924Board.org

[Mayhemlv]

My car has been running rich and smoking, even after new injectors, injector seals, plugs, fuel accumulator, and I had a shop adjust fuel pressure back to specs. According to the mechanic, it was running rich to compensate for leaky injectors/seals. It still runs rich, but not as bad. With the smoke, I cannot smog it in Las Vegas. My only concern with doing the conversion, is that my problem will still exist post conversion, due to a valve/cam issue. Thing is, for the cost of the parts (WUR, fuel pump, injectors etc etc), I could have bought enough parts to do two or three conversions!
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86 951
82 924 Gone to 924 Heaven
80 931

[ksis]

The nice thing about this conversion is, I can revert back to the old in a day.
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77 924
64 Spitfire
76 TR6
04 Jetta
77 Schwinn Scrambler
Awsome pair of Chucks

http://www.cardomain.com/id/ksiskin

[PorscheDrift]

Ive looked over this thread a few times before i registered and i have a few questions about this conversion.

In the pictures what kind of fuel rail do you have mounted? Is that the 420a neon rail, and if so what year neon rail did you use for this conversion?

Also i was curious about what digifant you used since the donor car was a 92 and they had a overlap of digifant 1/2 systems between 91-92. Also are you using a cis-e knock sensor with the control unit on this conversion?

[PorscheDrift]

I was also wondering with the setup the way you have it right now are you running the IAT sensor as well?

Looking over the diagrams of the digifant systems it looks very similar to most electronic fuel injection setups from the 80s and early 90s. The type 1 appears to have a full throttle and closed throttle(idle) switch on the bottom of the tb, which actually is almost the same as what the later 924's have, my 82 has the same set of switches on the bottom of it so perhaps a tb swap isnt needed on a newer model 24 just wire in the switches instead to save a couple bucks.

If it has closed throttle switches its safe to assume that when the switch is opened the car only uses inputs from the o2 sensor and the afm like most cars from the 80s did to get its information until it hits wot then it begins to run a preconfigured map for "full throttle"

I also noticed this has a heated o2 sensor which means that it uses the o2 and most likely the IAT to aid in idling until it senses that the car has warmed up. I also know these use the CTS sensor for alot of input as well.

Basically what i am trying to say is that its running right now which is sweet, but without a working o2 sensor and a IAT its running in limp mode, running a failsafe map and not actually doing what its supposed to do until full throttle which would explain the power loss in the lower rpms and the idle issues.

Keep in mind its also running a failsafe map for a completely different engine which could be very dangerous in the long run.

I plan on doing this conversion as well and am going out to the yard tommrow to begin sourcing parts, so i dont want anyone to think im bagging on this in any way shape or form. I really REALLY like this whole concept and am just trying to contribute and add some constructive input in areas that nobodys covered in this thread so far.

If i said anything incorrect please feel free to set me strait
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80 euro
82 usdm
and all kinds of rice

[PorscheDrift]

Alright ive been doing alot of research into this digifant conversion, and have already sourced everything needed to do a conversion except the yard closed before i could finish pulling the harness.

You can use the tb from the newer 2-4's that have the dual throttle switches at the bottom for idle/wot. The iat is built into the afm on these so it is hooked up regardless. Should of realized that because its just like the afms on my fc3's.

Also it is possible to run a newer maf (3wire hollow tube style) and a seperate iat on the digi ecus if you use a afm translator wired in...

It would be recommended to try and source the afm off a 85-87 5 series because of the larger inlet/outlet and it already has a conical adapter for the stock air box attached. A 5 wire flap afm from any bimmer 6 engine should work IF YOU ADJUST THE SPRING TENSION ON THE DOOR. I had found a maf from a 318i and pulled the adapter and threw it on the digi maf their basically the same unit...

ALSO it would be wise to look into using a bimmers efi setup from a mid 80's 1.8 as a possible swap candidate because everything seems to be the same even the firing order as the 924. Except the tb is the size of a quarter.....Lame, its a B-M alright.... back on topic.

