Couple more hellcat questions

[RonSSnova]

We turned the NN off and calibrated the VE using the loaded dyno.
Then moved on to WOT testing.

Power is 800+

I notice that the fuel system status indicates CL. Any other Dodge will show OL with your foot on the floor.
Is it really in CL at WOT? Due to the wideband O2 setup?

I changed from logging Desired FA Cyl 1 to AVG FA Open Loop and now it follows the FA table.
By the FA it appears to be commanding 11.49:1. FA = .0872
However, EQ commanded is .828 Lambda. Or approx. 12:1. Our tailpipe sniffer says it's at 12:1.......but it usually reads about .5 points higher than a WB screwed in the exh.
I'll do an experiment. I left the Stoich at .0722

Lastly, what is the function of the MAF? On GM it takes over fueling at 4K rpm. Is it simply a measuring device on the hellcat?

Ron

[HackAbuse]

Are you sure it has a MAF? Haven't seen any Dodge/Chrysler vehicles with a MAF yet

[RonSSnova]

Card style MAF located in the intake tube.
Also has a MAF calibration table
Hellcat is a different beast.

I changed the FA tables. Made the pressure ratio version richer than the Aircharge version.
It's using the aircharge FA table. And the EQ commanded dropped to match.
I suspect the offset in values is due to the odd FA Stoich value.

AF by the internal widebands is ruler flat. So if it is indeed trimming while at WOT, it does a damn good job of it.

[MarkTucker]

Are you sure it has a MAF? Haven't seen any Dodge/Chrysler vehicles with a MAF yet

2015 Challenger Hellcat.jpg
2015 Challenger Hellcat MAF.jpg

[MarkTucker]

I notice that the fuel system status indicates CL. Any other Dodge will show OL with your foot on the floor.
Is it really in CL at WOT? Due to the wideband O2 setup?

Ron

I have not even noticed to watch the Fuel System status while testing.

[MarkTucker]

Lastly, what is the function of the MAF? On GM it takes over fueling at 4K rpm. Is it simply a measuring device on the hellcat?

Ron

As far as I know of so far, the MAF is there for airflow measurement only, not providing a main purpose of fueling control like the GM's.

[UMSTuning]

The last one i did was closed loop the whole time...pretty good at doing it too.

Tony

[RonSSnova]

Ha! I just noticed it in the graph display. It still showed trims.
I did an experiment. I leaned the injector pulse it uses at WOT by 5%.
Fuel didn't change......neither did the trim at WOT
Somewhat of a mystery there......

[Jay@HAP]

after warm up it's always in CL due to the widebands.

[RonSSnova]

I finished the tune. Did quite a bit of driving working on the VE table. Not sure why it's thought you can do a few quick drives and its nailed......
Anyway it came out fine.
With the NN off, it really struggled at start up.
I simply modified the FA cold start table to give it some fuel, I could tell it was too lean and its happy as a clam starting now.

So we put slicks on and took it to the track.

Had issues with the inter cooler pump not turning on. That basically pisses it off. The IAT table thankfully removes timing. In the form of short term KR btw.....

Fixed that and it went 133. 10.6.....
Somewhat disappointing actually. Our track sucks, it spun pretty bad even with bias ply slicks.

We did not turn off any tq management. Not sure what the trans will handle......

Any suggestions appreciated. I think it should go bottom tens, closer to 138 given the power it made.

Ron

[Mep_q8]

Is it a stick?

[RonSSnova]

It's an auto.
And actually, after running the numbers through the Wallace HP vs weight and mph program, it's right about where it should be.
Heavy cars!

[Mep_q8]

great, did you increase the auto upshift? Auto shifting at 6500rpm would really help with the ETs.

[RonSSnova]

I had all the rpm set to 6400. But it was shifting at 5900. I'm not sure what mode he had the car in while racing.

[Mep_q8]

check your DM..

[RonSSnova]

Got it!
Thanks!