DBW throttle response

They go by many names, P01, P59, VPW, '0411 etc. Also covering E38 and newer here.
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yoheer
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DBW throttle response

Post by yoheer »

Does anybody has experience in tuning throttle? Make it more linear to pedal? Remove lags etc. All stock cars are lazy with dbw throttle.
Last edited by yoheer on Mon Nov 23, 2020 8:16 pm, edited 1 time in total.
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Gampy
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Re: DBC throttle response

Post by Gampy »

yoheer wrote:Does anybody has experience in tuning throttle? Make it more linear to pedal? Remove lags etc. All stock cars are lazy with dbc throttle.
DBC (Drive By Cable) is mechanical ... not easily adjustable in that sense.

Do you mean DBW (Drive By Wire) ??
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antus
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Re: DBC throttle response

Post by antus »

I think your right there. So assuming DBW, i'll mention that from the factory most cars have a delay before some kind of power enrichment system kicks in, this is so the richness isnt spiking up and wasting fuel as you foot moves slightly on the pedal over bumps when your cruising. To increase the response (and fuel consuption) there is usually a delay you can turn off to begin with. Having said that DBC has the same setting. In Australia our HSV performance tunes have these tweaks. Its a good idea for a given platform to get and compare the Commodore and the HSV tune for the same year and configuration car (yes, different diff ratio, exhaust etc, but still) and see what HSV changed. This is a good template to learn a given PCM, either DBW or DBC.
Have you read the FAQ? For lots of information and links to significant threads see here: http://pcmhacking.net/forums/viewtopic.php?f=7&t=1396
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yoheer
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Re: DBC throttle response

Post by yoheer »

I mixed up :) I mean DBW
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yoheer
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Re: DBW throttle response

Post by yoheer »

Antus, I cant find 2 good files, stock and HSV tuned. With the same OS. Can you help with it?
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antus
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Re: DBW throttle response

Post by antus »

which year or pcm type are you looking at?
Have you read the FAQ? For lots of information and links to significant threads see here: http://pcmhacking.net/forums/viewtopic.php?f=7&t=1396
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yoheer
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Re: DBW throttle response

Post by yoheer »

2004 p59
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NSFW
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Re: DBW throttle response

Post by NSFW »

I'll admit I haven't measured this in my C5, but I'm pretty sure the DBW throttle blade moves as fast as our feet do, and that what most people perceive as throttle lag is actually coming from other aspects of the tune. Power Enrichment, as Antus pointed out, is a likely culprit. But it could also be spark timing, VE accuracy, or even just the torque curve of the motor.

I've watched pedal position and blade position in my 2005 Subaru in a data logger (it's also DBW, with a similar servo design) and there is no perceptible lag. The throttle body motor can move at least as fast as my foot can. Maybe faster, I just don't have a way to test that theory. :)

All of that said, the P01 & P59 PCMs don't drive the throttle body directly - the TAC module does that, and unfortunately we don't have a way to tune the TAC. The PCM can take control of the throttle blade angle at idle, and in cruise control, and apparently there's a "power take-off" feature that also gives the PCM control in some situations... Both other than those scenarios, as far as I can tell, the control loop from the pedal to the throttle body is managed by the TAC, with the PCM just watching the signals for signs of trouble.

What I mean is, if you want to change the relationship between the pedal angle and the blade angle under normal driving conditions, you really want to reflash the TAC. Which we can't do yet. I bought one to play with, but it's sitting in a pile of other "someday maybe" projects so I can't promise anything. :)
Please don't PM me with technical questions - start a thread instead, and send me a link to it. That way I can answer in public, and help other people who have the same question. Thanks!
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yoheer
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Re: DBW throttle response

Post by yoheer »

Hm... there were parameters about throttle in 603 xdf. I'll take a look and post it here.
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yoheer
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Re: DBW throttle response

Post by yoheer »

ETC Max Throttle Rotation Vs. Pedal Position
ETC Max Throttle Position Vs. RPM
Electronic Throttle Control RPM Limit Vs. Gear
ETC Throttle Position Vs. Throttle Area
and some other
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