APS Adjustment ("Best Throttle Mod Ever")
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APS Adjustment ("Best Throttle Mod Ever")

This is a discussion on APS Adjustment ("Best Throttle Mod Ever") within the Kia Forte Turbo Performance forums, part of the Kia Forte Turbo Garage category; Has anyone on here tried adjusting their accelerator position sensor (APS)? This is the sensor that is on your gas pedal. I've been going back ...

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Thread: APS Adjustment ("Best Throttle Mod Ever")

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    Senior Member lephoenix's Avatar
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    APS Adjustment ("Best Throttle Mod Ever")

    Has anyone on here tried adjusting their accelerator position sensor (APS)? This is the sensor that is on your gas pedal.

    I've been going back and forth on getting a pedal/throttle box (sprintbooster, xlr, etc) for a few months. Essentially they would give me an adjustable "sport" button that nearly all "sport"/"sporty"/"aspirations of maybe being sporty one day" cars have. Our Eco button already does this, just in reverse. To test what I mean turn on ECO mode and drive for a bit doing some quick partial throttle acceleration. It'll feel like your car is a lot slower and less responsive. Then turn ECO mode off and try it again. It doesn't make the car faster. It just makes it feel sportier and faster. All you have to do is pay $300

    But in a quest to improve my throttle/accelerator related driving experience I stumbled upon this idea. It was/is pretty popular with the 1st gen forte group but has also been done with success on 2nd gens as well as elantras and maybe other hyundai/kias.

    Our pedal set up and APS are similar or the same to other 2nd gens and elantras.


    So the gist of the mod is this, the APS is adjustable. The screws that hold it together are either enlarged or slotted. By loosening a set screw which holds the adjustment in place and rotating the sensor you can adjust the gas pedal's resting position. What this means is that you can eliminate the initial 1/4-3/4" of travel in the pedal that doesn't do anything. This has been reported to result in a more responsive feeling pedal.

    To do a little test, I turned my car ON (not started) with the Torque app fired up and monitored throttle position. Default it was about 12.9% (or angle... seems to be some debate on this since I don't think you ever see a number higher than like the high 80s but someone please correct me here if I'm wrong). Something a little odd to me was that the number wasn't as static as I had assumed. It would jump up to the low 13s and then back down.
    Anyway, you can actually watch the throttle position change when you press the pedal (hmmm, makes me wonder if the plate in the throttle body is actually rotating...). So, I tried to check and see if there was any dead space in my throttle and turns out there was. A lot more than I had thought there would be.

    Another thing I noticed was that after the initial take-up before I was seeing my percent/angle increase, the response seemed to be non-linear. By that I mean that I pushed in the pedal a certain amount, lets say 10% for the sake of the example, and the throttle position only registered a 5% change. But going from 10% to 15% I noticed a 5% change. I wasn't surprised by this. It makes sense. Just verifies a suspicion.

    I plan to do a little more testing with this. Maybe see if I can measure pedal travel in relation to commanded throttle position. Might even try it with ECO mode on too.

    If all goes well with the testing I'll probably take out the sensor and see if I can adjust it a little bit.




    https://www.hyundai-forums.com/threa...-pedal.170185/

    https://www.forteforums.com/threads/...mod-ever.1342/

    https://www.forteforums.com/threads/...ttle-mod.3163/



    Notes:
    1. I don't think this is something that will result in a quicker 0-60 or anything. Just a sportier feel.
    2. An over adjustment can raise idle and throw a CEL. Not a big deal, completely reversible, just noteworthy.
    3. This was originally reported to increase ignition timing. I kind of doubt this. But I'll see if I can test that too.
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    PLP
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    Quite common approach on getting more response on FI engines.
    Even the OEM tune does similar thing.
    Basically you try to spool turbo sooner to get "better resposne". So the moment you push the pedal it will spike TPS and then drop to the position your foot it at. By doing that turbine will get a kick form a momentary extra gases to spool up a bit faster.
    If I am not mistaken, aftermarket tune takes it a bit further.

