2000 A4 B5 1.8t quattro manual differentials question

**GrandpaA4** · 01-26-2018 07:59 PM

hi, new guy here. I am working on a parts list and possible upgrades for my 2000 a4 1.8t Quattro 5speed. the engine is ATW. I would like to know what type, code or anyway I could identify the front and rear differentials so I can buy the right parts for it (LSD). I bought the car bone stock 5 years ago. I will retire from the military service in a couple of years and want to pay back the service it has given me by upgrading it. right now it has 86k original miles and the only things I have done to it have been regular maintenance (brakes, tune up, clutch, timing belt etc.) turbo upgrades? ECU tuning? your help is appreciated.

Jo

**Corrado_Guy** · 01-28-2018 07:32 PM

The transmission code is DWR and the rear diff is DAJ and both differentials should be listed for those codes. If I were to do upgrades I would swap the motor to a wide-band and on your car that is really easy. I did it with a Eurowise harness which has a resister for the VVT and the wide-band O2 connector, MAF, and a ECM. I used the original cars wiring and sensors with just the addition of a secondary harness which you could easily make yourself and then you are running wide-band. You can buy a lot of different tunes for the wide-band cars and it is safer/easier to do it with the wide-band motors. You can go a long way with exhaust, intake, tun, injectors, turbo, intercooler and rods if you are going BT.

**walky_talky20** · 01-29-2018 08:51 AM

I agree with the wideband ME7 swap. If you're going to be upgrading turbo and injectors, it would be best to have that in place for better access to good tunes.

I wouldn't super much worry about differentials until you have a lot more than stock power, though. Maybe if you're autocrossing it and lifting the inside rear tire or something. But other than that, the factory quattro system has plenty of grip for the entire 100 hp that is actually making it to the wheels. Triple that and put the car on the racetrack, then you might want to consider some limited slip diffs. There is a 4:1 washer modification you can do to the Torsen center diff. Basically takes the torsen magic that happens and doubles it. That mod is worth doing if you can find the precision washers to do it.

To make the car fun, I'd suggest at least a stage 1 tune, if not an upgraded turbo and a tune. Then some good suspension and a nice big rear sway bar. Like a 1" bar. That really changes the car a lot - kills the understeer and makes it much more racecar-like. A mild brake upgrade like the A8 setup up front (and rear if you want), some lightweight wheels and sticky tires and you'll be all set.

**Mad Cow** · 01-29-2018 02:49 PM

Just an FYI, the vvt delete resistor is useless, you'll still throw a code when it tries to change the cam angle. It's easy to code it out in a tune and then you won't need the resistor anymore. If you're comfortable with flashing your ECU I can send you a stock one with it deleted.

**Schmauster** · 01-29-2018 03:39 PM

Thanks Corrado and Walkie Talkie, Thats the same car I have and really good info. The 2000 has a 5 wire sensor in the exhaust but I guess the ecu doesnt use it for high loads? (when its really important)

**walky_talky20** · 01-30-2018 04:40 AM

Correct. The 2000 is just a narrow-band sensor. Only used for idle and light load cruising. Whilst the 2001+ ECU's pull data from a wideband sensor that is used at all times to hit the target AFR, even at full throttle.

**GrandpaA4** · 01-30-2018 05:41 PM

thank you all for the help. I was under the impression that you could convert it to a wideband and still keep the atw engine. or is that a pain to do? the engine in the car has been very well taken care off that it would hurt to swap it out for something else that I have no idea how it's been treated before. my goal is not 400whp. I would be happy with around 280-300 chp, I know I might be asking too much.

**walky_talky20** · 01-31-2018 04:13 AM

Yes, you can convert it to wideband. It requires changing the ECU itself, and adding a couple wires to the harness for the wideband sensor, and the VVT (if you wish to have it).

I'm not big turbo guy, but I think 300chp is fairly aggressive for the stock rods. Depending on the tune, you run the chance of a connecting rod failure. It would be advisable to change the rods.

**GrandpaA4** · 01-31-2018 07:58 AM

already heve rods and pistons ready for purchase. after that it will be the turbo upgrade (gt2871) and all the supporting mods. now for the ECU swap, is there any link or thread that you think might help me with the conversion? I honestly don't care about vvt. thanks again.

**redline380** · 01-31-2018 08:37 AM

Originally Posted by GrandpaA4

already heve rods and pistons ready for purchase. after that it will be the turbo upgrade (gt2871) and all the supporting mods. now for the ECU swap, is there any link or thread that you think might help me with the conversion? I honestly don't care about vvt. thanks again.

IMO, easiest thing to do would be find a 01 part out, snag the ecu, harness, o2 sensor, and MAF. Just install everything and bam, you have wideband.

You may not care about VVT, but you'll probably care about the CEL.

**GrandpaA4** · 01-31-2018 01:40 PM

Originally Posted by redline380

IMO, easiest thing to do would be find a 01 part out, snag the ecu, harness, o2 sensor, and MAF. Just install everything and bam, you have wideband.

You may not care about VVT, but you'll probably care about the CEL.

hi, when I said that I didn't care about vvt, I meant that I don't want to convert my engie to vvt.

**Mad Cow** · 01-31-2018 04:01 PM

You can buy/make an adaptor harness for the O2 sensor, easier than swapping the engine harness. You only need to run one extra wire to the ecu, the rest can be adapted from the narrowband connector. The ATW and AWM harnesses have different connectors and its a pain to swap out plugs and sensors to make everything match (learned that from experience). The only reason I did the harness swap was because I had cut up and modified my ATW harness for other reasons and didn't trust it enough to last long term.

**PsorianoPre99A4** · 01-31-2018 09:16 PM

Originally Posted by walky_talky20

I agree with the wideband ME7 swap. If you're going to be upgrading turbo and injectors, it would be best to have that in place for better access to good tunes.

To make the car fun, I'd suggest at least a stage 1 tune, if not an upgraded turbo and a tune. Then some good suspension and a nice big rear sway bar. Like a 1" bar. That really changes the car a lot - kills the understeer and makes it much more racecar-like. A mild brake upgrade like the A8 setup up front (and rear if you want), some lightweight wheels and sticky tires and you'll be all set.

I agree with walkie talkie. I've been stage 3 on my AEB for 25k now, daily drive it 60 miles round trip 5 days a week, my mods are below and there is stuff i'm missing too. I am Narrowband and love the tune for a daily. I'm about 280-290hp. Been tested against a b5 s4 and wrx 17'

**GrandpaA4** · 02-01-2018 05:02 AM

Originally Posted by PsorianoPre99A4

I agree with walkie talkie. I've been stage 3 on my AEB for 25k now, daily drive it 60 miles round trip 5 days a week, my mods are below and there is stuff i'm missing too. I am Narrowband and love the tune for a daily. I'm about 280-290hp. Been tested against a b5 s4 and wrx 17'

that sounds awesome, tell me more about your set up.