AFN+6 Gang+Motorkennfeld | Posts 16+

I had installed a longer fifth gear on my Ibiza AFN back then. Basically, I swapped the gear set from an ASD gearbox into the CYP gearbox. The engine speed was reduced by about 150 or 250 rpm, but I'd have to check the old forum posts to be sure.

Renovations are generally good when done from the outside and are relatively inexpensive.

Boro wrote:

...allowed the engine to run for a long time in 5th gear...,...installed an ASD transmission into the CYP. I think the RPM was around 150 or 250.

Based on the gear data for the 5th gear of the ASD, the axle is only about 5% longer, or approximately 70 rpm lower at 2000 rpm, compared to the CYP.

Uwe wrote:

I have an AHF engine that is very similar to the AFN engine, but it has been converted to a DRW gearbox. The fuel savings are limited. The conversion process isn't quick because you have to replace many expensive parts.

Does your renovation/remodeling experience align with: https://community.dieselschrauber.org/en/viewtopic.php?t=3761?

ddrler wrote:

Does your renovation/remodeling experience align with: https://community.dieselschrauber.org/en/viewtopic.php?t=3761?

Yep. The parts list should be pretty complete.

I was just looking into the translation of the DRW, and I have to say that I find it strange. There is hardly any difference between the 4th and 5th gears (assuming the values in the transmission overview are correct). Also, the 6th gear is only about 8% longer than a CYP or AFN, but the 5th and 6th gears in the DRW are almost 17% apart...

I dug up the thread again, so at 3000 rpm, it was 200 rpm less...

Okay, I'm ready. Please provide the German text you want me to translate into English. Just paste it here, and I will give you the translation.

Huh?

The 2nd to 5th gears are each longer than those in the AHF transmission. As far as I remember, it must be the EBF gearbox.

So, the 5th gear in the DRW transmission is already designed to reduce engine speed. Then there's the 6th gear, which further reduces it.

At maximum speed (Vmax), the engine speed decreases by almost 1,000 RPM.

Hello,

ddrler wrote:

I believe that there is sufficient traction available, at a real speed of 120 km/h, let's say 130 km/h on the speedometer, to reduce the engine speed towards 2000 rpm.

Don't be fooled by the pulling force. It reaches its limits faster than you might think, and that can become unpleasant. Or just plan to include a chip from the beginning .

Quote:

and to reduce consumption.

As others have already mentioned, you won't be able to measure that. There are much more effective ways to save fuel (e.g., using a chip tuning device, being mindful of your acceleration).

Quote:

I would also gladly accept a reduced noise level as a bonus feature.

"That's true. I also drive a lot on the highway, and when I had the engine replaced a few weeks ago, I installed an ASD at the same time. The engine speed is more pleasant with it, even though it's only just under 4% difference. The AFN still struggled a bit, but with the 0.216 injectors, everything is fine now. There's plenty of power, the top speed is slightly faster than before (215 km/h according to the speedometer instead of 210 km/h), fuel consumption is okay, and the noise level is more pleasant. I'm satisfied so far, and I would do it again. However, I wouldn't install it just for that reason, as the effort involved doesn't justify the difference."

Best regards, Uli.

Boro wrote:

I dug up the thread again, so at 3000 rpm, it was 200 rpm less... /viewtopic.php?t=13829

Thanks, I'm considering a shorter axle length, something around 0.7 or less.

Uli S. wrote:

Don't be fooled by the pulling force.

It reaches its limits faster than you might think, and that's no longer fun.

Uli S. wrote:

There's a rule of thumb that says approximately 15 kW at 100 km/h with constant speed (v) and no change in altitude (delta_h). Those values, exceeding 40 kW at 1900 rpm and going beyond 55 kW at 2500 rpm, should provide sufficient available traction force, even though the speed is related to the rolling resistance quadratically... What happens above those speeds doesn't really matter to me.

To save fuel, there are much more effective methods (chip tuning, controlling your accelerator pedal) }.

If it's not an "eco-downspeed chip," I don't think such a modification makes sense, especially for someone like me who uses cruise control.

Hello,

ddrler wrote:

There's a rule of thumb that says approximately 15 kW at 100 km/h @ v= constant and delta_h=0. Those values above 40 kW at 1900 rpm to over 55 kW at 2500 rpm should provide enough available traction, even though speed enters the drag equation quadratically... What happens beyond that doesn't really matter to me.

