The boost jets come with the Jim Wolf ECU upgrade and are what is responsible
for the increased boost. The ECU just makes it safe by adjusting ignition
timing curves and fuel curves to run the increased boost and does not raise
boost itself.
Boost jets are made of aluminum and look like a bullet with a hole in
the center.
The boost jets go in the wastegate vacuum lines and serve to block some
vacuum signal to them, which "fools" the wastegates into opening less/later
for more ultimate boost.
Contact welding tips, which meter a certain amount of gas out of a welding
torch, resemble boost jets, so many use them in place of boost jets. They
are made of brass or some other metal making them sturdier and easier to
work with than boost jets. They can be had in many different metering hole
sizes, such as 0.045 inch, 0.035, 0.030, and 0.025 inch.
Many have raised their boost to 14 psi with the welding tips with the
stock ECU and have had no problems, but they don't generally use the boost
too long or run their cars at high speed while in the boost for long.
Other precautions such as, colder pfr6b-11b(#6) or pfr6b-11(#7) spark
plugs are used to ward off detonation. An accurate boost guage(non-stock)
and a keen ear is needed to listen for the faintest amount of detonation
which sounds like "pebbles in a coffee can."
14psi sems safe on a stock ecu, but for $599 you can have the JW upgrade
ecu and have much more peace of mind knowing you have much less of a chance
of blowing up your expensive TT engine. Your choice.
Chris(Miami)