Variable intake valve timing. Variable geometry composite intake manifold
06-20-2001, 05:19 PM
#12
AudiWorld Super User
Join Date: Nov 2000
Posts: 4,219
Likes: 0
Received 0 Likes
on
0 Posts
The intake cam is driven by the exhaust cam via a chain and sprockets. (m)
The chain is extra long and is spread apart between the sprockets by a spreader ramp made of a slippery tough plastic material. This ramp can be moved hydraulically until one side of the chain is taught between the sprockets and the other runs over the fully extended ramp. Moving the ramp to the other side results in a change of the relative angular position of the two sprockets. The S4 has only two positions that are controlled by the ECU as a function of speed and load.
<img src="http://pictureposter.audiworld.com/12010/varicam.jpg">
The S4 has no variable intake geometry. On the 2.8 Ltr NA engine, it is achieved by sending the air along an expanding spiral path before it gets to the intake port. Part of that spiral path can be short circuited to achieve a different resonant path length.
<img src="http://pictureposter.audiworld.com/12010/variintake.jpg">
<img src="http://pictureposter.audiworld.com/12010/varicam.jpg">
The S4 has no variable intake geometry. On the 2.8 Ltr NA engine, it is achieved by sending the air along an expanding spiral path before it gets to the intake port. Part of that spiral path can be short circuited to achieve a different resonant path length.
<img src="http://pictureposter.audiworld.com/12010/variintake.jpg">
Thread
Thread Starter
Forum
Replies
Last Post
SC_09iduA
A8 / S8 (D2 Platform) Discussion
9
06-10-2024 08:45 AM
BinsuJiro
A6 / S6 (C6 Platform) Discussion
4
08-13-2017 03:41 PM
Mr. fix-it
Audi 90 / 80 / Coupe quattro / Cabriolet
4
04-21-2003 04:56 AM
