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Old 05-19-2012, 04:13 PM   #1
meebs
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Exclamation Fuel brand sensativity? 76 wins.

I like checking in on my Fine Learning Knock Correction table every once in a while just out of curiosity (my wife attributes it to paranoia).

Normally I fill up with 76 as they are the only station left in my neighborhood that doesn't have the "May contain up to 10% Ethanol" stickers.

On my way out of town I filled up with Chevron, I don't recall ever having an issue with them. However, after our trip, I checked the table and hmm... there's one cell starting to show a correction. Normally my car is all zero's across the table and IAM is always at 1. I'm on a stock tune apart from lowering the values for the OL/CL delay, which the car has always been happy with.

So then after the tank of Chevron, I filled up with Shell on my way home...Maybe the marketing got to me.

My question then is does 20% more "Nitrogen" in their new formulation = 20% more knock? I think the numbers speak for themselves. Could this have just been a bad batch? I don't really want to ever try again to find out.



Here is my log of condensed Learning View readouts. Ever since I switched back to 76, my FLKC table has stayed at 0 in all cells.

04/18 Chevron
04/24 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/26 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/29 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/30 Chevron -0.70 @ 2.0-5.0 @ 4400-5600
04/30 Chevron -0.70 @ 2.0-5.0 @ 4400-5600

Fill up with Shell

05/02 Shell -0.70 @ 2.0-5.0 @ 4400-5600
05/03 Shell -0.70 @ 2.0-5.0 @ 4400-5600
05/04 Shell -0.70 @ 2.0-5.0 @ 4400-5600

05/07 Shell
-1.05 @ 1.3-1.6 @ 3200-4400
-2.10 @ 2.0-5.0 @ 4400-5600


05/08 Shell
-1.05 @ 1.3-1.6 @ 3200-4400
-2.10 @ 2.0-5.0 @ 4400-5600


Mileage on car readout is 19.2.
Normal for me is 22.5

05/08 Shell - RESET ECU after 1/4 tank.
05/08 Shell 0 FLKC after 2 drives.
05/09 Shell 0 FLKC
05/10 Shell -1.40 @ 2.0-5.0 @ 4400-5600

05/10 76 Reset ECU add Gumout Fuel Injector cleaner and fill up on 1/8th of a tank with 76.

05/11 76 0 FLKC
05/17 76 0 FLKC 3/4 tank through.
05/19 76 0 FLKC

Does anyone else see this kind of fuel sensitivity between brands? Chevron, Shell and 76 are all considered "top-teir". While 76 does contain cleaning additives, my car appears happier with them. It seems to me like the less additives, the better. I'm almost considering trying Safeway or Arco (no additives) as a test, but I'm pretty sure they are all using 10% Ethanol as well, which could be unrelated though. Ethanol is supposedly what they use to control octane anyway.
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Old 05-20-2012, 10:44 AM   #2
rex.effect
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This entire post confuses me. I am WAY to ignorant on tuning values for it to make sense. Anyway, MY local shop in MD, says stay away from BP, Citgo, etc, and recommends Shell or Sunocco. I have a very strong suspicion that gas "quality" beyond the nitrogen enriched labels, varies greatly by region/ supplier. I think a compilation list, by region (and eventually local area), would make for a great sticky once more information can be provided
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Old 05-20-2012, 12:09 PM   #3
meebs
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Originally Posted by rex.effect View Post
This entire post confuses me. I am WAY to ignorant on tuning values for it to make sense. Anyway, MY local shop in MD, says stay away from BP, Citgo, etc, and recommends Shell or Sunocco. I have a very strong suspicion that gas "quality" beyond the nitrogen enriched labels, varies greatly by region/ supplier. I think a compilation list, by region (and eventually local area), would make for a great sticky once more information can be provided
A list by region would be an interesting sticky, but you would need hard data for it to be worth anything unless you just trust the butt-dyno.

Basically those numbers above are saying that my car was pulling timing and detecting knock while on Chevron and Shell. Shell being the worst. Once I ran the tank of Shell down to 1/8th... I reset the ECU and filled up with 76. After a full tank of 76, all hesitation has gone away.

"Quality" of gas is really down to what extra stuff they put into it since they all get it from pretty much the same handful of refineries.

Another thought: With the economy being what it is and gas prices where they are, I also suspect that people are buying less premium than before. Brands that have 10% ethanol might not see as much premium going through their pumps... Ethanol tends to attract water. I guess the best bet is to make sure your station is always fresh.

