Who has a 2-bar map sensor...or 3 bar map sensor....and where do you get them from? Also is there anything special that you have to do to use it with the Apexi PFC?

 

The stock sensor is a 2-bar sensor. I believe people usually use the GM 3-bar sensor (for a Buick Grand National?) when upgrading. Going to run over 17 psi, huh?

 

he he he...possibly eventually Do they just clip right in or do you have to do any special modifications? But shouldn't the 2 bar be good for 28-29 psi?

 

Easiest to do is grab a 3 bar GM map sensor and connector from the junk yard. You will need to make the adjustments through the datalogit.

 

You are forgetting that normal atmospheric pressure is about 1 bar....so the Mazda 2-bar sensor is only good for 17 psi.

 

I don't think you were as clear as you could be on that one...

1 Bar = 14.7 PSI right?
2 Bar = 29.4 then?

So why 17 PSI? I know that is the limit of the stock (actually thought it was around 15 but havent tuned enough to get up there yet - still having boost control problems at 14).

So why 17?

Shawn

 

A 2-bar sensor is technically only good to 14.5 psi ABOVE atmosphere (which is nominally 14.7 psi). However, the Mazda sensor is good til about 17 psi ABOVE atmosphere (safety factor and all that).

 

"2 bar". 1 for vaccum and 1. for positive boost pressure. I believe atmospheric pressure is read as 0 for our purposes. Otherwise an unhooked boost gauge laying on the floor would read 14.7 psi. (thats 1 bar)

 

The mazda stock part is 1.2 bar I think . Not 2 bar .Good for 17 point something .

 

Actually That kind of info helped me blow my motor. Eveyone was saying 17.5 psi and your ok till after that. Well My boost controller was reading 16.8 max so I felt like I had room. Well it was actually running who knows how high and the stock 2 bar map would only read as high as 16.8. Well take the info on the Forum for what it is. Free. Many people who dont know what they are talking about give advice and you can only blame yourself for listening if it costs you thousands from taking some of the advice you get here.

 

So the end result would be..... a 3 bar map sensor. Now...Do you have to do anything special to make that work with a Apexi PFC?

 

Here is what needs to be changed with the datalogit

Hope this makes sense:


GM 3 BAR MAP Sensor Part Numbers:
16040749 – sensor (71130)
12085502 – connector (71121)


GM 3bar // Function // Rx7 Factory Wiring
A // GRND // Black/Grey
B // MAP SENSOR VOLTS // Greeen/Yellow
C // 5V // Brown/White

PFC MAP Sensor Settings:
scale: 41800
offset: 0

 

There ya go. Eric gave ya what you need. Eric knows what its like to run high boost above the Stock Map.

 

I saw your note on GM boost sensor in an old post. Question - Can I replace my stock 93 rx7 boost sensor with this new GM sensor, wire it correctly and still ahve the stock ECU run correctly ? I am suspecting I have a bad sensor, getting code 13. I have the PMC along with the stock ECU for now. What do you think ?

Tom

 

Denso makes a 3 bar too don't they?

 

Where did you get the scale value from, the forum? Can somebody please explain what the scale value represents? There are a couple different numbers floating around on the list that seem to work to varying degrees. I would like to take a clean-sheet approach and hopefully come up with something that is more accurate for the pressure range my particular car operates.

 

The Apexi boost controller kit comes with a Denso 3 bar unti, but we cannot find out what car would have these fitted as standard.

We have checked against VW turbo models (inc. RS4), Subaru's, Mitsi's, etc etc. but with no luck. Once we know what car has them as standard, Denso can supply us them.

Fish