I'm going to be installing an SAFC on my s4 N/A tomorrow, and I'm going to be wideband tuning it tomorrow evening. Just curious, what AFR's would constitute a "safe" tune for an N/A rotary?

The only thing done to this N/A is the TB-mod and true-dual (full) Racing Beat exhaust.

~Erik

 

Stock NA's run rich so you have room to gain power by leaning back some.
You're not changing timing, so 12.5-13 from the high map works nicely.

 

I've heard 13.2:1 is good for power. I THINK that's what Chris Ludwig said.

 

honestly if you keep timing near stock and the car is running properly and maintained, almost anything is safe. tuning my car i have gotten all types of AFRs. i have seen close to 14.0 at full throttle and nothing bad happened.
i have tuned for around 12.7 to 13.0 as i feel that is giving me the best power, although it is hard to say without a dyno.

for highway cruising you don't need any richer than 14.7. keep going leaner until driveability is affected. i end up at about 15.0 to 16.0 on cruise.
for middle-load, such as half throttle, about 14.0 to 14.7 works good for me.

one thing to keep in mind is get the car fully warmed up and drive HARD for at least 15 minutes before tuning. your car might initially read rich on the wideband after start up but you want to get the car up to full temp so all ECU temp corrections are stable.

 

yep, my thoughts too...

the couple ive played with still had cats, so i've left it alone at cruise, and leave it a little richer @wot, the power difference between 12.5 and 13.2 is small...

 

Great answers guys. That was exactly what I needed.

 

i would shoot for low to mid 13's at WOT, mid to high 14's for cruise will be where you can gain a bit of mileage.

tuning on the highway can be done by feel, you should be able to tell what the car is telling you, going into the 15's the car probably will start to lose momentum and need more throttle to keep going so peak your AFRs to where the engine has it's best momentum curve and requires the least amount of throttle to maintain speed.