924Board.org

[McGyver]

I heard 931 DITC unit don't have any memory like EPROM or EEPROM and is build on logical gates and resistors. Have anyone get photos from inside of this unit, or better from rare 937 unit which should be simmilar to 931 so it's possible to make copy of it which could cost much more than new unit (850 Euros). What you think about makeing something like that?
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931 82' - 5000km after full engine rebuild

SOLD: 924 81' N/A- with turbo gearbox "dogleg" - great but mysterious car
www.mauser98k.internetdsl.pl - if someone like german rifles (English version avalible)

[gegge]

Seach and you will find the photos. Cedric posted a pict of mine.

By the way, there is a 937 DITC for sale on Ebay.de for EUR750
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Carl Fredrik Torkildsen

924 turbo -81 Carrera GT RESTOMOD
924 turbo -80 Dolomite De Luxe
924 -85 DP kit, BBS RS, M030 and tuned engine
924s -86 Black on black turbo with Fuchs

[Cedric]

http://forumbilder.se/show.aspx?iid=e61200911133P3631

I have plenty of more if you wish..
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1980 924 Turbo
www.instagram.com/garagecedric/

[gegge]

McGyver, if you got the knowlegde to understand the design of the circuitboard it would be much appreciated if you tried. Maybe it would be possible to make an adjustable DITC? Or compensate for increased boost? Just connecting the DITC to an oscilloscope and get the ignition map would be great!

Cedric you are fast - answering within a minute after my post!

EDIT: Sorry the 937 is costing EUR 790

http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&item=220524375583&viewitem=&sspagename=STRK%3AMEWAX%3AIT
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Carl Fredrik Torkildsen

924 turbo -81 Carrera GT RESTOMOD
924 turbo -80 Dolomite De Luxe
924 -85 DP kit, BBS RS, M030 and tuned engine
924s -86 Black on black turbo with Fuchs

[Dutch924-racer]

I think the 790 is a reasonable price. This is an extremly rare part, just like the 937 intcooler which will cost you more then double.

Of course I can only say this because I am the happy owner of a 937 unit
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937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

[morghen]

i'm seriously thinking of buying that 937 DITC...i've sent the seller an email.
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https://www.the924.com

[Khal]

Sometimes I wish I had've finished my computer science course at college. That old DITC (Carrera GT or otherwise) must be sooooo easy to duplicate with modern electrickery, and then make it configurable...
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'80 924 Turbo

[morghen]

To be able to replicate or create something similar we first need to study and understand how the DITC works.
A great idea would be if we could design a product that would BOLT ON in place of the DITC and would give CGT or better advance curves and some tuneability.

Basic description of the DITC is the following:

system has 5 inputs:

-charge air temp
-charge pressure
-coolant water temp
-RPM
-TPS

system has one output.

-advance/retard

Further:

A)It needs to be investigated and established weather the DITC reads analogue signals and processes them as they are or it has some sort of quantizer chopping the input signals and turning them into digitals.
All the input signals need to be identified(voltage,code whatever they are).

B)It also needs to be investigated what the output signal is, it could be voltage,amperage,or a hybrid complex signal, perhaps a code of some sort.

After we know all this we can move further to looking for ready devices that we could modify to behave as we want.
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https://www.the924.com

[924RACR]

What morghen just said. Electronics science has come a long way in the past 30 years; it should be relatively straightforward to design a controller board that will replicate the needs, with modern, cheaper, more powerful, more readily available, and more robust components - not to mention adding the adjustability requested.

Furthermore, while we're at it, why don't we get rid of the troublesome NLA crank sensor. We could probably upgrade some other sensors too, like ditch the switch-based throttle position sensor for a true potentiometer-based TPS.

So, anyone for a Megasquirt group buy?

Seriously - the major advantages for such a proposed project would be plug-in compatibility with stock sensors and wiring harness. Otherwise you're talking about a Megasquirt.

If I could find time to motivate my friendly local EE, also known as my crew chief, we could investigate what it'd take to drop in a new, commonly-available crank position sensor and use that to trigger the Megasquirt.

If I ever have any time left over after rebuilding my 931, we plan to drop in an intercooler and either go Megasquirt or similar, at which point we should look at it - seems easier, potentially, than having to add a trigger wheel.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[flosho]

It would be just amazing to be able to remap the stock ignition curve and then be able to change it via a controller..

Would benefit both EFI guys and CIS guys that want to raise their boost level. I wouldn't have to piece together my ignition map from scratch! See how close I got it to the stock map...
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[This Space For Rent]

[morghen]

bolt on would be the best, with the option of using another crank sensor as well.

the thing is if we base our design on MS we would have a binary logic system...this means tables and rigidity.
would be interesting to see if we could find a fuzzy logic controller that could do the work, anyone here that can back me up on the fuzzy logic controller?
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https://www.the924.com

[McGyver]

At start I need more detailed photos of that unit - so I can make a circuitboard project and some logical deductions how it work's.
Right now I check what logical elements could be found in that 931 unit.


Any ot that IC's is so easy to get right now, even make by Motorola like in original So it's possible to understand what is going on here... I'm working on it - maybe a little to slow but it going futher.
_________________
931 82' - 5000km after full engine rebuild

SOLD: 924 81' N/A- with turbo gearbox "dogleg" - great but mysterious car
www.mauser98k.internetdsl.pl - if someone like german rifles (English version avalible)

[morghen]

Great ! are you familiar with MathLab? i think so...am i right?
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https://www.the924.com

[McGyver]

I'm electronical & telecommunication engineer and I make several projects using logical gates... later I use I 8051 microprocessor.
I use matlab software on studies few years ago.
There's more quite good programs which could help with logical gates simulation.
There is few important imputs in this DITC:
1 - flywhell sensor - most important part - DITC can't work without it
And what can be disconected but DITC will still works - but not correctly
2 - pressure sensor
3 - Throttle swich
4 - Temperature sensor

Most imputs are analog.
I think flywheel sensor gives timming to counters so it's most important.
I have to check connections between all elements which is hard haveing only one photo... and the circuit board should have connections on booth sides - I wish to know what's there... and ofcourse what capacitors, diodes and resistors were used there.
It's not too complicated so could be copied and upgraded.
If I get more detailed photos and all info anyone can provide about used elements i can make circuit board in Eagle Layout editor.
_________________
931 82' - 5000km after full engine rebuild

SOLD: 924 81' N/A- with turbo gearbox "dogleg" - great but mysterious car
www.mauser98k.internetdsl.pl - if someone like german rifles (English version avalible)

[Rich H]

Where does the 'spark-map' live then? I'd have thought there should be an EPROM or something...
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1994 Lotus Esprit S4 - Work in progress...
1980 Porsche 924 S2 DITC Turbo - Original spec
1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec