[Supras] Awesome (escessive boost)

[berniek at technicaldevelop.com]

Dear Nick and group:

    Just called James at Performance techniques, who rebuilt and 
modified my CT26 to 57 trim.  Apparently it will take 18 PSI and run for 
50K-100K miles with proper care (synthetic oil, etc.).  21 PSI sounds 
tantalizing.  For the first time in 40 years I feel as if I have my new 
'65 GTO back again once over 3000 RPM.  What a beautiful feeling to be 
pushed back in the seat.  All of the usual mods based on 550cc 
injectors, Lex, 3" exhaust, single cat, Cometic, ARP, etc. accompany it 
on a freshened JDM engine (important:  using '98 hard urethane front 
mounts).  The car is a stunning black '91 bought in July from Houston to 
replace my tired '90.  The '91 has only 103K miles on it, is free of 
rust, and has late MkIV wheels.  It burns up the 275/40/17 rear tires in 
first gear, and to a small extent in second.  Awesome!.  Makes me 
happier than a pig in ****.


    Bernie



t72pwrd wrote:
> I ram a 60 trim for about a year at 21 PSI daily before having to part 
> the car  out for reasons unrelated to the turbo.  Never any problems 
> and it was a fun car.  Made ~400HP at the wheels.
> ----- Original Message ----- From: <berniek at technicaldevelop.com>
> To: <supras at supras.com>
> Sent: Thursday, November 01, 2007 3:47 PM
> Subject: Re: [Supras] Awesome (escessive boost)
>
>
>> Just remembered setting the ball and spring boost controller on the 
>> bench
>> tto 12 PSI, but forgot that it increases boost by the DIFFERENTIAL
>> PRESSURE across it, so the boost is really 12+6 = 18 PSI if I'm right,
>> where 6 PSI is the cracking pressure of the waste gate actuator.  
>> Although
>> I've temporarily attenuated the pressure transducer output to keep the
>> dash gauge from pinning, it will not read above about 14 PSI (output
>> voltage saturates at just under 5V).  From what I have understood about
>> CT26 turbos, the maximum it should experience is 14 or 15 PSI due to
>> bearing and shaft size.  The fact that it is 57 trim supposedly does not
>> enter into that limitation.
>>
>> Does anyone have any long term experience running a 57 trim CT26 at more
>> than 15 PSI?  Thanks.
>>
>> For the future, a better boost controller will be used.  The Dawes
>> presently used is just a temporary measure.
>>
>> BernieK
>>
>>
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>
>