[s-cars] #8 or #6 Turbine for K26/TO4E Garrett Hybrid

[Mihnea Cotet]

A little precision apart from what Pizzo, Hap and the others already said,
it's that the allegedly #8 turbine/stage 3 for Turbonetics is pretty much
equivalent to a K27 hot side, i.e. 63mm exducer, which is way too big for a
K26. A real K26 #8 hot side is 56mm. Now the point is that both the
Turbonetics #8/stage 3 and the "real" K26#8 make boost at about the same
RPM, i.e. 3500-4000 depending on the mixture (lean mixture and much advance
just below the knock limits help a lot with spool-up, Trevor Frank is
right) and provide with a nice kick in the a$$ at about 4000-4500 RPM.

And another precision, an RS2 EM can do 480 crank HP (400-ish at the
wheels, tranny loss correction factor 21% as measured in a friend's car
recently) but at the expense of the engine itself! The EM exducer is too
small and restricts gasses, which in turn increases heat inside the
cylinders and melts exhaust valves stems. That guy I know of has very
unfortunately BTDT last week and I had also unfortunately predicted his
engine's loss (he has had it tuned without an EGT).... another food for
thought is that, whatever the turbo, if someone goes to MTM's workshop and
has his car dyno tuned by Herr Peter Link, you can beg him on your knees
but he'll never give you the car with more than 420 crank HP on an RS2
EM..... food for thought guys... many people think they can do more than
MTM and some actually do (but I won't venture into explaining what it takes
to do real tuning as good as MTM without copying anyone), but when it comes
to serious HP engines that one can drive for hours at WOT on the Autobahn
during a 40-degree C day in the summer without having to worry about oil
temps or engine damage, I won't ever try to go past what MTM do with a
known combination of parts. MTM know what they do, lots of other people
don't and I'm trying to know as well... :-)

HTH and sorry for the WOB if my post is too long and it's boring....


Mihnea


At 20:03 12/08/2003 -0600, Cody Payne wrote:
>Gents regardless if I go w/ a 50 or 46 degree Cold-Side...I wanted to know
>if there are any real-world "disadvantages" to a smaller K26 Hot-Side
>Turbine i.e-#6 vs. #8.  Ray Tomlinson is installing a TO4E 50/K26#8 as we
>speak. (Good Luck Ray...drink lots of beer!)
>
>Since I received Corky Bell's book ultimate boost he states:
>"Selection of the turbine must focus on the principles of spinning the
>turbine fast enough to produce the desired response and boost pressures
>yet keeping back pressure to an absolute minimum."
>
>Smaller Hot-Side Turbine=Increased Back Pressures but increased response
>of turbo.
>
>Thus question is if the #8 is too big vs. #6?  Any experiences here either
>way?
>
>Cheers
>
>cp
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