Air Fuel Ratio

[rolyat]

I've noticed a lot of guys who mod their gtp's get wideband afr O2 sensors, and I was just wondering if it is absolutely necessary. I know running lean is dangerous, but wouldn't you have excessive KR if you're running lean?

[FoSHO99]

Not necessarily, you could run lean and still have no knock.

I would invest in a wideband if you are pushing around 300whp or going for 12's. But its really up to your budget.

[blowfishRus6]

i knocked a good bit with my canned intense tune when it was running really rich. made a commanded A/F ratio change and alot of the knock went away.

if your serious about tuning and would like to keep a check on it at all times, i would get a gauge. you can see what the fuel is doing via tuner, some dont even need a wideband to tune, but its not quite as accurate.

its something handy to keep an eye on.

[chrisb]

like what was stated above running lean wont necessarily cause knock. it will get you closer to the knock threshold. the correct afr has one of biggest impacts on how much if any knock a engine will see. its a delicate balance of afr, timing, and airflow. and other stuff if you want to get specific.

[rolyat]

okay, I'm not getting too serious with my car just looking to get around 250whp or so. I still don't know if I want to get hptuners or overkill but either way my afr shouldn't get so out of whack that I could justify buying one. I mainly just want to keep my engine safe.

[blowfishRus6]

well with out a tuner, if your A/F is off, you cant really adjust it. you would have to send your pcm off and find someone with a tuner.

a tuner really pays itself off in the long run.

[rolyat]

well with out a tuner, if your A/F is off, you cant really adjust it. you would have to send your pcm off and find someone with a tuner.

Very true.

I'll probably get the wideband if I go with the tuner and just won't get it if I go with the Overkill pcm.

[Bio248]

an m90 car running at 12.0:1 AFR with a bunch of boost knock free is FAST.