whipple install going lean at moderate throttle

[V8_Kind_Of_Guy]

Hey guys, looking for some help. Im doing a whipple for the first time and having some hick ups. For some reason, when slowly getting more load, the truck will go super lean, truck will loose lots of power, timing goes way up and cyl air goes from ~.61g to ~.35g at 30% throttle. Map also shows it going from ~75 kpa to ~65 kpa. You can see it multiple times in the log at 1:02, 1:10 and 1:46. I am trying to use only SD and not MAF. Also, Im in Denver so my kpa when it was an NA motor was 82 kpa and .75 cyl air mass at WOT.

Truck setup:
6.2 swap with PRC heads
BTR stage 3 blower cam
Whipple 2.9 ~10 psi kit
1 7/8 headers
3 bar map sensor
4l80
ID 1050x injectors
92mm throttle body
11:1 afr to start with
0 degrees timing to start out safe at WOT

Thanks!

jm whipple.hpt
jm whipple.hpl

[kevin87turbot]

There are a lot of things that need to be addressed in the tune.

Here are a few things to start with...

It's important that an tune has the proper engine displacement under the General TAB in the Cylinder Vol cell.
The AF ratio is bouncing around because of the VE table. It's a mess.
The MAF sensor isn't failed properly. Need to change P0101, 102, and 103 to MIL on First Error.
It would be better to target a more proper WOT AF ratio and timing value. Around 11.5:1 and at least 10 degrees at WOT will be a conservative start.
It's going to shift way to hard when you do fail the MAF properly. You'll need to disable the three Max Line Pressure DTC's under the Trans Diag tab in order to fix this.
If you haven't already done so, you'll need an upgraded fuel pump as well.

[V8_Kind_Of_Guy]

Thanks for your input. I have already upgraded the fuel pump to a 340 lph pump. I took your suggestions and see what happens.

[mecanicman]

You don't have enough fuel pump. Id change it before you get started so you dont run out of fuel and dont have to redo parts of your tune. 450 or bigger.

[V8_Kind_Of_Guy]

Quick update, back tracking and doing everything step by step (4l80 segment swap then 3 bar OS), the 3 bar map sensor OS is causing the issue. By only putting in the 1050 injector data and 4l80 segment swap, the issue went away. I can now get into boost and can hit 6500 rpms. So even though the 3 bar map sensor is plugged in, I did not change to the 3 bar os to get this to work. I have to figure out why the OS swap is not working correctly. I did try to just tune the MAF with the 3 bar OS but it still did the same thing. As for now, I am running off of the MAF to tune but Im already at 10,500 hz. Injector DC is at 45% and the fuel is still on the rich side. It looks like the pump might be enough for now, but I will do more tuning in the morning.

Anyone else have the issue with the 3 bar map OS? It is a genuine 3 bar GM sensor.

[5FDP]

Try the 2 bar OS if you are only running 10psi.

Did you change the platform type? This computer is a GMT-800 but it was changed, I wouldn't mess with that. I wonder if it causes background issues.

[V8_Kind_Of_Guy]

i forgot to mention, rolling into the throttle, the truck works great, but if you stab the throttle quickly, like from a stop, it stumbles hard.

[V8_Kind_Of_Guy]

I did not change the platform type. The only thing I changed was the engine type from 5.3 to 6.0 and the cylinder volume from 0.66594 (5.3) to 0.77499 (6.2) because someone mentioned this information should match the engine I have. It is a 6.2 installed into the truck. There was no 6.2 option in the tune that's why I selected 6.0. As for now, its back to stock values of 5.3.

I could try the 2 bar but I worry about later when I want more boost though. And running a 2 bar OS, I should buy the 2 bar sensor? Reason I ask is because the scaling of the 3 bar now and if it only gets me by for a little while until I put more boost on seems like a waste of money.

[DougO]

you can run 2 bar OS with 3 bar sensor, make sure to keep the 3 bar sensor linear and offset in there

[V8_Kind_Of_Guy]

ill run the 2 bar and see how it works out