Best activation of PE mode

[oztracktuning]

I am curious about what people are finding is the best settings to get PE mode activated with the E38s. I want it to enrich at low rpm when the map goes above 80Kpa. But so far im finding that its difficult to get the balance right between throttle % and kpa. Its easy to get it to come on too late and i want to squeeze more timing in than 14.6AFR can support down around 1600 to 2400rpm

[4wheelin]

I Have the same problem with an L76 I put in a GU Partol and 4L80e, I sent the file to support but havent heard back. As far as I could see it should be going into P.E. but won't under 80kpa and 3000 rpm. I had a miss under this load at 14.7 and had to command a downshift to avoid it. Support agreed it should be going into P.E. sooner.

[Black02SS]

Same here. The problem I am seeing is I can put 35% for the TPA% I want, but it still doesn't kick the car into PE.

[ringram]

Maybe it has to trigger both, not just either?

[oztracktuning]

Thats right it does need both. But its a the best combo of both thats tricky to find.

[ringram]

I used to trigger solely on MAP. Set TPS very low and there you go :)
After all the engine isnt under load until then anyway. That would be my approach fwiw.

[swingtan]

Hi all,
I've been looking at PE in the E38 PCM for a few days now. From what I've found, it seems that EFILive is still using the old LS1 TPS readings in an attempt to control PE mode. This results in the EFILive software settings not actually triggering PE mode when it indicates.

So far I've played with a number of setting for PE TP% ranging from 6% up to 30% ( all other settings unchanged ) and logged a number of runs at each setting. This is what I've come up with so far for TP% and PE Mode.

EFILive - Logged

06% - 33.3%
08% - 38.0%
12% - 41.8%
14% - 45.1%
16% - 47.2%
18% - 49.6%
22% - 52.8%
30% - 61.7%

I've graphed the results and placed a Logarithmic trend line against it and it's a very close match to the measured / logged values.

Another thing I've noticed is that PE sometimes comes in earlier than the figures above, particularly on fast throttle transitions. I wonder if the E38 detects quick throttle openings and predicts the requirement for PE, starting it off sooner.

So if you still want to use TPS%, then you need to allow for the difference in the software values vs what you get in the real world.


Simon.

[GMPX]

Another thing I've noticed is that PE sometimes comes in earlier than the figures above, particularly on fast throttle transitions. I wonder if the E38 detects quick throttle openings and predicts the requirement for PE, starting it off sooner.

Simon, I think there is a TPS change rate adjustment to the PE tables, we are looking in to it.

Cheers,
Ross

[swingtan]

Thanks, I thought that was there. I just wasn't sure if was a delay in the logging that gave the impression that PE was coming in sooner or if it really was a TPS% rate change setting as well. These E38 PCM's are pretty smart!

Simon.

[oztracktuning]

Which TP% did you log Simon?

[swingtan]

Hi Steve,

I'm logging GM.ETCTP. I've found that using the "correction table" for PE control works fine. PE comes in as expected with no random changes etc, so I believe that the "correction table" works ( at least for PE ). I posted a pic of the table I use here....

http://forum.efilive.com/showpost.php?p=80021&postcount=5

The green line was logged data, 20 to 30 instances where the ECM entered PE for each setting of TPS%, then the values were averaged.

The Yellow line is just a trend line so I didn't have to log every possible setting.

As for the actual settings, I'm finding that setting TPS% quite low and only relying on MAP to control PE is working well.

Simon.

[oztracktuning]

Ive been doing cars by activating off MAP, but i think setting the TPS activator a little higher and MAP a fair bit lower might let the enrichment happen a little earlier.

Its another topic but what have you found with Dynamic fuelling, i want to see more fuel after stomp. But what looks like it should work doesnt on the cars i have tested it on.

[swingtan]

I haven't really had an issue with PE not coming in fast enough. I do ramp it in pretty quickly though, currently the ramp in rate is at 0.8 for some testing.

Dynamic fueling is a whole bunch of excitement......

As others have found, dynamic fueling and injector timing both effect how the AFR's are affected on large throttle transients. Are you looking to get a rich mixture on throttle close or just extend the time that the stomp fuel is added for? You may find that injector timing will help here. I'm guessing that you've tried B2004, I would have though that that was the one but I think it needs B2002 and B2003 set up to make it work. From memory, the default settings simply turn stomp compensation on and off with no ramp out settings. I think B2002 needs to be a bit below B2003 to get the "ramp" effect.

Does this sound right?

Simon.

[oztracktuning]

I find that most mafless E38s dont richen up quick enough or enough early tip in. This is especially needed with any top mount supercharged cars.

I would like to get more fuel being added and decay it slower with my own car as well.

[ringram]

Sounds more like dynamic fueling than PE required for that then? Perhaps more is hitting the wall on tip in until air velocity picks up? (grasping at straws :)

[swingtan]

The only time I've noticed anything like this is on medium throttle movements. Go for a "big" WOT stomp and AFR's look pretty good, but medium transitions result in AFR traces with rounded bases on PE tip in. I agree with ringram that it's Dynamics that should be used to alter this, B2008 and B2009 would be a starting point...

Simon.

[hymey]

I find that most mafless E38s dont richen up quick enough or enough early tip in. This is especially needed with any top mount supercharged cars.

I would like to get more fuel being added and decay it slower with my own car as well.

I have noticed this with e38 mafless to steve. A slight lean spot on fuel tip in. It is not there with the maf on. But maf on I run into issues with reversion as the maf is mounted directly in front of the TB.

With stock cams it is not to bad but with bigger cams that have less vacuum and generally like more fuel on tip in it is very noticable. Adjusting pe earlier has no effect as it leans on tip in during stoich aswell. It is possible it is deactivated once airflow data is stopped from the MAF being disconnected.

I can see it could be a pain on blown engines and big cammed cars. It is annoying to live with in a way and it is the only reason I still have the MAF on. It definately works maf on as I commanded higher amounts in B2005 and I got very rich afr on tip in.

[DaveGuy]

I have a 2010 Camaro with a Whipple Supercharger on it and have been noticing this same initial lean condition on tip in transition between open loop fueling to PE with the MAF disconnected. What settings in B2005 are you using to get a rich tip in with the MAF connected? Does this table have any effect with out the MAF?

[hymey]

thats typical of mafless e38. Its a combination of dynamics pe enable