I've been busy working on logging all the engine data through the OBD port to record engine performance and operating parameters... I have the full onboard system working now and took the car out to Willow Springs to run some tests under track conditions...

Unfortunately the weather was HOT (105f ambient, 190f tarmac, 0 humidity)...

I ran the car with 91 octane pump gas without any of my normal track additives (KLOTZ COXOC / PROPYLENE OXIDE) and during the first recorded test I used "HOT PLUGS" then replaced them with "COLD PLUGS" for the second recorded test...

I logged the PID's that were relevant to my testing (19) which slowed the data transfer time from the ECU to my computer and only recorded a new frame every 5 seconds +/-... So many of the PID's that are accessible do not show-up on this log... The logs are generated as .csv files in EXCEL format, but I had to post them as .pdf to the forum...



You can follow my position on the track by observing the speeds (MPH) and referring to the track map... The last (TRIPLE DIGIT MPH) in a sequence is the front straightaway... It is preceded by a (TRIPLE DIGIT MPH) in the 7&8 complex...



I also uploaded some video to my website... Unfortunately, the dumb professional cameraman left the camera on auto focus so it keeps buzzing back and forth... But I did place the camera to help you see my perspective...

Hope you enjoy...
http://www.hollywooddigitalimaging.c...R_TEST_DAY.mov

 

so what's the verdict, did you learn anything?

 

Yeah, I learned that the ECU is retarding the timing on an average of -30 degrees and both long term and short term fuel trim is leaning out -30% avg... This is occurring at idle and WOT under full load...

???

 

I noticed that and the Vac from 5-(28) which seems high as well, but could be a spike from tb closing that was captured.

Some logs when the weather is cool would help tell if it's fully temp related on the FT of 40%
I expected around 20 % so there is enough available for cold start and for sudden enrichment, and the margin to allow some dwell time on the seat, so you don't have 100% duty cycle. The other 20 could be density?

Very good data to help us learn how to tweak their one size fits all PCM.

Dale

 

I updated the first post to be able to read the data logs easier... I'm still scratching my head about the timing and fuel trim... I consulted with an associate who work with Bosch Motorsports and he recommended a piggyback system to manage the fuel mixture and spark advance because the Motronic 2.8 will not allow independent timing adjustments...

So, even if I increased the LTFT & STFT via my aftermarket software, the ECU will continue to retard the timing more to adjust to this level... He believes that this is part of the CA CARB emissions program that is built into the software and is "locked-out" per federal regulations...

 

Have you done any ECU reflashes, or is this stock?

Is there any chance you can purchase a European Motronic 2.4 ECU, that doesn't have the CA CARB emissions BS??

 

No need, it would be more expensive and technically challenging to install than the MegaSquirt MSII system that will handle both fueling and timing as a piggyback... Plus the MSII comes with full software support with open app and freeware...

 

BTW, I have been looking at the numbers from last tests and the IAT is extremely hot... I think I'm going to re-work the air intake... I have a couple of ideas that may work for track purposes only...

 

That's the rub about speed density, timing and fuel are locked together.

My point was your AF might be fine, with a lot in reserve. find a way to map some EGT's under load. The timing is the one that looks extreme. Is there a knock sensor on the CF's??

And yes a cold air kit would be worth the effort with those IAT readings.
Keep us posted, I enjoy lurkin and learnin.

 

Yes the CF does have knock sensors but I didn't hear even the slightest hint of knock...
But something dawned on me last night that may account for some, if not all of this retarding... I have a custom ECU tune that was designed for 93+ octane and since the car is only used on the track, I normally run Sunoco 98 or 100 race gas with a mixture of Klotz Coxoc or Propylene Oxide. I'm wondering if the generic 91 octane fuel that I used during these tests caused a slight pre-ignition state or slight, inaudible knock that caused the computer to dial back the timing and fuel...

I guess I'm going to have to re-run these tests with my normal fuel and see where that puts me...

BTW: I already have a CAI believe it or not, it just doesn't seem to have much C in the AI...