LDA in T4 ACV: A Comprehensive Guide

hello

Today I installed my new LDA (likely referring to a laser diode array) and I have to say I'm very satisfied. It wasn't cheap, but the results are convincing.

- LDA sensor from Sandtler, manufactured by VDO (accuracy +/- 0.085 bar).
- Sintered material filters integrated into the LDA (Laser Doppler Anemometry) system.
Price: 85 euros.
- Connecting nipple from the model making hobby sector, price per piece: €1.20.

As I said, it's a bit more expensive, but the results are convincing. I don't have any filters in the line, nor foam or anything else. There are no fluctuations, nothing wobbles. The values can be read clearly and correspond to the measurements from VAG COM within the limits of reading accuracy and the error margin of the LDA.

Furthermore, I also tapped into my Lufika account.

hello peter,
I'd be interested to know why you chose these specific parameters for the query and what values you obtained.
especially at Lufika!
and whether the Lufika is still in its original condition.
With or without a spring mechanism in the Lufika?

best regards, michael

hello

'With the ACV engine, there aren't many good places for a verschandeln pressure tap. I didn't want to screw the fitting into the plastic somewhere on the pressure side. Also, the connection on the pressure side is right in front of the intake manifold, which is exactly where I want to measure the pressure. I can best identify errors on the pressure side there. Many models already have a threaded hole in the EGR valve that only needs to be drilled through, but unfortunately, the ACV doesn't have that. I could also have installed the fitting directly after the turbo, as there's a stainless steel pipe there instead of the standard silencer.'

I drilled a hole in the air filter to potentially detect any negative pressure that might be developing, but I haven't measured anything yet; I wanted to install a new air filter first.

I installed the new Lufika with the integrated fender.

syncro peter wrote:

In many models, the agricultural sprayer already has a threaded hole that you only need to drill through; unfortunately, this is not the case with the ACV.

Hi Peter,

On the Polo, I replaced one of the two mounting screws for the breather box with a hollow bolt that has a hose nipple and drilled a hole through the intake manifold to accommodate it, in what I would consider a "normal" way.
The hollow screw now secures the membrane dome and supports the LDA tube.

According to the photo, it should have worked for you too - or did it not ?

@ulf

I understand what you mean, but after measuring as accurately as possible, if I had drilled, I would have ended up drilling into the valve's hole.

I found the solution I chose to be the simplest.