Gasoline Octane Rating (87 is FINE)
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  1. #1
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    Gasoline Octane Rating (87 is FINE)

    With all the talk about gas prices (and some people asking me directly), I thought I would post this fax I just received from VW.

    Most of you have read your owners manual I am sure, and are aware that your engine will run fine on 87 octane (Regular Unleaded Gasoline). Here is a copy of the wording of a fax I recently received from VW:

    ------

    Please note that 87 octane (Regular Unleaded) is just fine for any of our High Performance engines (1.8t, VR6, V6 or W8 - it doesn't matter). All of our engines have an Electronic Control Module (computer) that will adjust the engine to help maintain the best performance based on the quality of fuel in the tank. The use of premium is recommended for these engines to achieve top performance, but is definitely not required - Regular Unleaded works fine. This is just another great example of VW technology working for the Driver.

    ------

    --Drew

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    Re: Gasoline Octane Rating (DrewAment)

    Well this is definately good to know. I was under the impression that I MUST put in at least 91. I am going to stop spending those extra bucks and see how it does with the 87.

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    Re: Gasoline Octane Rating (SGT Kermit)

    I'm sure you'll notice your MPG drop rapidly. Personally, I think using this RFG for winter uses is a line of BS. It just drops your MPG even more so you have to spend more in the winter. I think I got a tankful of summer gas at one station, and I got 32 MPG out of it whereas everyplace else at the same outside temp around 20F I can only manage 21-25 MPG.

    <![CDATA[I'm sure you'll notice your MPG drop rapidly. Personally, I think using this RFG for winter uses is a line of BS. It just drops your MPG even more so you have to spend more in the winter. I think I got a tankful of summer gas at one station, and I got 32 MPG out of it whereas everyplace else at the same outside temp around 20F I can only manage 21-25 MPG.

    [Modified by Wahaha, 7:07 PM 3/2/2003]

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    Re: Gasoline Octane Rating (TrauMattic)

    only way to know for sure is to put 87 on a dyno and 91 on a dyno. If you are chipped though, you have traded the ability to use 87 for higher performance. Also the performance loss in going to lower octane will be more obvious in the summer. The car will have to retard the timing more to prevent pinging because the air coming in will be hotter.

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    Re: Gasoline Octane Rating (DrewAment)

    does the fax stated that 87 octane works for any years? i just want to know if it work on the older year such as 98 passat?

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    Re: Gasoline Octane Rating (yiucycle)

    Times are tight and I respect pinching pennies, but for anyone spending money on mods to improve your car's performance you'd have to be cuckoo to downgrade to 87 octane to save $2 or $3 a fill-up!

  8. #7
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    Re: Gasoline Octane Rating (yiucycle)

    Can you upload this fax and link it please.... If I do decide to put in 87 in the future I’d like to have some documentation to back me up incase I’m denied any warranty coverage.

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    Re: Gasoline Octane Rating (Wahaha)

    <BLOCKQUOTE>quote:<HR>I'm sure you'll notice your MPG drop rapidly. Personally, I think using this RFG for winter uses is a line of BS. It just drops your MPG even more so you have to spend more in the winter. I think I got a tankful of summer gas at one station, and I got 32 MPG out of it whereas everyplace else at the same outside temp around 20F I can only manage 21-25 MPG.


    [Modified by Wahaha, 7:07 PM 3/2/2003]<HR></BLOCKQUOTE>

    I have a V6 variant and get crappy MPG anyway. I am going to try it in the next time I fill up and see what happens.

  10. #9
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    Re: Gasoline Octane Rating (DrewAment)

    Of course it will run on pretty much any octane, but as has been discussed countless times, you give up performance, fuel economy, and *engine longevity*. Knock sensors are hardly ground breaking technology and do not make it painless to run on low octane. There's no new information here.

  11. #10
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    Re: Gasoline Octane Rating

    <BLOCKQUOTE>quote:<HR>The use of premium is recommended for these engines to achieve top performance, but is definitely not required - Regular Unleaded works fine.<HR></BLOCKQUOTE>

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    Re: Gasoline Octane Rating (stockB5.5)

    I guess it depends how you define "works fine." To me, getting constant engine knock would not fall into that category (knock sensors and related ignition retard systems do not prevent knock). It's deceptive to imply the only thing you're giving up is performance.

