Patsy57

iTrader: (37)

Understood just trying to understand why those values are correct?

Like for example the offset?

Hart_Rod

iTrader: (3)

They come from the manufacturer of the MAP sensor.

http://www.fastfieros.com/tech/map_s..._they_work.htm

http://injector-rehab.com/shop/mapsensor.html

http://www.useasydocs.com/details/map.htm

Patsy57

iTrader: (37)

So would FAST have specific settings?

The Alchemist

iTrader: (19)

Yes, FAST should have some kind of spec sheet on it for offsets.

Hart_Rod

iTrader: (3)

I gave you the FAST settings....

Blown06

iTrader: (32)

This dude has a hard head.

The Alchemist

iTrader: (19)

Well, not everyone gets tuning, which is fine. The problem is when they go to a hack tuner how tells them lies or half truths because it's easier than explaining it, is what causes problems.

I'm not saying everyone needs to be an expert in tuning, I'm far from it, but if you are at this stage of modifying your car, that you need a 3-bar map sensor, you should have a good idea of what's going on and realize that the map sensor doesn't need to be calibrated at different elevations. It's job is to make adjustments based on those elevation (really it's air density) changes.

Patsy57

iTrader: (37)

Lol yea I do have a hard head.

I'm asking questions because that's how you learn

Patsy57

iTrader: (37)

So here is why I'm asking questions...

Currently my car is NA running a 3bar map. I have different values in the tune right now for map sensor linear and map sensor offset.

The settings are 283.01kpa map sensor linear and 10.33kpa map sensor offset.

These settings give me a MAP kpa reading of about 100kpa when running.

My car is a 02 transam with a 430lsx race block all setup for boost with a blower cam running a fast 102 and nw 102 tb. I have an sd tune on her now and I'm running NA currently.

This is why I'm asking because I am told when driving the MAP value should be at 100 for an NA car.

Blown06

iTrader: (32)

Map value should not be 100 with the car idling or cruising. It'll approach 100 at WOT, but depending on barometric pressure....it'll fluctuate a little bit.

Patsy57

iTrader: (37)

Correct so at WOT the map should be at our around 100.

So is it correct for me to adjust to get that value and deviate from the manufacturer linear values or is that incorrect?

Hart_Rod

iTrader: (3)

THE VALUES I GAVE YOU ARE SUPPOSED TO BE PLACED IN THE TUNE AS INSTRUCTED ABOVE. THE FACTORY CALIBRATES THE MAP SENSOR AND DETERMINES THE LINEAR AND THE OFFSET.

Did you even bother to read the links I gave you above?

OK, I will try again.....

At sea level with the key on, car off your map should read 100 KPA or 14.7 psi (which is approximatley one atmospheric pressure). Many things affect this reading, temp, DA, humidity, etc.... but generally with the key on car off, that's about what you should read. The manufacturers of the MAP sensor build and design there MAPs and then calibrate them (figure out what the linear and offset is) and provide those numbers for the tune so that when you are at sea level you should see 100KPA with the key on and car off (see the theme here).

Now when you start your car up, depending on what your cam is, you are going to pull some vaccuum (pressure less than 100KPA (14.7psi)) and you car should/will idle less 100KPA. For instance, the LS3 in my truck idles at around 55-60 KPA on most days (Comp cam 219/235 113 LSA). My 2014 Camaro SS with the factory cam idles at around 40-45KPA. Which makes sense, a smaller cam will generally pull more vaccuum.

On to the next part of the story, a NA engine at WOT as talked about above, you should pull virtually no vaccuum at all (100KPA). So if you are data logging, your MAP reading should be clsoe to 100KPA (14.7 psi or 1 atmospheric pressure).

OK, final part, forced induction. I have a TVS1900 Magnacharger, as my blower comes in, I start to build boost (boost equal any pressure above atmospheric(>100KPA)). So as my blower increases pressure, my MAP readings start going above 100KPA (hence the reason for needing a 3 bar map or one that will read up to 300KPA). In my case, my max reading is around 160KPA or approximately, 22PSI. If I subtract out the 14.7 (atmospheric pressure at sea level), 22-14.7 = 7.3. This tells me my blower/engine combo is making about 7lbs of boost....

I'm sure there are some guys on here that can explain this much more eloquently than I, but this is my shade tree mechanic version of how it works.

I ask a lot of questions my self, but I follow it up with researching. Actually I research first, then ask questions, and then do more research.

Patsy57

iTrader: (37)

Thanks for the reply and I did follow your links thanks again.

Working through some issues and because my car is NA I believe I'm having an issue with running a 3bar map.

I'm gonna drop it down to a 2bar GM sensor so I can get the right values in and see what happens.

I can't get the fuel right at the lower rpm range no matter what we do.

Hart_Rod

iTrader: (3)

It does not matter whether you are NA or FI, if you don't put the correct values in for the MAP sensor you have, your car won't tune correctly. I already gave you the right values to put in your tune for the Fast 3 Bar MAP.....why is this so hard?

Patsy57

iTrader: (37)

It's not hard sorry for asking questions!

You know my dilemma I outlined it above can I use a fast 3bar map with no issues for an NA car?

That's all I got once I have that answer I'll move on

hrcslam

Yes, you can use the 3bar MAP NA. It does have to have the correct values entered into the tune. If you're having issues after that look else where in the tune. Are you in SD mode or MAF?

Hart_Rod

iTrader: (3)

You need to re-read your posts. You never once asked "Will a 3 bar map work in my NA car?" But even with that, I think I answered your question several times. That's why I kept telling you to put the correct FAST values into your tune.

Patsy57

iTrader: (37)

I am running an SD tune. I will make the changes and see what happens thanks!

Patsy57

iTrader: (37)

HART_ROB Thanks you did answer my question all except one that I asked. Where did you get the settings for the FAST 3 BAR MAP? I reviewed all your links, called FAST multiple times and they cant provide those settings so I am curious where you came across them?

You have been very helpful and I truly appreciate it, just let me know when you can where you came across those settings because FAST cant even give them to me for whatever reason...

Thanks!

Patsy57

iTrader: (37)

Also in regards to asking "Will a 3 bar map work in my NA car" you are right i did not ask that because I did not need to know that at the time of the post, its only now that I started to second guess myself hence why I asked now

Thanks!