Which OS upgrade (if any) should I use?

[SydneyACE]

OK tuning gurus,

I've got a 2001 C5 Vette that I put an LS3 and a T-Trim Vortech on.
I'm running a medium camshaft (BTR supercharger cam), LS3 style card MAF in a 4"tube and an LS9 3-bar MAP sensor.
After doing some more reading, I realized that I may have screwed up a little bit with the 3-bar sensor, since I'm only shooting for about 8lbs of boost... but the LS9 sensor fits the intake with no mods, and the LS9 is using it with low boost, so WTH?

I want to start flashing some tuning on this thing.
Should I be using the 3-bar upgrade option when I start?
The upgraded OS is free right?
Is it easy to switch between the OS options?
Is there any good reasons to tune out the MAF? (I've heard lots of mixed opinions about MAF vs SD and changing elevations/density altitudes etc.)

Thanks in advance!

[Ben Charles]

Ls9 map is fine for low boost
MAF maxes out at 512gsec, but you can do s scales tune to get around that and double your timing table

[5FDP]

The MAP sensor itself never really matters, you can run whatever sensor you want even if you planned to run low boost. So long and the MAP sensor can read positive pressure it would have worked. So a 2 bar or 3 bar sensor would be just fine.

The biggest things that matter are the map sensor settings, they must be correct for the sensor installed.

That sensor uses 312.5 linear with a -11.25 offset.

You can run the 3 BAR OS if you want, it won't make a difference to be honest. If you never plan to run over 15psi the 2 bar would have a smaller VE table and be easier to look at because the 3 bar VE will be huge if you only run say 8-10psi max. Lots of un-used space if you did that.

Switching between OS's is simple if you always have a stock file to revert back too. Say you wanted to switch to a 3 bar later on, you'd flash back to stock, create a new file with 3 bar, write entire and then copy/paste your 2 bar stuff back into the 3 bar tune. The 3 bar is only adding more room the VE, so nothing is really that different.

Running a MAF is normally a preference and most people don't switch MAF styles on a GEN 3 applications, they just go to straight speed density and remove the MAF and also the MAF can max out in some case. Keeping it can be okay if you stay below a certain airflow limit.

[SydneyACE]

I was under the impression that since my MAF is in a 4" duct, I wouldn't need to worry about maxing it out in terms of htz right, just have to scale the g/sec?
I found MAP numbers of 329.41 linear with -6.35 offset. Is that not right? That could have been a gen 3 MAP instead of this LS9 gen 4 sensor that I have...
https://sites.google.com/site/sloppy...identification

^ That's where I found my numbers from... if you're sure on your numbers being from an LS9 sensor, I'll use those instead.
Also, I read that using a 3 bar sensor on low boost basically means that you're giving up resolution, which makes sense. Is that not a big deal?

[5FDP]

LS9 sensor is what I posted above. That site is for different 3 bar sensors.

There is no loss is resolution, the sensor still reads whatever is happening inside the engine.

The only way you lose resolution on a 3 bar setup is when the computer file itself loses resolution in the VE table because of a 3 bar OS upgrade. Some computers/OS's will suffer from this because theere is not enough space in the calibration for better resolution. The stock OS would be going up by 5kpa, a 2 bar OS would go up by 10kpa and the 3 bar by 20kpa because the size of the overall table was the same but they had to pack 30kpa to 310kpa in a small table.

A P01 computer shouldn't have that issue at all.