Wolf 3d + Large Injectors... Stability And Tunability Solved!

[GTRNUR]

Over the past few weeks i've been strugling to solve issues with my Wolf ecu and an inability to get the engine to run smoothly. Ever since upgrading to 440cc GTR injectors on the RB20 i'd been having issues with random misses and poor idle stability. Problems that were never an issue with the stock RB20 injectors.

The problem stemmed from the fact that the wolf can not run full sequential injection on the 6 cylinder RB engine. Injectors are normally fired in batches (pairs). Those pairs being Cylinders 1+6, 5+2 and 3+4, using 3 of the 4 injector channels.

The wolf fires every injector at least once per 360 degree rotation, where sequential fires each injector once per 720 degrees. The injector has a minimum pulse width at which it can operate stabely, below which the fuel delivery will become eratic. From my experiences with other injectors the smallest pulse width is generally around 1.45-1.5ms.

The Wolf displays the pulse width for injectors on the hand controller for a full 720 degree engine cycle.

With my RB20DET running the GTR injectors with a 1:1 rising rate regulator and 43PSI fuel pressure, the batch fire pulse width was 2.45ms at idle and around 2.8 at light loads when cruising at 80-100km/h. However the engine ran eraticly and you could feel it occasionally missing, as if you divide that value by 2, your below the 1.4ms which is below that safe operating time.

Increasing the pulse width to much larger values made the engine miss disappear, but also made the engine run way too rich. Running on boost was fine, as there was no miss at all but its not an option to drive at 5lb boost all the time!

A possible workaround which i I tried was using a 2:1 rising rate regulator, and then running a low pressure at idle to reduce fuel flow at the injector. Yet when on boost the pressure would also be enough to provide top end fuel flow. This was an absolute failure on multiple levels. It didn't reduce the fuel flow enough even at the lowest levels, AND it also made the tune eratic. I would tune at night, and then start the car the next day and see it running as much as 2 AFR points from where it should be. Malpassi need to be shot for making high rate regulators!

At last... How i fixed the problem...

To explain I first need to explain first how the Wolf fires the injectors and senses crank and cam angles. When installing a Wolf ecu you change the trigger disc in the cam angle sensor. The new disc has a notch at 60 degrees Before Top dead center for EACH cylinder. To identify 60 degrees BTDC for the #1 cylinder's Intake cycle there is an additional mark at 50 degrees BTDC. This is the reference pulse that resets the counting of cylinders. ... So, as the engine turns it calculates RPM between pulses but when it senses the reference pulse it knows also to reset the counter that it uses to fire the correct ignition and injection channels.

The Wolf 4 Plus ecu has 6 ignition channels. So that each of the 6 coils are fired at the correct time, each channel is fired in sequence after an appropriate count of pulses that occur AFTER the reference pulse. Eg. At the time of the reference pulse, cylinder 1 is about to begin its intake cycle. 3 pulses after that it begins its Ignition cycle, so thats when the coils must fire.

Yes it sounds complicated but in reality its not so bad. As the RB firing order is 153624 each channel of the wolf is wired as follows:

Ignition Channel 1 - 1

Ignition Channel 2 - 5

Ignition Channel 3 - 3

Ignition Channel 4 - 6

Ignition Channel 5 - 2

Ignition Channel 6 - 4

However as fuel and ignition delivery do not happen at the same time (instead they are out by 360 degrees for a 4 stroke engine), an offset needs to be added to correct the delivery of the ignition. So the wolf has a settings for each channel called an Ignition pulse offset and skip, which basicly tells each channel how many pulses it should count after the reference pulse before it fires, and then how many it should ignore after that.

So, look at the pulse offset and match that to the channel above and this tells you...:

Ignition 1 Pulse Offset = 3 (Coil 3 fires as cylinder 1 begins its intake cycle)

Ignition 2 Pulse Offset = 4 (Coil 6 fires as cylinder 5 begins its intake cycle)

Ignition 3 Pulse Offset = 5 (Coil 2 fires as cylinder 3 begins its intake cycle)

Ignition 4 Pulse Offset = 0 (Coil 4 fires as cylinder 6 begins its intake cycle)

Ignition 5 Pulse Offset = 1 (Coil 1 fires as cylinder 2 begins its intake cycle)

Ignition 6 Pulse Offset = 2 (Coil 5 fires as cylinder 4 begins its intake cycle)

Ignition 1 Pulse Skip = 5 (Means skip 5 pulses after its fired this channel and then fire again, (6 cylinders))

Ignition 2 Pulse Skip = 5

Ignition 3 Pulse Skip = 5

Ignition 4 Pulse Skip = 5

Ignition 5 Pulse Skip = 5

Ignition 6 Pulse Skip = 5

Injectors work simular but with 1/2 the number of channels, and with the channels wired to 2 injectors at a time:

