2 bar vs 3 bar map sensor

[just plain john]

What's the difference? Why would someone change from 2 to 3 bar?

 

[TurboDave]

Because a 2 bar can only measure up to 15 psi. While a 3 bar can measure up to 30 psi.

 

[I8AV8]

One bar is about 14.7 psi or one atmosphere. A two bar sensor will read 29.4 psi. If you are running high boost the sensor is not that accurate at the higher boost levels and you should go to a 3 bar sensor.

 

[TurboDave]

One bar is about 14.7 psi or one atmosphere. A two bar sensor will read 29.4 psi. If you are running high boost the sensor is not that accurate at the higher boost levels and you should go to a 3 bar sensor.

You're forgetting atmospheric pressure -14.7psi. At zero boost, it's already used up 1 bar, therefore, will only measure another 14.7~ psi.

If you only want to log/display 15psi, you need a 2 bar.
If you want to log/display 30psi, you need a 3 bar.

Or are we saying the same thing only different. :wink:

 

[just plain john]

Please bear with me here, I'm learning as I go. Let's say I want to run 25 psi. Would I want a 2 or 3 bar? My hybrid build will see mostly street miles, with maybe some test and tune sessions and maybe 1% track time (if I ever get it finished). Currently I only have a Scanmaster and cannot log any info.

 

[pacecarta]

the stock ecm doesnt use the map sensor , its only there for the regals indash 15psi boost gauge which is why the gn with analog dash came with a 2bar map sensor , the TTA ran a 3bar sensor for its gauge
going to a 3bar will do nothing for the engine unless you are running a speed density setup (tt sd chip, fast,xfi,dfi etc ) over 15psi or have a data logger like powerlogger that can record boost from a map sensor , or if you run a razor alky system which uses the 3bar map to regulate the pump speed based on boost

 

[just plain john]

Hmm, that's an interesting point about the alky kit. I don't have one, but I will before I consider the car 'finished'. Is that 3 bar map for any kit, or just his? Although this is a hybrid, I've swapped in the Regal dash and so I will retain the original gauge. I also have a piller gauge pod with a 30# gauge.

 

[just plain john]

One more thought....so if I'm not running a xfi or similar system, and I don't run an alky kit, then there's no benefit?

 

[pacecarta]

don't know what other alky kit you're considering but razors does use a 3bar and unless you have one you need to specify that you need one when ordering the kit .

 

[pacecarta]

One more thought....so if I'm not running a xfi or similar system, and I don't run an alky kit, then there's no benefit?

absolutely none ... unless you consider the weight loss of 85$ from your wallet

 

[Razor]

One more thought....so if I'm not running a xfi or similar system, and I don't run an alky kit, then there's no benefit?

Your car can run and operate without it. Only needed if you need to electronically track boost up to 30 PSI.

Guys that use a power logger can tie the signal from the 3 bar into the power logger input and record boost as the car goes down the track/surface. For example.

 

[just plain john]

I doubt that a powerlogger is in my future, but one of your alky kits most likely is. Until then though I'll just stick with what I've got.

 

[grass doctor]

will a 3bar map work on a mostly stock car or will it mess up the analog in dash boost gauge ...

 

[Jerryl]

will a 3bar map work on a mostly stock car or will it mess up the analog in dash boost gauge ...

It will throw off the dash boost gage.
To ensure the dash lights reads correctly, wire in a separate 3 bar map sensor for boost/alky/SD.