[Supras] richness under boost

[Jim Jobe]

Bernie, please do not tell us you are using this gadget to determine
a/f ratio.

http://www.3barracing.com/product_3.htm

You NEED a proper wideband sensor for tuning.

BTW, stock pistons have made 500rwhp reliably daily driven for years.

On Mon, Nov 05, 2007 at 10:51:56AM -0500, Walker, Brian (Rich. Dist) wrote:
> 
> 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
> 
> 
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