Top Speed: How Fast Can You Go?

Hi everyone, I've been following the discussion with interest and have to say I've chuckled a bit. I'm probably not as knowledgeable about the subject as most of you, but I do have a few comments.

The 90 hp and 110 hp TDI engines easily reach 4600 rpm, which, with a 5-speed gearbox, translates to a maximum speed of 208 km/h. If you want to go faster, you need more power and a different gear ratio.

The engine is definitely being regulated by the electronics, as you can see during the emissions test. For example, mine cuts off at 5100 RPM, but this varies depending on the vehicle (so it's often well into the red zone). Otherwise, the turbocharged engines would spin even higher.

3. Sicher ist es richtig das die Drehzahl über die Dieselmenge gesteuert wird, aber die Motorelektronik greift halt schon viel früher ein, sollte man vieleicht bei heißen Motor im 1. GaTry it out.

Matte

Mattes wrote:

Hello everyone, I have been following the discussion with interest and I must say I have chuckled a little. I probably don't know as much about the subject as most of you, but I do have a few comments.

Hi.

Which discussion are you referring to (thread?)?

Quote:

1. The 90 hp and 110 hp TDI engines easily reach 4600 rpm, which corresponds to a maximum speed of 208 km/h with a 5-speed gearbox. Those who want to go faster need more power and a different gear ratio.

Your 208 are likely just a rough estimate.

For example, the 2001 ALH-Ibiza (with a 5-speed transmission!) could reach a top speed of 216 km/h at 4600 rpm, while the 1Z-Golf 3 "only" reached 204 km/h (assuming standard tire sizes for the original equipment).

Quote:

3. It is certainly correct that the engine speed is controlled by the amount of diesel fuel injected, but the engine electronics intervene much earlier. Perhaps it would be worth trying this out in first gear with a hot engine.

?? Earlier than what??

Hi Ulf,

Do you know about the mechanical rev limiter? Screenggggg!!!!

Unfortunately, it only works once ... after that, you should retrieve the replacement motor from the basement (hopefully not submerged in water).

Sorry, Ulf,
I saved the wrong post; I should have replied to the article about the rev limiter in 5th gear.

The maximum speed should be considered an average value; there are certainly tolerances, as you can see from your own downloads.

By 'early,' I mean before the engine is disassembled.

Berti seems to be quite clever , but it's strange that both Bosch and VW mention that there is a monitoring of the maximum RPM, at least in my Golf TDI 98 with an AHF engine. Also, it seems that some people have experienced this before, where during an overtaking maneuver in 1st, 2nd, or 3rd gear, they reached the red zone (e.g., on mountain roads) and a rather strong RPM limiter was activated, which feels quite unpleasant. I'm happy to be corrected, but isn't this a clear case of engine derating?

Greetings, Mattes

Quote:

It's funny that both Bosch and VW talk about a maximum speed monitoring system, at least in my Golf TDI 98 with an AHF engine.

Also, it seems that some people have experienced this before, where they accidentally reached the red zone (e.g., while driving on mountain roads) in 1st, 2nd, or 3rd gear, and a rather aggressive speed regulation occurred, which feels quite unpleasant.

Hi,

Of course, the engine control unit limits the maximum engine speed by controlling the fuel injection amount, how else would it do that?
I've read it twice now, and I still don't understand what you're trying to tell us?! }

Best regards, Rainer.

Mattes wrote:

Berti seems to be quite clever , but it's strange that both Bosch and VW mention that there is a monitoring of the maximum RPM, at least in my electronic GOLF TDI 98 with an AHF engine. Also, it seems that some people have experienced this before, where they have reached the red zone (e.g. while driving on mountain roads) in 1st, 2nd, or 3rd gear, and a rather strong RPM limiter kicks in, which feels quite unpleasant. I'm happy to be corrected, but isn't this a clear-cut intervention or? Greetings, Mattes

Sorry, Mattes.

I think you mean me BERTIL. Not like the former national coach...

And I don't remember saying that there is no speed limit... ... that was AUDIFAN.

My thread "Speed Limiter using 'Schrengg'" was the answer to ULF's question to you: "Earlier than what...".
Every engine has this "limiter"!! As far as I know, and as you also described rather inaccurately, the TDI is slowed down before this event occurs. I have never denied this (but I have also never written about it ).

But no offense, misunderstandings happen.

"Regarding the maximum RPM and other claims, Audifan was supposed to explain those to us... but he didn't (or couldn't)..."

How exactly would a speed limiter work on a diesel engine, other than by regulating the fuel injection? It's a compression ignition engine, and there's no way to intervene, for example, via the pre-injection system.

In addition, an AUDIFAN had written that there was no speed regulation. As far as I remember, the question at the time was why the top speed was limited on an XX TDI at 4000 rpm.

Let's assume the materials could handle it and there were no electronic speed limits, how high would a diesel engine's maximum RPM be?
I've heard that the maximum RPM is around 5500-6000, because beyond that point, the combustion and ignition speeds become problematic, and the efficiency drops dramatically.

Who knows for sure?

Eike.

eike wrote:

Suppose the material could handle it and there were no electronic speed limiters, how high would a diesel engine max out at? I've heard that the maximum RPM is around 5500-6000, because beyond that point, the combustion and ignition speeds become problematic, and the efficiency drops dramatically. Who knows for sure? Eike

Certainly, the rate at which the inflamed diesel-air mixture spreads significantly limits the maximum engine speed... ...the material (Schrengg) is likely to fail later... ...however, with a tailwind and going downhill, you can reach the base of the Eiger North Face, which is .

Becker, Heinz wrote:

How exactly would a speed limiter work in a diesel engine, other than by reducing the amount of fuel injected?

That's exactly how it's possible... ... I'm not aware of any other methods for diesel engines.

Becker, Heinz wrote:

In addition, an AUDIFAN wrote that there was no speed regulation. As far as I remember, the question at the time was why the top speed was being limited at 4000 rpm in a certain TDI model.

Correction -- Audifan did not write about speed limiting; instead, he wrote about:

Audifan wrote:

Unlike gasoline engines, which have a regulated idle speed, as one might know from fuel cut-off patterns or speed limiters, TDIs do not have a fixed idle speed.

I don't believe that... at least, not regarding the speed regulation... I don't think there's a speed limiting feature.