More Data

[Bruce Bowling]

that could potentially identify which cyls get the lean puff, but it might be more informative to actually simulate the transition on the stim. this all assumes that the work is worth the effort.... in my opinion.... it's not. any transition to sequential is going to occur at startup and missing one fuel pulse with zero load really isn't a concern. in fact, during startup, the missing fuel is more than made up with the extra enrichments from cranking pulse widths being so big, and the ASE...

At the moment this transition being rich or lean is not a huge problem.. but its not that hard to fix, either. Like Al said - for this to work people are going to have knowledge on valve position when setting this up. Its not hard - just select if they inject on open-valve or closed-valve, this should drive the wasted-to-sequential transition type to be used.

Like I have said before, OEMs use closed-valve injection in order to minimize emissions, vaporize the fuel on the hot intake valve (wall-wetting Tau value reduced), and to stop the washing of oil off of the cylinder walls that would occur if the injector operates with the valve open. In fact I just was looking at a SAE paper where they have an injection timing diagram and they set up the injection so that it ends right when the intake valve starts to open - this way they have maximum time that the valve stays shut to inject.

What we need to do is make up a few charts of injection phasing vs intake valve position and let people choose what they want, and compensate accordingly.

my o2 sensor gives a signal only after startup, but i suspect you would not be able to identify the transition during startup the same way i can see it when cam sync is plugged in during steady state idle.

Remember there is a propagation time from when the cylinder exhaust empties in the manifold to when it reaches the sensor - and then add in the sensor response time, so correlating this to a particular cylinder event may be tough. Best would be to use NB O2 sensors on each header right on the ports and looks for deviations in O2 readback compared to other cylinders.

- Bruce

[TheMonkey]

Thought i would pop in an update.

Transition from wasted to sequential always happens immediately when motor first ignites and I've never been able to notice the transition.

I have been daily driving this car quite a bit. Have about 1,500 miles on the sequencer with both fuel & ignition.

I've played around a bit with ignition to see if I can take advantage of the more powerful coils. I'm using stock style plugs which are originally spec'd at a gap of 026, and with stock ignition system, these are known for NOT being happy with any bigger gap. The D585 coils are incredible. I've gapped up to 044 and the idle is very nice. Even with a stress test of dropping dwell down, there was no idle misses with the bigger gap. vacuum at 900 RPM idle has dropped from 34kpa to 31.5kpa, and the idle RPM range is within 10 (840-850), down from 50 (800-850). all this with just being able to ionize a bigger gap - very nice. Acceleration and responsiveness has improved so much too... although ignition tuning has been SOTP, so I'm sure some dyno time would help.

on the TO-DO list:

- still fool around with injection timing, although i'm finding this difficult because any differences seem to be smaller than the environment i can control (IAT changes between tests have a bigger impact on AFR than injection timing).
- swap power switcher to linear regulator and test in working environment
- prepare Pontiac for sequencer and play with offset/delay settings to see if i can find a setting that is happy like i found on this BMW. hopefully can find setting on stim first because i can't run fuel only first on Pontiac.

[TheMonkey]

thought i would just update my Sequencer testing before the West Coast MegaMeet that I won't make....

i have been nearly daily driving this BMW pretty much all Summer. i'm not a heavy commuter, but have put about 3,500 miles on it with Sequencer. i hardly ever put the laptop on it anymore, because it's pretty much a 'no maintenance' tune anymore. really love it. it does not pickup any additional or missed triggers at all. MPG is better by a massive factor; i think mostly from mapped ignition instead of a distributor curve. i have a lot of advance in the mid range load which i couldn't do previously, and the car loves it.

in the next couple weeks, i will button up this car for the Winter in a friend's barn. it just shouldn't be subjected to a Minnesota Winter (although I'm sure I could tune it for -60*f temps). if there are any particular things that B&G want tested before then, let me know. Bruce- i can test a new power linear regulator (as discussed), but i'm not sure if the PN i emailed would be an okay one to try. would still have to order it, but might be able to get that in before the freeze.

i really hope this unit gains more traction, and some interest is piqued at the meet next week.

