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

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In a message dated 10/20/2004 6:19:50 PM Central Daylight Time, 
jbufkin at austin.rr.com writes:
>You and I just disagree on this.
>Ned's turbo from a K26 with a 3.4" 72 trim wheel is fine and dandy.  I 
>definately call in question in relevance when discussing what audisport 
>used on their 20V cars.    Are you saying they should have used Ned's K26 
>Hybrid?   Has Ned's turbo run the 1000 Lakes Rally or the Dallas Grand 
>Prix?  I'd also question using a compressor that large on a K26 
>hotside.   Read Mihnea's comments about EGTs, backpressure on K26 
>hotsides.  

Be careful.  We haven't seen measures of backpressure to support that, only 
EGT's.  EGT's could be a hot side turbo backpressure problem, they could very 
well be caused by something else.  I also claim that EGT management is KEY to 
making turbos perform optimally.  I tried to take Minhea down that thinking 
road.  High EGT's mean high velocity as well, that's good for turbo hot side 
spooling.  EGT's *can* and *should* be managed with fuel.  It's not going to be 
easy to find the balance (I think the variance between mods is why), but I'm 
convinced that "more" fuel is not necessarily a great thing.  This is a much more 
complicated issue than N/A cars James.  I don't automatically buy into this 
EGT argument being a backpressure problem.  Not enough data to support that 
argument.

>  His numbers show that the Rs2 is falling off the map at higher 
>RPMS and higher Boost pressures.   So sticking a larger compressor on there 
>solves all that?  It might for a single dyno run or a drive around town, 
>and that makes it percieved as a good solution.   20 minute sessions has 
>given everyone the luxury of not pushing their cars for 2 hours 
>straight.  We have no real idea what running an RS2 at 6000 rpms and 2.6 PR 
>for 2 hours will do it.  I suspect VERY bad things.

Why 2.6 PR?  If you can supply the needs of the engine's air with more turbo 
air at a lower boost pressure....

>I'll stick by my comments.  You fail to persuade.  You cite examples of HP 
>restricted racing like Group A or mention 350cHP (near stock RS2).  I've 
s>aid before that the RS2 is fine for street use.  You're now claiming the 
>RS2 is good for racing as long as its HP restricted.   That doesn't really 
>make any sense to me with regards to what we've been discussing, but 
>okay. 

Mindset James.  "RS2 never in racing"?  Absolutely they were, including in 
YOUR car.  I disagree that racing is all out Horsepower.  It's just not.  Ck the 
results of Group A vs Group B stage times.  "The results speak for 
themselves".  I don't need to convince you or anybody else.  Look at Dawson's graphs of 
the RS2, his "killa" and the Hapersizer.  If you look closely at the RS2 graph 
it doesn't seem like a hot side problem to me...  Yet.

> I'll concede that the RS2 is a fine choice is the sanctioning body 
>limits HP and/or boost.   My car had a 40mm intake restrictor and an RS2 
>Comp turbo so I'd 100% agree with that.    So what turbo would you use if 
>the sanctioning body doesn't limit boost or HP?  I'm guessing your answer 
>would be RS2, and I still don't see the logic in it.  I'm citing Group B, 
>IMSA and TransAM where all HP that could be made could be used.   Those 
>builds did not use a K26.

I'll argue that "could be used" is relative.  When Walter Rohl, Stig 
Blomqvist and Mikkola have some pretty colorful quotes on lack of torque, I say your 
"racing" needs to be separated into LFB on track, and real world performance 
driving on and off throttle/boost.  That's where we all live 90+% of our time, 
and none of us are legendary drivers either.  Bring it back to the Scar list.  
Ck the comparative stage times James.  WRC Stages and SCCA stages don't change 
year to year, so the comparo is easy.  I encourage you to do some homework, 
it could change your thinking.

Maybe we can agree on this and call it a day:
>RS2=better suited for heavy car, wide gears, Street use, high torque, Easy 
>to drive
>K27=better suited for lighter car, narrow gears, track use, high HP, Hard 
>to drive

Maybe, what's the theatre at which we driving?  I'd hold off my choice, 
thanks.

>Which one of the above things sounds like an Audisport car and which one 
>sounds like an S-car.
>To me, this thread is definately more about Audisport and nothing to do 
>with S-cars so I can't see any point in continuing it.

Right now James, we have some audisport sized turbos getting bolted on Miss 
Piggy.  Remember too that the Audisport 20vt competed in the 450hp range for 
the majority of SQ competition.  I'd certainly say that comparing unlimited 
budgets and equipment is quite relevent to this list.  James, I'm an audisport 
guy, and an RS2 guy, a turbo and engine theory nerd, and the majority of my 
business is in S cars.  I am quite comfortable speaking in any of these arenas.  
I'm not as enamored with Audisport as you might be on the 20vt, cuz their 
"record speaks for itself".  

Peace and Cheers

Scott Justusson