[Supras] richness under boost

[Walker, Brian (Rich. Dist)]

Bernie, those spikes in boost seem a bit odd to me. I have a wideband
that measures press. and has peak storage. My peak boost is always ~14.5
(within ~.2 psi depending on ambient temps, ball & spring controller)
This is also the pressure I normally see under WOT (by autometer gauge
and real time Wideband display. To me spikes of 2-3 psi seem off. Have
you checked to make sure there is no play in the WG arm? Maybe that
variance is normal for other folks but my peak boost has been pretty
rock solid. (peak A/F on the other hand does tend to vary a little,
normally 9.6:1 -10.3:1 depending on weather)
Brian W

Date: Sat, 03 Nov 2007 18:59:37 -0500
From: "berniek at technicaldevelop.com" <berniek at technicaldevelop.com>
Subject: [Supras] richness under boost
To: "Supras at supras.com" <Supras at supras.com>
Message-ID: <472D0B69.9090809 at technicaldevelop.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Today, I temporarily wired up a Dawes A/F indicator, and found that as
expected, the engine runs richer under boost than needed for best power.
There are ways I will be considering to lower combustion temperatures,
such as water injection (already have the RV water pump).  
But for now, the Dawes readout always has the blue LED lit under boost,
I guess the way Toyota intended it (about 9:1 A/F ratio).  The car feels
good, so I'd rather be safe than sorry, but can use any number of means
to get the A/F up to about 11:1 under boost.  I'm particularly concerned
about safety since I'm running the stock pistions at 15 PSI, with one
second long spikes up to 17-18 PSI.  Has 550cc, Lex, 3" exhaust, 57 trim
turbo, Walbro and the usual mods which go along with these parts.


As always, any information would be appreciated.


Berniek