Audi A4 B5 AFN Quattro: Reliable and Practical?

Hello everyone, and happy Easter to you all.

I've just bought another A4 B5 AFN Avant Quattro, manufactured in 1999, with 215,000 km on the clock, for everyday use. It's simply the most affordable option.

It needs to gain a bit more horsepower, but it should remain reliable, practical for everyday use, and without any extreme or hardcore modifications.

Sure, here's the translation:

'Perhaps some background information on this is needed.'
My former A4 B5 Avant Quattro definitely cost me two years of my life in frustration.
The setup included: 232 Bosio, BV43 turbo, blocked AGR valve, PD intake manifold, EMS, organic SRE friction disc + SRE pressure plate, catalytic converter emulator, and switchable software from Vienna.
Level 1: LD (Low Duration) at 1800 RPM @ 2.0 bar (3 bar absolute), approximately 180/190 horsepower.
Level 2: Boost pressure approximately 1.4 bar (2.4 bar absolute), approximately 140 horsepower.
Problems back then: Excessive rattling of the rear wheels, 1 broken spring on the sprung SRE friction disc, strong vibrations up to 2500 RPM, 6 Torsen center differentials failed, oil was leaking everywhere.

I want to avoid that.

What I envision:

- 216 nozzles (installed)
- GT1749VA or BV43 (Germany)
- either a new complete wheel system or, if it's truly possible without compromising comfort, the Valeo 4KKit could be an option.
- KAT 'optimize'
- Optimize AGR.
- Consider converting to a 11 mm pump head?
- Possibly 'optimize' the mid-range damping.
- 312 mm front brake (Zimmermann slotted - installed).
- Rear brake, 245 mm (Zimmermann slotted, installed)

I was hoping for around 140-150 horsepower, but I'm afraid of ruining another Torsen center differential, so I'm not going to increase the power anymore.
The entire system should be stable and reliable, with built-in redundancies.

Questions:

- Who has experience with these modifications on an A4 B5 Avant Quattro, what setup did they use, and what were their experiences?
- What can you recommend regarding components/setup/etc.?
- Who can write the software for me? I would like it to be switchable with 2 levels again. I can no longer reach my former software developer.

Thank you very much in advance!

VG
Where?

To be honest: If the AFN Quattro is going to be truly practical for everyday use, then leave it in its standard trim. Either the performance is sufficient for you, or buy something with more power from the factory!

"An alternative would be the A4 B6 Quattro or the Passat Variant 3BG as a 4Motion, both with a 131 hp PD TDI engine, a 6-speed transmission from the factory, and sufficient power; definitely more powerful than the AFN."

I've been driving an AFN Quattro since 2011. My first one was modified by *** from the factory to around 130 horsepower, and it ran quite well. Anything beyond that level starts to affect the car's reliability and everyday usability.

Hi Rüdi,

Don't be offended, but something just doesn't feel right. Either get the original version and enjoy it, or leave it alone, or get it chipped to around 130 horsepower.

On the other hand, I'm glad to hear that the 130 horsepower apparently worked well/still work well for you.

Since you say it's not really durable... what, in your opinion, is the bottleneck?

VG
Where?

Hi,

There's no easy way to do this. It's simply unrealistic to expect old vehicles to function properly in everyday use after being restored.
Each component was built with a maximum load capacity in mind, and everything in the vehicle that converts energy operates within that load capacity.
If you want 200 horsepower, you'll have to opt for the 3.0 TDI engine. If that's too expensive for you, you'll likely have to settle for something with slightly less reliable power.

Best regards,

Hello.

Anything below 140 horsepower is generally reliable with the AFN engine and standard hardware, as long as no unnecessary modifications have been made. However, as mentioned before, it doesn't make sense to modify vehicles with such high mileage, as they are likely to break down anyway, even without chip tuning, and things may stop working as they should.

Best regards, Rainer.

The needle valve isn't the problem; it's the rest of the system – the ZMW (presumably a specific component), the transmission, and all the other technology. The entire system has a certain age (~20 years) on top of its existing mileage, which can also lead to failures in the technology.

"My *** AFN was a pleasure to drive, but it ended up costing me a transmission. Since replacement transmissions from DGW/EEP aren't readily available, I barely used the available power afterward. After 5 years, I sold the car to someone who paid me twice my purchase price. Despite the transmission issue and necessary repairs, it was essentially a break-even deal, or even made a small profit (a three-digit amount), but only because I did all the work myself."

It's difficult to extract significantly more power from a 110 hp AFN engine with a distributor injection pump.
Larger holes in the nozzles must be accompanied by a higher flow rate; otherwise, the injection pressure (not the opening pressure!) will decrease. And this is where the diameter of the pump piston comes into play.
With proper tuning, 130 to 140 horsepower is believable, but anything above that will likely only be achieved with a longer intake manifold and less efficient fuel injection.
It only makes sense if the valve timing and compression are correct. That's where I would start.
"Of course, anyone who really wants to can't be stopped from rebuilding an engine that's over 20 years old. The proud owner will then be surprised when they are outperformed by CR TDI engines of the same power. Man's will is his heaven."
hg
Herbert.