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    Re: Gasoline Octane Rating (not_too_shabby)

    <BLOCKQUOTE>quote:<HR>only way to know for sure is to put 87 on a dyno and 91 on a dyno. If you are chipped though, you have traded the ability to use 87 for higher performance. Also the performance loss in going to lower octane will be more obvious in the summer. The car will have to retard the timing more to prevent pinging because the air coming in will be hotter. <HR></BLOCKQUOTE>

    Just make sure you run an AVERAGE dyno test to get good results. Meaning run 3-4 tanks of the gas you are testing, THEN dyno it.

    --Drew


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    Re: Gasoline Octane Rating (SGT Kermit)

    <BLOCKQUOTE>quote:<HR>I have a V6 variant and get crappy MPG anyway. I am going to try it in the next time I fill up and see what happens.<HR></BLOCKQUOTE>

    Don't just try "one" tank. Average it over 3-4 tanks to get more accurate results.

    --Drew

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    Re: Gasoline Octane Rating (drive)

    <BLOCKQUOTE>quote:<HR>Can you upload this fax and link it please.... If I do decide to put in 87 in the future I’d like to have some documentation to back me up incase I’m denied any warranty coverage.<HR></BLOCKQUOTE>

    Your owners manual is the documentation, it clearly states what I said. This fax was just sent out to "remind" the salespeople at the dealerships.

    --Drew

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    Re: Gasoline Octane Rating (DrewAment)

    Was it signed by anyone with a last name and job title?

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    Re: Gasoline Octane Rating (not_too_shabby)

    <BLOCKQUOTE>quote:<HR>only way to know for sure is to put 87 on a dyno and 91 on a dyno. <HR></BLOCKQUOTE>

    Car and driver did just that with several cars not long ago, some tuned for premium and some tuned for regular: http://www.caranddriver.com/xp/Caran...=octane&page=1

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    Re: Gasoline Octane Rating (Macabre)

    <BLOCKQUOTE>quote:<HR>Car and driver did just that with several cars not long ago, some tuned for premium and some tuned for regular: http://www.caranddriver.com/xp/Caran...=octane&page=1<HR></BLOCKQUOTE>

    A Great article, and the last paragraph sums it up very nicely.

    --Drew


    <![CDATA[<BLOCKQUOTE>quote:<HR>Car and driver did just that with several cars not long ago, some tuned for premium and some tuned for regular: http://www.caranddriver.com/xp/Caran...=octane&page=1<HR></BLOCKQUOTE>

    A Great article, and the last paragraph sums it up very nicely.

    --Drew


    [Modified by DrewAment, 6:33 PM 3/2/2003]

  19. #18
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    Re: Gasoline Octane Rating (DrewAment)

    "The results were more dramatic with the test cars that require premium fuel. The turbocharged Saab's sophisticated Trionic engine-control system dialed the power back 9.8 percent on regular gas, and performance dropped 10.1 percent at the track. "

    I think I'll continue to pay the extra $3 a tank for my 10% (for now)

  20. #19
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    Re: Gasoline Octane Rating (DrewAment)

    OK, thanks for posting this. I've a coupla questions, though, and if I sound a little hostile, TIFWIW the hostility is directed at corporate:

    1. Why didn't *I* receive a copy of this newsflash? I'm an owner, after all. You deserve to know this, but I don't, except thanks to you on a web forum? VW technology may be working for this driver, but how will I know that, if VW doesn't tell me, except through you, in this bassackwards way?
    2. That copy and the manual copy are masterpieces of vagueness. The manual copy reads "recommended...minimum...91". OK, got that, the minimum recommended octane is 91. Next, "if...premium is not available...minimum octane rating of 87..." OK, check. I can use 87 in a pinch. Next, "However, this may lead to a slight loss of engine power." OK, NOW I'm confused. If the sole drawback of 87 is a loss of power, not a loss of longevity, why doesn't it say something like ~"use any gas you want 87 or higher, but you'll get the most power from 91 [or higher?]. There is zero detonation and therefore no longevity penalty for using 87 consistently." That would be the appropriate thing to have said in the context of an owner's manual.

    Maybe some of you don't remember this, but there WAS a time when you could seriously F an engine with detonation by using low-octane gas, and I've heard nothing since to convince me that is not still the case with certain cars, like this one.

    OK, now I'm looking at the "just fine" wording in your new dealer fax (thanks for posting it though, I guess I'm pissed at VW, not you)...even though the manual is vague, the manual does not say 87 is "just fine". I think most people would agree the meaning of these two documents is different.

    So now I want to know, now that VW has changed its stance on what gas to use, do I get a refund for having followed the manual's "recommended minimum 91" for the last 3 years? I figure that'd be about $450. Does that fax say where I can apply for my "owner documentation error" rebate?