    Quote Originally Posted by lephoenix View Post
    Our Eco button already does this, just in reverse. To test what I mean turn on ECO mode and drive for a bit doing some quick partial throttle acceleration. It'll feel like your car is a lot slower and less responsive. Then turn ECO mode off and try it again. It doesn't make the car faster. It just makes it feel sportier and faster. All you have to do is pay $300
    Our ECO does not really play that much with the engine, as it does with the tranny.
    The ECO system gets the torque converter to lock up much sooner and holds it tighter than non-ECO. Test it yourself.
    And yes, just because of that the car may feel sluggish, picture this: say at 30 mph you are in 4th gear with rpm at 2000 if the TC is locked. You push the pedal a bit further and it responds like MT - adds some boost, but it happens slowly as RPM is still low.
    In non-ECO, rpm will be at 2600 when you push the gas due to TC being unlocked. More rpm, more response. I'd call it fake response as it would be exactly the same if you dropped to 3rd gear with TC locked in ECO (at 30 mph 3rd is at 2600 rpm).

    ECO works almost like MT, of course pushing pedal further will unlock TC and you get response as non-ECO.
    Also, ECO upshifts a bit sooner than non-ECO.

    The above is for TC AT only. It does not apply to DCT.
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    Senior Member lephoenix's Avatar
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    Which part is "quite the common approach"? Just the whole adjusting the APS thing?

    Sorry, I'm not understanding what you're saying exactly.

    Interesting, I didn't know that about ECO mode. Could be what I am feeling. I had read that it cut throttle response (someone said 25% I think which seems to be an absurd amount) but I have no idea what their source was. I had assumed that it would be in the 5-10% range and probably vary but pedal position.

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    ECO slows down the response from the throttle input, but will not limit possibility (power wise), per se. Meaning, you suddenly push the pedal, it will react a bit slower (but again - that is two fold action - main thing is the TC lock and another is less spike).

    Quote Originally Posted by lephoenix View Post
    Which part is "quite the common approach"? Just the whole adjusting the APS thing?

    Sorry, I'm not understanding what you're saying exactly.
    I was referring to the sportier response.
    Just like you said - they do not produce more power, it is more how the power is delivered.
    Madness offers "go-pedal" for FIAT. I call it BS as it only changes throttle response.

    The other part of my post - when you are watching throttle response, that is pedal vs throttle plate (APS vs TPS).
    Scenario: you are at 12 APS, TPS say is at 12 as well (numbers are in %), this is steady state. Now, you slowly increase APS to 30, TPS will follow with the initial quick increase (say APS is 14, TPS will be 20 for a moment) and then will follow.
    Again, 12/12, you suddenly increase to 40, TPS will jump to 60 to then tapper off to 40.
    WOT is WOT... no going over 100% which most of the time is about 90% anyway.

    So, the sportier response is the TPS jump. This is responsible for the engine reaction. It quickly adds more fuel than needed for this fraction of a second and that makes it sudden jolt what translates into feeling of response/power.

    I hope it makes more sense now.


    Oh, and ECO - well, ECO will limit the second scenario, that is from 12 to 40 input will result in 50 TPS, not 60.



    One disclaimer - those numbers are not real, meaning I did not record them right now. They are only to represent the concept.
    The go-pedal, since I mentioned it, would only translate 12-40 APS with TPS 12-60 as 12-90 TPS with a shorter response time.

    Other things for sport button could include more fuel being dumped and not having injectors shut off - means, fuel is still being pumped even you are off the throttle only to keep the turbo "ready"...
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    Ah. OK. I see what you're saying and agree.

    The only thing is for products like the "Go Pedal" is I wouldn't call them BS unless they make claims that it will increase power or decrease times. Like I mentioned, plenty of manufactures include a sport button and often that button's only feature is ramping up throttle response. Why? Because it feels more lively and responsive. I'm cool with that.

