johntorg

I am in the process of buying a 1987 944 Turbo and would like to know how I can do datalogging of the ignition timing.

I have completed several VW 1.8T 20V big turbo projects and used Vag-Com for this function. Of course that's using OBDII which provides the Ignition timing to the Vag-Com.

I will probably be installing a Vitesse MAF setup and would like to fine tune it with the Perfect Power SMT6. The SMT6 will log the amount of change it makes to ignition timing, but as far as I can see, not the actual timing itself. I also have an LM-1 Broad band that can log the AFR, but i don't believe it can log ignition timing.

Thanks in advance for your help.

mark944turbo

This is impossible, without the MoMonitor only available from Vitesse.

johntorg

Thanks for the information. I found the MoMonitor on the on the Vitesse site, but got an e-mail from John saying they don't sell it.

Does anyone know about this? Tuning without knowing the actual ignition timing sounds a little scary. Are there any other tools like this around.

I may be paranoid but I just installed a highly recommended chip in a VW 20V turbo and found out that the timing is about 15 degrees too far advanced. While this may be caused by differences in the MAF or TPS at least I know about it and won't push the car until its remapped.

Bri Bro

Mark, lets see if we can find a reference that can determine the time between the ignition pulse and this reference. Tapping into the two flywheel sensors is doable but not a good idea, very low drive signals.

What about using the injector pulse as a reference to time the occurrence of the timing pulse? I think the injector pulse occurs at the same place in the engine timing, but the pulse length is adjusted to the fuel map. If this is true, just measure the time between the injector pulse and the ignition pulse and you have the answer.

mark944turbo

"What about using the injector pulse as a reference to time the occurrence of the timing pulse? I think the injector pulse occurs at the same place in the engine timing, but the pulse length is adjusted to the fuel map. If this is true, just measure the time between the injector pulse and the ignition pulse and you have the answer."

This sounds like a very good idea to me, for somebody with a good datalogger.

If I still had a 951 on the road, and I wanted to tune it, I would just measure ignition advance at a few engine speeds (no load) using a timing light and some special chips prepared with a constant advance in all maps.

Comparing the value I set in the chips to the value given by the timing light, I could find that elusive constant difference that is needed to use the formula:

Ignition advance = X * value in map + constant. frwilk's site shows how to determine X, i dont remember it offhand, but it is around .5 I believe.

Nothing else should effect ignition timing besides the idle/pt/fullthrottle maps in the stock chips, as air temp correction values are left constant.

Bri Bro

Why not get a good data logger for about $100 that monitors all these timing pulses? Yes, it will require a little development but it can be done. Interested?

Tomas L

Injection timing is linked to ignition timing, not to a certain crank angle.

johntorg

What kind of datalogger are we talking about? I think most are for the std. OBDII port, which we don't have. It obviously can be done, since John at Vitesse seem to have accomplished it. I saw on another forum that the knock sensors on the 951 pull boost but not timing. Can anyone confirm this? It would mean that you have no knock sensor protection if you go with Manual or perhaps even an Electronic boost controller.

I assume you can pick up the timing pulse from the coil driver. Can the TDC be found from the flywheel sensors? If not, an added timing wheel (like those used in standalone setups might work).

fast951

johntorg, With your MAF I can send yuou a custom chip with any timing you want, then you can adjust timing with the SMT6.

Tomas L

No, that is not correct. The KLR first pulls up to 6° ignition advance and if that doesn't stop the knocking it pulls boost pressure.

Bri Bro

I have had good luck with this datalogger.
http://www.measurementcomputing.com/...412&pf_id=1535

johntorg

I am very interested in that datalogger. What have you been able to accomplish with it so far?

Ski

why get an extra "thingamajig" when, if John sends the chip board, you can do it all with the SMT6?

johntorg

I would still like to be able to log the actual timing. The SMT6 can be used to adjust timing (although John Doesn't recommend it, maybe because the 952 uses the flyheel and not a 60 tooth wheel)) and log the changes it makes. I'm doing this on my Corrado 1.8T. It doesn't seem to be able to log the actual engine timing.

Vitesse is closed until Jan 15th, but I'll give John a call and see what he thinks.

The datalogger looks like a very useful tool, even if it can't directly do timing. It can monitor digital and analog signals. It can also be used as a scope, which is usefull for checking sensor signals. I think with some programming and reading the refernce signal from the flywheel and the coil trigger signal, it should be able to measure and log timing.

Anyone have any thoughts on this approach?

TRWright

It is too bad you can not get the MoMonitor from John. I watched someone use it once, it is a very cool tool.