2bar Map Sensor w/ MAF and Stock OS?

[ferocity02]

Can I run a 2bar MAP sensor with a 12212156 OS in a turbo application using the stock MAF? I would like the ability to log boost and the 1 bar maps cuts out around 104 kPa in my logs. I have a GM 2 bar MAP sensor on the shelf.

If this is possible how do adjust for it in the tune?

[ScarabEpic22]

Yes you can run it and it will log in the Scan tool, but you will be out of resolution in the OS itself. Whatever the highest g/cyl spark and VE values are is what will be used in boost (read, you will have no control over fuel and spark once you get into boost. 100/105kPa values will be used even at 200kPa in a stock OS. And REP will happen unless you change the rationality test values.). If you hit the 512g/s limit of the MAF, the PCM will use the highest value for fueling as well.

Time to upgrade to a COS, it's free and doesnt take much work if you script your existing tune into it.

Go into Engine Diagnostics->MAP and enter the values in there.

[ferocity02]

Thanks for the reply! What is involved in swapping the MAP sensors? What needs to be changed in the tune so it knows its a 2 bar sensor instead of a 1 bar sensor?

I realize the tune will "max out" at 1 bar. My tuner for one reason or another is not doing a COS.

[ScarabEpic22]

Thanks for the reply! What is involved in swapping the MAP sensors? What needs to be changed in the tune so it knows its a 2 bar sensor instead of a 1 bar sensor?

I realize the tune will "max out" at 1 bar. My tuner for one reason or another is not doing a COS.

I dont know who you're using for tuning, but I would never recommend using a stock OS for a boosted application. That's the entire reason that EFILive and HPTuners spent lots of time and money to develop the COSs. The only reason I can think of is that you cant use a MAF in a 2+ Bar OS, if you're dead set on keeping it then you'll have to run the stock OS. Watch your g/s values, if you get close to 512g/s, you're going to be better off ditching the MAF and going 2/3Bar SD with a COS as you will run out of resolution.

Depending on the MAP sensor you use, you'll need to change 2 or 3 tables in the Engine Diag->MAP section. I dont remember offhand as I dont do many LS1s.

[ferocity02]

I think that was it. He probably thinks the MAF will support my goals, which is around 600rwhp.

Thanks again!

[joecar]

12212156 easily upgrades to COS3/02020003 or COS5/0202005 (the upgrade is so simple it is pretty much thoughtless) which provide a boost VE table which works with the 2-bar MAP sensor (not to mention a boost spark table).

[picnic_george]

Let me get this 100% straight. There is no way to run a boost ve/spark tables and MAF at the same time? Obviously there isn't a point on a vehicle with 30psi but a car running 8psi I can see the advantage of doing both. Unless of course I'm missing something. And why can't or don't we have that option.

Thanks
Kris

[ferocity02]

Let me get this 100% straight. There is no way to run a boost ve/spark tables and MAF at the same time? Obviously there isn't a point on a vehicle with 30psi but a car running 8psi I can see the advantage of doing both. Unless of course I'm missing something. And why can't or don't we have that option.

Thanks
Kris

I too would like to know this. Can we run a COS with tables for boost with the MAF?

[joecar]

Let me get this 100% straight. There is no way to run a boost ve/spark tables and MAF at the same time? Obviously there isn't a point on a vehicle with 30psi but a car running 8psi I can see the advantage of doing both. Unless of course I'm missing something. And why can't or don't we have that option.

Thanks
KrisKris,

The EFILive COS's allow you to run MAF with boost (at the same time)...

edit: the COS tutorial says to disable the MAF... but just go ahead and try it.


[ I don't know where you got the MAF-less-only idea from...!? ] edit: oh, I see it in the COS upgrade pdf, sorry my mistake :doh: ]


Of course, you have to watch that the MAF does not exceed 512 g/s (limitation of LS1 0411 PCM).

[joecar]

The feature of the COS's is that they allow you to run adaptive spark (HO/LO park tables) when the MAF is failed...


( this is the idea that get's inverted into a misconception )

[ScarabEpic22]

Joe, I got that info from reading the 2BAR LS1 upgrade manual, I thought you could keep the MAF with a COS but the doc said otherwise so that's what I went with. If you CAN keep it, that'd be fantastic!

