Re: Boost in a teapot.

[Bill Samaras DTN 223-7322 06-Sep-1994 1325 <samaras@wrksys.enet.dec.com>]

Hi ya'll.

For those interested, I'm using a homebrew boost enhancement method. I did all
of my mods with vacuum/pressure bleeder valves and one-way valves.  I fake out
the computer by bleeding off boost pressure to the sensor (only under boost). I
have this set to hit the "shut down" limit at ~1.85 bar (13-14 psi). I did this
right at the computer hose connection. I believe this accomplishes the same
effect as electronically biasing the boost sensor voltage.


Instead of changing the wastegate spring, I re-routed the pressure line that
normally connects to the bottom side of the wastegate diaphram into the
passenger compartment. I have a valve in this hose so I can adjust boost while
I drive. 
                               *** CAUTION ***
                THIS MOD IS SIMPLE AND CHEAP, BUT IT TOOK ME 2 WEEKS
                TO MAKE IT WORK RIGHT. IT'S REAL EASY TO BLOW YOUR
                ENGINE SINCE IT'S EASY TO "OVERDIAL" MORE BOOST.

If I were doing this over, I'd just buy Ned's IA mod and not worry about it.

By the way, running 12 psi of boost is quite a kick. 

...bill

>Bill,
>
>	Thanks for the great explanation of the relationship of boost to
>engine management by the computer. What type of modification do you have
>for allowing extra boost on your car? One of the standard mods - Superchips,
>IA, or your own home brew? I have an '87 5000 TQ and am seriously considering
>mods to allow extra boost. If there isn't any great advantage in buying
>a mod from one of these performance places, I'd like to try my own if someone
>can detail what needs to be done.
>
>Zafer