AFR's
09-13-2009, 11:01 AM
#21
AFR @12 running 12psi and 500hp. You can run it leaner but it is your engine
OT question: do you have a problem starting the car when its warm-hot? mine wont start until it cool down.
09-13-2009, 12:06 PM
#22
Never a single problem starting my car; it always fires up like stock hot or cold. I'm running 440cc's and a fuel return.
So what do you guys think about retuning it to run mid to high 11's under boost? It was running mid 11's originally as you can see:
So what do you guys think about retuning it to run mid to high 11's under boost? It was running mid 11's originally as you can see:
Last edited by djamps; 09-13-2009 at 12:09 PM.
09-13-2009, 12:34 PM
#23
u think u are rich at 12 a/f at 12psi
....that s right where u wanna be if not a little richer..most try to get as close as possible to 11.8 full boost, anything over 12 is lean at full boost, and honestly at full boost id call 12 lean
Last edited by tylerxfire; 09-13-2009 at 12:36 PM.
09-13-2009, 01:28 PM
#24
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I am just passing the info from Sam at GTM. Not really rich at full boost but it is rich on the lower end . Just better off rich than lean especially on a stock motor. The car takes a few seconds to start if I have been running threw town and stop for a few minutes. driving around town afr is somewhere around 15:1 and with a white car it tends to leave a nice black film on the back.
09-13-2009, 01:42 PM
#25
i think that tune looks pretty good actually, for a few extra horsepower why risk it id say, that seems like a safe but not too safe tune and right about where u want it especially for a stock block at that power level already..i mean yes it could lean out a little more and still be safe but really not much...
09-13-2009, 03:04 PM
#26
i think that tune looks pretty good actually, for a few extra horsepower why risk it id say, that seems like a safe but not too safe tune and right about where u want it especially for a stock block at that power level already..i mean yes it could lean out a little more and still be safe but really not much...
The current tune I described in the OP (I don't have a dyno chart from it but I explained the AFR I see).
The *original* tune you can see in the graph above.
09-13-2009, 04:17 PM
#27
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I am just passing the info from Sam at GTM. Not really rich at full boost but it is rich on the lower end . Just better off rich than lean especially on a stock motor. The car takes a few seconds to start if I have been running threw town and stop for a few minutes. driving around town afr is somewhere around 15:1 and with a white car it tends to leave a nice black film on the back.
15:1 is very lean so it shouldn't leave black on your bumper. The higher the ratio the leaner the mixture. I guess it could leave residue on your bumper if your pipes aren't all the way out from the car.
09-20-2009, 08:41 AM
#29
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whats the black stuff?
Well I hooked the computer to the car this weekend to check afr's and as posted before I am between 11:1 and 12:1 at boost. cruising is 15:1 to 13:1. Which from what you guys are saying is a good place to be and not really rich. the question is why is the back of the car covered in black sh__ ! here is a pick.
Last edited by fla350tt; 11-27-2009 at 10:20 AM.
09-20-2009, 09:34 AM
#30
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Well I hooked the computer to the car this weekend to check afr's and as posted before I am between 11:1 and 12:1 at boost. cruising is 15:1 to 13:1. Which from what you guys are saying is a good place to be and not really rich. the question is why is the back of the car covered in black sh__ ! here is a pick.
Yours really isn't that bad. You should have seen what mine looked like before i tuned and it was sitting low 10:1 af....lol, THAT was horrible.
09-21-2009, 12:48 PM
#33
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no cats either. I was talking to adam @ z1 and he said that putting in some good high flow metallic core cats would eliminate most of the black stuff.
Last edited by fla350tt; 09-21-2009 at 12:50 PM.
They do make the car smoke and fume free though. The driveway behind my car has 2 black streaks from the soot from starting from the same place every morning.
09-21-2009, 02:25 PM
#36
09-21-2009, 02:55 PM
#37
How much you have to richen the fuel mixture really depends on your engine and your goals. Just because one guy is running an AFR of 12 does not mean that you should. He may have a lower compression ratio than you, in which case he will be able to run a little leaner to achieve the same internal temperature as you. If he has higher compression than you, he will need to run richer that you to get the same internal temperature.
imo, that AFR looks pretty good. You might be able to lean it out a bit, but you will reduce the margin of safety between normal operation and the onset of detonation. Also, you may need to pull the timing back a bit, depending on how much margin you have. I would discuss this with your tuner before making any changes.
EDIT: I just looked at your dyno graph again. I think the tune looks d@mn good. Whoever at AAM tuned it knows what he is doing. Again, speak with that person before making changes to your tune.
EDIT EDIT: I just went back and re-read the threads. I see that the dyno that is posted is your previous tune and not your current tune. Again, that dyno graph looks good. Did you ask them why they lowered the AFR this time around? If so, what did they say? Was it the same tuner?
Last edited by ttg35fort; 09-21-2009 at 03:27 PM.
09-21-2009, 03:03 PM
#38
cats will rob u of power and they will eventually fail ...trust me ...i went thru 2 pair of metallic high flow cats, and now with test pipes i made much more power also...i had 394whp with a very conservative tune and now am at close to 425whp with test pipes and little more aggressive tune but still a safe tune...they suck!!! end of story and with my motordyne xyz w/resonator has no rasp and ive personally never heard a better sound..nice and deep, if anything id do test pipes and a motordyne xyz w/cat over just running high flow cats that will eventually fail ...
Last edited by tylerxfire; 09-21-2009 at 05:54 PM.
09-21-2009, 03:04 PM
#39
[QUOTe The driveway behind my car has 2 black streaks from the soot from starting from the same place every morning. 
[/QUOTE]
i have nothing like that, could be your tune is too rich on a cold start? my tailpipes dont even get black or anything...if i go a while without washing my car i get a little bit of a haze just above tailpipes on my bumper, but nothing anyone would even notice and thats only if i go without washing for a few weeks it will start to do so
[/QUOTE] i have nothing like that, could be your tune is too rich on a cold start? my tailpipes dont even get black or anything...if i go a while without washing my car i get a little bit of a haze just above tailpipes on my bumper, but nothing anyone would even notice and thats only if i go without washing for a few weeks it will start to do so
Last edited by tylerxfire; 09-21-2009 at 03:07 PM.
09-21-2009, 07:35 PM
#40
Seriously, it doesn't happen to everybody with FI and test pipes? Hmmm... I'll have a look. I haven't had a problem with hot or cold starts so I'm leary about taking away fuel for startup, but I guess it wouldn't hurt anything to try... It takes my widebands about 15 seconds to warm up and by that time, the AFR reads 14-15.