Partial success - take 2

[dzorde at erggroup.com]

Thanks to everyone that have replied, let me try and sum all issues into
one email.

1.  The car is purely for racing purposes, noise is not a problem.  One of
my thoughts was to actually vent it into the exhaust just before the
muffler, with the right angle entering the exhaust the fast flowing exhaust
should hopefully help scavenge the blow off air ?
2.  An 850 engine bay is extremely small and the cylinder head only has 1
inlet port (ie. the inlet manifold is internally cast in the alloy head),
using the tbi style injection system I can only run it in a blow through
configuration as there is no room for any more pipework and the tbi fits
nicely in place where the original carby used to sit (custom head-tbi
adaptor required though)
3.  As for air temps, yes, when the s/c is blowing into the virtually dead
end you don't want to accidentally lean on the intercooler as you could
warm a cup of coffee on it (extremely hot would be a good description).  As
for normal running I have yet no idea what sort of temps to expect.
4.  On an original MR2 there is some sort of elaborate bypass system and
electronic clutch set-up, ie. I think theirs is blow through configuration
as well, except they disconnect the s/c and bypass it to still get air into
the engine under cruise and light load.
5.  Re-gearing the s/c to generate less boost would, I guess, reduce the
severity of the problem but not actually remove it.  Plus it would reduce
my overall possible boost (can't have that).
6.  Considering the design of the MR2 s/c I would like to run it in a dry
configuration as intended and I have not been able to find information on
the performance of the seals, so I don't know if they would like vacuum.
Also I've seen what happens during a back fire with a s/c full of a nice
combustible mixture (not a pretty sight).
7.  I'm running a MAP system.  The multiple BOV set-up could be feasible
but seems messy.

Can a flapper style bypass valve be used as a BOV, or would it leak ?
If it can, would it be possible to use a small (say 50-70mm) throttle body
and just rig up a vacuum solenoid to operate it (instant BOV) ?

If all else fails, I suppose I could pull the throttle plate out of the tbi
(ie. just use it as a port style injector mount) and fit a tpi style
throttle body to the inlet side of the s/c and use the system a tpi style
suck through set-up.  However, some major pipework would be required to
accomplish this, so I'd prefer to not go this way if I can avoid it.

Thanks again for the feedback.

Dan  dzorde at erggroup.com

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