V-10 Killer

iTrader: (22)

Earlier this year, when I had my car dyno'd, I ran REALLY rich. One of the guys at the dyno knew almost exactly how far off my AFR was from commanded. ~14%, which was what I had scaled my IFR's down by to get LTFT's negative. Now what I'm wondering, is if I scale my IFR's down by x%, should I also apply that to my PE vs. RPM tables too?

By the time I left the dyno, we figured I needed my PE vs. RPM #'s pretty closed to 1.000 which is a big change compared to what I noticed other people making (typically 93-94% of original)

Any ideas or opinions on this?

luv2spd

iTrader: (1)

To the top. I'm wondering the same thing.

foff667

iTrader: (2)

i dont think if you scale the ifr you have to scale the ve if im not mistaken...pe though should be scaled...keep in mind the larger the pe # the more fuel your adding.

V-10 Killer

iTrader: (22)

Why scale the VE tables for WOT operation? Doesn't WOT run off the MAF, MAP, IAT, and HO2's??

HumpinSS

iTrader: (1)

If you scale the IFR table it scales EVERYTHING including your PE vs. RPM tables. In order to keep the same AFR after a IFR scale you need to move your PE vs RPM by that much to keep the consistency.

HTH

marc_w

Wow... This bit of info is pretty damn important, and the first I've heard of it.

I had my IFR scaled back by .924. I just scaled back my Main PE by the same amount and HOLY ****, what a difference! (THERE'S THE CAM!!) I only used half throttle and hit FTC 15, but the motor sounded entirely different and reved out much quicker. No more slamming the pedal to the floor to get anything out of the motor.

Now the real kicker here... I got little to no KR, where I previously WAS.

I realize that I now I need a wideband more than ever. Probably more than I need headers or that converter installed.

V-10 Killer

iTrader: (22)

I agree. I have not read anything about that either, and I read probably 200 posts for every one I write...

I'm glad someone tried it and got positive results
I did the changes to my PCM yesterday but had to go to work and didn't get a chance to relearn my new LTFT's yet. So I still haven't tried it at WOT.
I'm praying that leaning this thing out this way now will get me that extra 50 rwhp I've been missing (I'm pretty sure I was between 10.8:1 and 11.8:1). I desperately need a wideband too.

HumpinSS

iTrader: (1)

IFR changes makes the car soggy if you ask me

marc_w

How do you tune fuel trims then, Humpin? MAF translation/calibration? (that's another one I **JUST** heard about today.) I previously thought IFR or the VE table was the only way to change fueling.

Now that I'm realizing VE is just airflow...

HumpinSS

iTrader: (1)

the ve table even though an airflow table correlates to fueling. More air more fuel. I wouldnt mess with the MAF unless it is ported or isnt stock anymore


https://ls1tech.com/forums/showpost....4&postcount=24

marc_w

Cool... thanks for the link.

I'm a little more confused now than ever. Previously - after reading the VE table cracked thread - I was thinking I should calculate out my VE table, see how it runs........ hit up my IFR table from there to get fueling right.......... then dyno/wideband for WOT.

HumpinSS

iTrader: (1)

Yes 2 yrs ago everyone was tuning with the MAF calibration table, then it moved on to using the IFR table. Today we should be using the ve table to tune trims and the pe vs rpm to get the WOT values together. The formula just gets you in the ball park from there you need to fine tune to really dial it in like horist is doing in the other thread.

foff667

iTrader: (2)

hmmm interesting reading

marc_w

I see...

Okay, I think it's starting to make sense now.

My when I do calculations for my VE table (through the nogo formula), my numbers are coming out on the low side. They would probably make much more sense if I was running the stock IFR table.

I think I'll move IFR to stock, and start trying out the VE table method.

Thanks.

CHRISPY

I scaled my injectors in the IFR table. (37 Lucas injectors) The LTRIMS were previously negative 15. Now they are -2 or so and -4 to -5 at cruise. I had to add THIRTY PERCENT more fuel to get the WOT fuel in the 12.7-12.8 range.

Previously the AF was in the 12.2 range.

So yes PEvsRPM is directly and drastically affected by IFR changes.

dmtnt

Just to clarify, you scaled PE vs RPM by -30 (i.e. 70%)??

CHRISPY

No I had to add fuel. I was running 15:1 at the start of the pull. Added 15% and it wasnt enough. Added another 15% and then fine tuned and it was perfect.
Previously I was at -15 LTRIMS and 12.2:1.

After scaling I was at -2 to -3 LTRIMS at idle, ~ -4 at cruise and had to ADD fuel at WOT. (Car was very lean at WOT)

1fastWS6

iTrader: (3)

Chris,
When I swapped out my TR224 for the F13, I added SVO 30's at the same time. I previously dyno tuned it to 12.8:1 AFR with the TR224. I scaled ONLY the IFR table by 26% after the injector/cam swap. My LTRIMs are in the 0 to -5 range now, and the AFR on the dyno was still at 12.8:1. Never touched the PEvsRPM table.

According to NoGo and others, the PEvsRPM is only a multiplier and you only need to change it when scaling the IFR to trick the computer into thinking you have smaller/larger injectors when you really don't. If scaling it to account for swapping larger injectors, then you shouldn't have to touch it. Don't know why you needed to on yours???

Craig

V-10 Killer

iTrader: (22)

The more I try to understand, the grayer it gets
To hell with it, I'm getting a wideband...

V-10 Killer

iTrader: (22)

Ya know, I just realized something.
I've been doing a lot of reading about open loop in WOT, and I don't think I have one recorded WOT pass in open loop!! EVERYTHING i have is in closed loop. Even if the Throttle position is only at 91%-99.6% or 100.0% Time to do some investigating...