Turbo Bypass

[Jim Zurlo]

We bypass from the intercooler inlet to the exhaust manifold just upstream
of the turbine inlet.  This is the best method for maximum efficiency, but
you probably don't care about fuel consumption that much.  It is also
impossible for us to place the throttle valve upstream of the compressor
inlet because turbo manufacturers don't make compressor seals for big
turbochargers and engine response would be very slow.  All of the above
applies to very large engines (~18 liters/cylinder).  For your application
I agree with Gary that the best solution for you would be to put the
throttle upstream of the compressor inlet.  That allows you to avoid the
complication of a bypass valve. Bypassing post intercooler air into the
inlet just heats up your incoming charge since intercooler effectiveness is
never 100%.
Jim Zurlo
zurlo at execpc.com


>Bypassing the turbo helps keep the compressor spooled up while shifting a
>manual transmission.  Bypass from the pressure side before the intercooler
>to the inlet side after the mass air flow meter.  With speed density there
>should be no affect.
>
>Gary Derian <gderian at cybergate.net>
>
>From: Jim Lill <jpl at vectorbd.com>
>
>>
>>Does anyone have any thoughts or references to info on the type and
>>positioning of Turbocharger bypass valves?
>>
>>Things I'm wondering about...
>>
>>- bypass to compressor inlet vs. dump to atmosphere
>>- pre-intercooler vs, post-I/C dump point
>>- effects on A/F Ratio
>
>