1983 URQ Alpine White/Mocha 20VT / VEMS / EFR

[Afterthought]

Kirk it’s a no go on the b5 [FACE WITH TEARS OF JOY] best orientation points it the outlet toward the firewall





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[vt10vt]

This is looking fantastic. All you need is a new coolant bottle

This forum and its obsession with coolant bottles

Always like seeing updates here, great work as usual!

[Nateflix56]

Have you tried a mk3 reservoir? Should be relatively easy to make one of those work, and it's small so would save quite a bit of space vs the B5 one.

[varia]

b3 90/cq fits

[the german]

Since I'm an instigator of scope creep.... you could do an aluminum one and paint it to match the motor. Plenty of options out there to either make or buy one that fits where you want it to be. That would also give you options to go with a higher or lower PSI cap if want as well.

This looks reasonable:
https://tprace.com/products/universal-coolant-expansion-tank-with-sight-tube

[the german]

This is looking fantastic. All you need is a new coolant bottle

This forum and its obsession with coolant bottles

that's why I said it!

Both of my CQ's still have old crusty coolant bottles in them. I've had a new OEM one for my red car for 3-4 years now that I've been too lazy to install. That said, the crusty old bottle does look rather out of place next to Pat's shiny engine bay.

[vt10vt]

This is looking fantastic. All you need is a new coolant bottle

This forum and its obsession with coolant bottles

that's why I said it!

Both of my CQ's still have old crusty coolant bottles in them. I've had a new OEM one for my red car for 3-4 years now that I've been too lazy to install. That said, the crusty old bottle does look rather out of place next to Pat's shiny engine bay.

It's definitely one of those "can't be unseen" things. Once you notice one gross coolant reservoir, you notice them all.

[alxdgr8]

Subaru ones are pretty small, bet you could find a place to put one.

https://www.mishimoto.com/subaru-wrx-02 ... -tank.html





Or a Mustang one

[Afterthought]

Well two tries now and they were all wrong when I got them . So aluminum would be an option and I do love making stuff . Mill is down for a while means I can’t cut anymore aluminum bungs but that wouldn’t be too much an issue . It’s not pressing now though as my reservoir holds fluid . And I have other things to do/time is running out/work/life etc so that will wait a bit . I have an idea in my head looks somewhat like a works fuel tank though.

So my love for working inside the car has brought me back , I got the steering linkage all out back together . It was removed from the rack on , so now I have cleaned all the little splines and re assembled everything . Interior is slowly going to start getting better .







And going to see if I can make anything reasonable out of aluminum for the top shroud on the radiator . Haven’t been able to find a plastic one yet , as easy as it would sound

[rennenmsports]

Looks good buddy!

[Afterthought]

Thanks ! It’s coming along .
Connected the 12V power to ECU and starter wire today run from the original location in the fuse box. So that takes care of two of the stock wires I needed to figure out .
Power to ECU is coming from this green/violet wire which is one of the original 3 wires that ran to the stock ECU from the fuse panel. so it’s a “15” which should be switched power from B50A

Other is br/green which I haven’t tracked back yet and a 1.5 black wire

Starter comes from the E plug.
Still need to look into this if it’s a ground and how to route the fuel pump and tach wire and then I * should * have all the terminations I need to make sure the ECU is getting the power it needs


Old stuff out

[Afterthought]

Was looking at this today and don’t know why I didn’t notice it before . The Indy turbo does not have a spot on it for the reference line where boost is provided to the N75.
I’m wondering if anyone has run in to this before. Thinking the easiest solution would be to take it off and tap it , find a suitable banjo bolt with a barbed fitting .




I could run it from the intake manifold but I don’t know if that would have some sort of delay or not ???

I’m trying to work on the layout for all the vacuum lines and what not and figure out what does where .
I have 4 barbs in the intake manifold now . So I was thinking
1- straight to fuel press. Regulator
2- straight to ECU
3- to blowoff valve
4 - tbd (can’t remember where supplies diff/etc)

[Afterthought]

Might run that line to the N75 off of the charge pipe . As I’m afraid to tap the turbo housing . THere isn’t a flat spot on it anywhere .
This is the best I could find locally


Throttle cable solution , found some coated cable and made my own ends . Now I can use the proper housing from a carbureted 80 and have my own length .

[the german]

Good problem solving, I like the detail.

[Afterthought]

Worked on the wiring a little . Still hate wiring .
I started tracing these three wires back from the ECU to the drivers side .
Green/violet - runs through a white/red plug then a green plug under the dash, then eventually to the black “B” plug on the fuse box , CEP pin S on the black plug.
THis should tell the fuel pump relay to activate . This is where I’m going to connect my fuel pump signal I think .
So if I have the idea right the fuel pump wire from the vems econoseal ECU will trigger the factory fuel pump relay. But I’m not sure because I think it’s already relayed inside the harness .





Next I need to find a suitable spot for +12v supply to the ECU , maybe from the ignition switch ?


Hope to get this wiring out of the way soon so I can get the interior put in.

Weld practice


Trying to organize tools

[vt10vt]

I can't read your diagram (pic is too small/fuzzy) but yes, the fuel pump wire from the Econoseal will ground the factory fuel pump relay closed. There should be a switched ground that went to the original ECU, and that wire should just go to the VEMS fuel pump relay circuit.

