terminology and turbo questions

Brian Devlin bdevlin at stanford.edu
Wed Feb 20 14:48:45 EST 2002

>What does the term "short-block"refer to?
>And then,...... "long block"
>is there a "tall block"?

Long block vs short block usually refers to whether there is a head
on the engine you are buying.

A tall block is version of a block designed to use longer connecting
rods or a bigger crank, it is taller so the cylinder bores (and thus
head) are further from the crank.

>Also,  the psi rating of a turbo....
>Is this the pressure on the turbo outlet, pushing into
>the intake?
>Or, is this the pressure of exhaust acting on the
>turbo spooling fins?


>I notice that the wastgate spring is denoted by
>pressure (psi or bar).
>Does the wastegate spring controll the amount of
>pressure the turbo can spool up to?

Yes, but the computer modulates the pressure via the wastegate
frequency valve. Intake pressure is piped into the bottom of the
wastegate and pushes up against the spring. The frequency valve
allows pressurized air into the top of the wastegate, adding to the
force from the spring and keeping the wastegate closed.

>I.E,.. getting a stock system to spool from a factory
>set 6psi to get to about 12 psi only requires a
>wastgate spring change????  is this right?

Yes, but the computer will shut off the fuel when you get to 1.6 bar.
Chipping or fuel pump relay mods will get around this.

>could someone please clarify
>Aaron Ryba
>87 4kcsq 106k
>Do You Yahoo!?
>Yahoo! Sports - Coverage of the 2002 Olympic Games

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