstGeo]

The 2.0 weighs less from not having 4Motion available as well as the obvious lighter weight of the engine...it's nearly 500 pounds difference if memory serves and is why the 2.0 2WD beat the 4Motion VR in a drag race published somewhere...

 

[Atlasuno]

We have a 2.0 GTI ('16) which makes 210hp in stock tune, and it calls for regular fuel on the fuel door and manual. Our V6 Atlas also asks only for regular fuel. Both run great, even when driving very quickly or when towing with the Atlas. If the 2.0 Atlas manual calls for regular, then you should be okay. I know the state of tune in the R version calls for premium to get the 292hp, but a lesser state of tune may not require it.

 

[Jojo Aquino]

Here’s my understand of it, please correct me if I’m wrong:
87 AKI = 91 RON = 91 octane

My gas cap says the following (see image):
87AKI or 91 RON

I guess 91?

 

[KarstGeo]

87 octane "regular" gas here in the U.S. is the equivalent of the 91 RON you get in other parts of the world. 91 RON is not the same as 91 octane premium fuel. On this topic...

Your car is tuned from VW to run efficiently (power/mpgs) on 87 octane fuel. It doesn't matter that "that motor always used premium in other VWs 5 years ago" or "that same motor in the Toureg calls for premium so my Atlas must need it too" - the motor in the Atlas is tuned to run 87 and is not the same as the motors that needed premium. It’s a compromise that sways towards mpgs vs. power for sure. “Tune” here essentially means spark timing i.e. advance (spark earlier in the compression stoke) vs. retard (spark later in the stroke). The timing is set at a point to not have pre-detonation or “knock” running 87. Your car doesn’t “know” what gas you are running. It only “knows” when you experience pre-det through the knock-sensor. If it senses pre-det, it retards the timing which doesn’t allow as much compression before the spark therefore reducing power output. If you run premium in a car tuned for 87, you aren’t changing anything beyond possibly reducing the retarding of the timing under WOT/hard acceleration which will yield a little more power and is the reason you will see hp/tq numbers in your manual/online with the *achieved with premium fuel. Your car's ECU doesn’t have A.I. and need “3-4 tanks for it to learn the gas” – it just runs on what’s in it and the ECU adjusts timing accordingly which happens on-demand. The notion that running premium in a car not tuned for it will yield significant mpg increase is simply fantasy land and most of the perceived increase in power is likely placebo. Under normal driving conditions, you car isn’t retarding your timing enough to cause a drop in mpgs that are all of a sudden remedied by running premium. Premium doesn’t have any more detergents than regular at most gas stations (yes, I know a few do) and if you use Top Tier fuel, you should get that same detergent package in all octane ratings. Premium isn't "burning cleaner" than regular or preventing carbon build-up in direct-injection motors. If you’re racing your car with 0-60 runs all the time, run premium. If you’re driving your car under “normal” conditions, save the $0.60/gal (that’s what it’s here in VA) and run regular, which saves me ~$10/fillup which is ~$400/year @ 12K miles and 18mpg average for mixed (but city-weighted) driving. That's $4K over a 10 year life of ownership....not chump change.

 

[kootenaydub]

Good post Karst, you speak the truth.

I often roll my eyes at the folks that can 'tell the difference' of 5 hp (if premium gas could even do that). If their butt-dynos are that well tuned, they should be chatting with F1 teams.

To fully take advantage of a difference in Octane, your ecu's mapping needs to change, which it does not on it's own.

Forced induction engines are much more sensitive to octane changes as you can take advantage and run higher boost, and you start to do the alternating limits of forced air vs fueling, upgrade turbo, upgrade injectors, etc.

With an N/A engine your air intake rate is pretty much set.

At the end of the day, you can spend $100's on the VR6, but you're not really going to gain much (arguably even noticeable) without dropping big coin on ported and polished intakes, etc, etc.

