stoich a/f ratio

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Sep 24, 2005 | 03:02 PM

Recon12thman

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stoich a/f ratio

whats a good stoich a/f ratio for a n/a with oversized injectors headers and intake and exhaust

Sep 24, 2005 | 03:30 PM

slow

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unless you change the fuel, you do not want to chance stoich ratio.

On gasoline, it is near 14.6x

Ryan

Sep 24, 2005 | 03:35 PM

Recon12thman

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ok thanks what about the maf tables im usin hp tuners

Sep 24, 2005 | 03:37 PM

slow

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You want to first determine what your commanded air fuel ratio you want to run, then set that into the tables that effect the commanded air fuel, the open loop, and the PE tables. Then you want to adjsut the airflow characteristics to get the fueling correct, depending on your setup, beliefs, or tuning style, this will be altering the VE tables and/or the maf transfer function.

Ryan

Sep 24, 2005 | 03:46 PM

Recon12thman

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ok thats where ii get lost i enriched the system through the pe table and some people say timing is a good thing to do here as well so what shouldi do

Sep 24, 2005 | 03:46 PM

Recon12thman

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ive also already adjusted the ifr table for my 42 lb injectors is there anythin else i should do

Sep 24, 2005 | 05:09 PM

slow

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After setting the ifr tables, you will want to dial in your VE and/or Maf table to get the part throttle fueling correct by the fuel trims, then you will want to get the wot fueling correct, but need a wideband for that.

After airflow it correct, which should result in correct fueling as well, then you can tackle timing.

Without proper airflow, your timing will be wrong.

Ryan

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Sep 24, 2005 | 07:00 PM

slow

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you need to get data from the vehicle, you want to get your fuel trims as close to 0 as possible. Some this might only take a small change, others might be a huge change.

Ryan

Sep 24, 2005 | 08:49 PM

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Recon12thman

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ok what method did you use the ltft + stft or just the stft stand alone method and how long did it take you to get it all smoothed out

Sep 24, 2005 | 08:59 PM

#11

slow

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I always turn off the longterms, and then tune from there.

Time really depends on your motor combination. The current tune in my car consists of 20 minutes of tuning on a mustang dyno to get the upper maf dialed in, and about 1 hour of street driving for the VE table.

Ryan