what exactly is meant by these terms in the tuning world?
I know what they mean in terms of fuel pressure, but I have yet to get a clear definition of each as they apply to tuning.

help

 

1bar is the pressure exherted by 1 atmosphere,2bar is about 14.7lbs of boost or the pressure exherted by to 2x atmospheric pressure and 3bar is 3x atmospheric pressure.A 1bar MAP sensor can't read boost,while a 2 or 3bar sensor can,allowing you to tune accordingly by adding fuel and reducing timing while under boost conditions and to add timing and reduce fueling while NA.

 

+1

Great explanation Whitt1.

Also make sure your software of choice can scale to the MAP sensor you're going to be using.

 

Correction: a 1 bar MAP sensor can read a teeny bit of boost depending on alt. The *2 bar* can read up to +14.7psi -- normally wot is ~7.5 psi *above idle* on a NA truck.

The x bar tune just refers to a special tune that allows you to use a x bar MAP sensor with a stock PCM (i.e. not a standalone like Megasquirt or FAST). Fancier versions of 2 and 3 bar tunes allow you to have 2 or 3 bar VE tables, or extended timing tables to account for the additional air flow.

 

what map sensor do we have in our trucks?

 

Thanks bro, not exactly understanding this, are you saying a stock (or 1 bar MAP sensor) can read up to 7psi of boost, and 14.7psi NA?

 

i really dont know what you are saying. my stock map will only read to 1 bar(100kpa) also known as 0psi. under any boost at all i just see 100kpa on the stock map.

 

so how we install a higher bar map sensor

 

That means your MAP sensor is maxed out. Not bad of course, as your obviously doing something right inregards to the power your making.

I'm assuming this is a 5V sensor (MAP sensors in general)

So for a 1Bar sensor at running at 0 psi, the sensor outputting near or at 5V (maxed out.

On a 2bar sensor, at 0 psi, it will only output some 2-2.5V.

One a 3bar sensor, at 0psi, it will put out around 1.5-1.7v

So it you want to run 14.7lbs of boost or less, a 2bar will get you going well. To run more, a 3bar may be needed. 3bar's work up to about 30psi.

But to use any of these sensors as I've mentioned before your engine management software has to have it's fuel tables COMPLETELY remapped and rescaled for the new sensor. I'm sure HPTuners offers this, it would be stupid not to.

 

A 1bar map will read to about 7lbs of atmospheric pressure depending on your altitude,the readings below that are vacuum readings needed for NA tuning.