6-speed gearbox, why such short gearing?

Hello everyone,

I have a 6-speed gearbox (FRK) installed in my Passat 3BG 1.9 Tdi AVF.
And I always wonder why the translation is so short. At 206 km/h, I'm already reaching 4000 RPM. What's really annoying on the Autobahn.
Even the powerful 2.5 TDI engine with 180 horsepower, equipped with its slightly longer-geared 6-speed transmission (DQS, FRF), reaches 4000 RPM at 220 km/h.

Why are the gear ratios so short? It can't be due to the power.

Best regards,
Alex.

alex2479 wrote:

It can't be due to the power.

However, if it is, a simple 1.9-liter engine will run out of breath much sooner than a 2.5-liter 6-cylinder engine.

Yes, but even the large V6 TDI engine has a relatively short gear ratio.
When I compare this to smaller, modern TDI models, some of them can run at 200 km/h with 3400 RPM.

Best regards,
Alex.

especially since even in my Octavia with a 6-speed manual transmission, the owner's manual states that the maximum speed is reached in 5th gear. The 6th level is then only about reducing consumption slightly.

The vehicles must achieve their minimum speed as quickly as possible during certification under the New European Driving Cycle (NEDC), where the engine can be adjusted to achieve a favorable emissions ratio. This is also possible with shorter gear ratios, as the engine can reach higher speeds with lower emissions because it needs to produce less torque.

Modern CR engines can be effectively optimized in this regard by integrating a downstream chemical plant into the exhaust system. Consequently, the gear ratios have become longer again. However, this results in increased fuel consumption. It also has internal, physiological reasons.

In short, the vehicle manufacturer is trying by all means to comply with the standards set by the legislature. The customer then has to live with the result. If not, he can apply it himself.

Best regards.

Diesel_Rudi wrote:

During certification, vehicles must reach their minimum speed as quickly as possible in the NEDC cycle, where the engine can be adjusted to achieve a favorable emissions ratio. This is also possible with shorter gear ratios, as the engine can reach higher speeds with lower emissions because it needs to produce less torque. Modern CR engines can be effectively optimized in this regard by integrating a downstream chemical plant into the exhaust system. Consequently, the gear ratios have become longer again. However, this results in increased fuel consumption. It also has internal, physiological reasons. In short, the vehicle manufacturer is trying by all means to comply with the standards set by the legislature. The customer then has to live with the result. If not, he can apply it himself. Best regards

Okay, I hadn't even thought about something like that.
I'm also considering installing the transmission from the 2.5 TDI engine, even though I'm not entirely happy with the gear ratios.
Of course, all of this would be done after a chip tuning.

Best regards,
Alex.

Be careful when using the DQS. You will experience problems without additional oil cooling if you tune the vaporizer. Also, the LLK (low-level coolant) should be modified. Best regards.

Diesel_Rudi wrote:

Be careful when using the DQS. You will experience problems without additional oil cooling if you modify the vaporizer. Also, the LLK (Low-Level Cooling) should be modified. Best regards

Are you talking about the torque? So, does that mean the engine is under more stress when driving on the highway?
The engine should definitely be tuned to produce 160 horsepower and approximately 360-370 Nm of torque.

And yes, I was thinking about the DQS or FRF gearbox, but unfortunately, those parts are not cheap.

Best regards,
Alex.

Hello TDI enthusiasts.

As someone who enjoys spirited driving (see signature), I don't mind occasionally working on my car and I don't expect immediate, "spontaneous" reactions to the slightest adjustments of my right foot. However, for a long time, key criteria were spontaneity, pulling power in the highest gear, and spontaneous acceleration (which were always viewed positively in publications like AMS and Auto Bild). Since the CO2 debate, the longest gear ratio has been reintroduced, and suddenly this behavior is considered "acceptable" and no longer leads to point deductions in relevant tests.
So, you can also interpret this as a long-term translation – it's no longer being publicly promoted on the testing side, but it's still being flagged as negatively impacting the image. It's all been done before.

