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ARMc Samba Member
Joined: February 10, 2012 Posts: 116 Location: Wisconsin
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Posted: Mon Dec 07, 2020 2:06 pm Post subject: Programmable ECU - Dr. Digifant |
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Has anyone heard of or had any experience with Dr. Digifant's products? He offers a programable digifant ECU that utilizes a modified throttle. It does away with the click closed, click full throttle design and employs a potentiometer to provide a signal for his modified control unit. He seems to indicate that his ECU makes the input from the AFM (LMM) superfluous. He also has a "freely programable" blue tooth version. Rumor has it that it will fire injectors individually instead of batch, but that isn't confirmed on his web site. Its great to see continued interest in developing waterboxer tech. Anyone know if this is this what Marco is using? Flame me if this is old news and I missed the post
https://doctor-digifant.com/
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khughes Samba Member
Joined: July 13, 2013 Posts: 736 Location: Phoenix AZ
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Posted: Mon Dec 07, 2020 2:48 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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Interesting, never seen this before. I would question whether it can fire injectors at all since it is merely inserted between the TB and the ECU. It wouldn't know what injector to fire without a crank sensor.
Apparently he's taking control algorithms from Motronic systems configured without a MAF, using a MAP sensor instead, to estimate mass airflow. Using the throttle plate angle, RPM, inlet air temp, and fixed engine displacement, instead of manifold pressure, TP angle, and RPM, value to calculate mass airflow, instead of direct MAF measurement. Should work as long as the temp sensor in the AFM isn't hinky from age.
If he has the fuel maps well designed and the algorithms tuned, it would be a fairly elegant solution compared with gutting the whole thing for a GW setup for e.g. I'd jump right on it and be the guinea pig, but alas, I have no WBX _________________ '86 Westy FAS GenV Turbo (Marvin) |
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valvecovergasket Samba Member
Joined: October 10, 2018 Posts: 1491 Location: pnw
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Posted: Mon Dec 07, 2020 3:38 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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khughes wrote: |
Apparently he's taking control algorithms from Motronic systems configured without a MAF, using a MAP sensor instead, to estimate mass airflow. Using the throttle plate angle, RPM, inlet air temp, and fixed engine displacement, instead of manifold pressure, TP angle, and RPM, value to calculate mass airflow, instead of direct MAF measurement. Should work as long as the temp sensor in the AFM isn't hinky from age.
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yeah that should work fine, as you said. its not alpha-n anyway so it should be relatively forgiving
as you said - im sure its not firing anything sequentially without additional position sensors
i guess it is possible it fires the injectors in batches but with individual (or paired up?) drivers... not sure how thatd be a benefit huge benefit but whatever works!
if it comes with a canned tune, its worth a shot!
curious to see what the interface looks like, i suspect this is some form of modified MS though (there are a handful of pretty popular MS modified variants floating around) _________________ MegaSquirt resource - SpitfireEFI.com
gone, but not forgotten: '83 tdi westy - swap thread |
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skills@eurocarsplus Samba Peckerhead
Joined: January 01, 2007 Posts: 16801 Location: sticksville, ct.
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Posted: Mon Dec 07, 2020 4:59 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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khughes wrote: |
Interesting, never seen this before. I would question whether it can fire injectors at all since it is merely inserted between the TB and the ECU. It wouldn't know what injector to fire without a crank sensor. |
done thru the distributor
https://www.efihardware.com/products/2622/Sequential-Distributor-To-Suit-Your-Engine
and honestly, you'd really want a cam sensor for precise injection control. a crank sensor is basically there for rpm and ignition timing.
batch fire works well to cool cylinders but you get cleaner emissions an a bit better idle with sequential _________________
gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
Jake Raby wrote: |
Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
Brian wrote: |
Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
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RawUmber Samba Member
Joined: June 23, 2019 Posts: 223
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Posted: Mon Dec 07, 2020 5:11 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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I didn't see much text on the website, but noticed a few things from the pictures. It looks like he's using a board from no-limits-motorsport.de which I deduce he has customized and programmed to control the WBX.
