What is the proper Air fuel ratios ??
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From: BLOOMFIELD, NY
What is the proper Air fuel ratios ?? What is the proper air fuel ratios for power on a superchared car. And when do you bring it to it. For instance my car is ideling at 14.4 af ratio. What can i set the af at before the boost starts kicking in. (boost kicks in after 3500 rpms.
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at idle and part throttle your car will be around 14.7:1 AFR this is normal closed loop operation. under WOT and boost you want to be around 11.5 on a dynojet, a load bearing dyno that simulates more load I would put you at higher 11s to 12.0, this is asuming a somewhat low boost setting.
oh and IF you have a the ability to set the AFR and your wideband corrects it on the fly, then 12.0. if you are running a lot of boost I would add some more fuel that that though.
oh and IF you have a the ability to set the AFR and your wideband corrects it on the fly, then 12.0. if you are running a lot of boost I would add some more fuel that that though.
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From: BLOOMFIELD, NY
so i can keep the air fuel to 14.7 at part throttal. When my boost kicks in should i go straight to 12.0, Or can i slowly work my way to 12.0. For instance at 1psi of boost. Can i be at like 13.5. ???
and 2psi of boost. Set at 13.2
3psi 12.8
4psi 12.4
5psi 12.2
6.psi 12.0
Is this the way to do it, ??
Thanks
Micah
and 2psi of boost. Set at 13.2
3psi 12.8
4psi 12.4
5psi 12.2
6.psi 12.0
Is this the way to do it, ??
Thanks
Micah
Michah, since you are running a FASt it's a bit different....
I just went thru a ton of phone calls with Kurt Urban and Chris Sikora to figure out where my FAST values should be.
Here is the hierarchy:
VE: Anything in the 40's is ideal. Might need to change injector offset if you have trouble getting the car to idle in the 40's.
Idle AF: some say 14:1, but some say 12:1. 14.7:1 is stock but that's lean for emissions. I suggest 13.5:1.
Idle Timing: I put mine around stock for an LS1, so it's 34 degrees.
TPS: Minimize usage of the screw to crack the blade for air, try to drill out the hole more for idle.
IAC: 30-40's for idle is great. FAST will allow up to 180. I'm at 70 and want 45 at least.
Idle Spark Table: Want it 0 to 10, left to right.
Boost tuning will be different.
Also, I have elected to tune the car in open loop up to about 4000, maybe 4500, we'll see how we feel this weekend. Most folks go closed loop over 1500. We just to minimize any part throttle to boost fuel transitions.
I just went thru a ton of phone calls with Kurt Urban and Chris Sikora to figure out where my FAST values should be.
Here is the hierarchy:
VE: Anything in the 40's is ideal. Might need to change injector offset if you have trouble getting the car to idle in the 40's.
Idle AF: some say 14:1, but some say 12:1. 14.7:1 is stock but that's lean for emissions. I suggest 13.5:1.
Idle Timing: I put mine around stock for an LS1, so it's 34 degrees.
TPS: Minimize usage of the screw to crack the blade for air, try to drill out the hole more for idle.
IAC: 30-40's for idle is great. FAST will allow up to 180. I'm at 70 and want 45 at least.
Idle Spark Table: Want it 0 to 10, left to right.
Boost tuning will be different.
Also, I have elected to tune the car in open loop up to about 4000, maybe 4500, we'll see how we feel this weekend. Most folks go closed loop over 1500. We just to minimize any part throttle to boost fuel transitions.
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From: BLOOMFIELD, NY
What are you setting your af table at. I have mine at 14.6 idle and slowly like the numbers said in my last post work my way all the way down to 11.5.
14.6---11.5. But i do not know if this is best for power.
Also i have no idea what our cars can pull for timming advance. I cut the timming down to 18degress after the boost starts kicking in at 4500rpms. But the rest of my timming chat is all at 34 degrees , Can use more timming. What is the max timming on our cars.