Last edited by meebs; 05-20-2012 at 12:15 PM. Reason: Another thought
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Old 05-20-2012, 01:55 PM   #4
JamesWilson2
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There is so much variation even station-to-station. One petroleum engineer put it to me, go to the station that is the busiest/most popular...the in-ground tanks are very prone to water contamination, and the stations that don't refill as often are the worst offenders. This worries me with 93-octane fuels in the Houston area, as it may sit for a very long time. I try to use Shell V-Power 93 only, and have found a few specific stations that are the least problematic. When racing the car, however, buying Shell URT100 or URT105 in a 5-gallon pail has been the safest bet, and the car runs great with that fuel in the tank.

YMMV. Great data points from you though. I would like to see the same thing from different stations (within the same brand), and possibly from different distribution companies (outlying towns, etc.) to see if there is a difference.
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Old 05-20-2012, 11:34 PM   #5
Uncle Scotty
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This thread is 1000% pointless and useless outside of the OP's area code

fuel is even different across the same CITY....much less state or the whole country.

this is why some tunes go out the window just driving a few miles....the fuel is different

and why you should NEVER tune to the bleeding edge

forget that last 10hp......it might cost ya a motor if ya get bad gas


this thread needs to be locked, I think....or moved, anyway
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Old 05-20-2012, 11:38 PM   #6
Uncle Scotty
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Quote:
Originally Posted by JamesWilson2 View Post
There is so much variation even station-to-station. One petroleum engineer put it to me, go to the station that is the busiest/most popular...the in-ground tanks are very prone to water contamination, and the stations that don't refill as often are the worst offenders. This worries me with 93-octane fuels in the Houston area, as it may sit for a very long time. I try to use Shell V-Power 93 only, and have found a few specific stations that are the least problematic. When racing the car, however, buying Shell URT100 or URT105 in a 5-gallon pail has been the safest bet, and the car runs great with that fuel in the tank.

YMMV. Great data points from you though. I would like to see the same thing from different stations (within the same brand), and possibly from different distribution companies (outlying towns, etc.) to see if there is a difference.

I have found that the 93 octane fuel i have got in houston, and texas in general, is of better quality and more consistant than what I got in florida, and jacksonville in particular.
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Old 05-20-2012, 11:48 PM   #7
Subarusesh
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Quote:
Originally Posted by meebs View Post
I like checking in on my Fine Learning Knock Correction table every once in a while just out of curiosity (my wife attributes it to paranoia).

Normally I fill up with 76 as they are the only station left in my neighborhood that doesn't have the "May contain up to 10% Ethanol" stickers.

On my way out of town I filled up with Chevron, I don't recall ever having an issue with them. However, after our trip, I checked the table and hmm... there's one cell starting to show a correction. Normally my car is all zero's across the table and IAM is always at 1. I'm on a stock tune apart from lowering the values for the OL/CL delay, which the car has always been happy with.

So then after the tank of Chevron, I filled up with Shell on my way home...Maybe the marketing got to me.

My question then is does 20% more "Nitrogen" in their new formulation = 20% more knock? I think the numbers speak for themselves. Could this have just been a bad batch? I don't really want to ever try again to find out.



Here is my log of condensed Learning View readouts. Ever since I switched back to 76, my FLKC table has stayed at 0 in all cells.

04/18 Chevron
04/24 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/26 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/29 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/30 Chevron -0.70 @ 2.0-5.0 @ 4400-5600
04/30 Chevron -0.70 @ 2.0-5.0 @ 4400-5600

Fill up with Shell

05/02 Shell -0.70 @ 2.0-5.0 @ 4400-5600
05/03 Shell -0.70 @ 2.0-5.0 @ 4400-5600
05/04 Shell -0.70 @ 2.0-5.0 @ 4400-5600

05/07 Shell
-1.05 @ 1.3-1.6 @ 3200-4400
-2.10 @ 2.0-5.0 @ 4400-5600


05/08 Shell
-1.05 @ 1.3-1.6 @ 3200-4400
-2.10 @ 2.0-5.0 @ 4400-5600


Mileage on car readout is 19.2.
Normal for me is 22.5

05/08 Shell - RESET ECU after 1/4 tank.
05/08 Shell 0 FLKC after 2 drives.
05/09 Shell 0 FLKC
05/10 Shell -1.40 @ 2.0-5.0 @ 4400-5600

05/10 76 Reset ECU add Gumout Fuel Injector cleaner and fill up on 1/8th of a tank with 76.

