Henry, yes I do this for my car (chips) but I can't burn stock UV-EPROMs I converted my box to take E-EPROM. Also, I do not give advice on howto burn chips or howto tune because of the risks involved in doing this. You can destroy an engine simply by creating a chip with a single bad data point! For this reason tasks such as this are best left to folks that really know what they are doing, like Steve Wong he really knows his stuff. This thread is about installing a WideBand O2 controller to evaluate the end results of a tuned chip, it is not about tuning chips. So, please don't ask for advice on tuning it's just to risky for me to give and I'm still learning (far from a pro in this area).

Hope you understand.

Didn't intend to ask for or go that way.. if I was going to do that I would contact SW. I was just curious... lots of good work there on your part.

No problem, just want to be sure folks know the risks in trying to tune these cars. They do not have knock sensors or any type of protection so they can easily be damaged. This is why it's so important not to stick just any chip in them you MUST do your homework when purchasing a chip. The SW chips are well researched and tuned they are a good choice. Simply I have choicen to take the risk of tuning my own car and if I damage it I can't blame anyone but myself. However, I would feel real bad if I gave advice on howto tune and this caused damage in someone elses car.

I finished adding MPH logging to my WBO2 setup, here are the results from a run I did. The blue line is the MPH, I have some noise coming into the circuit and it produces a few spikes in the MPH but all in all I'm happy with the results.

http://forums.pelicanparts.com/uploa...1225462869.jpg

This was a 2nd gear WOT run 1000-6800RPMs

Sal,

aside from it being an interesting project to design and build the mph converter (very nice job btw) what was your motivation for this? The RPM and the MPH signal should be identical unless you are chasing a clutch-slip issue, right?

Cheers,
Ingo

If only doing 2nd gear runs you are correct. But I plan to calculate some 0-60 runs. But you are still correct, it's easy to know what RPM matches 60MPH and do it this way. So in the end I guess it was just a fun project.

I posted the log view but in the live view I have a MPH gauge on the laptop as well and it shows a gauge, see prior post #97 it has a pic of the live dashboard. Just kind of cool to see MPH on the laptop dash.

Right now I'm using all the input lines on the controller but I plan to try logging Cyl Temp from the stock cyl temp sensor on cyl #3. To do this I will give up logging the WOT signal, I may simply put a SPDT switch to switch between these 2 signals so I can log one or the other.

Why log cyl temp? Well I have been adviced by several pros (including Steve Weiner-Rennsport Systems) that much can be learned from monitoring cyl temps. Steve has helped me much with my education and I am truly grateful for his help and time.

Sal,

another really cool project would be to log the times between your reference pulse and the first spark signal and the duration of injector openings with microsecond resolution. I think this would require some sophisticated high-speed timers and such but in the end this would be really neat.

With that and the RPM you'd have all information to calculate the spark advance and VE values at a given RPM and load. So you could essentially dump the effective spark and VE tables including all corrections made for IAT, V+, and CHT.

What do you think?

This would require a lot of external circuitry, way to big of a project at this time.

What is the goal here? Why would you want to know this? Right now I have everthing I need to tune my AFR. I simply look at a log and then tune the fuel maps.

As for knowing the maps, I already know where these are on the chip.

So the the AFM on this chart are from the stock bosch air flow meter? it looks like the air flow vs output is linear, I have read some of the earlier ones are exponential. I am planning on doing some AFM mods on my car and it would help me out a lot to know if the stock AFM on my 88 carrera is linear or exponential.

Thanks!

SmileWavy

How about an EGT?

That might react faster than the cylinder head temp sensor and would be a good safety test against how lean one can run under full accel.

The very early AFMs had non-linear curve. The AFM in the 84-89 Carrera cars are linear as seen in the graph. Also note they top out at 5225RPM and after this point they sort of go flat because the door is about 90% open. After the 5225RPM the DME calculates fuel based mostly from RPM only.