Wonder if it's COS # 1/2/3/5 dependent? Paul/Ross?

[picnic_george]

Kris,

The EFILive COS's allow you to run MAF with boost (at the same time)...

repeating: yes, MAF and boost concurrently at the same time (MAF + boost VE/spark tables)


[ I don't know where you got the MAF-less-only idea from...!? ]


Of course, you have to watch that the MAF does not exceed 512 g/s (limitation of LS1 0411 PCM).

Thanks Joe. That makes me happy to hear. It made no sense to me why :)

Is there any info on doing boost ve similar to an autove? I've searched and don't see anything.



Joe, I got that info from reading the 2BAR LS1 upgrade manual, I thought you could keep the MAF with a COS but the doc said otherwise so that's what I went with. If you CAN keep it, that'd be fantastic!

Wonder if it's COS # 1/2/3/5 dependent? Paul/Ross?I think that's where I first read it as well. But it seemed to be the general consensus. If you were to keep the MAF you couldn't change the map sensor and add boost tables, you were stuck 105 kPa.

[ferocity02]

The EFILive COS's allow you to run MAF with boost (at the same time)...
repeating: yes, MAF and boost concurrently at the same time (MAF + boost VE/spark tables)
[ I don't know where you got the MAF-less-only idea from...!? ]
Of course, you have to watch that the MAF does not exceed 512 g/s (limitation of LS1 0411 PCM).

This is good news! If the MAF maxes out, is a SD tune then required? Or is there away to tune it properly despite the MAX being maxed out?

[ScarabEpic22]

This is good news! If the MAF maxes out, is a SD tune then required? Or is there away to tune it properly despite the MAX being maxed out?

If the MAF is maxed out, either go full SD or buy a new LS3/7 blade-style MAF and increase the intake pipe diameter. Retune it with the new MAF and you'll be fine, the trend these days is to use a blade MAF and run the factory VVE/MAF blend even in boosted applications vs full SD because it gives the ECM more ability to compensate for weather changes.

[picnic_george]

If the MAF is maxed out, either go full SD or buy a new LS3/7 blade-style MAF and increase the intake pipe diameter. Retune it with the new MAF and you'll be fine, the trend these days is to use a blade MAF and run the factory VVE/MAF blend even in boosted applications vs full SD because it gives the ECM more ability to compensate for weather changes.I didn't think an 0411 pcm could do something like that.

[joecar]

Joe, I got that info from reading the 2BAR LS1 upgrade manual, I thought you could keep the MAF with a COS but the doc said otherwise so that's what I went with. If you CAN keep it, that'd be fantastic!

Wonder if it's COS # 1/2/3/5 dependent? Paul/Ross?Hmmm, I just reread the COS upgrade tutorial and it says you have to go MAF-less with a 2-bar/3-bar sensor... Erik, you're right, I guess I was wrong, sorry my mistake... :doh:

[ altho I thought I saw someone try it and it seemed to be working ]

You can run the MAF with a 1-bar sensor... I would just try it with a 2-bar sensor and see what it does.

[joecar]

This is good news! If the MAF maxes out, is a SD tune then required? Or is there away to tune it properly despite the MAX being maxed out?


If the MAF is maxed out, either go full SD or buy a new LS3/7 blade-style MAF and increase the intake pipe diameter. Retune it with the new MAF and you'll be fine, the trend these days is to use a blade MAF and run the factory VVE/MAF blend even in boosted applications vs full SD because it gives the ECM more ability to compensate for weather changes.


I didn't think an 0411 pcm could do something like that.The problem is that the 411 PCM/OS has an upper limit of 512 g/s on the MAF (it's not a limitation of the MAF, but of the PCM/OS).


So running a MAF even with small boost will easily execeed 512 g/s... so you would have to go MAF-less.

[ferocity02]

You can run the MAF with a 1-bar sensor... I would just try it with a 2-bar sensor and see what it does.

You mean try a stock OS with a 2 bar sensor, or a 2 bar COS with the MAF?

[ScarabEpic22]

I didn't think an 0411 pcm could do something like that.

If you use the LS3/7 blade style MAF, as long as you re-build the MAF curve it will work. Repin the harness and tune it. Doesnt matter what the PCM/ECM is, if you scale it correctly you're fine.


