Deliciou Tuning Speed Density Tunes - Important Notes and Closed Loop Fuel Correction
 

Hi All,

We have had a couple customer order some Flash & Go Tunes and not realize that when running a pure speed density tune, they will need to make sure you have the correct MAP (Manifold Air Pressure Sensor) sensor for the application. If the vehicle is not properly equipped it will cause incorrect fueling and ignition timing values, luckily we have some built in safety features we have been working on to handle such potential issues such as failing MAP sensors.

The reason the MAP sensor on a pure speed density tune is so important is so that scaling for load values for timing, fueling, boost, cam, port injection and direct injection is based 100% off the MAP sensor (we do not use the MAF load values sensor for these tunes). Without having a correct MAP sensor, the sensor can max out and this will cause, beyond a host of other things) improper ignition timing, improper air/fuel ratio values as seen in the log below.

http://www.delicioustuning.com/sites...?itok=E413UAJL

Notes on datalog provided above:
- MAP sensor maxed out at 6000 RPM at about ~10 PSI
- Engine Load values slowed drastically at 6K RPM, causing irregularly low Engine Load values
- Low Engine Loads will lead to abnormally high ignition loads causing knock correction values to drop
- Low Engine Loads will lead to static Injector Duty cycles, causing the AFR to lean out

This is an example of what can happen when improperly selecting a MAP sensor for a vehicle running more boost then what is allowed for the tune provided. For this tune one can see that our Closed Loop Fuel Correction was active and trying its best to maintain good AFR's.

CLOSED LOOP FUEL CORRECTION:
We have implemented a CLFC (CLOSED LOOP FUEL CORRECTION) to correct if the AFR becomes abnormal as seen in the datalog provided. When the MAP sensor maxed out in most cases the tuned ECU would not know what to do and just lean out drastically but with our CLFC implemented the AFR did not immediately start leaning out, Instead it kept adding fuel as seen by the port injector duty cycle adding an additional 20% to the port injector duty cycle.

The main issue was the boost on this car was determined to be 15 PSI (5 pounds over the MAP sensor limit of this vehicle). Our CLFC, currently at this time really can only accommodate about ~2 pounds over the limit of the MAP sensor, and this is why it leans out as it is has surpassed its limit. With this in mind we have actually been hard at work at improving the response time of our CLFC system so that if this were to happen again the ideal AFR would stay constant through the RPM band. This will be in the newest release of of Flash & Go Tunes version 15+.

We are continuously improving the dynamic control of these vehicles to add controlled safety margins into the vehicle. We would like to thank EcuTeK for their great support on building a kick ass system (RaceROM) that allows the professional tuner create incredible tunes for our customers. :party0030:

Cheers,
William Knose
Delicious Tuning

Great stuff, will this require a wideband sensor be wired to the ECU or can the system work with the factory sensor ?

No sir, all of the flash & go's actually count on the factory front o2, which is a wideband. We've recalibrated it in the software to read accurately richer than the tune will ever go, which gives you plenty of headroom.

Sincerely,

Zach
Delicious Tuning

I've heard so many different things about the factory front o2 sensor. From your experience, have you been able to get accurate readings as rich as <11.00 AFR? I've got mine scaled and dropped the rich limit to 11.00 (since that's as rich as I'm going with my tune) but I haven't done a comparison between the stock and aftermarket wideband. I was able to see a slightly lean condition under load where i jumped from ~11.04 to ~11.60 from the factory o2, just worried it may not be accurate at those AFRs.

We have it accurate down to 11.2, we can have it scaled to read accurately down a bit lower but we don't see a point since any lower than that is too rich anyways and needs an adjustment. :)

Sincerely,

Zach
Delicious Tuning

Ah okay perfect, I've seen a lot of the work you guys do so your words hold a lot of weight for me personally. I appreciate the response :)

Hi All,

We have been working on some small updates to our CLFC control which will be applied to newer version of the Flash & Go and Innovate tunes. This may be something we add to the NA tunes in the future.

One of the main aspects we are focused on right now is a quicker responding correction factor. The benefit of this is to help in case of overboost, vacuum leaks, and major issues that can lead to drastic AFR changes in a short matter of time. This is also helpful for those vehicles nearing the 500+ whp mark, as the AFR will change quickly in varying RPM's and maintaining a steady and repeatable AFR is very important in these cases.

As always it is important to maintain a proper working front O2 sensor for the CLFC to work properly.

Cheers,
William Knose
Delicious Tuning

This is why my car likes to pop off flame between 1st and 2nd isnt it :p

That would actually be something else we do to prevent any kind of misfire between shifts :)

Sincerely,

Zach
Delicious Tuning