I'm an automotive engineer from Finland.

My current engine is stock longblock Honda D14A1. Running on GenBoard V3.2 with 1.0.77 firmware. It has modified Blox Racing intake manifold, whole exhaust setup from my 200hp D16Z6, D16A7 cam, 410cc hi-z Acura/Denso injectors. It has coil-type cranktrigger with CamSync?, running fully sequential injection and CoilOnPlug ignition with Honda Fireblade coils.

CamSync? and sequential injection (injecting into open valve) plus CoilOnPlug made engine run very smooth and response much sharper compared to old batchfire config.

Old D16Z6 ITB-related info:

Pure AlphaN, WBO2 etc now working excellently! Engine runs damn smooth in ~any conditions, EGO correction works etc.

That AlphaN is very easy and straightforward to tune.

I also tried AlphaN blending first, but that doesn't work for NA engine with ITBs, it's only meant for smoothing idle with aggressive cams. config13 bit 2 has to be enabled via keyboard or config.txt to get AlphaN working! MegaTune doesn't have an option for changing it! I had some serious problems trying to get engine working without it first (and blending enabled in MT; It just doesn't work at all). This MegaTune / AlphaN - config13 issue is fixed in newest releases, under Alpha-N/Speed-Density Blending setting, MAP(load) multiplication.

D16Z6 Engine construction

D16Z6 sensors etc

Current firmware version; 1.0.38

Questions and answers

Q: I'm trying to drive VTEC-solenoid (it needs positive supply, and has R of 16ohms) from stepper driver IC, because it seems to be able to supply 1A. Somehow I'm not able to get it working; I use MiscOutput?1 for it(S259 Q3 = stepper_A, right?). AFAIK when that is activated, output should go to +12V, but that doesn't seem to work.

  • what do you mean by "does not work" ?
  • Measure voltage
  • measure current if possible
  • try to activate with mdh.. command (disable the output during this experiment)
What should I do? I was looking for V3.2 schematics, and found S259 Q7 going for stepper enable, and added that into RPM actuator; It still doesn't work, what might be wrong? -Janne

I ment that activating S259 Q3 didn't give ~Vbatt or anything else into it's output pin. I was correct, that IC needs to be enabled separately (S259 Q7).

Now it works perfect on VEMS-side, I use RPM actuation for enabling(Q7) and MiscOut?1 for VTEC control. This works now just like it should, gives good drive to solenoid. I still have some problems retated to solenoid(mechanical) or oil pressure. Oops, it was a bug in VEMS firmware, engine was perfect.. Read below.

Q: Is there any better way to enable stepper ic, than waste rpm-actuation for it? From software, hardwiring +5V to IC would be easy too.

A: Yes there are. Because MiscOutput? doesn't have CLT variable (and would be nice to have) I figured I could use waterpump drive for chip enable.

Now I've got VTEC working properly. I was considering that maybe stepper driver IC is inadequate, and made a stronger driver circuit with TIP127 PNP-Darlington transistor. I use P259 Q7 (drive_11) to active darlington (thru 330R base resistor), and also connected my CEL-light into same P259 pin to use it as a VTEC light. VTEC drive output goes to EC36 pin22 (yes, I don't have extra GND5 on it).

I still had weird behavior, and then I figured out that it works with TPS 99% and lower, but not at 100%. Then I tried to use pure RPM-actuation and it works perfect now! Later I get confirmed that this old firmware (1.0.38) has bug related to MiscOut? function, and it's been fixed in around .45-.48 versions!

Actually, I think I leave it to RPM-actuation, it seems to work so well in practice. Stepper driver seems to be adequate to drive 16ohm VTEC solenoid, if there's no other use for it.

Launch Control

  • Replaced 33k R138 with 511R (calculated timeconstant wrong, should use much bigger resistor). Should protect from hi-freq noise? Let's see how it works.
  • Wired JP18 into JP11_1, MCP3208 ch7
  • EC18 pin 2 (EBP) used for launch button