Twin turbos....Mental institution... Sign us all up...

[Michael Gough]

> Mike, ANYBODY can do a twin turbo I5 (ok, I'm teasing).  Why not a
> sequential Twin Turbo, say one K03 for 1,000 - 4,000 rpm, with a K27 Sport
> starting at 3,000 RPM, blending with the K03 between 3,000 and 4,000, then
> taking over at 4,000 to say 8,000(not a misprint, but would the MC handle
> 8,000 rpm??).  It would be a streetable version of the Audi Sport URQ.  You
> could probably look at some factory stuff (Mazda did one I think???) for
> ideas.  I offer to design the *sequential* WI in exchange for one drive
> around the block...
Yeah I am going to a parallel setup first, then maybe I'll look at doing
sequential. The way you said (K03 and K27 would be perfect) The little turbo
would be running out of steam just as the big turbo is kicking in. The car
would behave like it had a huge amount of displacement. Lots of low end
torque, and huge amounts of high RPM HP.

> Are you going to have the TT's share the center exhaust, or all the
> exhaust??  This could be an exhaust flow efficiency nightmare.  No worries,
> keep welding...
Still thinking about this, making some drawings. I'm either looking at a log
manifold with one turbo on each end, and a diverter in the center of the #3
runner to make half the gas go one way half the other way, or I'm going to
do a 5-1-2 manifold. Get all the gas together, and then split it off to the
two turbos. I'm sure it won't be as flow efficient as the factory would have
done it, though it'll be pretty good by the looks of things. Because of the
short distance to each turbo, and because of the cylinder firing order, the
log manifold I'm looking to make shouldn't really hurt flow as much as it
would on a "normal" application.

The thing I'm realizing though, how much power does anyone need? At 6psi
with the K24 and EFI the car was faster than needed for street use. I have a
feeling the new MC with the k26/27 running 18psi will even be scary to drive
on the drag strip. But! If I still want more power, and feel safe on the
track with it, you all can count on a twin turbo MC around Christmas time :)
Mike