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Anyone have link to a stock dyno with AFR's?
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04-03-2009, 06:22 PM | #1 |
Colonel
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Anyone have link to a stock dyno with AFR's?
Just learning about AFR's and how they work, and was wondering how they are for a stock map.
Saw some in another post for Dinan, and how they're running pretty rich (11's) above 4.5k, http://www.e90post.com/forums/showthread.php?t=241782 but saw some Procede ones on meth in the 15 to 13 range http://www.e90post.com/forums/showthread.php?t=225510. Learned a bit from this website http://www.bristoldyno.com/tech/airfuel.htm how lower AFR's are safer, but produce less power so I'm now starting to piece things together as to why some of the different tuning options give different power! Feels cool to learn this new stuff! |
04-10-2009, 02:14 AM | #3 |
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Hi, this is my car's stock dyno. Hope this helps.
http://www.e90post.com/forums/showthread.php?t=176108 Eric |
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04-10-2009, 05:31 AM | #4 | |
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04-10-2009, 06:30 AM | #5 | |
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04-10-2009, 03:39 PM | #6 |
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Two pulls in 4th gear on a 6MT135i with no tune. The only mod is the BMW performance exhaust.
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04-10-2009, 09:57 PM | #7 |
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Forget anything you read about normal port injection A/F ratios...our engines run direct injection that fully atomizes fuel droplets and creates a pure homogeneous mixture in the cylinder which facilitates much tighter control of mixture and means we can tune our cars to the lean limit and in some cases beyond perfect stoichiometric (14.7) safely.
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Former Car: '16 SUNBURST GOLD F80 ///M3--6MT/Carbon Cloth (ED Thread) Former Car:'13 SANTORINI BLUE E92///M3--6MT/Speed Cloth/ZCP(ED Thread) INSTAGRAM:@C2KMotorsports |
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04-11-2009, 08:45 PM | #8 |
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Thanks all for posting the stock AFR's. Interesting to see how close to the "perfect" 14.7 they are.
So you mean that by running rich, they would have been risking throwing codes, and ran stock-like AFR's instead? I'd have guessed they were running at the higher-than-flash-tuner-AFR's b/c they wanted to squeeze out all the HP possible... So you think now they'll start running richer than they have been to increase the safety margins? |
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04-11-2009, 08:46 PM | #9 | |
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04-13-2009, 10:15 PM | #11 |
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Because the closer to 14.7 you get the more unstable the combustion is...the combustion time is fastest at 14.7 thus leaving little error for timing variance.
Ideally you would want the combustion to start a split second before the piston reaches apex on the compression stroke and reach full combustion a split second after the apex of the piston (transition from compression stroke to power stroke) When you move away from 14.7 your combustion time lengthens which facilitates a larger amount of allowable error at the expense of power because the peak of the power produced by the combustion comes further after the apex of the piston depending on your timing setting. When flash tunes are dealing with the BMW computer, which is finely tuned from the factory for the factory settings, they want a large margin of error in higher RPM's especially when they are ramping up the boost because they are taking timing and boost pressure into their own hands. You will notice that piggyback tunes have near identical A/F's to stock because they are simply altering inputs to the computer algorithm, but the stock software is still operating under the same tolerances.
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Former Car: '16 SUNBURST GOLD F80 ///M3--6MT/Carbon Cloth (ED Thread) Former Car:'13 SANTORINI BLUE E92///M3--6MT/Speed Cloth/ZCP(ED Thread) INSTAGRAM:@C2KMotorsports |
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