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View Full Version : could it have really been that simple? im an idiot!



seanentrust
04-08-2013, 01:15 PM
for the last few months my car has been driving like crap, sputtering and misfiring under throttle, i was about to drive my car off a cliff. I havent really been driving the car much and i dont drive it hard so ive just been putting regular gas in not thinking twice about it (the car has an apr tune and a ko4). the other day i got gas and put premium in it like i should have been all along and almost instantly the car feels back to normal, no more lugging or misfiring. Could it really have been that simple? could running regular cause those problems? I feel like such a dummy :(

jvega21
04-08-2013, 01:24 PM
for the last few months my car has been driving like crap, sputtering and misfiring under throttle, i was about to drive my car off a cliff. I havent really been driving the car much and i dont drive it hard so ive just been putting regular gas in not thinking twice about it (the car has an apr tune and a ko4). the other day i got gas and put premium in it like i should have been all along and almost instantly the car feels back to normal, no more lugging or misfiring. Could it really have been that simple? could running regular cause those problems? I feel like such a dummy :(

yes.
the gas cover has a sticker that says the car requires 91. my 97 B5 said it required 91, min 89.
its a turbo, and you have a tune, so yes, lower octane fuel will cause knocking

SlickMachine
04-08-2013, 01:30 PM
Are you a blond female by chance?

seanentrust
04-08-2013, 01:35 PM
Are you a blond female by chance?

lol no but that would make sense. i know better which is why i feel stupid!

Sp8t
04-08-2013, 01:52 PM
Anything Turbo (big,small,1 or 2) should have 91 unless your tune tells it differently and then it would only go up from there. At least your man enough to admit your error. lol.

coolgraymemo
04-08-2013, 01:53 PM
How much money do you save by using 87 rather than 91?

98A4TurboAWD
04-08-2013, 02:15 PM
You will also get better MPG by running the octane recommended by the manufacturer.

You were not actually saving money by putting in the cheaper gas because it was coming out of your MPG, and obviously, your car ran like a turd.

catbed
04-08-2013, 02:18 PM
It's not even what the manufacturer says at this point, its what the APR tune calls for, which is 93. Any aftermarket tune calls for 93, and if you put anything other than 93 it will run like crap.

A1 A2 German
04-08-2013, 02:55 PM
Curious, 34 years in Arizona, 92 doesn't exist, 93 doesn't exist......period! There is and never ever, has there been above 91. Any one venture to guess if you'd even see results from a "first tank ever of 93"?

Trevman
04-08-2013, 03:35 PM
Yeah, there's no 93 in California either. You might be able to get some at a track or something. There's probably a list of states out there that do 93 octane. Being a california native I was very surprised and jealous to see 89, 91, 93 at all the gas stations my first trip to Boston.

seanentrust
04-08-2013, 03:38 PM
i grew up in the south and everywhere had 93, then i lived in philly for a bit and they had 94! now on the westcoast and everything is 91 and 92 :(

Trevman
04-08-2013, 03:40 PM
Since you've been running crap gas, you might consider swapping your fuel filter and putting in some injector cleaner. Hopefully clean some of that shit out...

jvega21
04-08-2013, 04:38 PM
Has anyone ever messed with the octane boosters? I mean the unlucky souls like myself that don't have 93? I know the muscle car guys love using it.

seanentrust
04-08-2013, 04:39 PM
Since you've been running crap gas, you might consider swapping your fuel filter and putting in some injector cleaner. Hopefully clean some of that shit out...

i have both :) just need to find time to do the fuel filter, it looks like a nightmare!

98A4TurboAWD
04-08-2013, 04:46 PM
i have both :) just need to find time to do the fuel filter, it looks like a nightmare!

No it's actually really easy. It was a nightmare for me because I wasted so much time trying to get the bolt out of the plastic bracket that holds the filter in place. Finally I decided to cut down one of my 12 point bits so that it would fit just to find out that the entire nut and bolt assembly was spinning. After all the time wasted, the stupid bracket had to be broken.

My advice to you is to not waste much time on that bolt. If you have the 12 point handy then you will find out right away whether or not it will come out. If it gives you fits, don't waste time trying to get it out because there is not enough room and you will get nowhere. Just break the plastic bracket so that you can get the job done.

