Golf 3 AC Compressor: Parts & Repair

Hi,

My new Golf 3 has manual air conditioning.
I recently spoke with someone who also has a climate control system in their 66kW TDI Golf 3.
I was trying to figure out with him why my TDi's performance was relatively low, with a 0-100 km/h time of only ~9.5 seconds, compared to 8.3 seconds for the crashed TDi without air conditioning.

He believed that this difference was due to the climate control system's drive mechanism, not the weight of the climate control unit and ABS. The drive mechanism here also uses a V-belt. I thought that the climate control drive essentially runs freely and is simply engaged when the manual climate control is switched on.
He said that the V-belt is constantly running, which results in a significant power loss, which makes sense because friction is generated, leading to a certain amount of power loss.

Does the V-belt that drives the air conditioning system always run continuously?
If that's the case, then there's essentially no way to prevent it, and that's probably why there are either no or very minimal performance differences with or without a climate control system.

Regards,
Henrik.

This difference in airflow is certainly not caused by the belt drive, which is present in a similar form even without the air conditioning system.
With manual operation and the magnetic coupling switched off, no power can be wasted. I suspect a different error that is compatible with a technical article .

The V-belt is a ribbed V-belt.

That's the one that also powers the water pump and the alternator. Only the servo has a separate belt.

The belt always drives the A/C pulley, but the compressor is engaged with a magnetic clutch. This should be noticeable by a fluctuation in the engine speed when the A/C is turned on and off. Additionally, there's a noticeable "click" sound coming from the engine compartment.

Perhaps your magnetic coupling is stuck.

But I also got a 9.3-second 0-100 km/h time without air conditioning (I don't even have it) - even though I have a 14% shorter 3rd gear than you (with the ASD) - so don't be sad, it could be even worse .

For that, mine also consumes 6 liters . But with the Variant tank, that's still over 1200 km per tank .

m;

Ah yes, the magnetic clutch. That's exactly what I meant by "freewheel."
Then we could check them, does anyone know how? In any case, I haven't noticed any significant difference in performance whether the climate control is on or off.
We can still run DZR tests with both states.

You have a different version, I have a 2-door model. There should be some weight difference, but I'm also surprised every time I see the fuel consumption reading in your profile. It's funny because I also used to get around 5.5 liters per 100km with the old TDI.
"But 1200km is good. I usually refuel around 900-950km, and then there are still about 7 liters of diesel left in the tank until it reaches the 55-liter mark."
It's annoying that you can't even pass a Honda Jazz or a VW Touran with a 100PS PD engine, which are definitely heavier .

@Roger
What do you mean by "your error"? Are you referring to an incorrect timing?
Kann ich eigentlich quasi ausschließen, ich habe mehrere Messungen an unterschiedlichen Tagen und Aussentemperaturen vorgenommen. With both cars.
Even with the calculated time obtained using a VAGCOM log, the result is still over 9 seconds; I no longer remember the exact value.

"By 'fault,' I mean a defect, such as an issue with the EGR system, the mass airflow sensor, etc."

If the same engine in the same car produces 1.2-second differences in 0-100 km/h acceleration times, the power output must be significantly different, so I believe there's a defect in the new one. Or, it could be considerably heavier, for example, a station wagon instead of a sedan.

Hi there.

My fuel consumption is probably more related to my driving style: whether I'm driving in the city or on the highway, and on the highway, I often tend to accelerate a bit more – sometimes even using the "sport" mode, and always with a lot of luggage. I rarely drive on fuel-efficient country roads.

I can't seem to get rid of the Bora with 100 horsepower that my colleague owns, even though I should have 105 horsepower and 250 Nm of torque, which is more than it does.

m;

x world one wrote:

.... It's annoying that you can't even pass a ..... VW Touran with 100 horsepower PD, which is definitely heavier ....

.
You can definitely forget about that.
- The Touran has 105 horsepower and 250 Nm of torque.
- The PD engines sometimes exhibit extremely high power output and are noticeably more agile during acceleration.

My 1Z wasn't slow, but it definitely couldn't compete with an AXR... not even close. A 110hp A3 couldn't outrun my AXR, but it could easily outrun my 1Z.

@ Bertil

Nope.

The Touran was initially offered with 100/136 horsepower, but now it's available with 105/140 horsepower.

m;

dieselmartin wrote:

Nope. The Touran was initially offered with 100/136 horsepower, but now it's available with 105/140 horsepower.

... it might seem that way on paper, but it's not the case in reality... at least not in the German market...
There were problems with the insurance... The 100PS PD probably had too much power.

"Yes, that's clear regarding the PD (direct-injection engine). But the estimated 300kg weight gain compared to a 2-door Golf 3 will offset that. I'm already having a hard time keeping up with my Touran. It doesn't really matter whether it's 105 or 100 horsepower, I should still be able to keep up."

Okay, I'll go get a diode; hopefully, I have one lying around. Maybe it's just the mass airflow sensor. Unfortunately, the EGR valve is already broken, which is a shame...

@Roger
It's the same car, but the first one had a faster 1Z engine without air conditioning or ABS, while the new one has both of those features, but lacks the heavy sunroof.

Let's see if our Dekra (a German technical inspection company) can weigh my car.

I estimate a maximum weight difference of 25-30 kg between the two cars, and I still believe the lap times are too far apart.
"Are/were there possibly wheels installed on the car that deviate from the standard rolling circumference?"

As I mentioned, I'm going to replace the LMM (lambda matrix measurement) with a fake one, as the soot limit is frequently reached during logging.

Both vehicles were equipped with 195/50 R15 tires, and the older one was even fitted with 195/45 R16 tires later on. This allowed it to achieve a DZR time of approximately 9.3 seconds.
I will definitely install a diode and log the data, as well as create a DZR log.

Remember that with diode-based LMMs, the air-fuel ratio can become extremely sensitive.

So, at the very least, it is mandatory to disconnect the plug from the pressure sensor.

But if it's already over, then that's fine.

m;
I'm using 195/60 14 tires - they are actually quite a bit larger than 195/50 15 tires!!