NefMoto

Technical => Tuning => Topic started by: kenmac on July 09, 2012, 08:43:26 PM



Title: Scaling/Interpolating KFZW?
Post by: kenmac on July 09, 2012, 08:43:26 PM
One topic that has always stumped me was how to go about producing a timing map after increasing requested load beyond stock values.  For example, if you've increased KFMIRL, LDRXN, KFMIOP, etc, you likely have KFZW(2) rl axis values that fall short of your highest LDRXN value.  So you can increase your load axis on KFZW, but the actual timing angle is pretty looney for that specific load now.  What have people done in this situation?  Retard the timing in the higher scaled load columns?  By how much? 

I know the true answer is to log, log, log, but realistically, how do you know the optimal firing angle for every load and every rpm by just logging without pushing the motor until it knocks?


Title: Re: Scaling/Interpolating KFZW?
Post by: nyet on July 09, 2012, 10:32:37 PM
honestly, you really only care about the load/rpm line that WOT follows.


Title: Re: Scaling/Interpolating KFZW?
Post by: prj on July 10, 2012, 02:31:40 AM
honestly, you really only care about the load/rpm line that WOT follows.

No, this is bad tuning.


Title: Re: Scaling/Interpolating KFZW?
Post by: azaiats on July 10, 2012, 03:57:28 AM
I guess nyet said that the first thing to do is caring about WOT, and then think about the other ranges. But only IF you really need it, and IF you have the tools or access to any kind of dyno to do the job... it's near impossible to care about everything on open road tuning like almost of us do.


Title: Re: Scaling/Interpolating KFZW?
Post by: kenmac on July 10, 2012, 06:56:29 AM
Yeah, I've modified the line that WOT follows... basically a warped bowl shape within the map.  I worry about all the other values at partial loads though.  I guess worst case if it was too advanced I'd hear/log knock.

The reason I ask is: I recently snapped a rod at low rpm, just cruising around town, at around 3000 rpm and very little load request (maybe 5-7 PSI tops).  I haven't yet determined what caused this (maybe a K04 torque spike).  Part of me wants to blame my tuning, but part of me realizes that shit just happens.  Basically, I was running KFZW(2)(OP) from the TT225 BAM. I am actually running an AWP 1.8T.  I realize this engine has a slightly different crank, but I don't think it'd really affect timing that much that I'd be snapping rods before knock recognition kicked in.  The only CFs I ever logged in this configuration were at WOT, and they were -3 at most.   I'm probably worrying too much... and my new fully built bottom end will be fine down the road.


Title: Re: Scaling/Interpolating KFZW?
Post by: nyet on July 10, 2012, 08:31:32 AM
No, this is bad tuning.

Many areas are simply unreachable.

If you're just talking about one load column, and interpolating the rest from the original map, there are at most 4 or 5 cells that will ever be used.


Title: Re: Scaling/Interpolating KFZW?
Post by: Snow Trooper on July 10, 2012, 10:20:27 AM
No, this is bad tuning.

Give advice then, to be honest I notice a pattern with your posts... Ever heard of Eric fletcher?  We don't want to just be told we are wrong like you like to do, if you going to take 30 seconds to say that take an additional 30 to drop some knowledge since you continually imply you have a lot of it.


Title: Re: Scaling/Interpolating KFZW?
Post by: s5fourdoor on July 10, 2012, 10:25:59 AM
ohh lord, careful don't feed the trolls!  hehe   ;D


Title: Re: Scaling/Interpolating KFZW?
Post by: nokiafix on July 10, 2012, 10:29:29 AM
No, this is bad tuning.

There is no right or wrong way to tune, just a method which is safe, works well and which makes the driver grin ear to ear.

I always scale last load/rpm site then log during steady state testing.


Title: Re: Scaling/Interpolating KFZW?
Post by: nyet on July 10, 2012, 10:31:30 AM
Lets put it this way:

Please tell me how a cell at 1000rpm and 210 load should look like.


Title: Re: Scaling/Interpolating KFZW?
Post by: kenmac on July 10, 2012, 10:48:11 AM
Yes, please, for the OP! LOL


Title: Re: Scaling/Interpolating KFZW?
Post by: nyet on July 10, 2012, 10:50:10 AM
I'd love to see a log with a SINGLE point near 1000rpm and 210 load.


Title: Re: Scaling/Interpolating KFZW?
Post by: Snow Trooper on July 10, 2012, 11:16:04 AM
LOL nye


Title: Re: Scaling/Interpolating KFZW?
Post by: prj on July 10, 2012, 08:47:36 PM
What I meant with my post is, that WOT is not the only important thing.
If you rescale the map, re-scale the axes so, that they give a good distribution according to engine characteristics.
And in that case you will not only need to tune WOT, but also lower load sites.

Now where did I leave the flame suit.


Title: Re: Scaling/Interpolating KFZW?
Post by: nyet on July 10, 2012, 09:35:26 PM
I agree, but all of that can be done by re-interpolating intervening points.

The only data that is missing is whatever load columns you add... and those columns generally are only used during WOT, since they are the maximal load cells...


Title: Re: Scaling/Interpolating KFZW?
Post by: Vitruvian Engineering on July 11, 2012, 04:55:37 PM
...


Title: Re: Scaling/Interpolating KFZW?
Post by: jibberjive on July 11, 2012, 06:27:14 PM
Give advice then, to be honest I notice a pattern with your posts... Ever heard of Eric fletcher?
Oh snaapp.


Title: Re: Scaling/Interpolating KFZW?
Post by: kenmac on July 12, 2012, 10:37:04 AM
I agree, but all of that can be done by re-interpolating intervening points.

The only data that is missing is whatever load columns you add... and those columns generally are only used during WOT, since they are the maximal load cells...

This was pretty much the point of my post.  Can anyone give a working example on how to interpolate this information?  Maybe I'm just not seeing it.


Title: Re: Scaling/Interpolating KFZW?
Post by: nyet on July 12, 2012, 10:40:29 AM
I haven't had time to do it, but i've been meaning to write a program to do it.

Excel would probably be preferable for most people, but I am not a fan of excel :)


Title: Re: Scaling/Interpolating KFZW?
Post by: rnagy86 on November 19, 2017, 08:44:52 AM
Just to revive this thread a bit, I am about to re-scale both my load and RPM axis
on KFZW/2, due to the fact that my max load is 360 and the RPM resolution is not
optimal either. Currently KFZW/2 axes cap at 6900 rpm and 200 load and I already
see in my logs that this is far from optimal depending on how boost builds in lower
gears, not to mention part throttle conditions where load is >200.

It is clear that changing the axis will need re-interpolating the affected cells, which is
fine and doable, but my main question is, how would you guys go at re-scaling the
load axis because by looking into my logs, all data columns are used depending on
idle, cruise or WOT conditions. Would you ditch low load columns or middle range?

Of course this will require dyno time, I am just curious how would you guys go at this.


Title: Re: Scaling/Interpolating KFZW?
Post by: nyet on November 19, 2017, 11:35:55 AM
Would you ditch low load columns or middle range?

Neither. I'd just shrink the existing rows to make room for new ones.


Title: Re: Scaling/Interpolating KFZW?
Post by: rnagy86 on November 19, 2017, 12:24:22 PM
Neither. I'd just shrink the existing rows to make room for new ones.

Yeah that seems like a good start. Something like this:

(https://i.imgur.com/jvylsJh.jpg)

converted to

(https://i.imgur.com/sZDrpWj.jpg)

Last three columns are the same now, waiting to be filled.