I have a very detailed doc I put together with everything I have learned about the AFM in the Carrera car. If you are serious about messing with your AFM you will find my doc very useful and a good read before you start. If you want it PM me with your email id.

Good luck.

I just sent you a PM, let me know if you didn't get it.

Sal,
looks like there must be something in the WOT map that keeps adding more fuel after the AFM signal is not going higher? This means there is still room in the PWM for the injectors. I guess

Yes, it's the RPMs. The WOT map looks at both AFM and RPMs after 5225RPMs it simply uses RPMs to calculate fuel.

And the injectors are not max out at 6800RPMs I can drive the AFR well down into the 12.5 range via the WOT map.

your afr looks pretty good (not too rich) to me at high rpms, I don't see a sign of the over rich people talk about... the SW chips are supposed to "fix" the over rich situation. If I remember correctly 12.5 is pretty close to optimum power.. but a better number may be found on a dyno.

I just noticed something... your afr trace is in "steps"... the steps seem like a long time compared to other readings... why is this? I would expect something looking more like an analog signal.

This has been a very interesting read. One thing I found confusing was the idea that a constant AFR value @ WOT was needed for optimal performance. Once the WOT map is activated (as discussed), essentially the chip's value points (as programed) try to obtain this ratio without system feedback. From what I've learned, the 911 engine functions optimally by having specific AFR values @ different rpm points, so the theory of having a fixed AFR value across the rpm range is counter productive. My manufacturing skills are not up par with Sal's, so I just purchased the LM-1 with the required accessories, and proceeded to plot the stock chip. I managed to plot AFR, WOT switch activation, rpm, and AFM voltage. Now I was able to see the 911's proprietary AFR line. Shorty there after SW was contacted and I bought one of his chips adjusted to the mods my motor. Again I log AFR values, as instructed by SW, and the logs emailed to Steve. Low and behold Steve sends me a chip spot on with a much smoother AFR line, set to the ideal value. One thing to note here is that the AFR line is not flat across the rpm range; between 5000 and redline you see the AFR value deviate. I believe this is done to optimize torque and keep the engine from pinging.


jp

Please do not assume my AFR readings are spot on, I'm still toying around with diffrent AFRs. I have some maps setup to go richer at about 5225RPM which is max torque. You really need a load dyno to fully tune these maps and I have yet to put the car on a load dyno.

This thread is mainly to show my WBO2 setup and how it can monitor signals. Please do not assume that my runs have properly tuned AFR

A few weeks ago I mentioned logging Cylinder Head Temps and I have now setup to do this. I gave up logging the WOT switch and altered this input to now log CHT. I simply moved the analog input over to pin #13 on the DME. Pin 13 is the ouput of the existing CHT sensor on cyl #3. The hard part was coming up with the maps for the WBO2 controller to convert the 0-5v signal from the CHT sensor into degrees F. I did this from some specs for testing resistance values at different temps for the CHT sensor. I also made some educated guesses for some of the data points in the map but I have something reasonable now, I'll further fine tune the voltage to temp map as I go.

Here's an example of what you can do with this, here is a recording (log) of my Cold start for my car. Simply I started recording before I started the car on a 40F day dead cold:

http://forums.pelicanparts.com/uploa...1227042703.jpg

My car has a modified startup, my Cold Start RPMs are set to 1400 instead of the stock 1200RPM setup. But you get the idea of what you can monitor, this graph shows:
- AFR
- RPMs
- AirFlow (AFM signal)
- CHT in Deg F

I'm really happy with this setup and monitoring CHT has been a real eye opener so far. For example I never realized how hot CHT gets if you let a car idle for extended time with fully warm oil! Also, I'm amazed how fast cyl head temps drop when you decel (injectors shut off) for any length of time on a steep down grade (hill). But the big surprise was how fast temps climb when you lug the engine, for example 5th gear up hill at 1500RPMs temps rise very quickly well past 320F! These engines really like the 3000-4000RPM range at part load, this keeps engine temps right around 300F or so.