VEP-TDI Nozzles: Available Options & Effects

Hi,

I have a question.

What nozzle designs are available for the older 4- and 5-cylinder VEP-TDI engines?
The following are examples: 1Z, AHU, AFN, AAT, AEL, AXG, etc.

Sizes I am familiar with:
1Z/AHU 0.184 (switching gearbox)
AFN 0.205
AXG 0.216

AAT?
AEL? (Does anyone know the spark plug thread size for this engine?)

Are there any nozzles larger than 0.216?
(Edit says: The shop offers 0.232 nozzles , and I have also read about 0.260 nozzles.)

What happens when you combine very large nozzles (0.232) with a standard fuel injection pump, i.e., one with a 10mm plunger?

Specifically: Let's say I were to install very large injectors in the AAT, but leave the fuel pump plunger and rocker arm as they are. As a result of the completely altered hydraulic system compared to the standard configuration, the pressure during injection would have to decrease, and the atomization of the diesel would become much worse.
At the same time, the injection quantity would be increased, even with the same control slide setting, because there would be fewer leakage losses.
Are there any limits that could damage the engine? For example, could there be such poor atomization that proper combustion is no longer possible? If so, where might these limits be?
0.232 still seems possible, as indicated by the offer in the tuning shop.
Of course, the boost pressure needs to be adjusted, that's logical.
What about the 0.260-ESD?

"0.216-inch nozzles with normal VEP (10mm pistons) are not a problem at all, as many user reports in this forum demonstrate."

(Please do not discuss emissions or legal issues; this is about racing purposes only, without road approval.)

Regards,
Jens.

Edit: new information added.

Okay, let me be more specific with my question:

"Does anyone have experience using a 0.232-ESD setup with a stock VEP cylinder that has 10mm pistons?"

It's possible if you adjust the software, but it's not really useful for a 1Z engine.

Best regards, Rainer.
PS: Why complicate things when it can be simple?

Rainer K. wrote:

It can be done if you adjust the software, but it's not really useful for the 1Z model. Best regards, Rainer. PS: Why complicate things when there's a simpler way?

This is not about the 1Z, but about a mechanized AAT. Therefore, software adjustments are neither possible nor necessary.

After discussing it with my fuel injection specialist, we agreed that it would be better to use the 0.216 injectors.

- The 0.216 nozzles (from AEL) work with AAT vials, and others have already tested this. So, you don't have to worry about an unsuitable spray pattern.

- The larger nozzles do not significantly reduce the pressure in the high-pressure section of the ESP. This would only be the case if the nozzles became so large that nothing could pass through them. Therefore, my assumption was incorrect.

- If you use the rotary injection pump from the AAT-ESP (which is essentially necessary), the pressure build-up and injection timing remain largely the same as with the original VP37. The principle of the distributor-type injection pump has not changed from the TD to the TDI; only the control system has been electrified. And because of this, it is possible to build a suitable injection pump with a mechanical regulator using components from Bosch.

Regards,
Jens.

Jens 16syncro wrote:

After discussing it with my fuel injection pump expert, we agreed that it would be better to use the 0.216 injectors. - The 0.216 nozzles (from AEL) work with AAT vials, and others have already tested this. So, you don't have to worry about an unsuitable spray pattern. - The larger nozzles do not significantly reduce the pressure in the high-pressure section of the ESP. This would only be the case if the nozzles became so large that nothing could pass through them. So, my assumption was incorrect. - If you use the rotary injection pump from the AAT-ESP (which is practically essential), the pressure build-up and injection timing remain largely the same as with the original VP37. The principle of the distributor-type injection pump has not changed from the TD to the TDI; only the control system has been electrified. And because of this, it is possible to build a suitable injection pump with a mechanical regulator using components from Bosch. Regards, Jens

Hello Jens,

Doesn't the AEL have 0.210 mm nozzles and the AXG have 0.216 mm nozzles?

tdi on water wrote:

After discussing with my colleague, does the AEL not have 0.210 mm nozzles and does the AXG have 0.216 mm nozzles installed?

Well, unfortunately, no one is telling me. So far, no one on this forum has commented on what nozzles the AEL actually uses. I've asked about this several times over the years, but no one has answered. Outside of this forum, 0.216 has been mentioned, but it's not confirmed.
You are the first person to make a statement about AEL nozzles here.
And even the first one to mention the size 0.210, that person has never been mentioned before.
What is your source for this information?
I can neither confirm nor deny that.

Perhaps someday, some light will shine on the darkness surrounding AEL nozzles .

Regards,
Jens.

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