[urq] Why are the L5 Turbo engine sounds different ?

[Louis-Alain Richard]

Andrew, you just destroyed my theory...

I was thinking that the difference between 10V and 20V was mainly the
exhaust valve placement and manifold shape (that kinda acts as a giant
flute). I thought that this difference was the main factor. 

On the 10V, intake and exhaust are like this :
http://www.zoocustoms.com/audi640/images/audi19.jpg 

E-I E-I I-E I-E I-E 

So there is 2 intake valve that are side-by-side.


On the 20V, not the case because the engine is crossflow :
http://tinyurl.com/b2k9km or from www.ebay.de  item #320340155908.
All the exhaust valves are evenly spaced.

But Andrew, you are saying that you didn't played with the EM or the muffler
and the change in sound was obvious ? Interesting.

Louis-Alain



-----Message d'origine-----
De : Andrew Dickinson [mailto:amdickinson at rogers.com] 
Envoyé : 11 février 2009 08:09
À : 'Louis-Alain Richard'
Objet : RE: Why are the L5 Turbo engine sounds different ?

I'd say that compression ratio, valve timing and size in addition to the
chamber and port sizes and shapes have a significant effect.

When I had the factory MC1 in my car the sound was a pretty plain 5000
turbo type sound.  After my rebuild I can hardly hear myself think in
the car.  It has become much deeper and richer.  I changed so much that
it is impossible to say what change made what difference to the sound.
What I can tell you is there is a huge difference.

I bumped the CR to 8.5:1
Used an MC2 cam
Large Ti valves
D-ported the intake runners

The exhaust runners and combustion chamber remain the same.

The results have been fantastic.  The car sounds amazing.  One of these
days I will finally get the timing and fuel dialed in and get her over
to the Sprongl's dyno.

Cheers;
Andrew

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com]
On Behalf Of Louis-Alain Richard
Sent: February 10, 2009 9:34 PM
To: urq at audifans.com; quattro at audifans.com
Subject: Why are the L5 Turbo engine sounds different ?

Spent the night at the pub with Brady (urQ, 4kq, 200qa20v, 240Z) and
Geraint
(200qa10v, 964, GTI Mk2, Spridget), obviously most of the talk was about
cars. One question is still unsolved : why is the sound of the L5 10VT
and
20VT so different ? We have some thoughts about it, but I'd like to hear
from others.

 

We agreed that the 10VT is better sounding : rougher, deeper, richer.

 

What is the list wisdom on this ? Which is better, but more important,
why
the difference ?

 

Louis-Alain