The integrated pressure sensor is notable, and may account for the comment about not needing an AFM, as others have suggested.
From the looks of the transistors, he may indeed have individual fuel injector control. But the programming would determine if they fire individually or not. While the Digijet (1.9l WBX) has individual Fuel Injection wires between the injectors and the the ECU (11,12,23,24), the Digifant (2.1l WBX) injectors share one (pin 12). In other words, using this with an existing Digifant system, you'd need a few more wires to individualize the fuel injectors if you want to go that way.
To my eye, some of the components appear a little under-rated for longterm use (though the pics may be of a prototype). The DB25 connector might not be able to handle the full current/amps and get worse in time. The spacing on the driver transistors is awfully close, which could lead to overheating on long/hot drives if the case is not actively cooled. But whatever, if this works it's an impressive start and he can improve upon it as needed.
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32432 Location: Reading Pennsylvania
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Vanagon Nut Samba Member
Joined: February 08, 2008 Posts: 10347 Location: Sunshine Coast B.C.
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Posted: Mon Dec 07, 2020 7:32 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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khughes wrote: |
....using a MAP sensor instead, to estimate mass airflow.
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So that metal nipple is where the vacuum hose to MAP interfaces?
Neil. _________________ 1981 Westy DIY 15º ABA
1988 West DIY 50º ABA
VE7TBN |
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valvecovergasket Samba Member
Joined: October 10, 2018 Posts: 1491 Location: pnw
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Posted: Mon Dec 07, 2020 7:49 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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RawUmber wrote: |
The DB25 connector might not be able to handle the full current/amps and get worse in time. |
For what it's worth different flavors of DB connectors have been on thousands of MS setups without issue. Surprising for a computer component, but, it works...
Vanagon Nut wrote: |
So that metal nipple is where the vacuum hose to MAP interfaces?
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Yup, there's probably a short run of internal hose inside between that case nipple and the sensor itself
khughes wrote: |
Apparently he's taking control algorithms from Motronic systems configured without a MAF, using a MAP sensor instead, to estimate mass airflow. Using the throttle plate angle, RPM, inlet air temp, and fixed engine displacement, instead of manifold pressure, TP angle, and RPM, value to calculate mass airflow, instead of direct MAF measurement. Should work as long as the temp sensor in the AFM isn't hinky from age.
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For what it's worth for a speed-density setup you don't need throttle angle. Engine speed, pressure and temperature, with a known displacement is enough. _________________ MegaSquirt resource - SpitfireEFI.com
gone, but not forgotten: '83 tdi westy - swap thread |
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Vanagon Nut Samba Member
Joined: February 08, 2008 Posts: 10347 Location: Sunshine Coast B.C.
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Posted: Mon Dec 07, 2020 8:04 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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valvecovergasket wrote: |
Vanagon Nut wrote: |
So that metal nipple is where the vacuum hose to MAP interfaces?
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Yup, there's probably a short run of internal hose inside between that case nipple and the sensor itself |
Thanks. Like it does on the 5 cylinder Eurovan ECU, if I recall.
Neil. _________________ 1981 Westy DIY 15º ABA
1988 West DIY 50º ABA
VE7TBN |
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khughes Samba Member
Joined: July 13, 2013 Posts: 736 Location: Phoenix AZ
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Posted: Mon Dec 07, 2020 8:47 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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Vanagon Nut wrote: |
So that metal nipple is where the vacuum hose to MAP interfaces?
Neil. |
No, I don't think so. I don't think it has a MAP sensor. Just saying that the "type" of algorithm that some Motronics use, with a MAP along with other sensors to calculate mass airflow, could also be done with a similar calculational approach. You can use RPM, displacement, Throttle position, and temp to do the same kind of calc. Just not as accurate as a direct measurement, but it works.