Here's an idea of the cost of some of these parts,
https://www.hpamotorsports.com/vr6/vr6-performance-parts-42?p=2

 

[Jojo Aquino]

87 octane "regular" gas here in the U.S. is the equivalent of the 91 RON you get in other parts of the world. 91 RON is not the same as 91 octane premium fuel. On this topic...

Your car is tuned from VW to run efficiently (power/mpgs) on 87 octane fuel. It doesn't matter that "that motor always used premium in other VWs 5 years ago" or "that same motor in the Toureg calls for premium so my Atlas must need it too" - the motor in the Atlas is tuned to run 87 and is not the same as the motors that needed premium. It’s a compromise that sways towards mpgs vs. power for sure. “Tune” here essentially means spark timing i.e. advance (spark earlier in the compression stoke) vs. retard (spark later in the stroke). The timing is set at a point to not have pre-detonation or “knock” running 87. Your car doesn’t “know” what gas you are running. It only “knows” when you experience pre-det through the knock-sensor. If it senses pre-det, it retards the timing which doesn’t allow as much compression before the spark therefore reducing power output. If you run premium in a car tuned for 87, you aren’t changing anything beyond possibly reducing the retarding of the timing under WOT/hard acceleration which will yield a little more power and is the reason you will see hp/tq numbers in your manual/online with the *achieved with premium fuel. Your car's ECU doesn’t have A.I. and need “3-4 tanks for it to learn the gas” – it just runs on what’s in it and the ECU adjusts timing accordingly which happens on-demand. The notion that running premium in a car not tuned for it will yield significant mpg increase is simply fantasy land and most of the perceived increase in power is likely placebo. Under normal driving conditions, you car isn’t retarding your timing enough to cause a drop in mpgs that are all of a sudden remedied by running premium. Premium doesn’t have any more detergents than regular at most gas stations (yes, I know a few do) and if you use Top Tier fuel, you should get that same detergent package in all octane ratings. Premium isn't "burning cleaner" than regular or preventing carbon build-up in direct-injection motors. If you’re racing your car with 0-60 runs all the time, run premium. If you’re driving your car under “normal” conditions, save the $0.60/gal (that’s what it’s here in VA) and run regular, which saves me ~$10/fillup which is ~$400/year @ 12K miles and 18mpg average for mixed (but city-weighted) driving. That's $4K over a 10 year life of ownership....not chump change.

Awesome!!!! Wow great explanation thank so much!! Here in california, gas price is important and if I don’t need 91, I’m going 87. Thanks @kartsgeo

 

[Super Wiseman]

Finally, someone who knows what they are talking about regarding octane ratings and performance.
Premium 91 is required for many performance turbos, like my 2019 GTI, in order to achieve the spec'd horsepower (228 hp), but it's not mandatory if you don't care about HP ratings. It's clear that the GTI will run just fine on 87 octane, but it's really hard to find, ANYWHERE, what the reduced horsepower spec's are. My guess, probably 210 hp.
What most people don't understand is that premium fuel has NO more energy density than regular fuel. The premium fuel is no more powerful than the regular fuel! Rather, what happens when you run on lower octane is that the engine must lower its effective compression ratio by reducing turbo boost so as to avoid knocking, which damages the engine. This is done real time using knock sensors. Reducing boost, understandably, reduces HP, and that's the trade off. THE QUESTION FOR VW IS: WHAT IS THE 2019 GTI'S HP RATING WHEN RUNNING ON 87 OCTANE? ANYONE ANYONE ANYONE????

87 octane "regular" gas here in the U.S. is the equivalent of the 91 RON you get in other parts of the world. 91 RON is not the same as 91 octane premium fuel. On this topic...