However, I use impacts for everything, so for me to take the 4 13mm tank strap bolts out and put them back in takes literally 30 seconds.

terraflata
04-08-2013, 05:08 PM
I wouldnt worry about the injectors from lower octane gas, perhaps a seafoam treatment though. The gas wont damage injectors because of its octane rating, it will cause knocking and odd fuel combustion, which would mean more along the lines of build up post-intake manifold. Pull your spark plugs and clean/change them. Don't worry about your filter or injectors unless they are old, but they wont get damaged from using regular gas, its just when it comes to the burning process the problems start. FWIW, we have 87, 91, 93 and 94, sometimes youll see E85.

A lot of people use premium fuel in cars that don't require it as well. Which is dumber than your mistake OP. Cause they are spending even more money, probably getting worse MPG and worse performance. They somehow think it will allow their engine to produce more power, just like people who throw octane boosters in their gas. I can throw C16 or race gas in my tank, if I don't have an engine to burn it properly it won't do me any good.

ElliottG
04-08-2013, 05:20 PM
Don't know...my uncle used to run 87 octane in his 2.7T Allroad all the time with zero ill effects...and that was being tuned APR stage 1 also...

The ECU will just compensate for the lower octane fuel and make less power...sounds to me like you have a different problem.

Anyone who thinks these cars can only run on 91 octane fuel are straight up retarded and need a lesson on how fuel injected cars work.

jvega21
04-08-2013, 05:32 PM
No one here said it won't run on anything but 91. But going to the extent of calling us retarded is uncalled for. I use 91 because my car manufacturer said so. But it also says 93, which I don't have access to.
so do use whatever is on tap or do you pump the same stuff every time? According to what you said whatever will work, right?

Trevman
04-08-2013, 05:38 PM
http://www.audiworld.com/tech/eng49.shtml

This is the DIY I used.

It can be frustrating because of how small of a space you have to work with. If you try to get the bolt out, definitely prepare for a bit of a fight. However, Like 98A4TurboAWD, tons of people have just clipped the plastic strap holding the filter, with no issues. So you can bypass most of the difficulty by doing it that way.

csosnowski
04-08-2013, 05:39 PM
Has anyone ever messed with the octane boosters? I mean the unlucky souls like myself that don't have 93? I know the muscle car guys love using it.

You can use toluene to boost the octane.

Read about it ----> Link (http://s4wiki.com/wiki/Toluene)

98A4TurboAWD
04-08-2013, 05:50 PM
Don't know...my uncle used to run 87 octane in his 2.7T Allroad all the time with zero ill effects...and that was being tuned APR stage 1 also...

The ECU will just compensate for the lower octane fuel and make less power...sounds to me like you have a different problem.

Anyone who thinks these cars can only run on 91 octane fuel are straight up retarded and need a lesson on how fuel injected cars work.

Because your uncle ran 87 in a car that was designed to run on 91 doesn't make it okay. yes the ecu will retard the timing to reduce the knock but that doesn't mean "zero ill effects." If it's as you say, that he ran 87 in a car tuned for premium, then I would venture to say that if he logged his car he would see that he had a good amount of knock and I would imagine that if he were to pull the engine apart he would find a hell of a mess on his valves, cylinder heads, and intake manifold.

You also allude from your anecdote that he has a different problem - again this is false. If you run 87 octane gas in a performance tune that calls for higher octane gas, you are going to suffer performance - period. With my LT1, even with my tune and running premium fuel, I opted for an upgraded knock sensor because it's that sensitive.

What you have said, outside of your uncles case as evidence, is baseless.

jvega21
04-08-2013, 06:12 PM
You can use toluene to boost the octane.

Read about it ----> Link (http://s4wiki.com/wiki/Toluene)

will definitely give it a try. There's a Sherwin Williams around the corner from my house :-)

ElliottG
04-08-2013, 07:01 PM
No one here said it won't run on anything but 91. But going to the extent of calling us retarded is uncalled for. I use 91 because my car manufacturer said so. But it also says 93, which I don't have access to.
so do use whatever is on tap or do you pump the same stuff every time? According to what you said whatever will work, right?

I agree no one said that it won't run on anything but 91, but OP said he had problems, changed to 91 octane and his car runs fine again. People then saying it was the fuel.


