Ben's 95 90 Quattro 20vT - now with corn power!

[vt10vt]

Also, congratulations on getting it going, this is looking awesome!

[ChrisAudi80]

Great news. Good to see it is sorted now.

[Grillage]

I think the Fuel Pump channel was doing something wonky, maybe not grounding properly?

What fuel pump are you running and did you have to re pin the harness with the new ECU? I had issues with the standard issue VEMS fuel pump trigger running my Walbro 400 and had to use an injector driver, but if that's the issue you'd have had to repin the FP relay trigger.

I am also running a Walbro. I had to move the fuel pump signal from EC36-15 to elsewhere - I used EC36-3 and it seemed to solve the problem

It had been behaving this way prior - I wasn't sure if it was "normal" due to being a big ass fuel pump and a FPR that I've never dealt with:

[vt10vt]

I think the Fuel Pump channel was doing something wonky, maybe not grounding properly?

What fuel pump are you running and did you have to re pin the harness with the new ECU? I had issues with the standard issue VEMS fuel pump trigger running my Walbro 400 and had to use an injector driver, but if that's the issue you'd have had to repin the FP relay trigger.

I am also running a Walbro. I had to move the fuel pump signal from EC36-15 to elsewhere - I used EC36-3 and it seemed to solve the problem

It had been behaving this way prior - I wasn't sure if it was "normal" due to being a big ass fuel pump and a FPR that I've never dealt with:

Sounds like a similar issue to what I was running into. If you're using the factory 12v to the fuel pump I'd recommend stepping up the wire gauge as well and I don't know how B4 wiring is, but maybe even a direct 12v from the battery to the relay and then back to the pump. Those 400s draw more amps at idle than an 044 does at 6 bar lol.

Anyway, glad you're making progress, and again, nice work as always!

[Afterthought]

Theres something funny about VEMS and the drivers like P259 .
I’ve had issues with mine as well, not working properly with my cooling fan.


Good to hear you got it running , probably time to get some test drive and seat the rings

[ChrisAudi80]

Theres something funny about VEMS and the drivers like P259 .
I’ve had issues with mine as well, not working properly with my cooling fan.


Good to hear you got it running , probably time to get some test drive and seat the rings

You should not use P259 for switching relays. They are sensitive to voltage spikes and backfeed (?).
When I made a dedicated relay for the fuel pump, I changed FP out from 36-15 to 36-9. Injector output seems to work way better.
A coil driver doesn't always work because it is logic level IIRC.

[Grillage]

You should not use P259 for switching relays. They are sensitive to voltage spikes and backfeed (?).
When I made a dedicated relay for the fuel pump, I changed FP out from 36-15 to 36-9. Injector output seems to work way better.
A coil driver doesn't always work because it is logic level IIRC.

I ended up moving it again after talking with Marc. I had an issue where the fuel pump relay was sticking ON after turning off the car. He mentioned that this was sometimes an issue and that the solution was to move the fuel pump signal to a stepper and invert. So far that has solved the problem


Also, I DROVE THE DAMN CAR yesterday! I had some major brake bleeding problems and it took me a few tries to get it to bleed all the way through. I had some issues but Marc is adjusting my tune and I’ll try again when I’m back in town next week. Either way, it was a really good feeling to get it out on the road. I forgot I had replaced the tie rods and that the car is WAY out of alignment but still felt good. Feels so much better than the V6 for sure - even on super low boost

[Afterthought]

Makes sense . As Chris was mentioning , some of those drivers are weak or something . For example on mine , the cooling fan is relayed and that is done internally to my engine harness. Vems grounds the relay to turn the fan on.
As a result when I powered up the car , as soon as the relay had power my cooling fan would be on no matter what .
If the battery was connected, fan was on.
I believe this is because some of the drivers in vems (like that P.259 for example) can maybe allow path to ground when they shouldn’t , not sure if that means they need a diode or what . I don’t fully understand it yet .
Anyway don’t mean to hijack your thread but maybe that will shed some light on what’s going on. Either way I’m sure Marc has a handle on it way better than I do.

In regards to the V6, it’s absolute useless
I much prefer any I-5 engine , However with the b3 vs b4 90 I think the b4 is a few steps ahead , even smoother driving with that v6, chassis is slightly more rigid feel to is due to the metal behind the rear seat . . . If I even build a 90 again I will likely do what you did , even if that means having to change the engine mounts .

[Grillage]

Been out of town for a week opening a restaurant but drove the car today with an updated tune from Marc.