    I've never owned a car before where there was so much uncertainty in the service network with how to run it and how to fix it, much less one where there were multiple errors in the owners' manual (I guess we can add octane reccomendation to the oil capacity error and timing belt ommissions).

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    Re: Gasoline Octane Rating (DrewAment)

    Okay, VWoA says you can run regular or premium. They tell us for "top performance", use at least 91 octane. The real question to ask VWoA is: How much does fuel econoomy suffer when running 87 octane fuel?

    If the fuel economy suffers by 5%, then at a certain price level and price differential, running premium could actually be more economical than running regular.

    Playing around with a calculator, assuming some basic tenets, it's almost cheaper for you to run premium in your Passat now.

    Macabre sited his gasoline prices in CA were: $2.07 regular / $2.15 mid / $2.20 premium.

    Let's assume you run 12,000 miles a year, you get 24 mpg (what I'm getting average as my total fuel economy to date) on Premium and 5% penalty on fuel economy if you run regular.

    12,000 miles / 24 = 500 gallons x 2.20 = $1,100 for premium gas a year.

    versus

    12,000 miles / 22.8 = 526.32 gallons x 2.07 = $1,089 for regular a year.

    A whole $11 a year difference!!!

    If the price creeps up a little more and the price spread stays the same, it will actually be cheaper for Passat owners to buy premium. Go figure! But for 11 bux a year, I'm sticking with the premium.

    You really need to analyse the whole picture and do the math to see what makes sense for you. The knee-jerk reaction to simply buying regular to save money may not actually net you the gain that you expect.

    DrewAment: Fax VWoA back and ask them what's the fuel economy penalty incurred by switching to 87 octane. It's the only part of the equation needed to see if this makes sense. I'm sure they know the answer.



    <![CDATA[Okay, VWoA says you can run regular or premium. They tell us for "top performance", use at least 91 octane. The real question to ask VWoA is: How much does fuel econoomy suffer when running 87 octane fuel?

    If the fuel economy suffers by 5%, then at a certain price level and price differential, running premium could actually be more economical than running regular.

    Playing around with a calculator, assuming some basic tenets, it's almost cheaper for you to run premium in your Passat now.

    Macabre sited his gasoline prices in CA were: $2.07 regular / $2.15 mid / $2.20 premium.

    Let's assume you run 12,000 miles a year, you get 24 mpg (what I'm getting average as my total fuel economy to date) on Premium and 5% penalty on fuel economy if you run regular.

    12,000 miles / 24 = 500 gallons x 2.20 = $1,100 for premium gas a year.

    versus

    12,000 miles / 22.8 = 526.32 gallons x 2.07 = $1,089 for regular a year.

    A whole $11 a year difference!!!

    If the price creeps up a little more and the price spread stays the same, it will actually be cheaper for Passat owners to buy premium. Go figure! But for 11 bux a year, I'm sticking with the premium.

    You really need to analyse the whole picture and do the math to see what makes sense for you. The knee-jerk reaction to simply buying regular to save money may not actually net you the gain that you expect.

    DrewAment: Fax VWoA back and ask them what's the fuel economy penalty incurred by switching to 87 octane. It's the only part of the equation needed to see if this makes sense. I'm sure they know the answer.



    [Modified by Altair 4, 10:05 AM 3/3/2003]

  22. #21
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    Re: Gasoline Octane Rating (Altair 4)

    Top theory Altair!!
    Its like everything in my opinion, cheaper in the short, but dearer in the long run..
    Oil, tyres, brake pads etc etc!!
    I thought we all bought VWs as we understood you have to pay for a better quality item!!

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    Re: Gasoline Octane Rating (fellie)

    <BLOCKQUOTE>quote:<HR>Top theory Altair!!<HR></BLOCKQUOTE>

    [Elvis voice] Thank yew, thank yew very much! [/Elvis voice]

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    Re: Gasoline Octane Rating (Altair 4)

    <BLOCKQUOTE>quote:<HR>...gasoline prices in CA were: $2.07 regular / $2.15 mid / $2.20 premium.
    <HR></BLOCKQUOTE>

    Or you could move from CA! I just filled up today with 93 octane for $1.67/gal.

    I think reg. is in the low 1.40's but I don't even bother to look.

