AGR Injectors: Review & Experience with Size 205

Hello everyone,

Today, I experimented a bit with an AGR engine and installed the 205cc injectors from an AFN or AHF (they are identical).
The result has truly convinced me. The engine responds much more directly to the accelerator, is significantly more rev-happy (especially above 2500 rpm), and pulls strongly from around 1200 rpm. The car feels considerably lighter and more agile.
"Hesitations are barely noticeable. In the RPM range around 1300 RPM in 4th or 5th gear, a slight hesitation can be felt at very low engine load. This hesitation was also present with the 184 injectors, but it now feels somewhat more pronounced, although this is purely subjective."
However, the driving performance is interesting and impressive. For my "test hill," a defined uphill route where I can always accelerate in 3rd gear from approximately 1200 to 4500 RPM with full throttle, the recorded time has been reduced from 12.1 seconds to an amazing 9.0 seconds !
Furthermore, the turbocharger now spools up much more effectively. Previously, there was unfortunately a problem where the target boost pressure wasn't reached until approximately 2500 RPM. Now, the target boost pressure is already achieved just below 2000 RPM. This also explains the improved acceleration from low speeds.
Das Auto schiebt jetzt auch noch im 5. Gang derart an, dass man sich fragt, wo denn nun der 6. Hey there! / What's up! / How's it going!
The running noise has not changed significantly either at idle or under load. I believe that replacing the old injectors with new, identical injectors would also have resulted in a similar acoustic change.
"Anyway, I'm currently very happy with the results. Now I'm curious to see how the average fuel consumption will change, if it changes at all. And of course, a short highway test is still needed."

More information will follow soon.

Regards,
Alex.

Hello Donalexo,

Then you have two options: either put the original nozzles back in or correct the signature to say '...all original' .

Hi Marco,

That's exactly what I wanted to write last night, but I was too tired }.

Best regards,

January.

donalexo wrote:

For my "Messberg," a specific mountain road section where I can always accelerate from approximately 1200 to 4500 RPM in the third gear with full throttle, the recorded time has been reduced from 12.1 seconds to an incredible 9.0 seconds ! Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. More information will follow shortly.

Hi Alex,

For me, the "regular" DZR (Dynamic Resonance Zone) times would be particularly interesting in order to estimate the performance gain.
Can you add anything else to that?

The uphill section, in my opinion, gives a somewhat distorted impression.
An analogous conversion to the DZR (German emissions standard) using the formula "12.1 seconds corresponds to 9.0 seconds, which equates to 90 horsepower becoming 121 horsepower" likely results in an excessively large increase.

The uphill section, in my opinion, gives a somewhat distorted impression.
An analogous conversion to the DZR, such as '12.1 -> 9.0 seconds corresponds to 90 -> 121 horsepower,' likely results in too large an increase.

Hi there,

In addition, there may be changed boundary conditions, such as the use of winter tires.

Hi Alex,

I'm glad that you are satisfied.

However, I still believe that new nozzles are worth considering once again.
behaved better.

How about the soot formation?

Did you take the 12.1-second measurement immediately before replacing the part?

Quote:

An analogous conversion to the DZR, such as "12.1 -> 9.0 seconds corresponds to 90 -> 121 horsepower," likely results in an excessively large increase.

I also think that's impossible. Why would an AGR (agricultural tractor) with 90 horsepower produce more power than a 110 horsepower engine itself, simply by using the injectors from the 110 horsepower engine? Then, theoretically, you should be able to "tune" the 110 horsepower engine with the software of the 90 horsepower one...
I would initially suspect faulty or worn-out nozzles, which might be responsible for the 12.1 seconds. Or perhaps thinner, smaller winter tires, colder air? Something like that... although the difference between 0.184 and 0.205 is twice as large as the difference between 0.205 and 0.216.

Greetings.
Thomas.

@Marco, Jan6K:

Quote:

...either put the original nozzles back in or correct the signature to say ".....all original"

.

Those who can read have a clear advantage.

Quote:

...on an experimental

engine...}

I never wrote that it was my car or my engine!

@Ulf:
I will still deliver the vehicles before and after the DZR tests. I will wait a little longer, specifically until I have roughly the same fuel level as during the last DZR test, so that the weight is also similar.

Regards,
Alex.

Thomas wrote:

I would initially suspect faulty or worn-out nozzles, which might be responsible for the 12.1 seconds. Or perhaps thinner, smaller winter tires, colder air? Something like that... although the difference between 0.184 and 0.205 is twice as large as the difference between 0.205 and 0.216.

Hi Thomas,

. . . und rechnet man das auf den Durchlaßquerschnitt um, so wird ein 90PS Motor mit 110er Düsen quasi "4 mal so stark geöffnet" wie ein 110er mit den 150 PS 5Zyl. DüSure, here's the translation:

"sen." translates to "Senator" in English.

Therefore, it appears that 120 horsepower is theoretically quite possible... but the actual result will naturally also be significantly influenced by the pump's flow rate (cam lobe shape and distributor piston diameter).

However, the comparison of transit times on the mountain is "artificially skewed."
Just imagine the following borderline case (an arbitrary example):
The mountain is so steep that a car X with an unmodified 90 horsepower engine only reaches 4000 rpm in third gear due to the drop in torque at higher speeds, and it takes about 50 seconds to go from 2000 to 4000 rpm.

Now the 110 horsepower injectors are installed, and with those, he can climb the same hill in 20 seconds, going from 2000 to 4000 feet.
The pure ratio of the times would suggest a performance increase of 150%, which equates to 225 horsepower .

And it is precisely this effect that, in my opinion, likely already plays a role to some extent during Alex's mountain climbing periods, which means that the "dwell time" values at altitude will be closer together.

