As I noted previously, a recent dyno day showed that the Air/Fuel ratios on
the 180SX were quite healthy throughout the entire rev range, which, along
with a recent intercooler upgrade, gave me the confidence that it would be
safe to increase the boost level a couple of PSI. Hopefully this with be
enough to bump it over the 200 RWHP mark (seeing as it is currently just below
this, at 193 RWHP).
I did consider a simple bleed valve, but these have a tendency to spike
and not give the degree of control I would like, while most commercial
electronic boost controllers are simply too expensive for my taste (OK, I'll
admit it - I'm a cheapskate!). The final solution was to combine both of my
interests (electronics and cars) and build my own electronic boost controller.
Rather than design one from scratch, Jaycar Electronics have some excellent
kits available which fit the bill very nicely.
The Jaycar Independent Electronic Boost Controller (IEBC) Kit has some unique
advantages over its more expensive brethren. One of the most important
differences is its method of controlling the wastegate. A typical electronic
boost controller controls the wastegate by bleeding pressure off the
"vacuum" line. The IEBC, on the other hand, controls the wastegate
by directly controlling boost pressure leading to the wastegate. This means
that the IEBC wastegate is held completely closed right up until the boost
level required is reached, which means that the boost will increase as fast
as the turbo can physically build it. In turn, this should mean that the turbo
will reach full boost much sooner than normal, which should also mean that
mid-range performance will improve.