DrK MrK iV said:I got my car dyno'd a few weeks ago. My air/fuel ratio numbers were in the high 10's/low 11's. My car is pretty much stock except for K&N/70mm mac tb, c&l plenum and catback. What do I need to do to get this to normal. N/A 04 gt should be in the 13's right? How much HP am I losing here? Pulls were around 230 to the wheels.
Absolutely not. 15:1 is lean for the 4.6 liters. Ideal for an na car is 13-13.5:1. 15:1 and he'll see some high-end detonation. On a forced induction car, 15:1 would be catastrophic. Go get a dyno tune. They can pull some fuel and add some timing.lwkauble said:Perfect comustion occurs at 14.7:1 (stoichiometric) so. if your car is in the 10s or 11s you'd have black smoke coming out of your pipes. way too rich dude. get as close to 15 as you can. but the question needs to be asked is: is that A/f ratio you posted @ idle or under load?? Find out what the a/f ratio is at under load. N/A under 14 for a non race motor is just wasting gas and hurting performance. You shhould be seeing a mil indicator at this point too. That is if you haven't disabled the mil. you'd be fouling the plugs at that point.
jas142 said:Ok guys, heres the question I always had because I fear that I am running rich as well. When you get a DYNO TUNE, you must also purchase a chip (like diablo for instance) for them to program the tune right? They can't "tune" it without a chip, correct?
03gtmustang said:I think you dont need a chip, at least I hope you dont. My engine light came on after my plenum and t/b install. Got the codes read and it said I was running lean. How long can I go runing lean before I start seeing problems? I think I am losing power also. Im planning on getting a tune this summer.
jas142 said:Running lean is much more dangerous then running rich. When you run lean you risk damage to the engine, I would get it tuned ASAP. When you run rich you just lose power, risk fouling spark plugs, and lose gas mileage.
13:1= A:Fsmokin'Red35th said:can someone explain the ratio to me? take 13:1 for instance, what is the 13?
BlackBadGT said:Absolutely not. 15:1 is lean for the 4.6 liters. Ideal for an na car is 13-13.5:1. 15:1 and he'll see some high-end detonation. On a forced induction car, 15:1 would be catastrophic. Go get a dyno tune. They can pull some fuel and add some timing.
If it was read at the end of the tail pipe that is about normal. When you are not under load the EEC is in closed loop and tries to keep the a/f at 14.7. with my wideband mine bounces back and forth between 14.0 and 15.5 reading atthe tailpipe would cause the reading to be a little leaner. So I think you are pretty close to what it should be.jas142 said:I got my AF read yesterday cause I was getting horrible gas mileage and it smelled rich. At idle its around 15.1:1-15.5:1, under heavy acceleration it dropped into the 12s. Is this normal?
jas142 said:I got my AF read yesterday cause I was getting horrible gas mileage and it smelled rich. At idle its around 15.1:1-15.5:1, under heavy acceleration it dropped into the 12s. Is this normal?
My engine light came on after my plenum and t/b install. Got the codes read and it said I was running lean.
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