Because your uncle ran 87 in a car that was designed to run on 91 doesn't make it okay. yes the ecu will retard the timing to reduce the knock but that doesn't mean "zero ill effects." If it's as you say, that he ran 87 in a car tuned for premium, then I would venture to say that if he logged his car he would see that he had a good amount of knock and I would imagine that if he were to pull the engine apart he would find a hell of a mess on his valves, cylinder heads, and intake manifold.

You also allude from your anecdote that he has a different problem - again this is false. If you run 87 octane gas in a performance tune that calls for higher octane gas, you are going to suffer performance - period. With my LT1, even with my tune and running premium fuel, I opted for an upgraded knock sensor because it's that sensitive.

What you have said, outside of your uncles case as evidence, is baseless.

Agreed it's one case.

If you drive your car around under full boost on every street then yes of course the engine will have some knock, but if you do that, you're just asking for it. Likewise, if you drive around normally, why would you even bother putting 91 octane in your car? It's a waste of money. Although keep in mind that here in Canada gas prices are 1.5x what yours are so I only speak for myself.

The car has been running this way for over 200k KM and the engine still looks minty inside...and he's not the only case of this. I really don't think you realize how many people on planet earth own VAG turbocharged engines and run lower grade fuel in their cars with no problems at all...because a few people post on a forum saying they had problems with fuel doesn't mean that it is the case for everyone. It's exactly like people complaining of turbo failures on 2.7T's. What makes you so sure that it's not only a few hundred people on some forums that blew their turbos, and not everyone else that drives their 2.7T's normally? That is just one example.

And yes I see now that the OP has a K04 and APR tune which I did not before...maybe the APR tune for a K04 is really sensitive on fuel...but most tunes are not that sensitive and you should not get any misfires on a stage 1 tune because of knock sensors, etc.

So why do these engines require 91 octane fuel, when a Hyundai 2.0T can make 270hp and have a fuel rating of 87 octane? ROFL. The whole thing with VAG cars needing 91 octane is a total joke and I feel bad for people who fall for it.

northcarohio
04-08-2013, 07:03 PM
Question for you guys..I have an APR stage one tune with Stock, 91, and 93 octane modes. Up here in the rockies we only have 87 and 91, but I have yet to notice a difference when I switch between the 91 and 93 octane maps (on 91 fuel). Car runs the same and performance feels the same. Does that have anything to do with less oxygen up here at 7000 feet?

98A4TurboAWD
04-08-2013, 07:14 PM
I agree no one said that it won't run on anything but 91, but OP said he had problems, changed to 91 octane and his car runs fine again. People then saying it was the fuel.



Agreed it's one case.

If you drive your car around under full boost on every street then yes of course the engine will have some knock, but if you do that, you're just asking for it. Likewise, if you drive around normally, why would you even bother putting 91 octane in your car? It's a waste of money. Although keep in mind that here in Canada gas prices are 1.5x what yours are so I only speak for myself.

The car has been running this way for over 200k KM and the engine still looks minty inside...and he's not the only case of this. I really don't think you realize how many people on planet earth own VAG turbocharged engines and run lower grade fuel in their cars with no problems at all...because a few people post on a forum saying they had problems with fuel doesn't mean that it is the case for everyone. It's exactly like people complaining of turbo failures on 2.7T's. What makes you so sure that it's not only a few hundred people on some forums that blew their turbos, and not everyone else that drives their 2.7T's normally? That is just one example.

And yes I see now that the OP has a K04 and APR tune which I did not before...maybe the APR tune for a K04 is really sensitive on fuel...but most tunes are not that sensitive and you should not get any misfires on a stage 1 tune because of knock sensors, etc.

So why do these engines require 91 octane fuel, when a Hyundai 2.0T can make 270hp and have a fuel rating of 87 octane? ROFL. The whole thing with VAG cars needing 91 octane is a total joke and I feel bad for people who fall for it.

No man, you are wrong. Your first few sentences claiming that unless you drive like johnny racer, it does not matter what octane you run, is simply not true. I am also skeptical as to the condition of your uncles engine after running low octane gas for 200km. I have seen many engines that have run cheap gas, and have done it to myself. It's not fun cleaning all the carbon off of the internals.

