Rogue, I think you are the one who needs to answer this: Has my thinking gotten way too far out there, or is this nothing short of a stroke of genius? How would this work out? Take the (MAP) signal from the KLR (that feeds the stock boost gauge), and feed it to the AFM input line to the DME. Then tune the ROM maps to use this signal, instead of an AFM or MAF signal. That would eliminate the need for having to use either an AFM or MAF (or separate MAP) sensor. Would this be doable/feasible? If not, why?

Good question. There are a few problems with this approach, which is also known as Speed-Density.

First, the MAP sensor in the KLR is limited to ~15psi of boost... So using the KLR's MAP sensor, then the most you could boost and tune for would be 15psi.

Second, the transfer function for an AFM or MAF sensor is 2-dimensional.
For example, if the voltage output from a MAF is 3volts, then we know, according to the transfer function, that the mass airflow is say 300g/s. However, the "transfer function" for a MAP sensor must be 3-dimensional. So the same 3volts coming from the MAP sensor does not mean an exact airflow - it only means a pressure. We must then take engine RPM as another axis to then develop a VE Table to be used in-place of the transfer function...

This conversion is possible - and I might get around to doing it at some point, but right now I do not see an easy way of representing this VE table in TunerPro and have it feed values that the DME needs.

Further, because each car breathes differently - your VE table wouldn't be the same as mine, which wouldn't be the same as the next persons. So each car using this Speed Density setup would have to be tuned, no pre-tune packages would work reasonably well.

So it would work, IF it was tuned for the particular car (I now have that capability), AND if ma x boost does not exceed 15psi (I would likely be exceeding that though). But it sounds like the ROM code would have to be completely rewritten with different mapping and arithmetic cells (if that's the proper term), in order to properly use the signal. And a new xdf file would have to be written for tuner pro, to allow the tunability? Maybe something to look forward to in the future, if you get around to it that is. My ostrich will be here tomorrow, and everything else is nearing completion. Rogue, would you be able to suggest some initial values to use in tuner pro, considering the mods that are listed in my sig?

Yes, Speed Density setup is possible with the stock DME/KLR hardware... But the code would need rewritten to understand it - and that rewrite is even harder than a MAF conversion rewrite.

Rather than using the stock KLR sensor, it would make much more sense to use a common GM 3Bar, so then the car could be tuned up to ~29psi of boost.

I've got a good idea on how to rewrite the code to understand the MAF, however, I do not have a good way of representing the necessary values in TunerPro...

Besides, I just don't have the time to make any of this a reality at the moment. Perhaps I will get to it this next summer... If nothing else I would like to do it, as a programming exercise / proof of concept.

I guess I would be good to go, then, with 3bar MAP sensor, if and when code and xdf files ever become available. But I'm still wondering how to start out running the car with all of the new upgrades (I'm pretty close, at this point). I plan on starting out low on boost (4-7psi), then going in stages to 11, 15, and finally 20psi. But should I start out using the APE MAF chip, or should I go right in with the ostrich2 and the base bin?

I'd like to start out with the values used in the APE MAF bin, and tune from there. But with the maps not aligned with the xdf data for a base/stock bin, I really don't know what those values are, to plug into the base bin. Did you see the last question that I asked in my previous post?

Sorry, I didn't see your second question...

Your WOT timing minimum should be at your peak torque - typically where you first hit set boost. On a K27/8 that should be somewhere in the early-mid 3000rpms. Peak torque is where you are most likely to knock. Once you get a few hundred rpm beyond this, then start slowing adding more timing.

Furthermore, the richest point should also be at peak torque. Again, after you get past this point, you can enlean it some, but I would stay in the mid-upper 11's for a pump gas car. Also, changing timing will affect your AFR AND the amount of timing should be a guide for how rich to make it. I.E. If you have a lot of timing, then you will need to run really quite rich to keep from knocking.

Also, realize that the AFR numbers in TunerPro will only be good for the stock AFM. With your MAF the numbers will most likely not be very close to actual AFR... So you MUST have a WBO2 to properly tune your MAF-equipped car. And I would believe the WBO2 numbers over TunerPro, for your application.


-Rogue

Thanks, that's a start, anyways. But since I can't properly read the values used by APE for the MAF (by design, I'm sure), it looks like I'll have to start with stock. And then I can tune from there, using feedback from the data acquired by the ostrich. As of now I only have NBO2. But I'm sure it will cover the range that I am interested in, which would be 11-16. I don't understand why would I need to go any wider than that?

Will the ostrich/tunerpro be able to acquire (and properly present) ALL of the data (parameters) relevant to what is required for tuning?

Hold on, I'm a little confused. You said that tunerpro will not properly display the AFR's, if using an MAF. The AFR #'s should come directly off of the voltages produced by the o2 sensor, no? The only thing I can see that would be "off", would be the air flow #'s (voltages) produce by the MAF, in lou of the AFM #'s. Is there something I am missing here?

A NBO2 is only good right around 14.7. Think of a NB02 as an on-off switch, on for higher than 14.7, off for lower than 14.7. You will need a WBO2 to tune.

The AFR values in TunerPro are calculated numbers, based off of airflow, they do not come from the O2 sensor.

Well THAT blows! I was under the assumption that O2 voltage data could be acquired using the ostrich2. Can signals like rpm, manifold pressure, throttle position, and coolant temp be acquired?

The only info possible is those that the DME uses.
The DME does not use true throttle position - only a three state selection (idle, part-throttle, WOT). Nor does the DME know actual manifold pressure (only a guess based off of airflow/rpm calculation).

And just to re-iterate, the DME sees the NBO2 is a binary signal, either lean or rich - not useful for tuning.

None of that is very encouraging. What it basically means, is that my only option is to use my own brain for the data acquisition device. That's scary - I would much rather depend an a computer's memory than my own. A digital volt meter will have no problem seeing the NBO2 as an analog device, but still no acquisition of that data, other than manually acquiring it. Ditto for manfiold pressure and throttle position, I guess. That does make it more of a hassle, but it still can be accomplished.

Limitations of the stock DME/Software...

Which is why I've spent a lot of time and work re-writing the software.