RE: Max Boost/HP? 87 5kcstq

[Mike Sylvester <Mike.Sylvester@aptis.com>]

> -----Original Message-----
> From:	Todd Phenneger [SMTP:phen9461@uidaho.edu]
> Sent:	Thursday, March 25, 1999 8:12 PM
> To:	PlyBoyDoct@aol.com
> Cc:	Quattro List
> Subject:	Re: Max Boost/HP? 87 5kcstq  
> 
> 
> 	You are Correct about the IC.  14psi will not only blow it apart
> in time but it is not efficient enough to do 14psi and keep intake charge
> temps at a reasonable level.  To run more you need a better intercooler
> probably of a single pass arrangement. 
> 
> 
> 
	[Mike Sylvester]  



	I don't believe that it is the 14psi boost that blows apart the IC.
I've found that
	when the hose or IC blows it is not under max boost, but just after
the throttle
	released after full boost.  At this point the pressure in the IC
goes way up.  Well
	beyond the 14psi, because the turbo is still generating max boost
and you have just 
	closed off the airway by closing the TB.  I've also destroyed an ISV
from this.
	Once the TB is closed, the ISV is the only open airway.  I believe
it is the ISV that
	makes the whistling sound after throttle release.  

	After blowing up the IC in my 87 5K, I bought a hot water heater
blow off valve from the hardware 
	store.  It opens at 30psi.  I drilled a hole in the plastic tank of
the IC and mounted it.
	Since the plastic tank had already been removed for me, it was
simple.
	I never had any problems afterward.


	Mike Sylvester
	Quincy, MA

	94 100CS Q
	86 5KCS TQ	awaiting its chip and modified IC