HOWEVER- I really, really wouldn't use the factory Econoseal Fuel Pump circuit. It's a very weak circuit (a P259) and can actually be pulled shut through the relay under high amp fuel pump operation. Marc and I had to troubleshoot this on his dyno; when I got over 20psi and my fuel pressure demanded higher amps from the pump, it would just pull the whole circuit shut and kill the motor. Key off/on and it was fine until we hit the same boost again. Solution was to switch fuel pump triggering to a spare injector output.

[Afterthought]

I did not know about issues with the VEMS relay. I don’t have any diagrams for mine to see how it’s set up but I could call Marc to ask exactly . He made the full custom harness for me with relays and all. With pulling power directly from the battery and starter circuit I would think I wouldn’t have any issues with voltage drop - but maybe I’m not understanding what causes is to pull closed .



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[Afterthought]

For power to the ECU , I traced back and found where the stock ECU gets its switched 12V power supply from . It comes from this red plug “I” and provides power to the Mac-02 ECU and the coils . I “15” . So tied into that wire for my VEMS ECU


THe last thing I have to figure out, interior wiring wise. One wire left to go.
I’m trying to trace back where the RPM signal gets to the cluster .
Starting at the cluster , red/blk/yellow wire.

Runs from there to the red plug pictured above , “I” plug pin 1. But I don’t know how it gets to that plug. Tracking things back the only other red wire with black and yellow stripe runs from the interior of the car to the coil .


Traced that one and metered out from the engine bay to plug “B” pin 1 .



Now at this point I feel comfortable assembling a few things because I know that I’m almost done with interior connections then the remainder of what I have to do is sort out what can go in the engine bay that’s left over from the old WX wiring . And how to delete it properly

[vt10vt]

I did not know about issues with the VEMS relay. I don’t have any diagrams for mine to see how it’s set up but I could call Marc to ask exactly . He made the full custom harness for me with relays and all. With pulling power directly from the battery and starter circuit I would think I wouldn’t have any issues with voltage drop - but maybe I’m not understanding what causes is to pull closed .

Think of it as a switch and a separate relay. The relay that actually powers the fuel pump is the OEM wiring in the car. VEMS contains an onboard PNP driver, which is basically a small switch that opens/closes to ground. This onboard driver is what turns the OEM fuel pump relay on/off as VEMS sees fit.

When pump voltage gets high enough, the internal resistance from the OEM relay can actually be enough that the onboard PNP driver can't keep the relay closed (on), so the fuel pump will lose power until you cycle the key. The solution is to use a stronger onboard driver like an injector or ignition output. The VEMS factory spec'd PNP driver is just not strong enough to drive a fuel pump at full boogie and high boost.

I've seen a few people have this issue, I'm sure there's ways around it through redundant grounding of the OEM relay or something, but it's probably easier to just swap around fuel pump output pins at this stage in the game and save yourself a potential troubleshooting/rewiring headache down the road.

[FFF]

Interior is starting to come together - the joys of chasing Audi wiring in particular has no bounds!!


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[Afterthought]

Interior is starting to come together - the joys of chasing Audi wiring in particular has no bounds!!


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Yeah... I’m still learning how to read the diagrams but I have learned a lot . Not sure If it’s me or the diagrams but I think this particular car has really been a challenge being that it was one of the first to have an underhood fuse box.
I have found some discrepancies . I’m working off of one 1983 wiring diagram and also a 1985 wiring diagram. And I think it’s kind of in between.
I find that the fusebox connections seem to be the same on both but easier to follow on the 85 diagram. However the ECU connections on the 85 diagram definitely aren’t right . So I have to refer back to the 83 diagram for that . Then follow each individual wire from one end back to connectors and fusebox one at a time and confirm by toning with multimeter. Then confirm those findings with diagram . even through all those layers I have found myself making a few mistakes
as I am looking at an upside down spare fusebox to see where wires come in to the right-side-up one in the car.
But by the end of it I’ll be sure what I have and where .
Additionally I am trying to cross check with this diagram and I’ve honestly only found a few differences in the B2 .

[Afterthought]

Oil lines mounted here for now . Will see how it looks once I get the bumper on and stuff .


Installed pressure tap. Decided to keep it out of the turbo housing .



N75 is tucked away behind the headlight as I didn’t want to drill any holes in anything to mount it . Most of he vacuum lines are done





Still many little things to do . This weekend I think I’ll drain and refill the trans and diff . Need to finish a few things then add oil & coolant .
Install new fuel pump (drain tank?)
Etc

[the german]

Your weld beads are looking goooood!

The all black looks mean. I love it.

[ringbearer]

Looks great, nice tight packaging. Any room to get that air filter farther forward?

[Afterthought]

Looks great, nice tight packaging. Any room to get that air filter farther forward?

I could , or could run a different air filter . But I was thinking maybe I can do a box around it at some point . I have some carbon fiber ducts from Indy car, maybe I could incorporate those to sweep air up from the valence area ?


Working on getting the fuel pump in. I am going to simplify a little bit under the car and have the pump with an new line out straight to the filter- which will delete the factory plastic lines and be braided high pressure line to metal.

This fitting for the Inlet is an adapter I made , in the outlet I am going to see if I can get a banjo that will work here . I could run an m12xAN 6 fitting on the pump outlet but I’m not sure if deleting this check valve will be a good ideA