Hmmm, I just reread the COS upgrade tutorial and it says you have to go MAF-less with a 2-bar/3-bar sensor... Erik, you're right, I guess I was wrong, sorry my mistake... :doh:

[ altho I thought I saw someone try it and it seemed to be working ]

You can run the MAF with a 1-bar sensor... I would just try it with a 2-bar sensor and see what it does.

I promise Im not crazy, I DID read it somewhere! :D

I thought I remembered someone doing a while back as well though Joe, so who knows.


You mean try a stock OS with a 2 bar sensor, or a 2 bar COS with the MAF?

I think he's saying 2 bar OS + 2 Bar MAP + MAF.

[picnic_george]

Hmmm, I just reread the COS upgrade tutorial and it says you have to go MAF-less with a 2-bar/3-bar sensor... Erik, you're right, I guess I was wrong, sorry my mistake... :doh:That's exactly what I was talking about. Boost ve/timing tables and a mass air meter. Just thought it would be cool. MAF cars just seem to run better for us people in the mountains that can easily change 7000ft of elevation and 60* of temperature in a very short time. A 5-10psi car works fine with a maf, and is easily tuned, but with a 2 bar setup could be better :)


If you use the LS3/7 blade style MAF, as long as you re-build the MAF curve it will work. Repin the harness and tune it. Doesnt matter what the PCM/ECM is, if you scale it correctly you're fine.I guess I'll need to do some serious reading on this. I knew those MAFs were better but one of my friends aborted that mission a while ago because something didn't work right.



I think he's saying 2 bar OS + 2 Bar MAP + MAF.Wouldn't it have to be? At least that's what I wanted to do lol

[ScarabEpic22]

I guess I'll need to do some serious reading on this. I knew those MAFs were better but one of my friends aborted that mission a while ago because something didn't work right.


My TBSS came with a regular LS2 style MAF (90mm?) and I replaced it with a 4" intake and LS7 MAF. Have to rescale the IAT sensor to match then adjust the MAF curve and that's it. No issues after 2k for me.

This said, I have an E67 but let me check on the LS1 to see if the tables are there.

EDIT:
Checked the LS1B calibration, the IAT scaling table isnt there. So you could run a LS3/7 MAF, but since you cant rescale the IAT part you'd need to either run a separate IAT sensor from a F-body or compare the LS3/7 MAF scale to the LS1 MAF and see if it will even be close. Otherwise 60F IAT from the LS3/7 could really be 70F IAT that the PCM sees, so it will change fueling and multipliers differently. You could probably make it work, but Id probably just use a F-body IAT sensor so everything lines up.

[picnic_george]

I'm pretty sure the iat was the issue my buddy was having, thanks.

[ferocity02]

Back to the original question, can I use a 2 bar MAP sensor with a stock OS? Erik says yes, others say no.

If yes, what do I need to change besides the MAP Sensor Scaler? I presume I'll need to change Predicted MAP Max and the Barometer Update settings?

[picnic_george]

Yes you can, it will run just fine. But without a COS it's not going to do anything the stock one can't. You're limited to what the PCM/OS will read, and it won't read boost.

[joecar]

You mean try a stock OS with a 2 bar sensor, or a 2 bar COS with the MAF?


...

I think he's saying 2 bar OS + 2 Bar MAP + MAF.


...

Wouldn't it have to be? At least that's what I wanted to do lol


I mean just try the COS with a 2-bar sensor and see if the MAF works, jut like Erik said.

[joecar]

Back to the original question, can I use a 2 bar MAP sensor with a stock OS? Erik says yes, others say no.

If yes, what do I need to change besides the MAP Sensor Scaler? I presume I'll need to change Predicted MAP Max and the Barometer Update settings?2-bar sensor + stock OS + MAF:

leave the MAP scaler for 1-bar, and shift all the tables that reference MAP on their axis (i.e. so that the MAP's 1-bar range represents 2-bar range)...


note that MANVAC = BARO - MAP so you have to shift the IFR table down also if it was sloped

(but it would be better if you had a manifold-referenced FPR in this case since the IFR table does not cover boost, or negative MANVAC).

[joecar]

And remember that the PCM/OS maxes the MAF out at 512 g/s.