Injector Channel 1 - 1+6

Injector Channel 2 - 5+2

Injector Channel 3 - 3+4

Injector 1 Pulse Offset = 0 (Injectors 1+6 fire together as the reference pulse is detected)

Injector 2 Pulse Offset = 1 (Injectors 5+2 fire together 1 pulse after the reference pulse is detected)

Injector 3 Pulse Offset = 2 (Injectors 3+4 fire together 2 pulses after the reference pulse is detected)

Injector 1 Pulse Skip = 2 (Means skip 2 pulses after its fired this channel and then fire again, (360degrees))

Injector 2 Pulse Skip = 2

Injector 3 Pulse Skip = 2

This had me thinking... What if I were to fire the injectors only once per 720 degrees, but still run three pairs of of injectors on the 3 channels. For this to work most effectively I'd have to re-wire the injector channels so that fuel delivery to each cylinder happened as close as possible to when the intake cycle begun. So I re-wired my injectors as follows:

Injector Channel 1 - 1+5

Injector Channel 2 - 3+6

Injector Channel 3 - 2+4

And then configured the pulse offsets as follows, simular to sequential ignition...

Injector 1 Pulse Offset = 0 (Injectors 1+5 fire together as the reference pulse is detected)

Injector 2 Pulse Offset = 2 (Injectors 3+6 fire together 2 pulse after the reference pulse is detected)

Injector 3 Pulse Offset = 4 (Injectors 2+4 fire together 4 pulses after the reference pulse is detected)

Injector 1 Pulse Skip = 5 (Means skip 5 pulses after its fired this channel and then fire again, (720degrees))

Injector 2 Pulse Skip = 5

Injector 3 Pulse Skip = 5

This essentially converts the injection setup from 3 bank multi-point sequential, to 3 bank semi-sequential.

Injectors for cylinders 1, 3, and 2 are running full sequential. Injectors for cylinders 5, 6 and 4 are also sequential but receive their fuel 720/6=120 degrees before its intake cycle is due to begin. Most importantly by firing the injector only once per 720 degrees, it does mean fuel delivery for large injectors CAN at last be controlled properly.

Although this is not as good as full sequential, it is better than spraying 1/2 the fuel needed for the cylinder's correct operation 360 degrees before its needed, and then the other 1/2 as the intake cycle begins... which in a nutshell is normal operation for a 3 bank operation.

With this setup implemented on my car, i did a quick street tune this evening. The map is scaled to 20lb boost. 43% load is 0 PSI on the boost gauge. The boost controller was set to 15lb. Max load peaked at 86%.

As for the results...

Idles like a stocker with a 13.8:1 AFR at about 12% on the load map(used to be 14 with the missing), revs smoothly and crisply. No missing, no hesitation. Has torque down low and doesn't falter at all when the airconditioning is turned on. The 2.8ms pulse width at idle ensures clean injector operation.

I've attached 3 maps.

rotamotivetune.wmf

- A wolf 3d V4 plug in ecu running 550cc injectors in 2 bank batch fire and 6 coils

Skyline12-06-2004-45PSI-OPEN-440CC.wmff

- Wolf 3D V4 Plus wire in ecu with 440cc injectors in 2 bank batch fire. Ignition is 3 coils in waste spark configuration with MSD CDI. Fuel pressure set at 45psi with the vacuum hose disconnected at idle.

Skyline-14-7-2006.wmf

- Wolf 3D V4 Plus wire in ecu with 440cc injectors in the above described 3 bank semi-sequential mode. Fuel pressure again set at 45psi. Ignition is as above.

You might notice that the values are getting very large towards the top end of the map. This will eventially result in me running out of duty cycle at max RPM, but this will soon be corrected with the addition of a 1600cc injector before the throttle body which will operate off the staged injector output of the wolf. This will greatly lower the pulse width values from the 50% load point onwards.

I hope this makes at least some sense to you all.

Cheers,

Ian.

[paulr33]

why is it so complicated? i dont get it? is there something im missing? why make a plugin ecu more complicated than it needs to be

[GTRNUR]

Advanved injector sequencing configuration... of course its complicated. But once the penny drops and you understand the internal workings of the ecu as i've tried to explain its not so bad...

Oh, and I used a wire in ecu, not a plug in. That gives me 5 auxilaries among other things.

Edited July 14, 2006 by GTST4Newbie

[Al]

GTST4Newbie: Ian

Have you updated your laptop software yet. My mechanic has and it made a world of differance. I am using s/h 550cc SARD injectors, just had all 6 cleaned and tested (again) and 2 are still rated as Fair (from a rating scale of; Good, Fair, Bad). Previously my idle was shit, poped, hunted and very rich. Now with the V400 tunning software my mechanic was able to make my car idle at 870-910rpm, A/F @ 14.2, with only a very occational pop. The air-con idle is also steady .

