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2010 Forester XT Automatic
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575 Posts
Discussion Starter #1 (Edited)
I just bought STG2FXT's car and in the process of driving it back across the country. Once I crossed into Missouri, the max octane shifted down to 91. Charlie has the AP set at Cob Stg 2, 93 oct. He gave me the AP as well, so I can change the map if needed. However, given that I am in a hotel in Oklahoma City, I really don't want to risk f*ing things up mid-way through my drive back to SF.

I am now on my second tank of 91 oct, and am noticing lag in the power, but no bad detonations. I still have another 1600 miles to go, so I am looking at 6-8 tanks of 91 oct until I get home.

What are the detrimental effects of continuing to run the 91? Does anyone feel like walking me through a map update to 91 oct? My smart buddy is currently in SF, and has not played with an AP before, so he is not helpful in this case.

Thanks.

edit: It was brought to my attention that I am an idiot. 2004 FXT Manual.

I just went out to switch the maps, and it said 'done', but it's still on the 93 map. This is a really stupid question, do I need to have the car in diagnostics mode?
 

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2008 FSXT M/T
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4,167 Posts
what year is your car and which cobb ap do you have v1 or v2? if its a 04-05 you need to put the car in diag mode using the green plugs above the brake pedal b4 you flash it...

if the map is meant for 93 just dont goose it and drive normal youll be fine...
 

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Premium Member
2004 FXT MT Cobb Stage 2
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858 Posts
I just went out to switch the maps, and it said 'done', but it's still on the 93 map. This is a really stupid question, do I need to have the car in diagnostics mode?
When you switch maps, it will still show the base map that is loaded. The 91 octane map will remain in effect until you switch maps or reset the ecu. An ecu reset reverts to the base map. You only need to enter diagnostic mode to change base maps.

Disclaimer: This is how it works on the AP V1. It may be different on the V2.
 

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2010 Forester XT Automatic
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575 Posts
Discussion Starter #5
When you switch maps, it will still show the base map that is loaded. The 91 octane map will remain in effect until you switch maps or reset the ecu. An ecu reset reverts to the base map. You only need to enter diagnostic mode to change base maps.

Disclaimer: This is how it works on the AP V1. It may be different on the V2.
that's it, becuase it felt a bit smoother just a few min ago when I drove it around. Less umph, but better.

I have the AP1, btw.

Has anyone run the economy map? how much better does it make mileage? I'm driving across the country, so I don't need umph, so much as distance.
 

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2017 VW Golf SportWagen 5MT
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10,784 Posts
Not sure if v1 AP is the same, but with v2 you have to options -- to switch to a different map in "real time" 'till you turn the car off, or reflash a new map to the ECU. You want to reflash the 91ACN map to the ECU.

I don't use the economy map. Just run the regular map for whatever octane is available and drive smoothly, you'll get close to 24MPG on the freeway.

Stan
 

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2004 FXT MT Cobb Stage 2
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858 Posts
Has anyone run the economy map? how much better does it make mileage? I'm driving across the country, so I don't need umph, so much as distance.
I tried the economy map for one tank out of curiosity. I ended up getting about 1 mpg less than stage 2.
 

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2010 Forester XT Automatic
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575 Posts
Discussion Starter #8
Glad this was sorted. Texas and NM don't have 91 octane... 90
only. Did find that the reservation/casino gas stations have 91 though.
 

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05 XT 5MT
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308 Posts
Here in WA, OR, we have 92. would the 91 map be the best or should we run the 93?
 
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