Dyno Air/Fuel Ratio Discussion
#21
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Does your dyno have a spare wideband sensor? We use them in the tailpipe when a bung is not available and have had no such problems. We use Bosch 6 wire wideband sensor. You will get a lean reading at idle due to reversion but should be pretty accurate under full throttle. Obviously you're not running that lean or you'd have much higher power numbers.
#22
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OK, I just got back from another road test.....damn...I am getting good at this..hope the neighbors dont complain.
I went ahead and datalogged RPM and A/F on the Profec. I did a WOT run in 2nd gear and I swear...i was staring at the AEM guage the whole time. At 6400...just before I let off, the last thing I saw on the AEM guage was 12.4:1. Remember I am running 7psi of boost..so I am a bit leaner than I would like becuase I havent done the fuel system upgrade yet.
I went back and slow-mo reviewed the log. Guess what....at 6400, the Profec logged exactly 12.4:1. The two readings are identical.
I went ahead and datalogged RPM and A/F on the Profec. I did a WOT run in 2nd gear and I swear...i was staring at the AEM guage the whole time. At 6400...just before I let off, the last thing I saw on the AEM guage was 12.4:1. Remember I am running 7psi of boost..so I am a bit leaner than I would like becuase I havent done the fuel system upgrade yet.
I went back and slow-mo reviewed the log. Guess what....at 6400, the Profec logged exactly 12.4:1. The two readings are identical.
#23
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Originally posted by ACP
Unfortunately I don't
The first Dyno place I went to, didn't have the A/F sensor hooked up.
I know the HP #s were the same in both places (but that doesn't help you)
But what I can help you with, is to show you my gains with the test pipes!
Big difference
Here is one of my early posts, that show my Dyno results with test pipes and high flow cats
https://my350z.com/forum/showthread....threadid=67663
Unfortunately I don't
The first Dyno place I went to, didn't have the A/F sensor hooked up.
I know the HP #s were the same in both places (but that doesn't help you)
But what I can help you with, is to show you my gains with the test pipes!
Big difference
Here is one of my early posts, that show my Dyno results with test pipes and high flow cats
https://my350z.com/forum/showthread....threadid=67663
#24
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Yeah, I did some research. It seems that the wideband O2 sensors actually put out positive and negative volts. They range from like +.2 to -.2 depending on whether you are lean or rich compared to stoich. The display is based on this number.
The output is an algebraic function that yields a 0-5v output. For instance, the PLX system uses AFR = 2 * volts + 10. Essentially, y = mx + b, which yields a linear graph. Other manufacturers, like zeitronix and AEM use exponential functions. (I guess, by looking at the curve.) Still others give adjustable outputs.
I agree, that if the output is linear, and you can set starting/ending volt and afr values, that you would have no problems. But what about the non-linear setups? They advertise being used in conjucntion with a stand alone.
Zietronix says that most stand-alones offer multiple adjustable values so that you can adjust for the curve, but what is going on with gq's profec. He hasn't entered anything, and his non-linear output is registering perfectly on the profec.
Hey derek, how do you like the ZT-2? And what is your 0-5v connected to? I want to find a way to get an analog gauge to work in conjunction with the ZT-2, any ideas?
The output is an algebraic function that yields a 0-5v output. For instance, the PLX system uses AFR = 2 * volts + 10. Essentially, y = mx + b, which yields a linear graph. Other manufacturers, like zeitronix and AEM use exponential functions. (I guess, by looking at the curve.) Still others give adjustable outputs.
I agree, that if the output is linear, and you can set starting/ending volt and afr values, that you would have no problems. But what about the non-linear setups? They advertise being used in conjucntion with a stand alone.
Zietronix says that most stand-alones offer multiple adjustable values so that you can adjust for the curve, but what is going on with gq's profec. He hasn't entered anything, and his non-linear output is registering perfectly on the profec.
