NTK AFRM gen2 to HP

trying to match logging output to HP tuners. does anyone know the function formula to read properly with NTK AFRM gen2? The closest match is AFR500 but still off.

I am using afr500 and chaged voltage to 9.5 instead of 9 and reading closer but still little off. If someone knows the correct imput please share

Best to figure out the actual formula, just arbitrarily changing the offset part of the formula isn't how you do it.

Also MAKE SURE you have a good ground ran from the gauge to the HPT interface. People just using whatever ground is easiest (or none at all) see this kind of issue all the time.

The manual for that gauge says:

0.5V = AFR of 9.0
4.5V = AFR of 20.00

y=mx+b, going back to basic algebra here.

So, figure out slope first

(20 - 9) / (4.5 - 0.5) --> 2.75 AFR per volt

Then figure out offset

You know at 0.5V the AFR is 9.0, and you know slope, so plug in what you know

9.0 = 2.75 * 0.5 + b
9.0 = 1.375 + b
b = 7.625

So the right formula is 2.75 * voltage + 7.625

Test to be sure

2.75 * 4.5 + 7.625 --> AFR of 20 (checks out)
2.75 * 0.5 + 7.625 --> AFR of 9 (checks out)

So, try this formula. I inverted the 2.75 to match the format HPT wants.

V / 0.3636 + 9

Quote:

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Originally Posted by schpenxel

Best to figure out the actual formula, just arbitrarily changing the offset part of the formula isn't how you do it.

Also MAKE SURE you have a good ground ran from the gauge to the HPT interface. People just using whatever ground is easiest (or none at all) see this kind of issue all the time.

The manual for that gauge says:

0.5V = AFR of 9.0
4.5V = AFR of 20.00

y=mx+b, going back to basic algebra here.

So, figure out slope first

(20 - 9) / (4.5 - 0.5) --> 2.75 AFR per volt

Then figure out offset

You know at 0.5V the AFR is 9.0, and you know slope, so plug in what you know

9.0 = 2.75 * 0.5 + b
9.0 = 1.375 + b
b = 7.625

So the right formula is 2.75 * voltage + 7.625

Test to be sure

2.75 * 4.5 + 7.625 --> AFR of 20 (checks out)
2.75 * 0.5 + 7.625 --> AFR of 9 (checks out)

So, try this formula. I inverted the 2.75 to match the format HPT wants.

V / 0.3636 + 9

---

wow thanks. totally impressed. will surely try it. I was using the balanger afr 500 gen1 and changing to voltage to 9.4. seemed to provide the correct reading.
cheers will report back

Changing the offset until you get one correct reading will only make it right in one spot.. the slope has to be right too or it will be further and further off the further you get from that one "right" value

Quote:

---

Originally Posted by schpenxel

Best to figure out the actual formula, just arbitrarily changing the offset part of the formula isn't how you do it.

Also MAKE SURE you have a good ground ran from the gauge to the HPT interface. People just using whatever ground is easiest (or none at all) see this kind of issue all the time.

The manual for that gauge says:

0.5V = AFR of 9.0
4.5V = AFR of 20.00

y=mx+b, going back to basic algebra here.

So, figure out slope first

(20 - 9) / (4.5 - 0.5) --> 2.75 AFR per volt

Then figure out offset

You know at 0.5V the AFR is 9.0, and you know slope, so plug in what you know

9.0 = 2.75 * 0.5 + b
9.0 = 1.375 + b
b = 7.625

So the right formula is 2.75 * voltage + 7.625

Test to be sure

2.75 * 4.5 + 7.625 --> AFR of 20 (checks out)
2.75 * 0.5 + 7.625 --> AFR of 9 (checks out)

So, try this formula. I inverted the 2.75 to match the format HPT wants.

V / 0.3636 + 9

---

Sorry if this is a dumb question or if I am missing something in this math but I am setting up the same W/B tonight in my hp tuners.

Why is the final formula V / .3636 + 9 ?

According to the math should it not be
V / .3636 + 7.625 ??

Just trying to clarify before I put it in.

Thanks for the help!

Looks like a typo on my part

Thanks for this info and the explanation and yes
V / .3636 + 7.625
Is correct