Variable Intake Manifold Links

[AusA8]

I did a quick search on the forums but couldn't find anything on this topic so I thought I'd post what I've just done...

A few months back whilst I was cleaning the engine, I noticed that one of the plastic links that controls the variable intake manifold was clean broken. So I started the search for how to fix as Audi Aust said that there is no fix, only a replacement manifold. The SSP clearly states this also - at $4,500 I figured that there was a better ways to spend the $$!

Anyway, cut along story short, I found some parts in the USA from a supplier called Gruven Parts. They make a replacement arm in Al. Given that the internal 'flaps' are plastic, it means that they become the weakest link and not the linkages.

The Audi SSP states that they work by varying the intake length to improve low end torque and top end power. The way it should work is as follows:

With engine off, the arms are under spring tension and therefore the internal flap allows the 'short' intake length. Upon starting and engine at idle, the vacuum pulls the arms down thereby making the length 'long'. It stays like this till 4,480rpm when the solenoid trips and releases the vacuum, thereby allowing the shorter run.

In 'long' length, better torque at lower rpm, in 'short' length after 4,480rpm, better power.

For me, with a broken linkage, I had one cylinder bank running in 'short' length all the time, hence under 4,480rpm I had one bank in 'long' and in 'short', effectively inhibiting low end torque.

After fitting the new links, I did actually notice a better response in low end torque, albeit not a huge gain.

Well made parts and took a few mins to install, here's a pic of before and after.

Before:


After:


Interestingly, whilst rummaging through the SSP, I also found that on WOT when revs swing past 3,000rpm, another flap opens in the air box to take additional air from the engine compartment! So darn complex!! But oh so smart!!

Cheers