This box can get the air temp directly, the TP directly, and the RPM from the ECU (Hall sensor pulses) and displacement to do a similar calculation. Different way to skin the cat. _________________ '86 Westy FAS GenV Turbo (Marvin) |
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uberaudi Samba Member
Joined: June 24, 2013 Posts: 494 Location: Hi-top Country
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Posted: Mon Dec 07, 2020 9:06 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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Very cool. Eliminating those tb switches and the afm would pretty much take care of any driveability issues I've had over the years. I'd love to see this in action. _________________ '84 Adventurewagen 1Z Tdi, '89 Tintop ABA, and a 86 Syncro tintop WBX. |
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Zeitgeist 13 Samba Member
Joined: March 05, 2009 Posts: 12103 Location: Port Manteau
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Posted: Tue Dec 08, 2020 12:43 am Post subject: Re: Programmable ECU - Dr. Digifant |
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I'd like to see a kit that also gets rid of the distributor. With nearly twenty years of WBX ownership, I've gone through two Hall senders, one coil and had several bouts of TPS issues. _________________ Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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hdenter Samba Member
Joined: October 14, 2008 Posts: 2749 Location: San Luis Obispo, CA
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Posted: Tue Dec 08, 2020 8:36 am Post subject: Re: Programmable ECU - Dr. Digifant |
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Is there a price on this thing that I'm not seeing?
Hans _________________ '79 triple white convertible bug
'84 sunroof vanagon
'85 weekender |
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4Gears4Tires Samba Member
Joined: October 08, 2018 Posts: 2982 Location: MD
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Posted: Fri Dec 11, 2020 6:30 am Post subject: Re: Programmable ECU - Dr. Digifant |
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This will be awesome. Having done the same swap on my e30 (megasquirt, using MAP) I know the throttle response, power, and delivery are all massively improved.
I, too, would like to see a price. I'm assuming somewhere around $1000-$1200. The dollar isn't doing too hot right through, so maybe quite a bit more. _________________ '87 Syncro
Ferric Oxyhydroxide Superleggera Edition |
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SyncroHead Samba Member
Joined: May 23, 2005 Posts: 1139 Location: Northern Nevada
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Posted: Fri Dec 11, 2020 9:12 am Post subject: Re: Programmable ECU - Dr. Digifant |
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Zeitgeist 13 wrote: |
I'd like to see a kit that also gets rid of the distributor. With nearly twenty years of WBX ownership, I've gone through two Hall senders, one coil and had several bouts of TPS issues. |
This would be GoWesty's EFI setup...
(Uses the previous distributer location for a position sensor.)
https://www.gowesty.com/product/electrical/23981/g...nt-kit-?v= _________________ "A Vanagon? It's not a car or a van. It's a hobby!"
Check out:
www.VANAVATION.com
www.SyncroSafari.org and
www.Vanagons.org
sphet wrote: |
I have *no* idea what the previous owner carried in his Westy... angry donkeys? |
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valvecovergasket Samba Member
Joined: October 10, 2018 Posts: 1491 Location: pnw
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Posted: Fri Dec 11, 2020 9:31 am Post subject: Re: Programmable ECU - Dr. Digifant |
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SyncroHead wrote: |
Zeitgeist 13 wrote: |
I'd like to see a kit that also gets rid of the distributor. With nearly twenty years of WBX ownership, I've gone through two Hall senders, one coil and had several bouts of TPS issues. |
This would be GoWesty's EFI setup... |
just skimming the long thread here on that system it seems like it could be a much more powerful add on if it allowed folks to further tune it themselves. _________________ MegaSquirt resource - SpitfireEFI.com
gone, but not forgotten: '83 tdi westy - swap thread |
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ARMc Samba Member
Joined: February 10, 2012 Posts: 116 Location: Wisconsin
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Posted: Fri Dec 11, 2020 7:07 pm Post subject: Re: Programmable ECU - Dr. Digifant |
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A few days ago I emailed Dr. Digifant to alert him to him of this discussion, to see if he might chime in and answer our questions. I figured he'd might also see it as an opportunity to build interest around his product. Maybe if more of us poked and prodded him he would give us some answers. |
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