05/11 76 0 FLKC
05/17 76 0 FLKC 3/4 tank through.
05/19 76 0 FLKC

Does anyone else see this kind of fuel sensitivity between brands? Chevron, Shell and 76 are all considered "top-teir". While 76 does contain cleaning additives, my car appears happier with them. It seems to me like the less additives, the better. I'm almost considering trying Safeway or Arco (no additives) as a test, but I'm pretty sure they are all using 10% Ethanol as well, which could be unrelated though. Ethanol is supposedly what they use to control octane anyway.



dude no offense but how and why and WTF?
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Old 05-21-2012, 09:40 AM   #8
Bacon117
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Quote:
Originally Posted by JamesWilson2 View Post
There is so much variation even station-to-station. One petroleum engineer put it to me, go to the station that is the busiest/most popular...the in-ground tanks are very prone to water contamination, and the stations that don't refill as often are the worst offenders. This worries me with 93-octane fuels in the Houston area, as it may sit for a very long time. I try to use Shell V-Power 93 only, and have found a few specific stations that are the least problematic. When racing the car, however, buying Shell URT100 or URT105 in a 5-gallon pail has been the safest bet, and the car runs great with that fuel in the tank.

YMMV. Great data points from you though. I would like to see the same thing from different stations (within the same brand), and possibly from different distribution companies (outlying towns, etc.) to see if there is a difference.
You don't have to worry about water much anymore. Ethanol is hydroscopic, so any condensate will be absorbed and burned in all the cars long before it builds up to dangerous levels. You have to worry about it more at places that don't use E10.

Last edited by Bacon117; 05-21-2012 at 09:53 AM.
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Old 05-21-2012, 09:48 AM   #9
Bacon117
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Quote:
Originally Posted by meebs View Post
I like checking in on my Fine Learning Knock Correction table every once in a while just out of curiosity (my wife attributes it to paranoia).

Normally I fill up with 76 as they are the only station left in my neighborhood that doesn't have the "May contain up to 10% Ethanol" stickers.

On my way out of town I filled up with Chevron, I don't recall ever having an issue with them. However, after our trip, I checked the table and hmm... there's one cell starting to show a correction. Normally my car is all zero's across the table and IAM is always at 1. I'm on a stock tune apart from lowering the values for the OL/CL delay, which the car has always been happy with.

So then after the tank of Chevron, I filled up with Shell on my way home...Maybe the marketing got to me.

My question then is does 20% more "Nitrogen" in their new formulation = 20% more knock? I think the numbers speak for themselves. Could this have just been a bad batch? I don't really want to ever try again to find out.



Here is my log of condensed Learning View readouts. Ever since I switched back to 76, my FLKC table has stayed at 0 in all cells.

04/18 Chevron
04/24 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/26 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/29 Chevron -1.05 @ 2.0-5.0 @ 4400-5600
04/30 Chevron -0.70 @ 2.0-5.0 @ 4400-5600
04/30 Chevron -0.70 @ 2.0-5.0 @ 4400-5600

Fill up with Shell

05/02 Shell -0.70 @ 2.0-5.0 @ 4400-5600
05/03 Shell -0.70 @ 2.0-5.0 @ 4400-5600
05/04 Shell -0.70 @ 2.0-5.0 @ 4400-5600

05/07 Shell
-1.05 @ 1.3-1.6 @ 3200-4400
-2.10 @ 2.0-5.0 @ 4400-5600


05/08 Shell
-1.05 @ 1.3-1.6 @ 3200-4400
-2.10 @ 2.0-5.0 @ 4400-5600


Mileage on car readout is 19.2.
Normal for me is 22.5

05/08 Shell - RESET ECU after 1/4 tank.
05/08 Shell 0 FLKC after 2 drives.
05/09 Shell 0 FLKC
05/10 Shell -1.40 @ 2.0-5.0 @ 4400-5600

05/10 76 Reset ECU add Gumout Fuel Injector cleaner and fill up on 1/8th of a tank with 76.

05/11 76 0 FLKC
05/17 76 0 FLKC 3/4 tank through.
05/19 76 0 FLKC

Does anyone else see this kind of fuel sensitivity between brands? Chevron, Shell and 76 are all considered "top-teir". While 76 does contain cleaning additives, my car appears happier with them. It seems to me like the less additives, the better. I'm almost considering trying Safeway or Arco (no additives) as a test, but I'm pretty sure they are all using 10% Ethanol as well, which could be unrelated though. Ethanol is supposedly what they use to control octane anyway.
I wouldn't worry so much. A lot of it comes down to the Ethanol content. Stoich for ethanol is 8.x:1, while E0, or gasoline is 14.7, so the more ethanol you have, the more fuel will have to be pumped into the engine to maintain stoich.

