Need the opinion of others ;)

[Tordne]

OK. So this is really getting on my nerves and I want to get the input of some of you other guys...

My dilemma is basically the large range in the BEN factors in some of my low MAP (decel) cells. For example the 1600 RPM vs. 20-25 kPa MAP ranges. Looking at one log the MIN value in this range is 0.88 and the MAX in that same cell is 1.21. Now as I calculate it that is a variance of 33%.

Is this what some of you are also seeing? Do you think there is a solution to it (changes to Throttle Cracker/Follower airflow for example)? Or is it just a case of "it's decel - give it up already"?

Would appreciate your experiences/opinions.

Cheers,

[redhardsupra]

dump the data into excel, make a pivot table with std deviation in it, based on that filter out all numbers beyond 2sigma

[Tordne]

dump the data into excel, make a pivot table with std deviation in it, based on that filter out all numbers beyond 2sigma

Holy shit. I'll have to send an email to Bill Gates first to decipher what the heck that means .

[ringram]

I think he is saying to discard all results outside of one standard deviation. Which is the middle 68% of results. Discard the highs and lows.

Did you try reducing cracker over say 30kmph?

[TAQuickness]

I vote for give it up, it's decel. The PCM is cutting way back on the fueling during decel, so that area will be prone to transients.

[Tordne]

I think he is saying to discard all results outside of one standard deviation. Which is the middle 68% of results. Discard the highs and lows.

Did you try reducing cracker over say 30kmph?

I made a map that plotted the total airflow added from Throttle Cracker & Follower and it was quite variable across all the hit cells. Therefore I don't think it is the major contributor on the basis that the variance is not that large in all areas.

It may be that you just have to "give up", but there are plenty of guys on here saying that their BENs are all at 1.00 +- 0.01 and I just don't see that this can be possible unless they are either 1) learning to ignore this particular symptom which appears to be unresolvable or 2) there is a cause which I'm not yet aware of

Having an BEN of 1.00 but a variance of 30% doesn't seem right, or is it just me?

[Tordne]

I vote for give it up, it's decel. The PCM is cutting way back on the fueling during decel, so that area will be prone to transients.

I know. Just interested in others opinions . Like I say in the above post... Having a BEN of 1.00 but a variance of 30% just doesn't seem right.

[ringram]

Get a good sized cam in there, so you dont go under 50kpa map that will fix it!

[SSpdDmon]

Filter out FTC#'s greater than 19. You have to really focus on hitting the low kPa cells while not letting the PCM out of FTC 0 or 1. Usually, 2-3% of pedal will work in doing that (I say pedal because some have ETC). You'll also need quite a few hits in these cells if you're using the LTFTs/STFTs because O2 switching tends to be proportional to exhaust flow (unless you're in open-loop with a WB of course). Give it a try and let me know how it goes.



Joe's right...it's probably best to ignore this since it's when you're off the gas. But if your anal like me, give it a try.

[joecar]

I vote to ignore it.