[Bruce Bowling]

in the next couple weeks, i will button up this car for the Winter in a friend's barn. it just shouldn't be subjected to a Minnesota Winter (although I'm sure I could tune it for -60*f temps). if there are any particular things that B&G want tested before then, let me know. Bruce- i can test a new power linear regulator (as discussed), but i'm not sure if the PN i emailed would be an okay one to try. would still have to order it, but might be able to get that in before the freeze.

i really hope this unit gains more traction, and some interest is piqued at the meet next week.

Thanks for the positive update! You have done an excellent job for sure getting this up and running. At this point we are getting the board spin with the new TI switcher power supply made up. This should ake the unit pretty uch ready for prime-time for sure. Al has also found a cam sync issue (the reason you had to add all of the advance teeth in your setup to get it working - Al will explain) and pretty much all other software is tested and operational. We new feel pretty good about the next unit revision that it will really work well without hiccups.

- Bruce

[TheMonkey]

... Al has also found a cam sync issue (the reason you had to add all of the advance teeth in your setup to get it working - Al will explain...
- Bruce

cam sync? the advance teeth settings fixed a problem that first showed up while still in wasted mode without a cam sensor hooked up.

look forward to hearing what Al says, but let me know if you want me to test any new coding, and i can put my advance teeth settings back to some starting points. i'll have access to the car after i put it in the barn, and i'm flexible on timing.

[krisr]

That is actually really good news to hear Scott/Bruce - now that you guys are coming into the cold season and we're warming up, I still have my old setup (harness & coils) ready to go back on the car any time. I've run into a slight issue of a brake line snapping and i'm going to replace all of them as soon as my 3/16" hard line turns up but other than that, the car is pretty much ready to begin testing again. The major body work that I needed to get done is all finished off too.

Would be keen to hear more about how changing the offset/teeth made it work vs running the same settings as I did with the 2.890 code/36-1 etc... also any other tweaks/modifications that were needed to get the first board spin to work. From memory I still have the 100uf cap on the input +12V which solved that reset issue.

Kris

[TheMonkey]

Kris-

Great that you want to come back to try this again. I know exactly what the problems are that was causing the backfires, and it sounds like Al found the coding that was creating the problem.

The tooth offset - delay teeth issue is pretty much covered throughout this 'more data' thread. Basically, there was some phase shifting going on. This became easy to identify when running fuel only and scoping all the outputs. Fuel didn't care too much about the shifting, but of course, when you shift ignition by a cylinder, or introduce new random little sparks.... that is really awful.

I discovered through the testing that the phases would start shifting (and introduce tiny random flanking dwells too) only at certain RPM/load ranges. Al suggested adjusting the trigger offset & delay teeth. When I did this, the problem still existed, but it changed when it was happening. I continued to try different trigger setting combinations until the problem did not come up anymore.

Has worked excellent ever since. I have zero tach drops, resets, or trigger +/-. Of course, the underlying issue needed to be identified yet, which sounds like Al did find it.

Can't believe another season came and went.

Scott.

[krisr]

Sweet! You didn't do any other modifications to the PCB or anything like that?

With your 36-1 wheel in the BMW, where is the first tooth in relation to #1 TDC and what did you end up using for offset and delay? From memory my first tooth after the missing is 11° BTDC.

The car at the moment has no brakes and i'm just waiting on some cashflow so I can get all the flex lines made in a teflon braid & rebuild all the calipers, make all the hard line etc... once it's stopping again i'll be able to pull it out to wash all the red dust off it that we had the other week and start playing again!

[TheMonkey]

the BMW has a 60-1 wheel on it that bolted directly on from a later M30 motor.

on the settings that worked:

read through pages 3,4,5 of this thread, it pretty much covers it. but the setting that worked for me was delay teeth of 20, and -36 degree offset. keep in mind, this is a 6 cylinder car with 60-2 wheel. what this means, is that delay tooth was set up to be the first tooth after what would have been a gap tooth. bit hard to explain without reading through all the posts, but, on our Pontiacs, I would start with trying to set delay teeth to 9 (which sets your tach points on your wheel), and correspond offset to wherever your TDC is - for you might be around -70 degree offset, but of course you'll have to go through the details to figure offset.

[Peter Florance]

Scott
Do you have any more picture or data of your coil installation?
Thanks!