throttle before or after turbo

[Gary Derian]

Old style carbureted turbos with draw thru carbs had decent throttle
response but the volume of the intake was small, carb, turbo, manifold with
no intercoolers, etc.  If you have a high performance turbo with high boost
and an intercooler, lots of plumbing, etc, you definitly need to have the
throttle after the turbo.  In that case, you also need a valve to prevent
surging the turbo when closing the throttle after a high rpm run, say a
shift.

Gary Derian <gderian at cybergate.net>


>At 12:32 PM 3/6/99 EST, WLundquist at aol.com wrote:
>
>>A better alternative is to put the  tb's before the turbo inlet
>>so that when the tb's are closed the turbo will spin in a vacuum and
maintain
>>rpm, this will make for guicker recovery when you stab the throttle.
>
>Frederic mentioned poor trailing-throttle response as a possible drawback
>to this approach... I personally don't believe that, for various
>reasons, but the thing I do worry about is having lots of oil sucked
>into the air in the turbo. How much of a problem is this, really? I
>know some turbo vendors have special sealing options avilable, but I'd
>like to hear from people who have set any old turbo up with the TB
>before it, if you had much problem with sucking oil into the intake.
>
>The only reason I care this week is a weird turn of events has led
>to the possibility that I'll get a turbo'ed car soon, and I'd like to
>know, if I move the throttle before the turbo, how much trouble am
>I asking for? Yeah I could get a new turbo/upgrade it/etc, but for
>various reasons I would not like to have to do that.
>
>   TIA,
>   Chris C.