MAF or MAF/SD

[GraphiteSRT]

This winter i will be turboing my 05 GTO

At the moment i am running the 2 bar enhanced OS but still using the MAF and the 1 bar map.

It seems their are two direction to go and id like some opinions on what is better.

I'm going to start by running 2 57 trim turbos on the stock LS2 approx 620 RWHP but i want to have the tune "set-up" for a built block and upwards of 18 psi so only have to do this once.


should i go with the 2 bar map and use the MAF until i reach boost and then have the MAP sensor take over from there. I will have to use the AFR spark adder to adjust timing at different boost levels as i will reach the max Cylinder Airmass at a low boost setting.

or

Should i have the the IFR and MAF and other tables scalled in half to allow up to 1024 instead of 512 airmass. This will also give me a bigger range for spark control in boost but will this give me enough room for my goals of 18+ psi and not hit the 12K limit.
I would be using the 100mm MAF
Are their any cons to this method?

[RWTD]

What turbo setup? What size piping?

If you go with a larger MAF, like the PowrMAF, you should be okay, BUT you do NOT want a larger MAF housing that is mismatched in size with the turbo piping, otherwise you'll get turbulence issues. You're going to need to scale down anyway, more than likely, as you'll probably be using Siemens (Continental) 60# injectors (73.x on a GM) anyway, so might as well scale by 50%, this way you get double the IFR, double the MAF g/sec, and double the airflow ranges on any other table (i.e spark).

[GraphiteSRT]

What turbo setup? What size piping?

If you go with a larger MAF, like the PowrMAF, you should be okay, BUT you do NOT want a larger MAF housing that is mismatched in size with the turbo piping, otherwise you'll get turbulence issues. You're going to need to scale down anyway, more than likely, as you'll probably be using Siemens (Continental) 60# injectors (73.x on a GM) anyway, so might as well scale by 50%, this way you get double the IFR, double the MAF g/sec, and double the airflow ranges on any other table (i.e spark).

2x 57 trim turbos with .82 exhaust housings
2.5 inch to the intercooler with 3.5 or 4 inch to the MAF/TB
Those are the injectors i will be using.

it looks like i will be going the route of the scaling

since i have the 2 bar OS i have the boost PE table will it still reference that table without going into SD mode? this way i can have an out of boost (eq ratio vs RPM) and an in boost (eq ratio vs MAP) PE table.

I am very new to this scaling procedure, i am not sure how to scale all the needed tables. I want to get a quick file ready for when it comes time.


thanks

[RWTD]

A4 or M6?

[GraphiteSRT]

A4 or M6?

A4

[RWTD]

Okay, read my post #22 here concerning scaling for the autos:

http://www.hptuners.com/forum/showth...564#post181564

It's quite simple to do.

[GraphiteSRT]

Okay, read my post #22 here concerning scaling for the autos:

http://www.hptuners.com/forum/showth...564#post181564

It's quite simple to do.

ok that part is easy. Also in my A4 file i can edit the Torque axis like the A6so i can cut them in half.

i will however have to manually edit the spark tables as i cannot edit the airflow axis.

what do i need to do to the IFR and MAF tables, im having a hard time understanding how this doubles my airflow

[yellz06]

Because you will not have the 512g/s limitation if you scaled everything by half.. you would suddenly have a 1024 g/s limitation.

[RWTD]

ok that part is easy. Also in my A4 file i can edit the Torque axis like the A6so i can cut them in half.

Yeah, on the Gen 4 vehicles, you are able to do that on both the A4 or A6 calibrations, provided one has the latest beta (I changed up my previous post I linked you to explain this). The Gen3 vehicles do not have an editable axis for this.

[GraphiteSRT]

ok, i understand it well now.

one last question i hope......will doing this screw with my fuel mileage estimates and instant MPG in the cluster DIC

[RWTD]

That's possible but I'm not sure to be honest. On a Ford, if you ratio, it will. However, there is a parameter you can modify in the calibration to alter the signal so you can correct the estimated mpg. Some jackleg tuners use this to their advantage (cough cough JDM). I may be wrong but I bet GM has a similar strategy. If that's true, maybe Chris can add in those parameters.