Hello everyone!

Here you will find the graphical representation of the changes described above.

The graphs showing the sensor data over time clearly illustrate how much longer it takes for the engine, with a 184 main jet, to reach an RPM of over 4000.
The increase in power is very noticeable.

The graph showing the boost pressure reveals better boost build-up at low engine speeds, and that the target boost pressure is reached earlier, around 2000 RPM (indicated by the intersection with the target line).

Regards,
Alex.

Hello everyone!

Here's a small update on the average fuel consumption.
The modified AGR has now completed its first fuel stop with 205 injectors. With a typical driving style consisting mainly of country roads (75%) and city traffic (25%), I was able to achieve an average fuel consumption of 4.77 liters per 100 km using the 205 injectors.
I haven't been able to detect any increase in consumption so far; rather, the opposite seems to be true .

The generous torque makes it quite suitable for shifting up a gear slightly earlier. This might even allow you to optimize fuel consumption.
Let's see where this leads us once you get properly used to the new torque characteristics. I think 4.5 liters per 100 kilometers is realistically achievable.

Regards,
Alex.

donalexo wrote:

So far, I haven't been able to detect any increase in consumption; rather, the opposite.

Hi Alex,

So, another parallel to the turbo-tuned AFN .

Do we ever get any information about the "regular" DZR (Dynamic Resonance Zone) times, as a guide for performance gains?

@ulf:

Here's my update on the DZR (German term for "duty roster") times:

before (tank almost empty): approx. 6.4 seconds.
Later (tank almost full): approximately 6.0 seconds.

The subjective impression conveys a much larger difference, and the DZR result is disappointing .

I then experimented a bit with adaptation channel 1 and shifted the pump characteristic curve towards a leaner setting. This allowed me to essentially generate any time between 6.0 seconds and 6.4 seconds.
Of course, this could also be used to reduce the partial load rocking at 1450-1500 rpm.

While reviewing the data logs, I noticed that the coolant temperature display value occasionally jumps (Group 1). It constantly fluctuates between 81 and 72°C.
Based on your experience, does this more likely indicate a loose connection or a faulty temperature sensor?

I have to admit that I'm now a bit lost and, at the same time, disappointed. It seems the engine still has another problem (see thread: slow build-up of boost pressure) that was somewhat masked by the injector tuning.
It looks like I need to slow down a bit.

Regards,
Alex.

donalexo wrote:

before (tank almost empty): approximately 6.4 seconds. afterward (tank almost full): approximately 6.0 seconds

Hi Alex,

6.4 seconds for a standard A3 with 90 horsepower is already incredibly fast, especially if the 3rd gear isn't geared slightly shorter .
Otherwise, it reads more like at least 110 horsepower .

How fast is the car going at 2000 rpm in 3rd gear? Do you know the gear ratios and the axle ratio?

Hi Ulf,

The A3 has a CZL transmission with an axle ratio of 3.647 and a third gear ratio of 1.308.
Currently, I'm using 185/65 R 15 tires (winter tires), which results in a speed of approximately 48 km/h at 2000 RPM.
I've been planning for a while to have my car weighed. That would allow us to define the "vehicle weight" parameter more precisely.

Well, if you feed the DZR with this data, then you'll see that things aren't looking great in terms of performance .

I think my turbo isn't quite kicking in properly at the lower RPMs.

Regards,
Alex.

Hello everyone,

Today I took my car, which has a modified engine with an EGR system and also features a deactivated EGR valve, for its mandatory technical inspection (TÜV) and emissions test (AU).
The vehicle passed both tests without any issues .

For those who are interested: The turbidity values from the last AU measurement in December 2001 were 0.81, 0.93, and 1.13 1/m (average 0.96 1/m).
The measured values today were 1.10, 1.16, and 1.09 m (average 1.12 m).

On average, the exhaust opacity has increased by 0.16 m^-1.
The speed of the metering pump has increased by approximately 65-70 revolutions per minute.
According to the display, it would have even been running too lean, as the device was outputting a steady 5000 1/min. However, this is likely due to the fact that the device only rounds values to the nearest 100 (my assumption). Before driving to the testing station, I did a short logging session using VAG-COM during such a test cycle. I was simply curious whether the engine was already exceeding the tolerance limits. If it had been, I could have saved myself the fees.

The inspector, incidentally, used a flashlight to examine the area around the AGR valve, but a 0.2mm thick spring steel sheet is simply not visible.

Finally, a small addition regarding the DZR test. Today, I finally had my car weighed. With practically an empty tank (only 5 liters remaining), without any additional weight, and with only the driver (me) inside, my A3 weighs a hefty 1260 kg .

This means that the stated acceleration time of 6.0 seconds was measured with a combat weight of approximately 1290 kg. Consequently, the measured performance is very close to the expected performance of 110 horsepower.

That's not bad at all. However, the engine still has a noticeable lack of boost pressure in the lower RPM range, which I plan to investigate further with a turbo analysis soon.
I think there's still some potential to be unlocked here. The DZR test measures the average power output. In my opinion, the power delivery at lower RPMs is too weak, and (according to the dynamometer), the peak power should exceed the calculated 110 horsepower.

I will keep you updated.

Regards,
Alex.

For those who are interested, I've also included the logging data. The engine was simply accelerated from idle, without any load, to full throttle until it reached its maximum RPM, just like in an emissions test.

What I find interesting in this context is that the boost pressure remains at 0.66 bar even above 5000 RPM. The fuel injection amount would have to be drastically reduced.

Okay, does anyone know how to interpret this unit, "1/m," for smoke density? I'm afraid I don't quite understand it.

Regards,
Alex.