Your inference from the Hyundai is a total failure. The Hyundai is designed for 87 octane. It was designed and engineered around that octane, just as the Audi was designed and engineered for premium. They don't just tell you that you need to run premium for the heck of it - they have nothing to gain by you paying extra t the pump. I'm not saying that running premium will yield you gains if the manufacturer doesn't call for it. People run premium in their F4i's while I never did, simply because Honda designed it to run on 87. So in no way am I suggesting that premium gas is beneficial in all cases, what I'm saying is that when a manufacturer who spends millions of dollars on designing and engineering a sophisticated piece of machinery and they do so based around a particular fuel and recommend that fuel for the engine, then that is what you should run if you want to avoid knock, poor mpg, and poor performance.

A1 A2 German
04-10-2013, 01:00 PM
Was this written in the 1970's?--->>>> http://s4wiki.com/wiki/Toluene

Toluene $2.50 a gallon my ass, try $32 a gallon. Well, throw that out the window.

"And sir, if you wanted 5 gallons......." Yeah.......$140+ for 5 gallons...no thanks.

seanentrust
04-10-2013, 01:16 PM
well it appears the problem isnt totally gone. I drove 150 miles this morning on the highway and in 5th gear at full throttle it starts to lug and sputter pretty hard :( the power is still there but it just doesnt feel good

woolveren
04-11-2013, 02:37 PM
well it appears the problem isnt totally gone. I drove 150 miles this morning on the highway and in 5th gear at full throttle it starts to lug and sputter pretty hard :( the power is still there but it just doesnt feel good

Just change your spark plugs. And coil packs if needed. This will probably fix your car's problems.

I ran 87 gas in my 1.8t(250k miles) for some 3 months and it didn't throw any symptoms. Audi engineers are smart enough to have a calibration setting in the ECM to compromise for a low octane fuel. This said, I did get the said symptoms after some 1 yr when the car was running on Shell v power 91. It was just spark plugs, changed it and it ran like a champ.

Kromodus
04-11-2013, 03:21 PM
Question for you guys..I have an APR stage one tune with Stock, 91, and 93 octane modes. Up here in the rockies we only have 87 and 91, but I have yet to notice a difference when I switch between the 91 and 93 octane maps (on 91 fuel). Car runs the same and performance feels the same. Does that have anything to do with less oxygen up here at 7000 feet?

Not less oxygen but lower atmospheric pressure. We don't have 93 in CO because of our altitude. Octane requirements are for a car at sea level. Our 91 is equivalent to 93 in Florida. Because our pressure is lower, we can use a lower octane and still achieve the same resistance to pressure induced ignition. [;)]

Oh, and my two cents about the "change your fuel filter and flush your rail" opinion. Why? Higher octane fuel isn't necessarily cleaner and it doesn't burn faster or burn more thoroughly. All it does is do a better job of igniting only when told to ignite. Yes you get more power, but that is because your engine with it's increased compression was able to run ideally at it's proper engine timing because you used the proper fuel, not because the fuel itself produced more power. If octane (resistance to knocking) determined performance then we would all be trying to put diesel into our gasoline engines (which I wouldn't recommend). [:D]That's it for today. Thanks for allowing me to share my opinion folks. [;)]

jvega21
04-11-2013, 03:26 PM
i thought higher octane fuel was just harder to ignite, as in it needs a bigger spark to set it off, but also has more "explosive power".. Like diesel, super powerful, but needs crazy amount of heat and compression to get it to ignite.
seeing as we have turbos, and the heat can get high pretty fast, to avoid detonation when, the higher octane makes sense.

Kromodus
04-11-2013, 03:36 PM
i thought higher octane fuel was just harder to ignite, as in it needs a bigger spark to set it off, but also has more "explosive power".. Like diesel, super powerful, but needs crazy amount of heat and compression to get it to ignite.
seeing as we have turbos, and the heat can get high pretty fast, to avoid detonation when, the higher octane makes sense.

You are correct. It's just harder to ignite. And yes, you get more explosive power, but not because of the fuel, it's because it ignites exactly at peak compression and not a nano-second sooner.

Remember folks: The 87 octane fuel that you buy at the pump is only its minimum octane rating, not it's absolute rating. You could be pumping 88, 89, 90, etc and not even know it. When you buy 91 rated, it could be 92, 93, 94, just not less than 91. Using higher octane fuel than what your engine requires causes no ill effects (it's just pointless). Using fuel rated below the minimum does.