I know the formulas too, and I'm not saying that the pulling power isn't sufficient to accelerate; I just gave you a tip from practical experience. Whether someone is bothered by the poorer acceleration due to the longer gearing is totally subjective.

Quote:

Unless it's an "Eco-Downspeed-Chip," I don't think something like that makes sense. Especially for me, with my cruise control.

Fuel-saving tuning has nothing to do with downspeeding; just ask Rainer.
In our case, simply adjusting the static timing advance (due to fuel pooling) of the pump to 11° BTDC at idle on a Golf 3 Variant resulted in a half-liter reduction in fuel consumption per 100km (5.3 instead of 5.8 liters/100km). This only provides benefits during partial load conditions. With a suitable chip, you can extend this effect to the entire operating range.

Best regards, Uli.

Uli S. wrote:

I also know the formulas, and I'm not saying that the pulling force is no longer sufficient to accelerate; I just gave you a tip from practical experience. Whether someone is bothered by the poorer dynamics with the longer gearing or not is totally subjective

.

This shouldn't be taken as a criticism. I just wanted to say that I am aware of the lack of dynamism, but I am willing to accept it.

Uli S. wrote:

Fuel-saving tuning has nothing to do with downspeeding; just ask Rainer. In our case, on a Golf 3 Variant, simply adjusting the static advance (due to fuel quality) of the pump to 11° BTDC at idle resulted in a half-liter reduction in fuel consumption per 100km (5.3 instead of 5.8 liters/100km).

This only provides benefits under partial load conditions. With a suitable chip, you can extend this effect to the entire operating range.

That's heading in the direction of what I meant by an "ECO-Downspeed chip." It would be really interesting to know where the combustion peak is located with the original application.

Hi,

ddrler wrote:

This shouldn't be taken as a criticism. I just wanted to say that I am aware of the lack of dynamism, but I am willing to accept it.

Okay, I didn't take that as an accusation.

Quote:

That's kind of heading in the direction of what I meant by an "ECO-Downspeed-Chip."

It would be really interesting to know where the combustion peak is located with the original application. }

The only term that bothered me was "downspeed," because it doesn't necessarily have to be the case. It is definitely possible to achieve more power with less fuel consumption.
What do you mean by "combustion focus"?
Here are the original fuel injection start map and the one with my static early timing adjustment, so you can see where the savings come from.

Best regards, Uli.

P.S. I found the original data table somewhere on the internet years ago; I no longer remember where (maybe here???). If anyone feels their copyright has been infringed, please don't immediately involve a lawyer, but rather let me know (then I can delete it, add a source, or whatever...).

Uli S. wrote:

What do you mean by "combustion focus"?

The point [in °KW] at which 50% of the fuel mass per ASP has been injected (dQ50) is defined as the combustion center. Ideally, dQ50 occurs between 7° and 8° KW after Top Dead Center (TDC). The injection timing plays a significant role here, alongside the amount and pattern of fuel injection.

Uli S. wrote:

Here's the original fuel injection start map and the one with my static early timing adjustment, so you can see where the savings come from.

At lower loads, the injection start is after the top dead center (TDC)...?! I hope this wasn't just done to reduce NOx emissions...

ddrler wrote:

At the lower load level, the injection start is after ZOT...? I hope that wasn't just done because of NOx...

Keywords: Comfort + Noise environment

guste100 wrote:

Keywords: Comfort + Noise environment

I don't know what the valve and injectors can provide in terms of a minimum amount, but there was another way to do it. The combustion process is completely lagging behind the piston movement.

ddrler wrote:

guste100 wrote: Keywords: Comfort + Noise environment I don't know what the VP and the nozzles can provide in terms of a minimum quantity, but there was another way to do it. The combustion is completely lagging behind the piston.

Huh .

If you're talking about multiple injections, a standard ventilation system probably can't handle that...

So, then tell me how you plan to improve comfort and reduce noise in the partial load range without delaying the injection timing.

Greetings.
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It can also be used as a verb, meaning "to gust."

guste100 wrote:

If you're talking about multiple injections, a V-pump system probably can't handle that...

No, I mean the minimum injection amount. It's likely that the injection amount cannot be adjusted continuously from 0 mg.

guste100 wrote:

So, then tell me how you plan to improve comfort and reduce noise in the partial load range without delaying the injection timing.

Reduce the amount and advance the timing; performance should remain the same. The derivative with respect to alpha (dp/dalpha) should be lower, resulting in less knocking. In my opinion, the noise level is the same.