Knock correction is affected by so much, ambient air temp, fuel octane level, ambient humidity, and how many leaves or dead birds are on your TMIC. The corrections, short and long term are there for this very reason. I would have a hard time concluding that one fuel is better than the rest simply from the corrections in the ECU. There are SO many other variables that are changing, it's impossible to say it's all in the fuel.

If you hear knock, and the knock corrections are maxed out, then I would worry. You should get a CEL if this happens.
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Old 05-21-2012, 10:06 PM   #10
meebs
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Quote:
Originally Posted by Uncle Scotty View Post
This thread is 1000% pointless and useless outside of the OP's area code

fuel is even different across the same CITY....much less state or the whole country.

this is why some tunes go out the window just driving a few miles....the fuel is different

and why you should NEVER tune to the bleeding edge

forget that last 10hp......it might cost ya a motor if ya get bad gas


this thread needs to be locked, I think....or moved, anyway
Holleeeeee ****!!! ELLLIPPPSEEEEEESSSSSSSSS!!! Friggiiiiiin' rights buddy! You got some good info in there even if it's all cute n hard to read because you're dickered on the liquor. By all means, report it and get er locked and moved or whatever you need to make you sleep better at night. I thought this was a good spot as it deals with liquids....

Quote:
Originally Posted by Bacon117 View Post
I wouldn't worry so much. A lot of it comes down to the Ethanol content. Stoich for ethanol is 8.x:1, while E0, or gasoline is 14.7, so the more ethanol you have, the more fuel will have to be pumped into the engine to maintain stoich.

Knock correction is affected by so much, ambient air temp, fuel octane level, ambient humidity, and how many leaves or dead birds are on your TMIC. The corrections, short and long term are there for this very reason. I would have a hard time concluding that one fuel is better than the rest simply from the corrections in the ECU. There are SO many other variables that are changing, it's impossible to say it's all in the fuel.

If you hear knock, and the knock corrections are maxed out, then I would worry. You should get a CEL if this happens.
Thanks for that. I do probably worry way too much. It was more of an interesting observation for me and I wanted to share. I like learning how it all works, it's interesting to me. I'm definitely staying away from Shell in WA state, even if the ECU is doing it's job just fine. I just don't like feeling those flat spots.
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Old 05-21-2012, 10:27 PM   #11
Uncle Scotty
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Quote:
Originally Posted by meebs View Post
Holleeeeee ****!!! ELLLIPPPSEEEEEESSSSSSSSS!!! Friggiiiiiin' rights buddy! You got some good info in there even if it's all cute n hard to read because you're dickered on the liquor. By all means, report it and get er locked and moved or whatever you need to make you sleep better at night. I thought this was a good spot as it deals with liquids....

d000000000000000d....your head is so far up your ass you couldnt smell the beer if you were drowning in it

and.......I have not knowingly consumed any ethanol in many years.

and at least i didnt waste my time(and everybody elses) with this thread
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Old 05-22-2012, 08:27 AM   #12
rex.effect
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Quote:
Originally Posted by Uncle Scotty View Post
d000000000000000d....your head is so far up your ass you couldnt smell the beer if you were drowning in it

and.......I have not knowingly consumed any ethanol in many years.

and at least i didnt waste my time(and everybody elses) with this thread
ya, unsubscribed
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Old 05-22-2012, 11:11 PM   #13
meebs
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Join Date: Dec 2000
Chapter/Region: NWIC
Location: Lake Tapps, WA
Vehicle:
2009 WRX Hatch
DGM

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Quote:
Originally Posted by Uncle Scotty View Post
d000000000000000d....your head is so far up your ass you couldnt smell the beer if you were drowning in it

and.......I have not knowingly consumed any ethanol in many years.

and at least i didnt waste my time(and everybody elses) with this thread
Then stop crying and report it! The irony is almost too painful. If you don't want to participate in a discussion, then don't? OHH **** I FORGOT ABOUT THAT POST COUNT THING.......

Don't worry I'll report it so it can be locked down and you and everyone else's time will be spared.

and.....on my second tank of 76 and still all zeros.

and......ELIPSEEEEESSSS!!
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Old 05-23-2012, 01:18 AM   #14
Uncle Scotty
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