Adjusting the AFM?

[spud814]

I heard from my dad's friend that u could adjust the AFM with a HEX key to make it run a little bit leaner and it's a great performance gain. He says the knob is covered with a plastic cap to prevent the US owners to adjust it. He tells me that the Euro cars had it adjusted at different settings to have better power. But he told me not to adjust it myself and have a knowledgeable mechanic do it that has the right equiment, because he told me that he fried a AFM back in the day by adjusting it himself on his car. But he makes it sound like a mod that u must do that will make the car run a lot better with better gains, what do u guys know about it?

[mspiegle]

you won't get much of anything unless your car is horrible tuned. and going leaner will lose power, not gain.

in short, i have 172K miles on my car, i've never adjusted that thing, and my car runs just fine and pulls pretty damn strong and smooth. i wouldn't worry about it, get a jim c chip

[modifiede30]

The adjustment you are mentioning under the plastic cap, if not mistaken, is used to adjust the mixture at idle, and not for anything else. In order to adjust the ratio more accurately, you need to unseal the black box and make the adjustments inside. Not extremely difficult but I'm not sure its really worth it.

[Spaz]

the adjustment under neither the blue cap on the afm, if my memory serves me right it only controls, "co" or carbon monoxide at idle, which i do not see how it could give you any performance gains.

i hope that helps.

[spud814]

Well maybe my dad's friend doesn't know what he's talking about. But he did do it to his car, but he sold it years ago so i couldn't drive it, so i don t know what to say. thankz guys for all the help

[diegom6]

runing it lean and gaining more hps at the same??? :roll: impossible!! more power measn more gas need, not less... also, if you want to improve the your bimmer, get a m30 big AFM...

[modifiede30]

If you're going to adjust the A/F ratio, it doesn't make sense to do it with stock components. Get the m30 AFM and larger injectors and it will make sense to do it. Otherwise, you're likely to get the car rich or lean and this sorta defeats the purpose.

[shadowracer]

You can possibly gain a little something by leaning it out a little, I gained 8hp in doing so, and have the dyno sheet to prove it. More fuel is good if you're forcing more air in (turbo, superchrgr, or N2O). On my first run on the dyno, with stock afm, and inj. using a bav-auto chip, bav-auto headers, B+B triflo cat back, and a rising rate fuel press. reg. set to the directions, it ran so rich it dropped off of the wide band O2 graph on the screen, with a little playing around, and leaning out there was an 8hp gain at the wheels. I'd recommend if you are going to try leaning it out, get an adjustable fuel regulater. You can leave the AFM alone. The idle the press. should be around 40-45lbs. (stock) according the reference manual I used. I installed a fuel press. guage to verify that, we then, after doing our playing around, lowered the press. to 20-22lbs. at idle and achieved the 8hp gain. You SHOULD find a way to check that it isn't too lean cause this can, and usually does cause damage to an engine, most commonly starting with burning a hole in a piston. Hope this helps :)

[RedBaron86325]

it ran so rich it dropped off of the wide band O2 graph on the screen, with a little playing around, and leaning out there was an 8hp gain at the wheels.

It worked for you because you were running way to rich. You just brought it back down to normal levels.

[shadowracer]

it ran so rich it dropped off of the wide band O2 graph on the screen, with a little playing around, and leaning out there was an 8hp gain at the wheels.

It worked for you because you were running way to rich. You just brought it back down to normal levels.

It wouldn't make sence to have been brought down to normal levels if my friends E36 m3 had the same problem, and was completly untouched 100% original. While yes these are 2 different cars, and engines, we got his car to put down 205 rwhp, and it was putting down less before. According to the guy who owns the dyno, he told us that some manufacturers make a car run a little rich for drivabilty puposes. Who knows though maybe my car was brought back to normal levels? Considering certain perameters were checked before hand, we did believe that the car was at normal levels to begin with.