Date: Thu, 3 Jan 2002 23:01:02 -0500
Reply-To: Ed McLean <email99@BELLSOUTH.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ed McLean <email99@BELLSOUTH.NET>
Subject: tiico intake manifold and Motronic MP 9.0 info
Content-Type: text/plain; charset=us-ascii
With the discussion concerning the use of the tiico intake manifold on a
engine conversion kit based on USA parts I think there are a few facts
that are being overlooked. Most importantly, the tiico cylinder head is
a 1800cc Polo head (1HS 103 265CV from their parts list). Based on the
pictures in the Robert Bentley 1993 through 1999 Jetta, Golf, GTI,
Cabrio Service Manual (page 15a-14, Fig.15) this head looks like the
1800cc head for the ACC engine. The reason this is important is the
shape of the intake ports and the positioning of the intake mounting
studs is different from any head I've found here in the US. There will
be problems attaching the manifold to the head if the ports are
different. The ports are essentially figure 8 shaped with a small top
part of the eight and a fat waist. Another way to describe them is a 3
cm round port with an upside down 2.3 cm wide U on top. Check out the
picture in the Bentley manual. I think the 1800cc engine is sold in
Canada (at least I think a 1800cc Polo is sold) so it might be possible
to get this head without too much trouble. I don't think the intake
will do much good without the correct head.
The ACC engine is a 9:1 compression ratio 1800cc engine. If this head
is put on a 2.0L engine, the compression ratio will be approximately
10:1 as the tiico engine is advertised.
Another difference that is not mentioned generally in the discussions is
the particular version of the Motronic fuel injection system and the
implications of this. The tiico engine is a Motronic MP 9.0 system
which uses manifold vacuum instead of an air flow or air mass meter. No
US imported VW gas model uses this configuration of manifold vacuum
detection. To use this manifold with a US spec fuel injection system
would require including an AFM upstream of the throttle body. This is
not a major problem but it would require some additional plumbing where
there is not much room.
The use of the manifold vacuum sensor (aka Duosensor 030 906 051A or
Bosch #0 281 230 011) is also why I am somewhat amused at the talk of
buying a performance chip for the tiico system. I would be very
surprised if any commercial tuner would be willing to invest the time in
developing such a low volume product. However, I've been wrong before.
The Motronic MP 9.0 system is used on several VW models in other markets
but they are all smaller displacement engines (1.0L and 1.4L). An
oxygen sensor is used in markets where unleaded gas is available.
I also noticed that some Volvos built around 1990 use a vacuum modulated
fuel pressure regulator adjusted to 3.0 Bar with no vacuum applied.
This looks very much like the 2.1L Vanagon regulator.
Just a few thoughts on the subject.