Flatline Rich Shifts (2010 Ralliart)
 

Alright,

So since installing my wideband and starting to fine tune my setup off the GST basemap for 93 octane I have been noticing a consistent post shift hesitation when accelerating. I'm 99% sure it is down to the fact that the fueling goes pig rich (my wideband won't read lower than 10:1 and it flat-lines every shift).

I can speculate all day about why this is, and I have been, but since this is my first SST vehicle I wanted to get some feedback from the community and see if this is just a problem with my setup or if all sst vehicles (MR's and RA's) are affected, or just ralliarts, or just specific years etc etc.

The first snippet of log is part throttle 1>2 shift then 2>3 shift. The map used has lean spool turned off, but very minor fueling changes from the base map.

This next snippet is WOT 2>3 with lean spool ON (turning it back off asap... just testing to see if that was the cause):
I'm attaching the full logs (taken via stand alone logger) 6 and 7 are part throttle lean spool off. 11 is wot lean spool on.

Has anyone else seen this issue???????
Map attached, only difference between 6,7 and 11 is that I bumpped the timing on the lower bound table to see if that would help for log 11 and also turned lean spool back on for log 11. Fuel and timing map load tables etc are the same.

Current Modifications: UR lower ic pipe, UR upper IC pipe, X bov, UR resonated test pipe, 3 port (tactrix version)

Have you tried to match the lower bound a little closer? 1-2*?

It's odd to see fueling change on shifts. Mine is basically flat 2nd-5th gear. However I also hold flat boost and load because of my larger turbo.

Working on that now. What I tired today was:
1. adding 2* to the lower bound table (now at -4* from high octane map)
2. Reducing the map load tables at 19 psi and up just a little bit

So far it seems to be helping some. As we have seen, with the RA anyway, above 4500 rpm you are running of the map load tables more than maf load so I was thinking the rich dip could be a combination of the retarded timing and high map-load that results from the shift boost spike. Could also be a little bit self feeding in that retarded timing causes rich mixture with combined with retarded timing created an antilag effect wich causes higher boost and higher load and so on...

On a positive note... my logged load has really smoothed out since adjusting the map load tables last week.

Anyone else seeing similar rich shift behavior?

Still have not found anything that consistently helps with the rich shifts... keeping the lower bound table a little closer to the high octane timing table seems to help some, but not enough to clear up the issue...


Any other SST's noticed this behavior?

I have heard that some folks have found another fuel table that is used during shifts..... but I have yet to see this table in any rom with any combination of XML.

It could just be a side effect of the instant drop in RPM. The ECU won't be that quick to react, and the air is still flowing while RPM drops. The ECU reacts to changes; it doesn't predict.

Yeah, I understand what your saying and I'm very much aware of how the ecu works... You can see the load spike during the shift... but honestly we are only talking about 5-10 load units and as you can see from the logs... the afr in those same load areas is no where near that rich except during the shift. It almost seems like an accel enrichment function or something is kicking in during the shift...

Just would have thought if this was a known thing more people would have noticed it by now... because it is very annoying and produces a noticeable pause in acceleration.

Guess I'll start logging the IPW and see if that points me in any particular direction.. if there is a radical change in IPW then it's a safe bet another fuel map is being referenced especially in comparison to the same load and rpm cells under wot without a shift. If not then I guess I need to be searching for a minor boost leak that gets worse at 22 psi.

If your load is spiking, then that is where the fuel is coming from. Increased load means the ECU thinks there is an increase in air. It compensates by adding fuel.

I actually found a AFR limit map for SST's the other day actually...

I havn't disasm'd it totally, but my feeling is its for shifts, but not sure if its a lower bound or actual shift AFR...

Once Jon stops testing my other SST stuff he can check that out as well :)

But then you can't tell us for 6 months, right?

yup :(

yeah, I was fairly positive it is / was using another map... glad to see Tephra found it already :) After logging the IPW you can clearly see the PW jump up during shifts (essentially while the clutches are doing their thing) and then fall right back in line where they should be once the clutches lockup and the afr returns to the tuned value.

Will be interesting to see how this develops... I have a feeling getting control of shift fueling will also allow you to tune out the boost spike that occurs.... with the lower bound timing you can dial back the ignition retard and with the suspected fuel map you can lean out the shift fueling... both of which will cut down on the anti-lag effect and should hopefully result in less tendency for boost spikage... w00t!