Boost Gauge vs Map sensor

BoostedGT

New Member
Joined
Dec 18, 2003
Hey guys got a question for ya. Currently I am running a 9psi spring in my wastegate. At WOT my gauge reads right at 9-10 psi, but in my datalogging my Map sensor is showing 17.7-18.2psi on my Fast bank to bank. I am just wondering if there is a formula that makes these two even or if there is a table I need to make changes to in order for the Map sensor to match the boost gauge. The map sensor is one from a 87 grand national 3.8l... Thanks!
 
makes sense, almost double, thats a 2 bar map sensor, do you have the fast set for 2 bar, or 1 bar, or 3 bar?
 
Are you sure the FAST is not reading KPA instead of PSI? The FAST unit reads KPA for everything, we users always want to relate it back to PSI

There should not be that great of a variance between the gauge and the MAP sensor.
 
2 bar?

I think you will find that the 2 bar sensor is maxed out. I'd also check the accuracy of your boost gauge.
Are you running only on the spring??
 
Originally posted by norbs
makes sense, almost double, thats a 2 bar map sensor, do you have the fast set for 2 bar, or 1 bar, or 3 bar?

I thought the grand national's were 3 bar map sensors... I have the fast set to 3bar... Is it actually a 2bar map?? I guess changing the fast to 2bar would make it read accurately then?
 
Believe it!

It's a 2 bar... just like we both said....:D
And yes, the setting in the program has to match the sensor value.
The Turbo TA is a 3 bar sensor.;)
 
i run on my fast the map (psia) which reads psi boost and also i you the kpa as well, so you do not have to convert it does it for you. set it up on data log screen then you can see actual boost psi, your gauge is way off.
 
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