Golf II 5e - boring but long, translated to 7-8.5 liters - recently scrapped - came after the oil crisis.
Audi 80, 5-cylinder, 5-speed - also with a long gear ratio, fuel consumption is fine - runs well, and you can hear the 5-cylinder engine running at a lower RPM a great summer car.
Passat 1Z, 90 horsepower, 220,000 km. I'm dreaming of getting 5-7 liters per 100 km (that's just a joke, I still have it as my second car). The cargo capacity is really impressive.
New A4, B7 3.0 TDI automatic - something with a longer wheelbase would be nice; it might help me reduce my fuel consumption from 10 liters per 100km.

Based on my experience with vehicles and the historical context (oil crisis, as a child I was still CO2 neutral riding my tricycle during the Sunday driving ban, then a focus on power and performance, and now the CO2 debate again), the statement above can at least be supported.

By the way, I temporarily had a 1.4 TFSI with a 6-speed transmission. It was possible to drive at 50 km/h in 6th gear - the fuel consumption was quite close to the diesel 1Z, so it's definitely achievable if you want. It's a great car.

Greetings.

heizfoss wrote:

Hello TDI enthusiasts. However, for a long time, the criteria for evaluation included: spontaneity, smooth operation in the highest gear, and spontaneous acceleration (which were always viewed positively in publications like AMS and AutoBild, among others). Greetings.

My AFN (Account First Name) in the G3 system also originates from that time. He was setting record-breaking performances back then.
Exercise 80 - 120 km/h in 5th gear. Okay.
Meanwhile, I had 2 gears replaced, and it's much more pleasant to drive now.

Greetings, Klaus.

alex2479 wrote:

Hello everyone, I have a 6-speed gearbox (FRK) installed in my Passat 3BG 1.9 Tdi AVF. And I always wonder why the translation is so short. At 206 km/h, I'm already reaching 4000 RPM. What's really annoying on the Autobahn. Even the powerful 2.5 TDI engine with 180 horsepower, equipped with its slightly longer-geared 6-speed transmission (DQS, FRF), reaches 4000 RPM at 220 km/h. Why are the gear ratios so short? It can't be due to the power. Best regards, Alex

Maximum speed at maximum power...
Is the AVF (maximum speed) specified as 201 km/h?

Regarding the debate in general:
You also have to consider the operating conditions. If someone is constantly driving on freeways, they might appreciate long translations for stress-free cruising. I, on the other hand, appreciate having good acceleration at all speeds in dense traffic, and I'm happy to accept the (rare) 4,300/min at maximum speed. And I'm glad that the first gear also allows for creeping below 10 km/h without straining the clutch. I do this creeping every day for at least 5 minutes. My ASZ+ERF system drove me crazy.

Regarding the 1.4 TSI 122 HP engine:
"I had that car yesterday as a rental, a 450 km trip mostly on the highway in binary mode. In the city, it really does a lot in 6th gear at 1,200 rpm, almost silently. The idle is quiet at 600 rpm and 0.6 liters per hour. However, starting from a standstill or parking only with the clutch almost made the car jump. And on the highway, the 130 horsepower diesel versions in the Passat wagon and Focus wagon kept up with me as long as I was in 6th gear. In 5th gear, I could then keep up, but the constant shifting was annoying. Also, I lacked the power around 100-120 km/h, which again required shifting." Then I'd rather have a short 6-speed without all that rush.

Key points:
Average fuel consumption after MFA: 9.9 liters per 100 km.
Fuel consumption at maximum speed in 6th gear. Gang 19.4l
My 170 hp CR model achieves a real-world speed of 22 km/h faster, despite the short gearing.

Here's the diagram for the Golf 5 105 HP TDI 6-speed (BLS JYJ MQ250).

This is short!!!

TDI-GTI-4-Motion wrote:

alex2479 wrote: It can't be due to the power. However, if it is, a simple 1.9-liter engine will run out of breath much sooner than a 2.5-liter 6-cylinder engine.

THAT is what the person with ARL and planned Haldex control is saying right now.

Deus Violentia wrote:

That's what the person with ARL and planned Haldex control is saying right now.

Right, I know that I can't do much on the track, and I don't intend to.
If I wanted that, I would have something else under my hat.

Okay, I understand. Please provide the German text you want me to translate into English. I will only provide the translation.

That actually makes me like it even more!