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What AFR is normal from OTS Cobb St 2 maps?


SlightlyEvil

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Cobb Stage 2, v1.15 - what is a 'normal' AFR to see under full (WOT) load? Do the cobb maps aim for stoichiometric or do they run rich as a safety?

 

I will post up later, but stoichiometris when idling and low load/rpm.

 

EVERY TUNE will have richer then 14.7:1 for WOT part of the map, every tune!

 

Off the top of my head about 11:1 for WOT.

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at WOT and COBB ofs Stg1 i get 11.:1 all day. It not that accurate though because when i lift it shoots up to 20:4 which i think is because it only a close loop gauge.

Remeber the stock sensor will not read below 11:1...

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Ok so the 11.14-12.0 I get under full load is pretty normal. Just wasn't sure. Has anyone logged a stock LGT to see what the stock maps are at under load? I'm just curious how much of a richness "safety net? Cobb (and I guess other tuners) put in their maps. I'd imagine Subaru could get away with running it a bit leaner - especially with all the cats in the stock system?
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Ok so the 11.14-12.0 I get under full load is pretty normal. Just wasn't sure. Has anyone logged a stock LGT to see what the stock maps are at under load? I'm just curious how much of a richness "safety net? Cobb (and I guess other tuners) put in their maps. I'd imagine Subaru could get away with running it a bit leaner - especially with all the cats in the stock system?

 

12 is very lean, maybe not for 3000 rpm at peak torque, but after that it better lean out to low 11s pretty soon.

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mmmmm you're askin the wrong person. 14.7 is stoichiometric, which as I understand is ideal for idle/cruisin. Stock sensor won't read below 11.0 for me - sometimes it dips pretty far down pretty fast and then just flatlines at 11 until I lift. Logically 11-12 would be good at WOT I think - perhaps someone with a better sensor setup can talk about it with authority though and show what the AFR REALLY drops too?
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I didn't want to post COBB's maps, but here are some fuel maps, first is stock (05 LGT I believe), and the second is a stage2 map. Doesn't mean this map will work perfect for you, but it will give you an idea on the ballpark.

 

 

OEM fuel map

http://i248.photobucket.com/albums/gg194/littlebluegt/OEM05LGTfuel.jpg

 

 

Stage2 fuel map

http://i248.photobucket.com/albums/gg194/littlebluegt/stage2fuel.jpg

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Wow, thanks LBGT - very informative!

 

Pardon my ignorance - what program turns out a spreadsheet like that? I'd like to output with that detail...

 

Go to romraider, download the program, read the basic forums on tuning.

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The Cobb Stg2 Basemap that I started my ST tune from(05LGT_5MT_Stg2_91_Base) looked more like the top table LBGT posted when I started adjusting it. Maybe the Stg2/93oct map would look more like the bottom table.
Let's kick this pig!
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On pump gas you definately want to be south of 12:1 at peak torque or your asking for problems. I'm targeting more like 11.3:1 at peak torque and lean out to 11:1 from there.

 

I thought it was odd that COBB stage2 had peak torque at 11.8, I would have gone a bit richer then that.

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On pump gas you definately want to be south of 12:1 at peak torque or your asking for problems. I'm targeting more like 11.3:1 at peak torque and lean out to 11:1 from there.

 

Booster, is the difference between 11.3 and 12 really that substantial? How much of a difference does it make between 91OCT and 93OCT with regards to ideal target AFRs?

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Booster, is the difference between 11.3 and 12 really that substantial? How much of a difference does it make between 91OCT and 93OCT with regards to ideal target AFRs?

 

11.3 to 12 is a very big difference.

 

I don't think people will target that much different AFR depending on fuel going 2 octane points higher, I think most of the extra power would come from an extra degree of timing or so.

 

 

Looking at COBB's stage2 91 vs 93 octane maps:

 

93 octane they run about 0.1 point leaner, and about 1 degree extra timing.

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Ok, now that the nastiness has been cleaned out of the cars system I seem to be hitting 11.14 at peak torque but the reading just hits that and then flatlines staying solidly at 11.14 which points to the built in sensor being unable to read BELOW 11.14 (or above 20.33 since thats what it spikes to when I lift off) - is this true or does the stock sensor go below that and I'm just actually flatlining at that level for a sustained amount of time under max load?
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Ok, now that the nastiness has been cleaned out of the cars system I seem to be hitting 11.14 at peak torque but the reading just hits that and then flatlines staying solidly at 11.14 which points to the built in sensor being unable to read BELOW 11.14 (or above 20.33 since thats what it spikes to when I lift off) - is this true or does the stock sensor go below that and I'm just actually flatlining at that level for a sustained amount of time under max load?

 

The stock sensor can read below that, but the ECU will cap it at around 11:1.

 

Either way, as soon as there is considerable pressure on the exhaust manifold any O2 sensor will read incorrect (it will be farther from stych then it really is).

 

That is why you need an O2 in your exhaust stream post turbo to measure AFRs.

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Basically as soon as you hit the area around full boost your stock o2 sensor will peg to the rich side at 11.1:1. The actual requested AFR is usually programmed to be richer than that and will be achieved by the ECU. The problem is that the ECU will only allow us to log down to 11.1:1 from the OE front o2 sensor. Those of us with wideband o2 sensor installed in our DP's can get accurate AFR to 10:1 and below if needed.
Let's kick this pig!
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