NYSS Guy

iTrader: (1)

I followed the help section in HP Tuners, and made all the necessary changes to do the sd tune. But, after my first sca, my afr % error was between 15-25%. So, I changed my VE table by 10%. The problem that I found is, the % error is taking me to 14.7!! So, that tune was very lean.

I tried changing the commanded afr to 12:1 (what is usually stoich). Now, with no other changes, I'm between 10:1 and 10.5:1???? I read the help file 4 times to make sure I didn't miss something. This is version 2.0, and it's a 2 bar speed density tune. Anyone have any ideas?

oange ss

iTrader: (50)

what's you open loop set for ?

NYSS Guy

iTrader: (1)

In the help file, it says to set the open loop f/a to 1.00, and then change the PE table to command whatever afr you want. This didn't make sense to me, but I read it several times, and that's what it said. So, that tells me that my open loop afr is gonna be 14.7, and I'll only hit 12:1 when in PE. Now, it is always possible that I'm reading things incorrectly, but something just doesn't seem right.

foff667

iTrader: (2)

nope thats correct...in ve tuning your only trying to get your commanded/actual to mate up nothing more...you can set your OFLA table to 10.0:1 or 14.7:1 and your VE should come out to the same number. Keep in mind though that writup is mainly for mildly modded naturally aspirated cars. "This tuning guide is for semi mild setups as in the end we will be putting the car back in closed loop." i dont think a turbo setup falls under semi mild setup

NYSS Guy

iTrader: (1)

Okay, fair enough. But, what commanded afr is the histogram telling me how far I'm off of. Is it a % away from the commanded afr (where it is usually 14.7)? Now part of my problem might be the fact that this is my first trip in to speed density tuning. The tuning I've done to this point was only WOT (also just got the EIO for my wideband), so, under part throttle, is 13:1 okay? I haven't floored it yet because I'm concerned with the lean afr. Now, when I do get the throttle to a certain point, PE will take over, and it should richen up...right?

foff667

iTrader: (2)

personally if your not going to a 2 bar map I wouldnt bother too much with VE tuning, but thats me.

NYSS Guy

iTrader: (1)

Yeah this is a 2 bar map (speed sensity only). That's why I'm messing with all this stuff. Once I find out if I have changed the right thing as far a commanded afr, the rest is pretty easy. I just want to be sure I'm doing the right thing.

foff667

iTrader: (2)

ok so you have a 2 bar map, did you also purchase the 2 bar license then I assume?

NYSS Guy

iTrader: (1)

yep. Would a sd tune be different for a 2 bar as opposed to a one bar?

foff667

iTrader: (2)

I personally would attack it differently & lean towards the side of caution.

NYSS Guy

iTrader: (1)

I am trying to stay on the cautious side, that's why I'm asking this question. As it sits now, the car is running around 10:1 afr. But, I have a feeling that might be because I have the wrong thing changed as far as commanded afr is concerned.

YellowToy/A

iTrader: (1)

I would use closed loop to get close. Set the afr to 14.7. AFR needs to be set to 14.7 for O2 to work. Enable to O2. Then look at what the stft+ltft is. This is what u will add to the VE table. Make sure u have a 2 bar presure sensor and the cal is correct or it. After to do that then then u can tune with WB. PM me if u want. This might be faster on the phone.

white2001s10

iTrader: (4)

You do have your O2's unhooked correct?

foff667

iTrader: (2)

why would he unhook his o2's if hes doing a closed loop 2 bar speed density tune?

foff667

iTrader: (2)

using trims to tune a turbo setup isnt necessarily the best route imho

Phil99vette

iTrader: (11)

We tune the open loop to 1.00 up to 70kpa and 1.13 from 75kps and above.
Phil

foff667

iTrader: (2)

just remember he has a turbocharged application...1.13 would not be a "safe" number

white2001s10

iTrader: (4)

Because he said he was changing the stoich ratio around. That's not going to work with factory O2's. They only work like the software expects in a certain AFR range.

foff667

iTrader: (2)

you could command the car into open loop and basically do the same...also its pretty widely accepted you don't just change the stoich a/f and would change your olfa table to reflect your commanded afr.

YellowToy/A

iTrader: (1)

U should get the VE close in closed loop. After that u can go open loop. IMHO this is the best way. I am talking about the area that is not PE.