RE: RS2 IM v EM's - actual comparos

[QSHIPQ@aol.com]

I'm smiling at the cloak and dagger.  I have two RS2 ("powered by Porsche") 
intakes in my office, 1 RS2 EM (stock), 1 IARS2+ EM (Extrude honed) copy, and 
saw Ned's IA IM at MH99.   Also, in my shop are 2 20vt motors side by side, 1 
3B and 1 AAN. Here's my btdt take:

INTAKE MANIFOLDS:  The RS2 is ala 3B, that is to say, it goes around the back 
of the valve cover, but uses the stock S4/6 Throttle body, and needs the 3b 
cruise control bracket from a 3b to make cruise fit the AAN.  The RS2 is 
slightly longer than the 3b and has unequal length intake runners.  To use 
the RS2 on the AAN motor requires modifications to the fuel pressure 
regulator, or one can use the 3B fuel rail.  Water manifolds on the AAN need 
to be changed to 3B, or modified for center exit (my btdt)

The MTM/IA IM:  This allows the placement of the TB at the driverside of the 
car, and possibly allowing better IC location (since Ned's car at MH99 had NO 
IC, not sure I can comment on the thinking here), the MTM design should be a 
bolt in for the AAN equipped vehicles.  From the casting, it sure looks like 
a cut and paste job, the casting for the front mount TB is rough and visually 
easy to see where the 'paste' was.

After looking at the design benefits of both manifolds, my thinking is that a 
swapped AAN into a 90/4k/Urq chassis would be easier with the stock RS2, the 
S4/6 cars would be easier with the MTM.  From a performance standpoint, 
either is acceptable, the chamber volume stays the same, the runners stay the 
same, so should peak performance.

Exhaust Manifolds:  The Stock RS2 unit and IA's copy are virtually identical, 
but I give Ned a bunch of credit on the design of his for a couple reasons 
(the PN and the USA castings not withstanding).  His casting has a larger 
turbo mounting area, for those interested in monster turbo applications (per 
his phone call to me re: design), a larger turbo inlet diameter (whether 
planned or EH dictated that is up for discussion), and very smooth EH 
compared to the stock RS2 unit.  Price no object, Ned's sure seems like it 
has more potential and applications.

Bottom Line:  Either IM is worthy of upgrade, either EM is worthy of upgrade. 
 Having seen an S2 AAN conversion to the exact ETKA RS2 specs (including 
crossover pipe, IC, IM, EM) vs my RS2URQ design, I'm convinced there is a 
better way to get more power and more IC efficiency simpler and with less 
effective intake bends and length than the RS2.  

Seeing the intake manifold in Ned's car, all I can say is that the TB is 
REALLY close (like whisker) to the front crossmenber of the smaller chassis.  
Anxious to see the IC design he has in mind...

HTH

Scott Justusson
QSHIPQ Performance Tuning
QSHIPQ@aol.com