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Re: Improved S-Knob

On Thu, 19 Jun 1997, russ southerlin wrote:

> When we spoke on the phone a few months ago I mentioned that I was going
> to try putting a check valve inline with the W/G vacuum line to prevent
> engine vacuum from being applied to the W/G. 
> At any rate with the check valve installed I think there is a noticable
> difference in how fast the boost pressure comes up during gear shifts. I
> have a mechanical boost gauge and can see that the pressure comes right
> up to about 6 psi when shifting before it lags for a second or two and
> then takes off for 15 psi. Without the check valve the boost only comes

Hmm, I'm not sure a check valve is the right thing to do here.   I used a 
pressure regulator in the lline to the top of the wastegate, and that 
worked well.   The thing that makees me wonder though, is why does your 
boost sit at 6psi and then rise to 25?   My car has alaways gone directly 
to the max pressure set point with out any hesitation at all.   
Occasionally it will rise one psi or so higher than the setpoint, but it 
generally gets to the setpoint very smoothly.

> put a small pin hole in the hose to the W/G to prevent any pressure
> spikes from gradually building up pressure on the W/G above what is
> required for the 15 psi of boost.

Top side hose or bottom side hose?   I don't like leaks.   I'd rather 
tune the control system to work at the desired boost pressure than to 
fool the control system into providing something it isn't designed for.

Russ, do some testing and report back please.  Sounds interesting.

Graydon D. Stuckey