280zjoel Posted September 28, 2009 Share Posted September 28, 2009 Ive been doing some research on how to read the Air Fuel Ratio on for the purpose of filling my brain with more info:hs: and I was wondering if anyone can chime in and let me know if im on the right track with this, So far I have found out that: Stoich is 14.7 to 1 Anything lower than 14.7 to 1 is considered Rich Anything Higher than 14.7 to 1 is considered Lean Running Lean(on Turbo engines) cause Detonation A.K.A NO BUENO:fmad: Running Rich Just burns alot more fuel and tends to run cooler than normal You want to be somewhere around 11.5-11.0 to 1 AFR @ WOT Am I somewhat on the right track? Any Other Tips on would be nice. Quote Link to comment Share on other sites More sharing options...
DeleriousZ Posted September 28, 2009 Share Posted September 28, 2009 Depending on how efficient your cooling system is, you can venture towards the 12.0 side of things at wot runs, just make sure your fueling system and wastegate are top notch to prevent any overboosting or unexpected lean conditions as well. Quote Link to comment Share on other sites More sharing options...
trwebb26 Posted September 30, 2009 Share Posted September 30, 2009 http://www.innovatemotorsports.com/video/moto_0002/sniffer_content.html Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted October 6, 2009 Share Posted October 6, 2009 The A/F ratio range that is acceptable for turbo cars is completely dependent on the engine/turbo/intercooler as well as octane, etc. Rotaries usually stay at 11.0 or richer, whereas a high octane 4G63 can hang (and make best power) upwards of 13.0. To be honest, most tuning stuff is left to tuners and no "rules of thumb" are given due to variations of the particular vehicle. I continue to be surprised by ppl that publish target A/F ratios for turbos. 14.7:1 is indeed stoich, but some cars run somewhat leaner (in cruise) for fuel economy, somewhat richer for high rpm cooling, quite a bit richer for normally aspirated full throttle and in the ranges we discussed for high boost turbos. Watch enough youtube vids of the big posters on here and you'll see a wideband in the corner showing you what they run at. L motors typically run around in the 11's. Be aware that the extra fuel is for cooling purposes to defray detonation. At the same time, the more timing you use, the more the combustion process is occurring in the actual combustion chamber. This increases the heat that is soaked into the engine (which causes detonation). Therefore, most turbo platforms can run richer/more timing or leaner/less timing and anywhere along that sliding scale. Most platforms are identified by tuners as demonstrating a typical sweet spot along the scale. Rotaries are very far toward the rich/retarded end of the range and 4G63's are more toward the lean/advanced end of the range, etc. I have personally found L-motors in the middle, but I never tuned a big range of L-motors during my full-time job as a tuner and my own car runs high octane since I have not had a massive amount of time to dial every last bit out of 17 psi on a stock L28E. Quote Link to comment Share on other sites More sharing options...
280zjoel Posted October 6, 2009 Author Share Posted October 6, 2009 Cool, thanks guys for the info. It really helps out Quote Link to comment Share on other sites More sharing options...
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