[s-cars] Re: RS2 definitive answers

Tue Oct 19 21:30:54 EDT 2004

Share some of the radical cold side wheel and housing examples please.
I just invested in a GT30R, and I hope that has some of the newer cold side
technology in it, at least it better.

I have to share some of your views on the size vs. drivability on turbos.
I hope that ball bearing CHRA and latest hot / cold wheel design will show
itself favorably with my latest experiment.

It certainly has to make more power than the RS2, but I hope it will make as
much low end torque that miss piggy loves so much.

Mark S
----- Original Message ----- 
From: <QSHIPQ at aol.com>
To: <jbufkin at austin.rr.com>; <s-car-list at audifans.com>
Sent: Tuesday, October 19, 2004 8:55 PM
Subject: Re: [s-cars] Re: RS2 definitive answers

> In a message dated 10/19/2004 4:26:37 PM Central Daylight Time,
> jbufkin at austin.rr.com writes:
> >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.
>
> Ok.
>
> >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.
>
> And k26 based turbos as well.
>
> >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.
>
> Interesting.  I haven't seen a inlet restrictor ck in SCCA ProRally in 25
> years.  I'm sure they had it, but we never ran it in the '95 S2, in fact
we
> didn't even take it to the rallies most of the time.  Lehmann sent the 26
based
> turbo for the S2, and that cold side was awesome.
>
> > You cite two
> >examples of K26 turbo use in I5 competition, but both of those are much
> >later and possibly non-works examples.
>
> Are you sure of that?  I'm not.
>
> >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.
>
> Depends on venue.  "Racing" is all inclusive.  There is a big difference
> between WRC efforts (1000 turns usually blind) vs Tarmac racing (10 turns,
LFB on
> turbo/cam).  There is factory works driver complaints regarding the off
> cam/off turbo lag of the WRC cars dating back to the A1>S1
>
> >The IMSA
> >example that Mihnea cited isn't fitted with the 2nd wastegate
> >anti-lag.
>
> I understand that.  They didn't need it for Tarmac racing.  They did need
it
> for Hillclimbs, and it was tried in rally.  They needed it because
Audisports
> problems with FIA Group B 1.4 equivelency Rules.
>
> >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 S1 Evo II (all SQ's were technically S1's James) was indeed to make an
> tolerable system.  The problem Audisport had was twofold in '85.  First,
the
> success of the S1 chassis was plagued with reliability problems, and had
works
> driver complaints of off turbo/cam lag just as the A1 and A2 before it.
> Audisport didn't want to give up HP to give the drivers more torque.  Why?
Cuz the
> awd competition (namely Puegeot) had a better awd car with a better
winning
> record.  Audisports days of buying the best drivers (Mikkola, Blomqvist,
Mouton,
> Rohrl) was falling to better equipment.  Rohrl had to be begged to come
back
> for '85, and Audisport was pulling all the stops to get wins in '85.  So,
IMHO,
> not only was this system for "tolerance" it was just plain desparate
attempts
> to keep HP at the highest level, and still give the drivers "torque".  For
> the Pikes Peak win, the "whackies of the whacky" setup ever was needed,
since
> you have a small motor with a huge turbo and a 9000ft elevation change.  A
> really tough opinion you carry there James, since this desparate attempt
by A.S.
> gave it's race motors a half life of 1 hour.  I'll suffice it to say I
disagree.
>
> >   The IMSA car ran a large frame
> >K27 and they just Left Foot Braked it to keep it spooled.  The results
> >speak for themselves.
>
> Yeeha.  Light chassis, massive HP, massive turbo, legendary drivers.
Well, I
> see 1 of the 3 comparing the scar list.
>
> >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
>
> Massive jump there James!  Never implied, and I might argue the "speaks
for
> itself" with a healthy dose of Audisport '85 WRC history and works driver
> quotes.  720HP IMSA motors need k27 (or bigger), 900HP IMSA motors
probably bigger
> than that.  500HP Trans Am motors didn't exclusively use k27's.  I'd also
> argue that Audisport used even larger turbos too James, don't limit
yourself to
> k27's,
>
> To bring it back to the S-car list....  I'm not sure I understand this
quest
> for monster turbos on small displacement I5's.  Audisport was restricted
to
> 2.1 liters in FIA for years, and it made for some laggy monster race cars
(at
> half the weight of miss piggy too).  We on these lists, on the other hand,
> aren't at all restricted to 2.1 or 2.2 liters.  Want to run a k27 with
lots of HP
> and torque?  Add the couple hundred cc's to the I5, and do it right.  This
> quest for HP confuses me some, especially on these lists.  Miss Piggy
*needs* it's
> own equivelency formula, and I'm just not convinced a k27 is the answer.
>
> My own prediction?  Cold side technology is going to really shake down to
> street turbos.  I've seen some pretty radical cold side wheels and
housings over
> the last few years.   After bolting one of these radical cold sides up to
the
> '95 S2 group A car then driving it, I'm certainly convinced.
>
> Scott Justusson
> QSHIPQ Performance Tuning
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