Boost gauge calibration

[rogerch]

OK an 88 Turbo, the boost gauge is calibrated in Bar, but what do the marks represent ?

ie, is the verticle mark 0.5 or is .5 the 5th calibration ? because either way it's not coresponding to what I set the waste gate acctuator to 0.8

[karmavore]

That boost gauge is notoriously inaccurate.

Also, the actuator and the MAP aren't going to match exactly. The wastegate is going to begin to crack well before .8, plus you have to take barometric pressure into account. I don't know how the mechanical gauge handles that, but I imagine it's "calibrated" assuming sea level.

Am I crazy?

[rogerch]

Much to my surprise the gauge seems accurate, wastegate pops at .8 bar, which is where I set it. So my next mod will be to pull it back to .6 and then add a controller, to take it up 1 bar. For purposes other than shopping.

[Quicker]

I'm in the same mode - about to add a wideband and boost controller as well.

The reason you are going to a softer wastegate spring? Is it to allow that to be the low-bar and you will still set the 'normal' mode of your controller to 0.8?

I have 89 SE - does anyone know how we allow the 15secs of over-boost? reading the service manual - it specs the max boost pressure for the wastegate at 0.65bar - tuning the movement of 0.38mm at 0.58bar. so how do we allow an spurt of overboost?