Any digi ecu 8v or 16v would work, stick or autotragic and actually sourcing a digi1 ecu would be a better option because there are chips available, and tuning/logging is a option with them.

The distributor is a great idea if your going to something like a megasquirt and dont want to run a coil pack and a cps wheel, a friend who is a hardcore vw tuner had recommended that to me awhile back when i first started kicking around a low budget ms build. He also found it amusing that i would "downgrade" from a cis to a "digifart" setup but understands because we recently ran into fuel issues during hard sliding. And carbs would actually be worse soooooo digi seems to be the direction until the itb manifold is fabbed up......

The injectors in these cars are 22lb/hr or in useful terms 231/cc at roughly 34psi and 80% duty cycle which translates to hp capability of 145 at stock fuel pressure. Possibly in the 150 range if you bump it to the more standard 43. These cars rarely are capable of running anything other than their stock injectors so please keep that in mind when sourcing parts.

O2 sensor from a newer 2-4 can be used as well you just dont wire in the 2 heater wires or you could run it with a universal 4 wire which is what i am doing and running the extra ground wire as a sheild instead of having it pick up ground through the exhaust like a 3-1 wire does. All o2 sensors are pretty much the same when your talking narrowband.

The idler valve, cts, and o2 can also be swapped over if you plan on doing a ms conversion so really this is a great thread because if you do this and convert to digi it would make a jump to megasquirt EXTREMELY affordable as in under the 700 range and a simple pinout would be used to wire up the ms box.

As far as performance....... I cant judge on that yet, but from what ive experienced with other digi cars its not a performance based system, it was designed for economy. But, it is reliable when properly maintained so really is it that much better than the cis?? probably not. Possibly worse because digi was a very economy based system on everything but the g60 and on the Gti's.

Also please keep in mind the original swap was done with a **GTI** computer so it has a more aggressive tune than the ecu out of a jetta or a fox or golf. The nice thing about digi is that it can handle a decent size agressive cam and 10:1cr all day without causing issues as long as your staying NA with the car.

Digifant doesnt work with a turbo setup if anyone was wondering. If you would upgrade to a header Audi5k tb a bimmer 5 afm and ditch that goofy tb coupler you MAY see a boost over the 924's cis system in its stock form. Im more curious if this is going to make a sh!t worth of difference with the header and full 70mm exhaust on my car.
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80 euro
82 usdm
and all kinds of rice

[ksis]

PM sent.
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77 924
64 Spitfire
76 TR6
04 Jetta
77 Schwinn Scrambler
Awsome pair of Chucks

http://www.cardomain.com/id/ksiskin

[Jeremy924]

1981 924 N/A. 15in spiderweb wheels(two sets, minus one)

ive owned the car for about 7 years. unfortunatly it hasnt been on the road in about 4 or so. In an attempt to get it drivable, i replaced the main fuel pump, relay, ditched the in tank secondary pump and got a 928 fuel screen, fuel filter. As i was making my way to the front i came to the fuel distributor, seemed to be in working order. so i cranked it over a few revolutions and then it suddenly stopped! Took out #1 plug and sure enough.. vapor locked with fuel!! come to find out the K-jetronic plunger is seased up....Max fuel pressure, injectors in full blast mode... (FML) Going to junk it and go with EFI

Thus, i came online here and found this thread about EFI conversion! Ksis is on the right track here.
Origional conversion plans was to do a SBC conversion "renegade hybrids style", unfortunatly out of my budget range...

Ksis:: what year varience of GTI have those parts you pulled for your conversion?? also, could you do a walk-a-round youtube vid of your success? Please!?

Also, how much $ would you estimate the build would cost?

Here, in Phoenix, the junkyards are pretty expensive... (Ecology, Pull a part, Pick a part, and many others on Broadway and 32nd ave)

Thanks for your support.
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1981 924 N/A
1999 Suburban 454
1989 BMW 525I

[Jeremy924]

what do you guys think about these injectors?? there a little bit longer.

Fuel Injector/Nozzle For NISSAN OEM 16600-ED000=FBY1160
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1981 924 N/A
1999 Suburban 454
1989 BMW 525I