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Author Topic: No KFPED debates?  (Read 10033 times)
KBUR
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« on: March 04, 2013, 01:13:42 PM »

Hi!

Well - power is nice, but much of the driveability comes from the proper pedal map (KFPED).
Can't seem to find much discussion on that around here.
You all happy with whatever you've got?

For anything but a drag racer, probably the most important map in the car.

I dislike most of the production maps. In my mind, the pedal angle is an expression of need for power, nothing else. 10% larger pedal (absolute) should give you 10% larger power (relative).  Moreover, the power may increase a little with engine speed (say 10% per 1000 RPM) which gives the car a lighter feel. However, you do not get exactly the same power in the next gear when you shift.

How do you reason when you make your pedal maps?

Cheers

/K
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Gonzo
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« Reply #1 on: March 04, 2013, 01:33:48 PM »

I guess you are forgetting about KFMIRL...
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masterj
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« Reply #2 on: March 05, 2013, 05:39:50 AM »

Well, What I'm normally doing is semi linear response in kfped. First I find out idle engine load and that becomes my kfped = 1. Everything else up to kfped = 100 is linearization of this number and 100.

For example at idle I have ~20 load then kfped=1 (lowest number in axis) I set to 20.

KFPED:
0 - 0
1 - 20
20 ..
30 ..
40 ..
50 ..
60 ..
70 ..
80 ..
90 ..
100 - 100

I'm doing this because I want to have full pedal range. And lower than idle load you will not feel, that's why I'm doing linearization from 20 and not 0
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RaraK
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« Reply #3 on: March 05, 2013, 05:51:27 AM »

I do the same thing on BT tunes, helps a lot when using MBC and a quick spooling turbo to control the spool better by pedal, its more logical for drivers i suppose.  I know i had no issues because i adapt to it, but if you put somebody in the car who is not familiar, sit back and laugh!
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jibberjive
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« Reply #4 on: March 05, 2013, 06:27:59 AM »

I've tried both a linear and stock-type, not sure which I like better.

I know Julex prefer's to linearize his KFPED.
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KBUR
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« Reply #5 on: March 05, 2013, 10:23:19 AM »

Interesting.

I defined my desired pedal - power relation as described above, and then calculated backwards to required torque for that power (i. e. pedal), as a function of engine speed. That gives you a nice 3-d map of load (PED is NOT rl but % of max torque if I remember correctly - Ped = 0 is idle, 1 is already positive torque).

Check if you were really correct with your PED = rl in the map assumption, I'd have to do some thinking then.

Currently I have other trouble with my bricked ECU (back on the bench), but when that's over I will get back and post my maps and reasoning for further discussion.

Cheers,

/K
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phila_dot
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« Reply #6 on: March 05, 2013, 10:27:09 AM »

Torque request not load.

KFMIRL converts the torque request to load request.
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prj
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« Reply #7 on: March 05, 2013, 02:57:46 PM »

The stock mapping usually tries to emulate a drive-by-cable throttle.

On a drive-by-cable throttle when you push the throttle a little bit at lower engine speeds, the engine torque increases quite rapidly, because the throttle limits the engine relatively little compared to higher revs.
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sweegie
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« Reply #8 on: March 05, 2013, 04:04:29 PM »

Yes, and this is why I always favor numbing low end throttle response in my tuned maps. Makes driving around the city a bit more manageable IMO.
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MoparFreak69
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« Reply #9 on: January 18, 2015, 09:24:17 PM »

Well, What I'm normally doing is semi linear response in kfped. First I find out idle engine load and that becomes my kfped = 1. Everything else up to kfped = 100 is linearization of this number and 100.

For example at idle I have ~20 load then kfped=1 (lowest number in axis) I set to 20.

KFPED:
0 - 0
1 - 20
20 ..
30 ..
40 ..
50 ..
60 ..
70 ..
80 ..
90 ..
100 - 100

I'm doing this because I want to have full pedal range. And lower than idle load you will not feel, that's why I'm doing linearization from 20 and not 0

Old thread bump I know but,
I was having massive boost control problems and around town drivability sucked. I did some searching and decided to look at my pedal map. Holy cow I couldn't believe what I saw, and instantly knew why I was having all this trouble. I was to the point of converting to DBC. Anyway, set my map up like you described here and VIOLA, nice throttle control and boost no longer rising then being released the. Repeating at slow speeds. Thanks for the guidance!
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