MAP Havoc

[Frank F Parker]

> Hello all, I am going to turbocharge a previously non-turbocharged
> engine. I am wondering what needs to be done with the MAP sensor, it
> seems to me (intuitively at least) that when boost is present that the
> ECM will not know what to do...... is there a simple way around this?
> Maybe a varistor of some sort between the ECM and the sensor? By the

I have done 2 cars like this, the 87 port fi car was not bothered
by the boost- no errors or lights. The 93 was a different story. It
gave check engine light and went into limp home mode since boost caused
it to exceed the prescribed limits. Turn off key and restart would fix
but only till nest dose of boost. I used  a simple hobbs switch set to
about 1" of vac to switch the vac/press to the map sensor with a 3 way
miniature solenoid from McMaster car. It used tiny #10 fittings and
took little room. What it did was trap 1" vac ( eg: wot nat asp) to
the sensor and switch away the boost to the other port which was blocked.
Worked well- no lights , errors . I ran 8-10 psi on a 9.25 CR motor
by carefull selection of turbo, backpressure , and a good closed loop
retard system.

Regards,

Frank Parker
Motorsports Data Acquisition>