Also John , I found that while useing the fast and tuning my car, watch out for ramdom spikage. What happens is sometime when you tunning live and the laptop slows down or the car almost dies or some fluke like that. The data in the windows will randomly spike. I have had this happen 3 times. I can not find the exact casue. But the last time i was just driving with the ae vs tps open I made a change to it. Saved it casue it worked good. Then started driving again and then all of a sudded the car started bucking and hesitating. I look over at my labtop and some how the numbers got all skewed. Also when entering data into cells.I would not select more that 1 or 2 cells at a time. I tried to select the left side of my af table and change them all to 14.5. What happend wasI enterd in 14.5 and hit enter .And i could see the computer thinking ... then my car stalls. I look over and the cells i selected to be 14.5 were all 9.5. I hope this saves you some time. Good luck.
14.6---11.5. But i do not know if this is best for power.
Also i have no idea what our cars can pull for timming advance. I cut the timming down to 18degress after the boost starts kicking in at 4500rpms. But the rest of my timming chat is all at 34 degrees , Can use more timming. What is the max timming on our cars.
Also John , I found that while useing the fast and tuning my car, watch out for ramdom spikage. What happens is sometime when you tunning live and the laptop slows down or the car almost dies or some fluke like that. The data in the windows will randomly spike. I have had this happen 3 times. I can not find the exact casue. But the last time i was just driving with the ae vs tps open I made a change to it. Saved it casue it worked good. Then started driving again and then all of a sudded the car started bucking and hesitating. I look over at my labtop and some how the numbers got all skewed. Also when entering data into cells.I would not select more that 1 or 2 cells at a time. I tried to select the left side of my af table and change them all to 14.5. What happend wasI enterd in 14.5 and hit enter .And i could see the computer thinking ... then my car stalls. I look over and the cells i selected to be 14.5 were all 9.5. I hope this saves you some time. Good luck.
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From: BLOOMFIELD, NY
Originally Posted by 96SCTA
What are you setting your af table at. I have mine at 14.6 idle and slowly like the numbers said in my last post work my way all the way down to 11.5.
14.6---11.5. But i do not know if this is best for power.
Also i have no idea what our cars can pull for timming advance. I cut the timming down to 18degress after the boost starts kicking in at 4500rpms. But the rest of my timming chat is all at 34 degrees , Can use more timming. What is the max timming on our cars.
Also John , I found that while useing the fast and tuning my car, watch out for ramdom spikage. What happens is sometime when you tunning live and the laptop slows down or the car almost dies or some fluke like that. The data in the windows will randomly spike. I have had this happen 3 times. I can not find the exact casue. But the last time i was just driving with the ae vs tps open I made a change to it. Saved it casue it worked good. Then started driving again and then all of a sudded the car started bucking and hesitating. I look over at my labtop and some how the numbers got all skewed. Also when entering data into cells.I would not select more that 1 or 2 cells at a time. I tried to select the left side of my af table and change them all to 14.5. What happend wasI enterd in 14.5 and hit enter .And i could see the computer thinking ... then my car stalls. I look over and the cells i selected to be 14.5 were all 9.5. I hope this saves you some time. Good luck.
14.6---11.5. But i do not know if this is best for power.
Also i have no idea what our cars can pull for timming advance. I cut the timming down to 18degress after the boost starts kicking in at 4500rpms. But the rest of my timming chat is all at 34 degrees , Can use more timming. What is the max timming on our cars.
Also John , I found that while useing the fast and tuning my car, watch out for ramdom spikage. What happens is sometime when you tunning live and the laptop slows down or the car almost dies or some fluke like that. The data in the windows will randomly spike. I have had this happen 3 times. I can not find the exact casue. But the last time i was just driving with the ae vs tps open I made a change to it. Saved it casue it worked good. Then started driving again and then all of a sudded the car started bucking and hesitating. I look over at my labtop and some how the numbers got all skewed. Also when entering data into cells.I would not select more that 1 or 2 cells at a time. I tried to select the left side of my af table and change them all to 14.5. What happend wasI enterd in 14.5 and hit enter .And i could see the computer thinking ... then my car stalls. I look over and the cells i selected to be 14.5 were all 9.5. I hope this saves you some time. Good luck.
