Re: Widebands That You Would or Wouldn't Buy
Posted: Fri Apr 21, 2017 5:38 am
OK. Looks like I'll give the Spartan II a shot
TRUE DIY engine management discussion forum
http://forum.diyefi.org/
The Ballenger Motorsports AFR500V1 is the same as an NGK Powerdex AFX. The Ballenger Motorsports AFR500V2 is essentially the same controller with these customer requested improvements:HelmutVonAutobahn wrote:I think the AFR500 V1 is the same as the NGK Powerdex ? Generally, any wideband that uses an NTK sensor is going to be limited to about 80ms, at best, in response speed. So, the AFR500 V2 may be significantly faster, with the Bosch sensor. The NTK sensors are durable but, sluggish.
Doesn't jive with the ability of the old LC-1s to pick out individual cylinder AFRs from a collector at low RPM, by synching the scope to the #1 spark. I have watched this be done. And you can see the adjustments made to the idle mixture of individual carbs, up to maybe 2000RPM. That requires a response time of about 25ms. But, that was the old LSU4.2 sensor.Based on my experiments and testing, an O2 sensor installed into the exhaust of a real engine gives at best a response time of 50ms to 75ms, that is the sensor itself, the wideband controller will add it's own delays.
Spartan 2 used PID pump control. Spartan 2 should be a bit faster than the average wideband that uses PID pump control. My prior post, I gave the impressions that it is as fast as a PID pump control wideband could be, but thinking back over it, that is not the case. I forgot that I use a 4.16v internal bandgap ref for the analog parts of the PSOC, typically most widebands will be able to drive the pump cell to 5v but mine can only drive to 4.16v. So that leaves some performance on the table. The reason I used the 4.16v is because it is an internally generated and compensated bandgap voltage and I gain ADC accuracy by forgoing full 5v operation.HelmutVonAutobahn wrote:All good stuff.
So, you don't use a PID pump current. And you don't use a constant current PWM ( like Innovate and AEM ) ?
Something in between ?
Right. That's about another 40ohm. I didn't think about that because the Innovate and AEM designs don't go through that pin. Still about 1v p-p. Maybe 1.2vYou also have the calibration resistor in parallel with the 62 ohm resistor.
I would hazard to guess that anyone experiencing faster than say 50 ms has installed their sensor in such a way that the gas blows directly into the face of the sensor,
You don't want to transport it "into the chamber" you want to deliver it to the diffusion orifice. Basically, at the surface of the element. That's where the diffusion-vs.-pump-current fight happens. The "very fast" recovery indicates that this is not the bottleneck. As is reinforced by the data from running the element "bare-back".The issue to me is the transportation of the exhaust gas into the measurement/sample chamber.
I actually have done that Hiz test, though it was not to monitor the response time of the nernst voltage as a proxy to gas diffusion speed. Looking over my mental notes, the recovery is very fast.