Is there any direct advantage to higher AFR or just a sideaffect of tricking PCM?
Question:
If the reason for using a piggyback or mapclamp is to trick the PCM into letting you boost higher and having higher timing levels (up to KR anyway), what is the advantage of the higher AFR, is there is any? Or is it just a side affect of the clamp and the PCM thinking there is lower boost and giving fuel/timing for that level?
The higher the AFR the more prone the car to Knock/Detonation right?
Or is there an advantage in the mix being lighter and has anyone proven this?
like a standalone car running AFR of 10.5, 34degrees advance and 20psi VS
a clamped car, AFR 12.0 running 34degrees advance and 20psi?
I did sooooo much damn searching for this and found a one or two pretty old posts with people arguing about it but can’t seem to find them again if anybody has them that would be great…
Hey thanks for the reply but not really what I was asking… question is: Is there any direct advantage to higher AFR or just a side affect of tricking PCM? So everyone (should) know that when you pull fuel (give the PCM lower map bar voltage) in order to trick it into higher timing levels (or not pulling timing) for your boost level (everyone should also know that KR is something to monitor…) But the question is there any directly related advantage just from the higher AFR other then the side affects of increased timing levels… All other things considered if you leaned the car out with out increasing timing at all would you make any more power with the leaner A/F mix?
I’m just looking for a definitive answer, it seems to me you would not and it’s just a side affect (the PCM thinking your boosting lower) and something to monitor.
Why does everyone say to turn for a set AFR it does not make any sence since, wouldn’t you make more and safer power by increasing the timing without affecting the fuel levels? (For example Stage2 from Mopar makes, so they say, 20hp more with HOM engaged then without it, and it does not “lean” the car out at all and yes I know the only way to do this is a standalone..but...)
So its stands to reason that leaner AFR does NOT = more power (like you said, and I know this) I’m just wondering why everyone always says: “oh shoot for this AFR you’ll get more power” when this it most defiantly is not always the case. (and if fact its not the AFR that is making more power that is a SIDE AFFECT it’s the timing that is making the extra power..)
But then if a lean mix does not = more power (apart from the increase in timing) why do all the “tuner” that “know” what they are doing always, always shoot for a AFR of 12.0 – 12.5, all things be equal (no knock ect ect ect)
Just like to know HOW things work....and I know that there are some lines of thought on this...
Last edited by ToMuchBoost : 10-12-2006 at 12:28 AM.
leaning out is a way to gain timing, theres i a safe target limit (11.5 and 12.5 with w/i).
let me put it to you this way on same boost levels my friend with only k&n intake, down pipe w/ cut out, agp wga, safc could hang with me right on my front fender when i had BFMIC, 3"o2, 3"dp w/ cut out, agp waste gate, 62mm tb and spacer, walbro fuel pump, jmb 3" ultimate intake, and an afr of 10.0 - 10.5 but when i got my ftm and tuned the car to hold steady 11.5 i walked him. so leaner mixtures within safety parameters does make power.
leaning out is a way to gain timing, theres i a safe target limit (11.5 and 12.5 with w/i).
let me put it to you this way on same boost levels my friend with only k&n intake, down pipe w/ cut out, agp wga, safc could hang with me right on my front fender when i had BFMIC, 3"o2, 3"dp w/ cut out, agp waste gate, 62mm tb and spacer, walbro fuel pump, jmb 3" ultimate intake, and an afr of 10.0 - 10.5 but when i got my ftm and tuned the car to hold steady 11.5 i walked him. so leaner mixtures within safety parameters does make power.
Because of the increace in timing, not becasue its leaner...!!!!! being leaner as far as i can tell is a SIDE AFFECT!!!!!!
No offence to you man and thanks for the attempt it is a nice gesture...
But god damn can't people read? I know this, I know, I know, I know all of this and this is not what I'm asking for. (Me beating my head against the wall.)
Question: the question: is there any directly related advantage just from the higher/leaner AFR OTHER (<--OTHER OTHER OTHER ) then the affects of increased timing levels.
Anyone that knows a technical reason why/why not>>> *(NOT looking for a Parrot response about timing I KNOW THIS)
So if you could run a 2cars all else totaly equal SAME TIMING LEVELS would a leaner AFR result in any more power? more Efficient power or anything?
If not why do people always talk about their damn AFR all the time when really they should be talking about timing/boost/EGT/KR levels! Because, if AFR being leaner is just a SIDE AFFECT then why talk about your 12.0 AFR making more power, IF ITS NOT THE LEANER AFR BUT it's the increase in timing, boost, good AIT temps, ect ect ect ect that is making the power and the leaner AFR is just something your monitor and try to negate
Last edited by ToMuchBoost : 10-12-2006 at 02:59 PM.
With my big turbo, and dtec, it doesn't really matter if I pull 25% or 10% fuel, I always get the same timing within a couple of degrees... And being leaner does make a HUGE difference. On my last dyno, I had a rich spike at about 4500-4800. Going from a 11.6 down to a 10.2, and then back up. I lost 30lbs/tq when the car went rich...
With saying that, my timing on those 3 runs was always consistent. My car didn't suddenly retard timing because it saw 21lbs of boost like you might be implying due to me going rich and not pulling enough fuel out at that rpm window. I lost power because my car went too rich.
I will tell you this. Pure AFR will help, I've tuned and watched enough cars being tuned with standalones to see it. Literally with the standalone, keeping the timing the same and increasing the AFR from 10.0 to 11.0 will result in an increase in power on the dyno.
