[s-cars] Why audi I5 started as 2.1 liters - Audisport Historical Trivia

[James Bufkin]

Right on Scott!
Good stuff there.

Hmm.. Pictures of Big turbos on Tubular Exhaust Manifolds.
How about these.
http://www.bufkinengineering.com/101004progress01.JPG
http://www.bufkinengineering.com/101004progress08.JPG
http://www.bufkinengineering.com/Lehmann%20EM%20on%20Head%2001.JPG
http://www.bufkinengineering.com/mockup.htm

Things to note:  This is a Lehmann manifold.  The top of the 930 wastegate 
is about 1/2" from the bottom of the hood.  The wastegate is perfectly 
plumb.  The Turbo flange is perfectly plumb so the turbo aligns to the axis 
of the car.  The #3 cylinder, Wastegate and hotside housing align.  This 
makes the downpipe flanges perpendicular to the axis of the car.  I think 
this is typical german symmetry and thinking.  This setup provides alot of 
room for the downpipe which has to snake above the subframe and below the 
steering rod to clear the skidplate.   It also provides alot of ventilation 
to remove hot air from the aft of the downpipe.  This will be extremely 
useful for long stints.  I've seen video of S1s taking jumps at dusk with a 
bright red glow coming from the enginebay and illuminating the ground under 
the car.  The turbo is glowing so hot it looks like a red light in the 
engine.

This also means an S1 style airbox affixed to the front of the turbo is 
ideal for airflow.   To use this manifold, the engine has to have solid 
motor mounts cause the clearances are too close for hydraulic mounts.  Also 
the fender has to be removed.  The turbo comes in and out through the front 
headlight opening.

James "Running a 2.144L motor and lovin it" Bufkin :-)


James E. Bufkin, P.E.
Bufkin Design and Engineering, inc.
2309 West 8th Street
Austin, Texas 78703
512-236-8070
fax 512-480-5927