Next time you fill up, look at the sticker: Minimum octane rating.


http://img.auctiva.com/imgdata/4/3/5/6/6/5/webimg/383698933_o.jpg

seanentrust
04-11-2013, 08:55 PM
So I was just driving home on the freeway I put it in 4th and gave it gas and it started to sputter and pop. I swear I heard the DV go off before I lifted off. It was running really bad and the cel starting flashing? Could my DV be bad and causing a boost leak?

jvega21
04-11-2013, 09:03 PM
Sounds like have misfires. Flashing CEL could be a giveaway. I forget, but did you already replace your spark plugs and gap them correctly? Check the codes with VAGCOM, I bet it'll show misfires

catbed
04-11-2013, 10:44 PM
And yes, you get more explosive power, but not because of the fuel, it's because it ignites exactly at peak compression and not a nano-second sooner.

What exactly do you mean by that?

98A4TurboAWD
04-12-2013, 05:53 AM
flashing cel is misfires. Could be coils, could be ICM. ICM is easy to test. I put a video up on youtube on how to test it via walky's instruction.

seanentrust
04-12-2013, 08:24 AM
flashing cel is misfires. Could be coils, could be ICM. ICM is easy to test. I put a video up on youtube on how to test it via walky's instruction.

I just replaced the icm. Buts its an audi so I guess it could be bad again

Kromodus
04-12-2013, 08:32 AM
What exactly do you mean by that?

Only that using the proper octane fuel is what allows your turbo engine to run at peak performance. Higher octane fuel isn't "magic". It's not somehow "more powerful" or "cleaner". Higher octane fuel is simply better at resisting heat/pressure induced combustion. That is all that the minimum octane rating ensures. And only one thing determines which octane you should use: Your final maximum compression ratio- that's it. There's nothing more to it than that. Don't be fooled into thinking that "premium fuel" is cleaner/better/magic just because it's 20 cents more. It's only more expensive because they sell less of it.

terraflata
04-12-2013, 09:30 AM
Only that using the proper octane fuel is what allows your turbo engine to run at peak performance. Higher octane fuel isn't "magic". It's not somehow "more powerful" or "cleaner". Higher octane fuel is simply better at resisting heat/pressure induced combustion. That is all that the minimum octane rating ensures. And only one thing determines which octane you should use: Your final maximum compression ratio- that's it. There's nothing more to it than that. Don't be fooled into thinking that "premium fuel" is cleaner/better/magic just because it's 20 cents more. It's only more expensive because they sell less of it.

Your on the right point but your over simplifing it. Perhaps you meant more when you said `final' compression ratio, but compression ratio isnt the only thing which determines octane rating, although Im sure you know this. Turbo, non-turbo, direct or port injection, etc all have to be looked at. A turbo car with low (8.5:1) compression can still require higher octane fuel then a non-turbo car with a significantly higher compression (10:1,11:1,12:1). Cylinder temperatures are more the deciding factor, and we all know the more boost and compression you run the closer you get to knock.

Kromodus
04-12-2013, 12:08 PM
Your on the right point but your over simplifing it. Perhaps you meant more when you said `final' compression ratio, but compression ratio isnt the only thing which determines octane rating, although Im sure you know this. Turbo, non-turbo, direct or port injection, etc all have to be looked at. A turbo car with low (8.5:1) compression can still require higher octane fuel then a non-turbo car with a significantly higher compression (10:1,11:1,12:1). Cylinder temperatures are more the deciding factor, and we all know the more boost and compression you run the closer you get to knock.

You are correct, I did over-simplify, and yes, temperature plays a huge role. Basically, whatever variables create an environment for self-ignition (heat+compression) are what determine which Octane you should use. Final maximum potential compression is probably 80%. Would you agree? [:)] Take my car for instance. It's the 2.8L ATQ naturally aspirated (non-turbo) engine, but it's stroke still creates 10:1 compression (or something like that). That is enough for Audi to require "premium" (read: higher octane) fuel to ensure that it does not knock on hot days. They specify 92 (I think) but in CO, we don't have 92 (we don't need it). 87 or 89 works just fine. [up]


A turbo car with low (8.5:1) compression can still require higher octane fuel then a non-turbo car with a significantly higher compression (10:1,11:1,12:1).

I'm certain that you know this, but most turbo engines must have a low starting compression ratio because they are turbo. If they started at 10:1 then your forced induction would make the final compression 20:1 under high boost which would likely send engine shrapnel all over the place. [:)]