how does the stock boost gauge read boost?

[diputz42]

i know the stock boost gauge isnt the most accurate. and i read somewhere that it isn't a "true" boost gauge. but how does it read boost levels? does it just measure the speed at which the compressor wheel is spinning?

 

[92awddsm]

It doesnt read boost at all. The stock gauge is just a display for what the ecu thinks the boost is based on mas readings.

 

[JoeWagon]

Exactly. And it reads based on a few factors like load, which doesn't say anything about the actual boost.

 

[saw wave analog]

on mine the first line on the gauge is always accurate as being 0 vac 0 boost, but beyond that its useless

 

[diputz42]

so in that case, a datalogger would be useless as far as measuring boost?

 

[saw wave analog]

yep, thats what you have an aftermarket gague for though.. right

 

[diputz42]

not yet.... i just bought the car. so im kind of low on cash right now

 

[Dieselboy]

so in that case, a datalogger would be useless as far as measuring boost?

A datalogger does not read boost or vacuum pressure, only the airflow metered at the MAS (which is not boost or vacuum pressure).

 

[Attack Eagle]

not yet.... i just bought the car. so im kind of low on cash right now

check around with fellow enthusiasts... i got a spearco vac/boost guage (kind of old school 25-0-20) for $10 + ship and built a little pod to hold it from abs for free...

you really do need it, if only for pressure checks to find vacuum leaks and to see if yuo really are making full boost diagnosis issues etc.

I foulnd 2 disconnected vac lines I could not even see and a huge leak tonight thanks to my guage and a pressure tester