If I use a 2 bar map sensor I will have to rescale down almost everything in 1/2.

But the question is... Once I reach the MAF limitation will the computer compensate via MAP... In this case using the 2 bar map sensor the PCM will be able to "see" boost if adjusted correctly and all tables are fitted accordingly... but will it use the boost signal when you reach the max of your maf or will it get stuck in the same way it does now?

 

The problem is I have yet to see anyone use a 2 bar map with the stock pcm. If you get it to work...then great, please post it.

jose

 

It's not gonna happen with the oem LTx pcms. You need to got back to the older ecms to find an oem control module that will recognize boost.

 

I ran one in mine for a short period of time by mistake when switching from FAST back to the Stock PCM. The car ran fine. The car should respond to timing changes based on boost via this route, you will have to remember that if you use a 2 bar MAP sensor when the voltage from the MAP is 5 volts you will have a pressure of 14.7 psi. So at atmosphere it should be 2.5 volts or about 50KPA as indicated on a scan tool. I think this will only work with the spark advance, and not the fuel though. I'm not for sure, but thats what i think.

Bill

 

Like I stated, it ain't gonna happen. The LTx oem pcms do not recognize boost pressures, regardless of the map sensor in place. The fuel/spark tables stop at 101 kpa, thus pcm would not have ability to provide fuel or spark for pressures above atmospheric, unlike earlier ecms #1227749 or #1228707.

 

It will see boost because the 2 bar map sensor will have the same range as the 1 bar map sensor...

It means that at 5v it will be 100KPA on the 1 bar and 200KPA on the 2 bar.... so.. with the 2 bar map sensor the computer will receive, at 14.7 psi of boost, a reading of 5v which will mean 100kpa ON THE PCM, but you will tune as if they were 200kpa..every step would be double what it is...

So it is a good idea for timing then... It would be better if you use it as speed density then?

I dont like speed density as the rideability is far from what a MAF feels like... I ran it in speed density for a while and I hated it...

 

It will see boost because the 2 bar map sensor will have the same range as the 1 bar map sensor...

And just where did you get THAT info from? I don't believe it is a good idea to spread baloney! IOW, make sure of your info first!

I (or the pcm) could care less what it sees. It wouldn't know what to do with it if it did see it! Would it help if I typed slower? GRRRRR.

 

YOu are missing the point...

the 1-bar map sensor has a voltage range of 5V as the 2 bar map sensor.. at least that is the data I have gotten with my 2 bar map sensor...

You would be able to adjust everything accordingly... timing and VE.. since VE for open loop. That way you wouldn't need to rely on anything else rather than your PCM!!!!!

 

OK, I give up. (hands in air) I tried. Believe what you want. Just please don't attempt to get anyone else mixed up. Happy tuning!

 

Then explain why wouldn't it work rather than be acting like a jirk

 

All MAP sensors work on the same principle, they have a 0-5 volt range

1 Bar Map 5 volts = 1 atm or 0 psi on a boost gauge
2 bar MAP 5 volts = 2 atm or 14.7 psi
3 bar MAP 5 volts = 3 atm or 29.4 psi

As you can see the resolution gets worse the higher Bar sensor you use. So arni what was trying to be explained to you is this: say you are a NA car and i have a turbo set at 14.7 psi of boost. You have a 1 bar MAP and i have a 2 bar. When you are at WOT you will be seeing atm press on the MAP, or 5volts or 100kpa in your ECM table. The computer will be using (if your speed density) the 100kpa VE tables and Spark advance. Now if you were to put a 2 bar sensor in your car and go WOT you would only see 2.5 volts from the MAP, and thus be in the 50kpa tables. So if you now had my car and could have the possibility to have boost, everything from the 2.5 volt range to the 5 volt range (atm to 14.7 psi boost) would effectively be seen by the computer and could be modified using the 50kpa-100kpa tables. You understand now?

Bill

 

Of course I do.. .so what is the point with this:

It will "recognize" the boost, but only with 5 blocks instead of 10 blocks as previous pcm's as stated by arnie.

When you change the map sensor from the 1 bar to the 2 bar the 50-100kpa will be the boost part of the calibration... I know that.. the point is if it will fuel up the car even though the MAF hits the limit? That is my real question.

 

Sorry that post wasn't directed to you highlander. When the MAF is Maxed you will need to use the enrichment at WOT vs RPM table to supply the extra fuel and the MAF will not add any more fuel. Your still in closed loop (though in power enrichment mode at WOT) I am not sure if the VE tables come into play with the MAF at WOT, so I cannot give a definitive answer. If they do then i would think that extra fuel could be programmed in. Hopefully someone with some more knowledge will chime in, or you could try to find out in the programming forum what variables come into play for WOT fuel delivery.

 

It's not that easy (or everyone would have done it.)

The MAP is referenced in places all over the code that aren't ever shown in LT1 edit, trust me.

The VE tables aren't referenced unless the MAF is disconnected, so don't waste time there.

If I might make a friendly suggestion, just use a MSD BTM and dynotune it with a wideband (mounted in collector area. )

Hope this helps,
-Christian

www.carprogrammer.com

 

That is exactly what I have been doing... I just wanted to see if I could get the pcm to control everything except the MAF limitation...

I will be using 50# inj and the additional 3 on my superfueler would almost kick in when the maf limit has been reached...

Do you know any way that I can get it to read 510gps???

LMK
Thanks