[s-cars] Re: RS2 definitive answers

[James Bufkin]

Scott,
Getting off the RS2 stuff for this post.  I don't think  you or I are in 
disagreement about the RS2's potential and limitations.  Its fine for 
street cars.

I personally think you are reading way too much into the few instances of 
Audi's attempt to implement the Anti-Lag system on their I5s.  They did try 
it.  Yes.  And they subsequently dropped it.  yes.  They then continued to 
use K27 turbos for their cars.   Now RS2 variants, etc from the mid 90s are 
interesting and I'm sure they tried the smaller turbo but, I suspect it was 
due to intake restrictions by the rules.  My machine had an RS2 7200 comp 
turbo but was also fitted with a 40mm restrictor according to SCCA 
rules.  Interesting choice.  Lehmann mentioned that the more appropriate 
turbo for my car without the restrictor would have been a K27, and that is 
what he would have used if it weren't for the restrictor.    You cite two 
examples of K26 turbo use in I5 competition, but both of those are much 
later and possibly non-works examples.  I still contend that the K26 family 
was just as commercially available to Audisport and they could have put 
together whatever K26 they wanted, but they didn't.  What that tells me is 
that with the right driver who can take advantage of the power and handle 
the lag, the K27 is the better turbo for racing on the I5.    The IMSA 
example that Mihnea cited isn't fitted with the 2nd wastegate 
anti-lag.  That system was tried in the 1985 Season on the S1 and at the 
1985 Pikes Peak which is where my setup is from.  I see the anti-lag setup 
as an attempt to make a good setup even better.  Not to make an unworkable 
system tolerable as you seem to see it.   The IMSA car ran a large frame 
K27 and they just Left Foot Braked it to keep it spooled.  The results 
speak for themselves.

So respectfully, I think the K27 choice speaks for itself in the racecars 
and I hope your not implying that the IMSA would have been faster with a 
K26 hotside.

James




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