My N/A air to fuel numbers

[DrK MrK iV]

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.

 

[Go HoTO!]

Sounds a little rich. I would say maybe as much as 10 hp based on your mods, but probably more like 7-8 hp. Worth a dyno tune, not likely for the cost.

My Ford guy tells me many run rich from the factory. Better rich than lean, I guess. Your car might respond much better with the timing advanced with it being rich.

Go to www.modulardepot and post this question under the SCT pre-order question section. If you have your dyno graphs, these guys could make a custom tune program for you that might really help which would be used with an SCT chip or flash programmer.

 

[DrK MrK iV]

Alright, I'll register with them tomorrow. I plan on getting an Xpipe (probably O/R). I hear those make you run even more rich. Would a dyno tune then be worth it? The only other bolt on mods I can think of are pullies, x pipe, and perhaps the MAF-TB pipe (from densecharger or something).

 

[Go HoTO!]

Most guys with lightly moded cars like yours are only disappointed with their dyno tune results. If you were to add a C&L MAF, cams, blower, or something like that, then a dyno tune would be needed.

SCT mail order custom tune is really VERY good. They have data on thousands of combos. And they can be tuned later by a dealer with a dyno. I have the SCT programable flasher with three stored programs (including stock). If you add a mod that would require an adjustment, for about $75, they can give you a different program. You either ship to them to be downloaded (the programer) or they can email to you if you have the correct setup.

Check out the "Racers Package". More than you need probably, but fun to read about.

 

[lwkauble]

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.

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.

 

[DrK MrK iV]

It was a mobile dyno, and it said under load. I do plan on getting cams within the next year. Would a MAF really help me out? I know they just lean that **** out. I guess I need to lean it out more though. Do I have a weak car, or is it just not tuned at all.

 

[BlackBadGT]

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.

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.

 

[jas142]

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?

 

[XStanger]

My 04' GT has the same issue with the a/f ratio. I was in the low 11's throughout the rpms all the way to 6k. The dyno guy said I had the a/f that a blower car should have.

 

[smokin'Red35th]

can someone explain the ratio to me? take 13:1 for instance, what is the 13?

 

[03gtmustang]

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?

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]

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.

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.

 

[03gtmustang]

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.

Thats what I thought, I was thinking about putting my stock plenum or filter back on so I could stop running lean until I get my tune.

 

[BlackBadGT]

can someone explain the ratio to me? take 13:1 for instance, what is the 13?

13:1= A:F
13 parts air per one part fuel.

 

[yellow5.0cobra]

Tuning shops provide you the chip...

Thats why it cost about $450 to DYNO TUNE you the chip.

After you buy the chip the first time thru the dyno tune, additional tunes to add ons are only about $225 or some nonsense like that.

 

[Joel's98GT]

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.

absollutly agree with you, theoretically 14.7 is perfect, but because of air and fuel density, temp, and individual cylinders can vary. It's not safe to even get close to 14.7 most NA guys tune to 13.5-13 and many PA like to stay south of 12.5, on spray or boost a little detonation a can go a long way toward buying new pistons, among other things.

 

[jas142]

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?

 

[jstreet0204]

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?

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.

 

[Joel's98GT]

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?

what jstreet said.

totally normal.

 

[DonLord]

My engine light came on after my plenum and t/b install. Got the codes read and it said I was running lean.

I have been battling the same thing.... my mods are in my sig, all done at the same time, are you running a similar setup?