Now that MS is working in the Fiat, it is time to really nail down the AFRs. 13.2 is where I want to be high in the RPM range, correct?
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Aug. 31, 2008 12:42 a.m. m4ff3w Dork
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Aug. 31, 2008 7:28 p.m. Hal HalfDork
I think that would be a minimum. I would be happier (feel safer) with 12:1.
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Sept. 1, 2008 10:08 a.m. m4ff3w Dork
Really? 12:1 on a NA engine?
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Sept. 1, 2008 12:17 p.m. bluej Reader
I always remembered hearing that about 12.5:1 was powerfull but safe for an NA. please take with a huge grain of salt.
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Sept. 1, 2008 12:31 p.m. dan_efi New Reader
My stock compression (9.2:1) 2.0L SOHC 8-valve Ford engine has no issues at 13.5 AFR. I have ran it as rich as 11.0 but that was only a safe tune until I could concentrate on whittling it down to where I wanted. It is a very tough engine though and I haven't pushed the timing advance too far yet.
I'm not familiar with Fiat engines, but I would think 13.2 would work great but you may want to work your way towards that as I did. Get a safe tune, then keep leaning out whatever part of the datalog happens to be richest until your whole WOT pull is where you want it. I like the VE analyzer in MegaLogViewer but you really have to run a pile of datalogs through it to narrow down your table. Setting "Cell Change" to hard or very hard will prevent overshooting the VE values. A few datalogs and a calculator can accomplish the same thing if you are comfortable with that.
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Sept. 1, 2008 1:26 p.m. MadScientistMatt HalfDork
Our usual rule of thumb is between 12.6:1 and 13.0:1; this seems to make best power and is a safe place to be on an NA car.
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Sept. 3, 2008 8:12 a.m. Paul_VR6 New Reader
I always tune customer cars to 12.5:1 until I hit the dyno.