    Also I wasn't implying that ECO limited power. Maybe you hadn't thought I was saying that. But I agree. No power difference. Just a change to driving dynamics to promote fuel efficiency.

    Makes sense about the TPS spiking after quick APS responses. Hmmm. Very interesting actually. Thats a cool idea.

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    So, whats your thoughts on APS adjustments?

    I'm actually not completely sold. I really don't mind the 3/4" of take-up before it registers anything. In a manual I might care more. But, responses from people who did this on NA fortes are pretty positive.

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    Very nice. No cost mod that helps. Thanks for the info.
    I never seen anything on this topic.
    Thanks again
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    Actually, I personally liked the pedal a lot.
    All cars I had previously, except two that I did not own, just drove them for a while, had very touchy gas pedals.

    I can see why hey say the car is said to be more responsive (that is exactly what go-pedal does and sport button would do).
    The same adjustment was suggested in my old 2007 KIA Rondo and 2009 Hyundai Elantra. I never did them, though.

    Anyway, going back to Forte 1.6T.
    I will say it again - I love the long travel linear pedal response. The initial dead space - I do not remember if it was really dead when engine was running. Also, if I recall, when engine was off, TPS was about 12-13, but - yet my memory may be corrupted now - when engine was running, it would drop to less than 10%.

    By "killing" the dead zone, if that exists, you will simply achieve that at what currently is 30% travel APS is at 25%, TPS is at 25%, it will become 40% with TPS at 40 as well. It will be more touchy and because of that it will seem more reposnsive.
    That is why I call gopedal BS, because from using torque app I noticed that previously I would reach WOT at about 75 travel, but with GP it was reachable at about 50%. Car become more touchy, that's it.

    If it produced more torque (torque is LIMITED in Fiat 500X in certain gears), or if it unlocked - then yes, I would be satisfied. Yet, if I am asked to pay 250 USD for a tool that simply does exactly same thing as me pushing the pedal a bit further - I will pass.


    So the mod will do basically same thing here - it will just shift the input and now the pedal will be same, but with less offset. You will get the same correlation, yet it will just reach higher rpm at lower pedal input.
    That seems more responsive.


    Oh, as for ECO.
    It does limit power in lower bands in terms of slightly limiting the throttle. It is not killing the power, it is just electronically shifting the input. Think of it like stretching the lower pedal range over larger distance. However, when going close to WOT, it returns to normal and gives you all power.
    I did a few 0-60-ish runs with an app and the best times I was actually getting with ECO on in automatic mode.
    Definitely worst times I had in non-ECO manual shifts. I guess the TC lockup adds something to it.
    Keep in mind that TC "eats" up power. I do not have anything to support it, but spinning plates I'd say drain about 20% of power, until the TC locks up.
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    2015 AUDI Q5 (for wife...)
    2016 FIAT 500X Trekking Plus AWD with Roof and Beats (for wife)

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    Senior Member lephoenix's Avatar
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    Quote Originally Posted by PLP View Post
    I did a few 0-60-ish runs with an app and the best times I was actually getting with ECO on in automatic mode.
    I was actually thinking about this last night. With FWD traction is pretty much always an issue. By limiting initial throttle input the wheels may not spin quite as much. May not be a factor on your runs but it was something I was curious about.

    If I cared about it a little more I would head to the track and do some tests but... I don't care that much. lol
    Although my daughter does like cars so maybe I'll convince the wife to have a family night at the drag strip.

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    PLP
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    The tires were quite warm and slip was minimal. I'd say it was much more about the shift to the 2nd gear.
    All runs were with boost build up from dead stop.

    First I ran no-ECO 4 times (2 one way, 2 back) and then ECO on. Final was MT shifting, but those were rough due to shift 1-2. Either I was a bit too early or too late. You can definitely feel that - as I said in the beginning.
    Drives:
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    2014 FIAT 500e (my first EV - awesome toy!!)
    2015 AUDI Q5 (for wife...)
    2016 FIAT 500X Trekking Plus AWD with Roof and Beats (for wife)

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