Hey derek, how do you like the ZT-2? And what is your 0-5v connected to? I want to find a way to get an analog gauge to work in conjunction with the ZT-2, any ideas?
#25
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Thought I would thow up a A/F chart comparison with the
Test Pipes w/stock exhaust (Kinetix) in Red
High Flow cats w/stock exhaust (Kinetix) in Blue
Test Pipes with Evo2 in Green
I will post the HP and Torque charts in this thread
https://my350z.com/forum/showthread....threadid=67663
Test Pipes w/stock exhaust (Kinetix) in Red
High Flow cats w/stock exhaust (Kinetix) in Blue
Test Pipes with Evo2 in Green
I will post the HP and Torque charts in this thread
https://my350z.com/forum/showthread....threadid=67663
#26
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Originally posted by CaneZMD
I agree, that if the output is linear, and you can set starting/ending volt and afr values, that you would have no problems. But what about the non-linear setups? They advertise being used in conjucntion with a stand alone.
Zietronix says that most stand-alones offer multiple adjustable values so that you can adjust for the curve, but what is going on with gq's profec. He hasn't entered anything, and his non-linear output is registering perfectly on the profec.
Hey derek, how do you like the ZT-2? And what is your 0-5v connected to? I want to find a way to get an analog gauge to work in conjunction with the ZT-2, any ideas?
I agree, that if the output is linear, and you can set starting/ending volt and afr values, that you would have no problems. But what about the non-linear setups? They advertise being used in conjucntion with a stand alone.
Zietronix says that most stand-alones offer multiple adjustable values so that you can adjust for the curve, but what is going on with gq's profec. He hasn't entered anything, and his non-linear output is registering perfectly on the profec.
Hey derek, how do you like the ZT-2? And what is your 0-5v connected to? I want to find a way to get an analog gauge to work in conjunction with the ZT-2, any ideas?
from Zietronix email
The Zt-2 's output is accurate to 0.1 AFR but keep in mind the most important is how consistent are AFR values in the RPM range not how close you are to the magic AFR number. Typically 0.5 AFR difference doesn't mean much. There are many more factors like intake temperature, octane_and ignition timing affecting the performance.
The Zt-2 's output is accurate to 0.1 AFR but keep in mind the most important is how consistent are AFR values in the RPM range not how close you are to the magic AFR number. Typically 0.5 AFR difference doesn't mean much. There are many more factors like intake temperature, octane_and ignition timing affecting the performance.
-D
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I should add that they offered to reprogram the control unit for a linear curve and I might take them up on that.
Right now I would expect the curve looks like the AEM one.
-D
from Zietronix email
Right now the Zt-2 AFR/voltage curve matches the natural curve of the wideband oxygen_sensor. We can write a software to change the Zt-2 output into the linear mode. This would require shipping the Zt-2 unit only. We will reflash the Zt-2 with a new software adding_full scale 0-5V_linear output in place of simulated narrowband output.
Right now the Zt-2 AFR/voltage curve matches the natural curve of the wideband oxygen_sensor. We can write a software to change the Zt-2 output into the linear mode. This would require shipping the Zt-2 unit only. We will reflash the Zt-2 with a new software adding_full scale 0-5V_linear output in place of simulated narrowband output.
-D
#28
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Originally posted by ACP
Thought I would thow up a A/F chart comparison with the
Test Pipes w/stock exhaust (Kinetix) in Red
High Flow cats w/stock exhaust (Kinetix) in Blue
Test Pipes with Evo2 in Green
I will post the HP and Torque charts in this thread
https://my350z.com/forum/showthread....threadid=67663
Thought I would thow up a A/F chart comparison with the
Test Pipes w/stock exhaust (Kinetix) in Red
High Flow cats w/stock exhaust (Kinetix) in Blue
Test Pipes with Evo2 in Green
I will post the HP and Torque charts in this thread
https://my350z.com/forum/showthread....threadid=67663
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