I can not talk highly enough of the potential the software has released in the Wolf3DV4 ecu. The new software also has a "data logging" feature!

PS: BTW, V5 is due to be released with full sequential drivers (up to 8 cyl), and steady to 0.5ohm. Not to mention a whole bunch of other goodies .

Also note: That at the same time as the retune, i replaced the main 12V cable from the boot to the engine bay, as i was seeing my voltage drop down to 12.4V at idle, with the air-con, headlights, stereo, etc, on. This may have affected the ecu and caused alot of my night time idle problems. Now with the new cable my voltage doesn't drop below 13.6V at idle.

[Al]

Ian,

the last two links/files are not working, can you please fix .

Al

Great read by the way, good to see you found a solution.

[rb26s13]

buy powerfc.. instead of a wolf.. cheaper.. and less problems

[GTRNUR]

Ian,

the last two links/files are not working, can you please fix .

Al

Great read by the way, good to see you found a solution.

Links are fixed...

[GTRNUR]

GTST4Newbie: Ian

Have you updated your laptop software yet. My mechanic has and it made a world of differance. I am using s/h 550cc SARD injectors, just had all 6 cleaned and tested (again) and 2 are still rated as Fair (from a rating scale of; Good, Fair, Bad). Previously my idle was shit, poped, hunted and very rich. Now with the V400 tunning software my mechanic was able to make my car idle at 870-910rpm, A/F @ 14.2, with only a very occational pop. The air-con idle is also steady .

I can not talk highly enough of the potential the software has released in the Wolf3DV4 ecu. The new software also has a "data logging" feature!

PS: BTW, V5 is due to be released with full sequential drivers (up to 8 cyl), and steady to 0.5ohm. Not to mention a whole bunch of other goodies .

Also note: That at the same time as the retune, i replaced the main 12V cable from the boot to the engine bay, as i was seeing my voltage drop down to 12.4V at idle, with the air-con, headlights, stereo, etc, on. This may have affected the ecu and caused alot of my night time idle problems. Now with the new cable my voltage doesn't drop below 13.6V at idle, which acceptable considering the battery relocation. With less hardware running, its around 13.8-14.2 at idle depending on engine temp, colder makes a little more voltage.

Nope I havn't updated my software to V5.00 yet. Although I did see the new version of wolf will be available soon. Looks cool as! I'd been in touch with Steve at wolf and he says that members will all get a mail out anouncing the ECU when its release later this month (hopefully). The new V5 hand controller looks cool as too! Has anyone tried that yet...?

With any luck they might do a reduced price buy back on the V4 wolf to upgrade to V5, like they did with V3 users... but Steve would not confirm this as a possability.

I did have AFR's around the 14.2-14.7:1 at idle, but it still missed occasionally so thats why i investigated and went down the above mentioned path of modifying the injector sequencing. It would sit within 50 RPM of the target RPM generally, and idle as low as 850 rpm. It still struggled to run properly with the aircon on though.

After swiching to semi sequential i also had the idle control variables all set to 0 to disable it. Turned on the aircon and it idled smoothly at about 500 rpm(too low obviously, but it still ran properly). The diference to engine running and drivability is that huge.

My battery has been re-located to the boot, although I never had any power related issues anyway. I run a seperate power distribution circuit via a relay for injector power, idle control and the CDI ignition enabling circuit(provides 12V ignition power if CDI is bypassed too). Power for the CDI comes directly from the front power distribution terminal. With high beam, driving lights, stereo, air con and the fans at full, it will sit around the 13.2 volts at idle and pick up to about 13.4 if given a few RPM's.

It would be interesting to know if the new auto-tune feature is part of the new software using the logging and feedback capabilities, or if its an ECU feature. There is a guy called Michael Smith (introduced to me by another SAU member) off the RX7 forums that developed a data logger for the V4 wolf a while back, and he's since been working on writing an auto-tuner as well. Id imagine that his project might have been superseeded with the release of V5 software, but at least he was releasing it for free.

Edited July 14, 2006 by GTST4Newbie

[RB30-POWER]

Yeah on my EMS changing from 360injection to 720injection (once per cycle) made the afr alot more stable/controlable on idle. Infact they specifically suggest this mode with any injectors bigger the standard. Trying to control very small pulsewidths on idle is not something you can do easily when its injecting twice per cycle (effectively having to half pulsewidth of that when in 720 mode.

As for sequential i run simple batch injection getting the fuel sprayed on the back of the valve to help atomization and don't have any issues at all with driveability. In fact with single pintle injectors like GTR etc i would suggest it, as the spray pattern is not real good or atomized when compared with say R33 GTST injectors have have a 4 outlet disc injector or the like of the new 380 Mitsubishi that has 12 outlet injector, ideal for true sequential operation.