[s-cars] Re: RS2 TURBOCHARGER CALCULATIONS - LONG - definitive answers

[Mihnea Cotet]

James, thanks for the post, it proves me I'm not the only one on these 
lists who thinks this way. :-)))

Now bring that turbo on and show us what you can get out of it, is Javad 
going to help you with tuning? He'll do a great job, he's also one of the 
people who know their stuff very well when it comes to high HP 20vts. He 
has recently passed the 400 HP ATW barrier on his 80tq too BTW, and I do 
believe his figures.

Mihnea

www.mrc-developments.com


At 10:04 18/10/2004 -0500, James Bufkin wrote:
>I'd like to interject some of my own amateur experience and conclusions.
>I've spent a great deal of energy researching what turbo and manifold 
>would be appropriate for my car and have talked with Lehmann about it as 
>well as many people here in the United States.  I've also looked at the 
>maps (RS2, etc.) and have come to the same conculsions that Mihnea 
>has.  The RS2 seems limited at the upper RPMs at high boost.  Limited in 
>its ability to supply air without overheating and its ability to flow the 
>air out of the exhaust without a rise in EGTs.   Hence the reason why Audi 
>ran K27s on All their I5 race machines.   That is huge 
>evidence.   Audisport could have made any K26 they wanted in the 
>1980s.  They had custom runs of only 15 turbos made and chose to use 
>exclusively K27s.   Surely if those guys felt the K26 was the way to go 
>they would have used one in their race cars.    Lehmann is quite adamant 
>about it for high HP cars and anything that will race or see extensive 
>track use.    I've gone against his advice a bit and opted to use the #7 
>K27 instead of the #9 K27 hotside.  Now perhaps his decisions are based 
>more on controlling EGTs and DRs for prolonged high HP production and not 
>drivability.  But if we're talking about making HP to get speed then 
>drivability takes a backseat.
>
>I would however recommend an RS2 for any street car that is designed to 
>make 350 Crank HP or so.  Like the original RS2.   Going beyond that is 
>wishful and/or time limited for short durations of high HP in optimum 
>environments.
>
>James E. Bufkin, P.E.
>Bufkin Design and Engineering, inc.
>2309 West 8th Street
>Austin, Texas 78703
>512-236-8070
>fax 512-480-5927