It's overboosting a little bit and I'm working on why, but it's GREAT

The tie rod ends were previously fused to the inners before and I couldn't get them loose to get an alignment so I replaced the whole thing. As a result, the car is a little terrifying to drive. So I dropped it off today for an alignment to make it less scary to drive.

Hope to get it so I can dial up the boost by the weekend!

[Grillage]

More progress this long weekend




Huge thanks to Marc for putting up with my constant barrage of questions. I feel like we've had some weird stuff on this project though. A bad new in the box VEMS being the first and foremost.

We got things running way better and it was time to do a couple logged pulls from 2000 RPM in 3rd to see how everything is working. I had massive bucking and a trigger error at about 4000 RPM each time I tried to do this. In fact, the car would then run like crap until turned off and key cycled. Then would run great until I hit 4000 RPM again.

This turned out to be NON-RESISTOR plugs. The electrical noise from my non-resistor plugs was causing the secondary trigger to not be seen - and making the engine misfire.
I bought the ones Marc told me to and problem solved!

I now have an overboosting issue that I'm tracking down. the N75 is closing itself when powered up. I'm hoping inverting it is all I need to do.

This car is FUN

[PRY4SNO]

Yeah Marc has been on about the resistored plugs for some time now.

Love it when an easy fix presents itself.

Great project, glad it's been fun so far. Once it's dialed in, I bet it'll be a riot.

[Afterthought]

Do you have the number of the plugs handy ? I would like to try this as well with troubleshooting my trigger error in VEMS . Hat would be like F5DPOR as appears to FR5DTC... right?

[Grillage]

I originally had Bosch fr5dtc

Switched to ngk bkr7e and problem solved!

[Marc]

correction: you had f6dtc. which is a non resistor plug. the "r" denotes resistor.

[Grillage]

correction: you had f6dtc. which is a non resistor plug. the "r" denotes resistor.

Correct!

[Grillage]

Got the Cabriolet Bumper to fit finally.

Required a couple holes where the intercooler corners are. Also had to notch the grills a bit. It's still hitting a little at the bottom of the IC but I don't want to hack it up more.





And remember, this is the spray painted one - really looks decent for spray paint

[Grillage]

Also solved my overboost problem - the signal to the N75 needed to be inverted. When the engine was running it was CLOSING the N75 and not letting air from the turbo to the WG - so it never opened up.

[DE80q]

This is coming out great Ben! Looking forward to checking it out in may.

[ChrisAudi80]

Also solved my overboost problem - the signal to the N75 needed to be inverted. When the engine was running it was CLOSING the N75 and not letting air from the turbo to the WG - so it never opened up.

There ya go. That is a significant issue to have solved.

[jbrentd]

Bumper looks really good. Hard to balance clearance, fitment and not removing too much material.

[Grillage]

Thanks guys!

Just tested the latest config from Marc and now we're turned up to about 275 kpa (25psi or so) and the car is running beautifully.

I want to take the JHM short shifter from the cabriolet and put it on this car - the shifter is a bit sloppy.

also, here it is all prettied up in the driveway:

[ChrisAudi80]

Thanks guys!

Just tested the latest config from Marc and now we're turned up to about 275 kpa (25psi or so) and the car is running beautifully.

I want to take the JHM short shifter from the cabriolet and put it on this car - the shifter is a bit sloppy.

also, here it is all prettied up in the driveway:

Winning!

[Afterthought]

Daaamn 25 PSI . I’m still at 15 and my car feels fast to me.

[Grillage]

Short Shifter in, all the interior bits back in and driving it like it should be!

Still working on a few little things with Marc in the tuning but things are great!

Next on the list are bigger brakes! Looking like that will happen in conjunction with a 5x112 conversion - so I'll need new wheels. Thinking RS2 spec wheels would look great! (http://greggearhead.com/store/p38/Audi_ ... heels.html)

Eventually an E85 tune and will need to install a flexfuel sensor. We planned for E-85 the whole time so injectors and fuel pump are sized appropriately

I got a few other things done too

Finally got a proper pulley for the alternator and the weird/narrow serpentine belt from the ADU pulley:
Old to new:





Previously, I was just running the belt in the center of the old pulley - which seemed to be working just fine, but this is correct.

Also, I got a boost gauge that would fit in the instrument cluster. My autocheck system is pretty much useless now that the injectors and fuel pump are different so I pulled it entirely in favor of a 45mm boost gauge.

works pretty well!





I want to see if I can actually remove the lens over the top of the gauge but I'm happy enough with the gauge where it is

[sayoda]

Gauge looks great!

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