My assumption (and what others have described as well) is that this occurs simply due to the laws of thermodynamics (I believe its the 1st one but don't quote me). Essentially this law says heat, internal energy, and work are all related:
As you lean out the AFR you are effectively creating more heat inside of the cylinder(s). This extra heat translates directly into extra energy and in our case more work(torque).
I will tell you this. Pure AFR will help, I've tuned and watched enough cars being tuned with standalones to see it. Literally with the standalone, keeping the timing the same and increasing the AFR from 10.0 to 11.0 will result in an increase in power on the dyno.
My assumption (and what others have described as well) is that this occurs simply due to the laws of thermodynamics (I believe its the 1st one but don't quote me). Essentially this law says heat, internal energy, and work are all related:
As you lean out the AFR you are effectively creating more heat inside of the cylinder(s). This extra heat translates directly into extra energy and in our case more work(torque).
so if you have an srt4 on HOM and then you get a piggy back to lean it out to a stoich level, would you make even more power?
I will tell you this. Pure AFR will help, I've tuned and watched enough cars being tuned with standalones to see it. Literally with the standalone, keeping the timing the same and increasing the AFR from 10.0 to 11.0 will result in an increase in power on the dyno.
My assumption (and what others have described as well) is that this occurs simply due to the laws of thermodynamics (I believe its the 1st one but don't quote me). Essentially this law says heat, internal energy, and work are all related:
As you lean out the AFR you are effectively creating more heat inside of the cylinder(s). This extra heat translates directly into extra energy and in our case more work(torque).
so if you have an srt4 on HOM and then you get a piggy back to lean it out to a stoich level, would you make even more power?
There is a point at which it is dangerous to continue leaning it out. Peak power in engines is actually made just below stoich, however it is unsafe to go that lean because you are extremely prone to knock (even with high octane gas) and because the EGTs get so high. So basically too much heat is a bad thing.
This is why you dont want to be too rich or too lean. Too rich you will be wasting energy, too lean and you have a high risk of hurting your engine. You want that sweet spot in the middle
I will tell you this. Pure AFR will help, I've tuned and watched enough cars being tuned with standalones to see it. Literally with the standalone, keeping the timing the same and increasing the AFR from 10.0 to 11.0 will result in an increase in power on the dyno.
My assumption (and what others have described as well) is that this occurs simply due to the laws of thermodynamics (I believe its the 1st one but don't quote me). Essentially this law says heat, internal energy, and work are all related:
As you lean out the AFR you are effectively creating more heat inside of the cylinder(s). This extra heat translates directly into extra energy and in our case more work(torque).
so if you have an srt4 on HOM and then you get a piggy back to lean it out to a stoich level, would you make even more power?
There is a point at which it is dangerous to continue leaning it out. Peak power in engines is actually made just below stoich, however it is unsafe to go that lean because you are extremely prone to knock (even with high octane gas) and because the EGTs get so high. So basically too much heat is a bad thing.
This is why you dont want to be too rich or too lean. Too rich you will be wasting energy, too lean and you have a high risk of hurting your engine. You want that sweet spot in the middle
a yes or no would be great im still lost on that one
I will tell you this. Pure AFR will help, I've tuned and watched enough cars being tuned with standalones to see it. Literally with the standalone, keeping the timing the same and increasing the AFR from 10.0 to 11.0 will result in an increase in power on the dyno.
My assumption (and what others have described as well) is that this occurs simply due to the laws of thermodynamics (I believe its the 1st one but don't quote me). Essentially this law says heat, internal energy, and work are all related:
As you lean out the AFR you are effectively creating more heat inside of the cylinder(s). This extra heat translates directly into extra energy and in our case more work(torque).
Thank you, thank you, thank you, thank you for the data/reply,
Thank you for posting somthing more then just plane empirical data, althou real world results can speak for themselves....and are useful but... Fact based is AWSOME!
Just the type of answer I was looking for! Your awsome!
Anyone else?
Last edited by ToMuchBoost : 10-12-2006 at 03:01 PM.
I will tell you this. Pure AFR will help, I've tuned and watched enough cars being tuned with standalones to see it. Literally with the standalone, keeping the timing the same and increasing the AFR from 10.0 to 11.0 will result in an increase in power on the dyno.
My assumption (and what others have described as well) is that this occurs simply due to the laws of thermodynamics (I believe its the 1st one but don't quote me). Essentially this law says heat, internal energy, and work are all related:
As you lean out the AFR you are effectively creating more heat inside of the cylinder(s). This extra heat translates directly into extra energy and in our case more work(torque).
so if you have an srt4 on HOM and then you get a piggy back to lean it out to a stoich level, would you make even more power?
There is a point at which it is dangerous to continue leaning it out. Peak power in engines is actually made just below stoich, however it is unsafe to go that lean because you are extremely prone to knock (even with high octane gas) and because the EGTs get so high. So basically too much heat is a bad thing.
This is why you dont want to be too rich or too lean. Too rich you will be wasting energy, too lean and you have a high risk of hurting your engine. You want that sweet spot in the middle
a yes or no would be great im still lost on that one
I guess maybe I am a bit confused about the question. Here is what I am trying to say:
Basically its a bad idea to lean out the AFR mixture to near stoich at WOT because the heat is SOOO immense. Its so hot that the mixture is very prone to detonating (which would make the car slower, and break internal engine components) and also gets so hot that you run a risk of literally melting things.
So I guess if you decided to lean out your car under WOT to just under stoich then yes it would probably (other variables are at play as well) be faster, but it would also be a ticking time bomb and eventually blow up.
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Is there any direct advantage to higher AFR or just a sideaffect of tricking PCM?
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