Flex pipe issues on the 1Z: Is the AFN really that much better?

Subject: Considering a 1.9 TDI (74 kW) Engine - Pros and Cons

The question is: Should I go for a 1.9 TDI engine? On the one hand, I haven't had bad experiences with this engine (the turbocharger issue doesn't really bother me, and the tensioner problem seems manageable based on what I've read). Also, cars with the 1.9 TDI (especially the Passat 35i 3A5) are relatively cheap on the used car market. On the other hand, I'm someone who values comfort, and I'm considering a VR6 engine with LPG. I dislike high noise levels in the car, and my 1.9 TDI had that problem due to the flex pipe. But, is the AFN engine really that much better? It's supposed to have some kind of support that the 1Z doesn't have (but you can always modify things, anyway ). Please clarify the situation, as I'm somewhat biased towards TDI engines (meaning I'm definitely open to getting another one), and on the used car market, an AFN engine often costs the same as a 1Z engine, even when the AFN has very little equipment compared to the 1Z's full range of features.

Best regards, WarLord.

AAAAAAAAAAAAAAOkay, so:

The 1Z has a very wide front: http://people.freenet.de/golf-schrauber/getriebe.jpg

From the turbo to the MSD (under the rear bench), the entire exhaust system is completely free.
That's easily 1.5 meters long, which allows them to swing nicely.

These vibrations put the FR under significant tensile stress, which eventually causes it to "stretch out" or become deformed.

If it's loose, it can rattle internally, which can produce a droning noise at certain engine speeds.

I had the front axle (and consequently the catalytic converter) replaced on my car. The noise level didn't change significantly, but there was noticeable play in the front axle.
The G3 Var seems to be too soft overall, which can therefore cause it to droop.

The AHU (identical to the 1Z) has a significantly longer front end, just like the AFN.
This can better keep engine vibrations away from the exhaust, but it's not as resistant to tensile stress as a result. Therefore, here, the front pipe (FR) and the catalytic converter (Kat) are connected as a single unit (in the 1Z engine, this was separated at some point), and the exhaust pipe is additionally supported between the front pipe and the catalytic converter.

The engine can vibrate quite a bit without the FR needing to hold any weight, and yet the exhaust pipe remains relatively stable.

Since 1Z and AHU are essentially the same, I believe that an AHU FR should be compatible with a 1Z. Then you only need to retrofit the support for about 30 EUR, and you should be happy.

Regarding the Passat, I heard about AFNS (Adaptive Front-axle Negative Suspension) without support, which would then resemble the 1Z design – but I can hardly imagine that.

Although... the AFN engine has a larger exhaust pipe than the 1Z engine in the Golf.
Both of them have a large one in the Passat. Therefore, differences are conceivable.

m;

Okay, I drive a 1Z and have never had any comfort issues with it.

According to my experience, my Passat 35i is even a little quieter than the 1Z in the Golf 3.

The front was also defective for me, after 150,000 km. It's a terrible job to replace without special tools, but it can be done .

'Based on the design, in my opinion, it doesn't offer anything significantly different compared to the A3 or the Golf.'

I'd be glad to believe that the Passat is quieter. Simply because it has more sound insulation in the engine compartment (the 1Z also had the large cover in the Passat, but only the AFN engine had it in the G3; the G3 has no insulation above the BKV, but the Passat does).

I also believe that we need to distinguish between "Variant" and "Limo" here.

Because, at the very least, the G3 Vari TDI is already a noisy box even without the engine – something is resonating there; it's enough that it vibrates when I drive over bumps.

I suspect the roof or the rubber-metal bearings of the axle(s).

Okay, so that clarifies things. 90 horsepower is actually enough. It was just because my old Passat sometimes made a rumbling noise (in the range of 1,200 - 1,500 RPM).

Best regards, WarLord.

As I said:

Flexible pipe defect -> ROARING/HOWLING.

Never mind.
Drone -> FR broken.

"For me too, 1200-1500 isn't exactly a comfortable range."

And recently, it's been slightly shaking, very slightly, at 1400 RPM in 5th gear (but really only in that gear).
With it, you can glide so beautifully through the city .

m;

dieselmartin wrote:

"For me too, 1200-1500 isn't exactly a comfortable range."

Luckily, mine is quiet, but unfortunately, I'm not very good at driving it.

dieselmartin wrote:

And recently, it's been slightly shaking, very slightly, at 1400 RPM in 5th gear (but really only in that gear). With it, you can glide so beautifully through the city . m;

I experienced the same thing. Having a speed limit of 50 km/h on a road where 70 km/h is the minimum is unacceptable. Currently, hardly 50 units are being produced in the 4th quarter, and all of them operate within the range of less than 1500 RPM.
No idea why. Actually, the third gear is still okay; you can drive at 30 in that gear.

Is this really the famous 'pump and grind' technique?

Best regards, WarLord.

"Pumping can definitely happen, but why only in 5th gear?"

I haven't done the "leave the speedometer sensor disconnected" test yet, but I will.

But I suspect that the engine mounts (specifically, the hydraulic mounts) are slowly starting to wear out.
Because there's quite a bit of play that can be felt during load changes...

m;

Engine misfires can happen, but why only in the 5th gear????

Okay, here we go... In 5th gear, the engine has to produce significantly more power at lower RPMs. Typically, the progression of this issue is that the RPM range where the engine jerks in 5th gear expands, and then later it starts to manifest in 4th gear as well. The rumor spreads quickly and widely.

Will we ever get a handle on this situation?

Or does that ultimately just mean replacing the pump?

m;