Decel Pop Fixed.

[geophb]

Recently I installed a Akrapovic Titanium on my 2019 MT07.   After importing pcv fuel tables and adjusting some part throttle fuel, this thing rips! Even with stock timing (87oct).  But I had a huge amount of decel popping.  Pop......Pop Pop.....Pop all the way to the stop! 

So I dove back into the fuel maps and check this out.

Firsts things first: This table is not labeled correctly, I have been back and forth many times with converting and its just labeled wrong. Assume column 1 (19.6xx) is full vacuum and increases from there to atmospheric pressure. Also assume any readouts from my pv3 monitors are only correct when correlating to the tables. 

 Under the map table (above), look how it goes down to single digit fuel numbers. This is where I was getting all my decel pop.  FYI the bike does not care what the tps fuel tables are during decel, it only looks at the map tables.  Just to confirm a couple things I plugged in my Powervision3 and the bikes idles at about 44 inhg  (column 12ish), then increases from there when revved. 

So I highlighted everything below idle vacuum, did some vertical interpolating and some smoothing.

This is what ended up with. Second picture is a comparison to stock map, yes you are reading that correcting it is a %60+ increase over stock.  I was very skeptical of my changes but after reanalyzing the maps again, remember the bike idles at 44 (column 12), this was still less fuel than at idle.   

Test: Flashed my bike and Fixed!  Not one pop. Zero. I tried engine braking for as long as possible, still no popping.   

They must do this for emission purposes.  Tuning this bike is all still a work in progress but so far so good.  

[stickshift]

I reckon there are perhaps issues using the PCV maps in others’ software (or hardware).

I use dynojet’s Akra map with my PCV and have never heard a an exhaust decel ‘pop’ even once. And yep, the bike rips!

[geophb]

3 hours ago, stickshift said:

I reckon there are perhaps issues using the PCV maps in others’ software (or hardware).

I use dynojet’s Akra map with my PCV and have never heard a an exhaust decel ‘pop’ even once. And yep, the bike rips!

Def'n not the case. I only imported the fuel maps into the tps tables not the map.  Even then it only adjusts the fuel about 50% throttle and above (dyno range). 

[stickshift]

Yes, but the dynojet fuel maps have been created alongside their ignition map. Using just their fuel map is not how it was intended to be used by dynojet.

Edited September 24, 2019 by stickshift

[geophb]

9 hours ago, stickshift said:

Yes, but the dynojet fuel maps have been created alongside their ignition map. Using just their fuel map is not how it was intended to be used by dynojet.

Does not matter. Dynojets pcv map when imported into the c3 software put a multiplyer on spark tables and tps fuel tables above 40% throttle ONLY.  Decel fuel and decel popping does not occur in these areas and only uses the map table for fuel. 

[geophb]

Update for all.

So I figured there's no point in burning excess fuel upon decel. So I edited that area again, attempting to get to the least amount fuel used to prevent popping.  Ended up with this comparison to stock.

Just look at the main green area.  Don't worry about all the ugly little decimal values, its because of small rounding discrepancies.  

Test:  Runs great, same as before.  BUT on decel only between 4000-5000 rpm I can get 1-2 pops, not every time though.  So I will have to add some fuel in that area.

Obviously, if I clutch in (or neutral, not safe) and brake to a stop it won't pop but that is not the point.

 

[geophb]

Another update.

I ended going back to the first map I made because everything I tried gave me a couple decel pops.  Must have hit the nail on the head first swing I guess.

[vcyclenut]

On 9/20/2019 at 9:27 AM, geophb said:

Recently I installed a Akrapovic Titanium on my 2019 MT07.   After importing pcv fuel tables and adjusting some part throttle fuel, this thing rips! Even with stock timing (87oct).  But I had a huge amount of decel popping.  Pop......Pop Pop.....Pop all the way to the stop! 

So I dove back into the fuel maps and check this out.

 

Firsts things first: This table is not labeled correctly, I have been back and forth many times with converting and its just labeled wrong. Assume column 1 (19.6xx) is full vacuum and increases from there to atmospheric pressure. Also assume any readouts from my pv3 monitors are only correct when correlating to the tables. 

 Under the map table (above), look how it goes down to single digit fuel numbers. This is where I was getting all my decel pop.  FYI the bike does not care what the tps fuel tables are during decel, it only looks at the map tables.  Just to confirm a couple things I plugged in my Powervision3 and the bikes idles at about 44 inhg  (column 12ish), then increases from there when revved. 

So I highlighted everything below idle vacuum, did some vertical interpolating and some smoothing

This is what ended up with. Second picture is a comparison to stock map, yes you are reading that correcting it is a %60+ increase over stock.  I was very skeptical of my changes but after reanalyzing the maps again, remember the bike idles at 44 (column 12), this was still less fuel than at idle.   

Test: Flashed my bike and Fixed!  Not one pop. Zero. I tried engine braking for as long as possible, still no popping.   

They must do this for emission purposes.  Tuning this bike is all still a work in progress but so far so good.  

 

 

 

good job!   what software is that??

[geophb]

Dynojet c3 software.  I use it for my Powervision 3.

[vcyclenut]

nice, I haven't used it yet 

 

according to the stock file image in the woolich software at closed throttle it is using between 16-28% of the pressure table.  Not 100%.  Doesn't really matter as you got it to work but just giving you some information to use for your tuning 

 

[geophb]

That is similar to the FTecu map bias table. Dynojet c3 has the same table.

Thats not the whole story though.  The Dynojet c3 software has additional information on how the fuel maps are biased. 

This is the equations it uses.  The other table is just a factor table for the fuel values to be used in the above equation.  If you follow the equations the ecu uses only map below 10% tps, blended between 10-47%, and alpha N only above 47% tps OR alpha n (tps vs rpm) only if you crack the throttle fast. 

This is assuming the software is correct.  I know when it is idling the Powervision 3 says 100% bias Spd den, via the live PID readout similar to live sensor data for a car. I also know if I quick rev from idle it says 100% bias alph n (condition 1 in above picture). 

A test for me tonight: If the software is correct, in theory I should be able to set all alpha n values (tps vs rpm) to 0 and idle should NOT change after I flash it. 

[vcyclenut]

awesome,  look forward to your results !

[geophb]

So I went home over lunch break and tested it.

Test 1: Set all alpha N values to 0. Flashed bike. Starts up and idles fine. As expected slowly increase throttle, it revs up and cracking throttle it shuts off instantly, all due to the biasing equations.

Test 2: Set all alpha N values to 0 and afr factor/bias table to 1 ( essentially "0" in FTecu or woolichs program).  Thinking maybe there was some funny business with that table. Flashed bike. It seemed to start are more difficult maybe a fluke but still starts idles and operates same and Test 1. 

So this confirms that Dynojets software is correct. The bike only idles using map tables.  Note:  Key ON, engine OFF it says 100% alpha N, then goes to 100% speed den (map) when I crank it and idling.  

@vcyclenut  That table your referencing/labeled in FTecu or Woolich software as "tps map bias" is called afr factor alpha N in dynojets software.  It does not say exactly what this table does as the biasing equation does not reference it. The name suggests its a fuel multiplier for the alpha N tables but I can't believe its used all the time.  I have an idea what it is, probably a whole thread on its own.

 

Edited October 1, 2019 by geophb

[vcyclenut]

thanks for the work and  info!! 

 

when I tune I data log and adjust both the tps and pressure tables to be where they need to be so the bias really isn't a huge deal  but it does show how important getting the MAP tables correct is.

 

Software that gives you the tools to properly adjust them is key!