Your car is tuned from VW to run efficiently (power/mpgs) on 87 octane fuel. It doesn't matter that "that motor always used premium in other VWs 5 years ago" or "that same motor in the Toureg calls for premium so my Atlas must need it too" - the motor in the Atlas is tuned to run 87 and is not the same as the motors that needed premium. It’s a compromise that sways towards mpgs vs. power for sure. “Tune” here essentially means spark timing i.e. advance (spark earlier in the compression stoke) vs. retard (spark later in the stroke). The timing is set at a point to not have pre-detonation or “knock” running 87. Your car doesn’t “know” what gas you are running. It only “knows” when you experience pre-det through the knock-sensor. If it senses pre-det, it retards the timing which doesn’t allow as much compression before the spark therefore reducing power output. If you run premium in a car tuned for 87, you aren’t changing anything beyond possibly reducing the retarding of the timing under WOT/hard acceleration which will yield a little more power and is the reason you will see hp/tq numbers in your manual/online with the *achieved with premium fuel. Your car's ECU doesn’t have A.I. and need “3-4 tanks for it to learn the gas” – it just runs on what’s in it and the ECU adjusts timing accordingly which happens on-demand. The notion that running premium in a car not tuned for it will yield significant mpg increase is simply fantasy land and most of the perceived increase in power is likely placebo. Under normal driving conditions, you car isn’t retarding your timing enough to cause a drop in mpgs that are all of a sudden remedied by running premium. Premium doesn’t have any more detergents than regular at most gas stations (yes, I know a few do) and if you use Top Tier fuel, you should get that same detergent package in all octane ratings. Premium isn't "burning cleaner" than regular or preventing carbon build-up in direct-injection motors. If you’re racing your car with 0-60 runs all the time, run premium. If you’re driving your car under “normal” conditions, save the $0.60/gal (that’s what it’s here in VA) and run regular, which saves me ~$10/fillup which is ~$400/year @ 12K miles and 18mpg average for mixed (but city-weighted) driving. That's $4K over a 10 year life of ownership....not chump change.

 

[KarstGeo]

I think I posted this somewhere else/another thread but here is your data to show that you do get less timing correction using 93 vs. 87 and this is the source of the little bit of extra power that will be stated sometimes in manuals/specs/etc. w/r to using premium fuel. Clearly more timing retard on 87 than 93 (but funny you still see some with 93 so maybe a few gal of E85 would zero it out and max the power). These are 2/3 gear pulls from 2K RPM to redline. Same gas station, complete tanks (so not partial fills).

87 Costco:

93 Costco:

 

[KarstGeo]

Finally, someone who knows what they are talking about regarding octane ratings and performance.
Premium 91 is required for many performance turbos, like my 2019 GTI, in order to achieve the spec'd horsepower (228 hp), but it's not mandatory if you don't care about HP ratings. It's clear that the GTI will run just fine on 87 octane, but it's really hard to find, ANYWHERE, what the reduced horsepower spec's are. My guess, probably 210 hp.
What most people don't understand is that premium fuel has NO more energy density than regular fuel. The premium fuel is no more powerful than the regular fuel! Rather, what happens when you run on lower octane is that the engine must lower its effective compression ratio by reducing turbo boost so as to avoid knocking, which damages the engine. This is done real time using knock sensors. Reducing boost, understandably, reduces HP, and that's the trade off. THE QUESTION FOR VW IS: WHAT IS THE 2019 GTI'S HP RATING WHEN RUNNING ON 87 OCTANE? ANYONE ANYONE ANYONE????

It's not actually dropping boost, it's backing off the timing advance (retarding it back a bit) to avoid "knock". Running 93 in the GTI with the stock ECU tune is likely adding about 15 hp from the additional timing advance.

 

[Barry T]

You can use regular. The premium fuel burns hotter and the combustion is more complete and will give you a few more horsepower, which you might notice or not at all. As KarstGeo mentioned, your O2 sensor(s) automatically adjust your timing so that your engine runs with the best combustion to reduce carbon emissions. All these tuning mods which I have tried actually make your engine run less efficient and it has never been proven to me that a less efficient engine actually made any notable increases in power.