OutlawZ

iTrader: (4)

Anybody that runs a datalogger like BS3's or XFI do you notice that your car will go a bit rich on gear shifts? Is this because of the RPM drop and the box correcting for the reduced engine speed for a moment? My car will target 11.5:1 for example and will be dead on thru the RPM range then on gear shifts it'll go fat for a tenth or two down to like 10.5:1 or so then come right back into range. I'm getting ready to lean it out a bit to get my plugs where I want them and sneak up on the tune but i'm wondering if others see this anomoly and what causes it....

BAKED

iTrader: (14)

I haven't really noticed mine doing that, I'll go back and check a few of the logs. I wouldn't worry about it though, I would think it would get better when you get the tune up closer to where it needs to be.

Beer99C5

iTrader: (21)

From my VERY limited track time and logs, I see that my fuel pressure is about 55 PSI just before the shift (6200 RPM), and after the shift its about 60 PSI (4100-4200 RPM) the shift seems to give the fuel pump time to recover. It effects my afr anywhere from .3 to .7 AFR for approx .6 secs.

Likely could it be the increase in Fuel pressure that is making you go rich?

ATVracr

iTrader: (5)

Mine has a slight lean spike 13.2 or so from 12.6..... if its just a blip and comes right back not much to worry about.

SPEEDYws6

iTrader: (9)

Mine spikes lean, but mine is a stick car and I no lift shift it if that matters.

ShiznityZ28

iTrader: (11)

Like atv said quick lean spike. get the alpha n done and turn off the corection. and just use iat for heat adjustments.

ShiznityZ28

iTrader: (11)

Are you using alpha n or map? watch your TPS or map on the log where it dips the rate of chage for those sensors can mess with the fueling. does lbs/hr stay close?

OutlawZ

iTrader: (4)

i'm using load indexed speed density.... making runs in closed loop allowing it to correct to currently 11.5:1 AF ratio... I know i'm gonna hear it about making runs in closed loop but that's what my tuner does (and he has a 7 second nova so i'm nobody to question him)....

we are going to start leaning the car out and using the datalogs and looking at plugs to confirm what the wideband is telling us. Even without target AF ratios his tune is within 2-3% from our current target. we're going to start leaning it out starting with about 12:1 and see if the car picks up.

We're keeping it safe with very conservative timing (11 degrees on a 300 shot roughly)

The lb/hr stays pretty close and doesn't seem to dip at all since once the car gets set in gear it stays dead on at 11.5:1 which is our target.... seems that gear shifts changing the load on the engine makes it go fat really quickly...

ShiznityZ28

iTrader: (11)

We used close loop up until this weekend. its fine just limit it to 2-3% change so it does not wig out. also turn the gains down. The map reading probably jumps and even if your cells are right the rate of change will add fuel making it rich. you have to cut down the rate of change table. But by doing this you will make tip in and throttle stabs lean so you will need more work in those cells. The alpha N fixes this since its rpm based and tp so the map can jump all it wants and you can almost turn off the rate of change table.

OutlawZ

iTrader: (4)

hmmmm interesting..... might need to try the alpha N.... yeah i don't see anything wrong with running in closed loop...

ppl were asking me "what if your wideband dies during a run" it's gonna destroy your motor..... I say let the technology in the box do what its supposed to do, and use the wideband to confirm what the plugs are telling you to do. So many things can go wrong during a run that could destroy your motor you can "what if" yourself to death...

thanks for the info shiz, I appreciate the insight... I might have to try out alpha N.... Ultimately long term I want to datalog 8 seperate egt's in each header tube and also run a cam sync for individual cylinder timing. I'm running bank to bank right now with a dist without a cam sync.....

ShiznityZ28

iTrader: (11)

No problem man. these are issues we had to work threw also. but i wish i would have alpha n tuned it day 1. made the part throttle stuff so much nicer. instead of the map jumpng around if you on or off the gas fast. we still log map to see if anythign funny is going on it just only effects the tune with rate of change wich is there for tip in and off.

2Tightwads

It actually should spike lean...read up on it...its called DFCO "Decel Fuel Cutoff Off".

ericg69ss

Jason and I both have the same tuner. Jason, Theo had me get the cam sync and XIM box for what you mentioned above. It certainly can be a powerful tool especially when you know your intake and exhaust valve events with your camshaft. I'll check my datalog's when I get back from my honeymoon and check. I don't recall the car getting fat between shifts.

SPEEDYws6

iTrader: (9)

DFCO requires 10% or less TPS to activate, Not going to happen durring a full pass. Also they arent using a factory PCM so I doubt they have DFCO anyway and mine is turned off.

1BadZ95

My car does the exact same thing. I'll be at 12.7-12.9 shift to 3rd and watch it drop to 10.1 and slowly climb back up, shift to 4th and back down to 10's. I can't figure it out. Let me know if you get it fixed/better! It's driving me crazy.