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    Re: Gasoline Octane Rating (B12Teuton)

    here is another good link:


    http://dynospotracing.com/octane.htm

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    Re: Gasoline Octane Rating (scotty_passat)

    Yeah I thought the 4 banger was not even alowwed to look at the 87 sticker on the pump

    I'll stick to 93

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    Re: Gasoline Octane Rating (Macabre)

    <BLOCKQUOTE>quote:<HR>...getting constant engine knock would not fall into that category (knock sensors and related ignition retard systems do not prevent knock). It's deceptive to imply the only thing you're giving up is performance.<HR></BLOCKQUOTE>

    This is the key point to me. Use 87 octane and your engine will be knocking more. You won't notice the knocking b/c the knock sensors will detect it long before you do and retard the timing.

    OTOH, if you are trying to sell a car, it is definitely to your advantage to be able to say that the car doesn't require higher octane.

  28. #27
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    Re: Gasoline Octane Rating (tenbroeck)

    Deception in the car sales business?! Blasphemy!

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    Re: Gasoline Octane Rating (DrewAment)

    I drove about 22,000 miles per year and average about 25 mpg. So, at a $0.15 price differential between 87 octane (regular) and 93 octane (premium ), I'd save a whopping $132 per year.

    Heck, I'd pay that for a modest performance mod -- and that's how I look at using premium rather than regular unleaded fuel.

  30. #29
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    Re: Gasoline Octane Rating (tenbroeck)

    <BLOCKQUOTE>quote:<HR>...OTOH, if you are trying to sell a car, it is definitely to your advantage to be able to say that the car doesn't require higher octane.<HR></BLOCKQUOTE>

    haha, maybe VW is just trying to help us out on the resale values....
    VW must get this question often, especially considering Honda recommends regular.

    I've run 89 (unleaded plus) in my V6 before with no noticeable effects on power or economy.
    Referencing the tests from C&D, It would seem that the V6 is a better candidate to try a lower octane fuel than the 1.8T. (Thanks for posting that Mac.)
    I think that's fair since in my experience the V6 gets about 15% lower mpg compared to my old 1.8T Passat.

    Altair, those numbers seem to be a valid calculation of fuel savings based on your assumption of 5% loss of economy.
    I guess the question is whether that 5% number is accurate, depending on driving style, etc.

  31. #30
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    Re: Gasoline Octane Rating (Der Meister)

    <BLOCKQUOTE>quote:<HR> Altair, those numbers seem to be a valid calculation of fuel savings based on your assumption of 5% loss of economy. I guess the question is whether that 5% number is accurate, depending on driving style, etc.<HR></BLOCKQUOTE>

    Yah, I agree. Some here and on the 'tex report as much as ten percent difference in the past, but I view fuel economy findings from most people to be anecdotal. It's too easy to make a difference either way (drive with a light or heavy foot, even subconsciously). I suspect that VW has that answer to 5 decimal places, but probably won't share. The on-line C&D article about premium fuel usage is really aimed more at performance as in "how fast" not as in "how economical".

    But even if there is no penalty in mileage (which I don't believe) between regular and premium, at $0.15 per gallon difference, you would only be looking at $75/year difference (based on 12,000 miles a year and 24 mpg). Amortize that per day and you'll find another $0.20 in your pocket per day. It's just not really that much money. Take it out per mile and it boils down to $0.006 per mile.

    For 20 cents a day, it's premium for me (it's a no-brainer). I'll keep my performance and sleep the sleep of the pure of heart, knowing that I'm not even taking a chance on the whole knock-detection, ignition-timing-retard thing.

    <![CDATA[<BLOCKQUOTE>quote:<HR> Altair, those numbers seem to be a valid calculation of fuel savings based on your assumption of 5% loss of economy. I guess the question is whether that 5% number is accurate, depending on driving style, etc.<HR></BLOCKQUOTE>

    Yah, I agree. Some here and on the 'tex report as much as ten percent difference in the past, but I view fuel economy findings from most people to be anecdotal. It's too easy to make a difference either way (drive with a light or heavy foot, even subconsciously). I suspect that VW has that answer to 5 decimal places, but probably won't share. The on-line C&D article about premium fuel usage is really aimed more at performance as in "how fast" not as in "how economical".

    But even if there is no penalty in mileage (which I don't believe) between regular and premium, at $0.15 per gallon difference, you would only be looking at $75/year difference (based on 12,000 miles a year and 24 mpg). Amortize that per day and you'll find another $0.20 in your pocket per day. It's just not really that much money. Take it out per mile and it boils down to $0.006 per mile.

    For 20 cents a day, it's premium for me (it's a no-brainer). I'll keep my performance and sleep the sleep of the pure of heart, knowing that I'm not even taking a chance on the whole knock-detection, ignition-timing-retard thing.

    [Modified by Altair 4, 3:03 PM 3/3/2003]

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