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View Full Version : What should be the AFR value at WOT for a NA engine?


ulmi
02-12-2016, 06:31 AM
Hi guys, I've just installed a wide band sensor, and I'm guessing what should the AFR be with OEM software?
I want to be sure everything is correct before getting an alpha n tune or something like that.
Engine is stock, just custom exhaust setup and air intake.

Thanks!

I made a little test drive video:
http://youtu.be/L1f9WLTmvTc
1215
02-12-2016, 09:26 PM
No idea exactly what BMW targeted as stock. Trying to figure that out myself.
I'd imagine your WBO2 would read somewhere in the mid to high 14's (and then the ECU/DME would compensate from there (if it has these features: altitude, common country fuel additives at time of production, etc.)

https://en.wikipedia.org/wiki/Air%E2%80%93fuel_ratio

What type of fuel are you running? I have never checked on an e36 however I used to have an e30 running a WBO2 and I saw a huge difference between regular pump, premium pump and non-pump E0 (91 octane, 0% ethanol).
328 Power 04
02-12-2016, 11:02 PM
I'm no expert tuner, but I have seen quoted for full throttle its is around 13:1 minimum, but highly dependent on the engine.

Excellent sounding S54. That makes me want to hunt for one for a swap.
digger
02-13-2016, 04:00 AM
WOT anywhere from 12.5-13.5 is pretty safe and normal. some run a bit leaner like 14:1 at low rpm and richen up to 12.5:1 or there abouts and some engines run richer like 12:1 at the topend to keep the combustion chamber a bit cooler but it gives up power when youre this rich.
ulmi
02-13-2016, 02:03 PM
Yes the S54 sounds good :)

I get a little over 14all the time at WOT, it goes to ~12 just before the rev limiter.
I run only with 98 RON fuel (wich equals to 93-94 of US octane).
hide1
02-22-2016, 04:40 AM
WOT anywhere from 12.5-13.5 is pretty safe and normal. some run a bit leaner like 14:1 at low rpm and richen up to 12.5:1 or there abouts and some engines run richer like 12:1 at the topend to keep the combustion chamber a bit cooler but it gives up power when youre this rich.

Based on what my tuner was saying 13.5 may be too high. He stated optimal/ what he likes to see at wot is 12.5- 13.2.