If my tuner set my IFR incorrectly according to RHS's spreadsheet, what would happen to my current tune if the only thing that I changed was to input the correct IFR numbers?

Would that throw the whole tune off alot?

Thanks in advance!

 

Changes made to the IFR will alter your tune. The amount it alters the tune depends on how big of a change you make. Ideally, a 5% change to the IFR should equal ~5% change in the AFR. That's why the old school way seems easier. It's the side effects of fudging the IFR table that people want to avoid when they tune the VE/MAF tables. But, that has it's side effects too (i.e. A4 transmissions make calculations based on MAF readings).

 

It really depends on how much fueling was compensated in other places. I wouldn't recommend changing the IFR blindly though, it won't help anything unless the other tables are modified accordingly.

 

Thanks for the help SSpdDmon! Here's what I figured out according to RHS's spreadsheet. I kept plugging numbers until I got to where the numbers matched my tune. I thought that the tuner knew his stuff, but looks like I was wrong. I just got my WB02 sensor and am going to put it in and attempt to fix this. I'm pretty nervous because my car has a blower on it and it seems a little overwhelming for my first attempt at tuning. I Really do Appreciate the help though!

Row one is now and row two is 60 lbs. MotoTrons at 68 lbs. of Fuel Pressure.

7.565597927 9.452172164
7.612749029 9.502440813
7.659609882 9.552444932
7.706185783 9.602188654
7.752481867 9.651676006
7.798503117 9.700910911
7.844254371 9.749897193
7.889740326 9.798638581
7.934965544 9.847138712
7.979934458 9.895401134
8.024651378 9.943429306
8.069120492 9.991226609
8.113345875 10.03879634
8.157331491 10.08614172
8.201081199 10.13326588
8.244598753 10.18017192
8.287887811 10.2268628

Would it be better to start over or just try to fix this?


Thanks SMOKINV8!

 

I'm assuming you meant 58lbs.

If you load that IFR table into your tune, you're going to run 18~20% leaner. Smaller numbers to the PCM mean the injectors don't flow as much, which in turn leads the PCM to believe the pulse width needs to be longer (effectively adding more fuel).

My suggestion is to hook the WBO2 up and see where you're at. If the car runs fine and the AFR is reporting sane values, I'd ignore the fact that commanded AFR doesn't match reported AFR and let it be. If there are driveability issues with the car and the WBO2 is reporting some funky numbers, I'd consider a retune. But, be cautious and get as much info as you can since you're boosted.

 

Thanks SS!

No, I meant 68 lbs. At idle, my car is making 68 lbs. of fuel pressure, and when at maximum boost, the FP drops to around 58 (from what I could see because most of my attention was trying to keep the car straight ). I should do the setup that allows me to log fuel pressure so that I know exactly what's going on.

Thank You again for the help! I'm learning quite a bit here.