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Tuning to remove the spongy throttle response on fast shifts

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#1
I took my almost bone-stock Fiesta ST to the track this weekend with the Nor-Cal Shelby Club. Drag raced and open-tracked it, generally kicking the crap out of my daily driver, lol.

Car performed great overall, passing lots of track prepped Mustangs as driven by a friend of mine, who is quite the experienced racer.

One thing we both complain about, however, is that the car falls on its face when shifted fast at high rpm. It feels much different from hitting the upper rev limiter. The power just goes numb for a moment instead of responding to the throttle input. It's like the ECU is softening the power to save the drivetrain from idiots?

I would like to put an AP3 on the car to add some crispness to the response. What do you recommend?
 


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#4
I will second a recommendation for buying from a vendor who will give you a custom tune - MAPerf, DHM, Mountune, etc. Because the free COBB base tunes don't eliminate that slight between-gear hesitation
 


OP
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Thread Starter #5
I am used to driving older, less nanny-controlled cars with mechanical throttles. I am new to the drive-by-wire stuff. Thanks folks! Tuner is my next mod!
 


pelotonracer2

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#6
I was just complaining about this to Adam [MENTION=3178]maperformance[/MENTION] today. I used to complain about this issue in my Subaru WRX. It would just fall on it's face when you'd shift hard/fast. Even my stage 3 car does it. Maybe it's just because it's so hot outside but I don't remember this being an issue on my OTS stage 1 tune.
 


maperformance

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#7
I was just complaining about this to Adam [MENTION=3178]maperformance[/MENTION] today. I used to complain about this issue in my Subaru WRX. It would just fall on it's face when you'd shift hard/fast. Even my stage 3 car does it. Maybe it's just because it's so hot outside but I don't remember this being an issue on my OTS stage 1 tune.
Check out my last email to you, should clarify how to avoid the "bonk" as you explained it lol.
 


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Thread Starter #11
I reached out to Randy Robles directly and he stated that his Mountune programming eliminates this hesitation. I subsequently purchased the AP3 and drop-in filter kit from Mountune. I'm really excited to see what all you folks have been raving about with how great the AP3's improve the car.[driving]
 


pelotonracer2

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#12
Mind sharing with the rest of us? Especially if its controllable.
I'm sure Adam won't mind me sharing...

"The "bonk" you feel is probably your throttle closing because you are neither off the throttle or on the throttle. There is a threshold set for flat foot shifting and if you play with it you are going to make the car close the throttle on you and cause the bog. Either come off the throttle, or keep in the throttle with a flat foot shift :-D"
 


pelotonracer2

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#13
I reached out to Randy Robles directly and he stated that his Mountune programming eliminates this hesitation. I subsequently purchased the AP3 and drop-in filter kit from Mountune. I'm really excited to see what all you folks have been raving about with how great the AP3's improve the car.[driving]
There's a reason the AP V3 is all the rage! [twothumb]
 


BoostBumps

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#14
.

Sounds like Ford's "shift assist" (i.e. "rev hang") feature simply needs to be disabled which I believe Cobb does in all their OTS maps...

"From the factory this feature can cause issues with shifting as it can cause the engine speed to remain static between shifts."

[HR][/HR]
Other approaches in improving throttle response can be achieved by modifying the "throttle requested torque per gear" ramp rates....

"These tables allow for the manipulation of the relationship between requested engine torque based upon the current Accelerator Pedal Position dictated by the driver's foot in gears 1-6"

Addtionally the "throttle translation" table can be modified as well...

"This table allows manipulation of the translation between actual driver demanded accelerator pedal position and reported accelerator pedal position"
 


maperformance

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#15
.

Sounds like Ford's "shift assist" (i.e. "rev hang") feature simply needs to be disabled which I believe Cobb does in all their OTS maps...

"From the factory this feature can cause issues with shifting as it can cause the engine speed to remain static between shifts."

[HR][/HR]
Other approaches in improving throttle response can be achieved by modifying the "throttle requested torque per gear" ramp rates....

"These tables allow for the manipulation of the relationship between requested engine torque based upon the current Accelerator Pedal Position dictated by the driver's foot in gears 1-6"

Addtionally the "throttle translation" table can be modified as well...

"This table allows manipulation of the translation between actual driver demanded accelerator pedal position and reported accelerator pedal position"
Correct, my information posted above was only for his situation. If you aren't tuned, the rev hang will cause some of the "lagging" in between throttle. This is still a little present on the AP3 but can be shut off. Whoever has an AP3 should have their tuner setup Flat Foot Shifting properly, I do it for all my customers and it works swimmingly.
 


CanadianGuy

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#16
[MENTION=241]pelotonracer2[/MENTION] [MENTION=3178]maperformance[/MENTION] [MENTION=1333]BoostBumps[/MENTION] Thanks definitively helps the community. My self is due to the Shift assist as I have not received my MP215 setup yet(don't ask not happy with the dealer I bought the car, good thing they are not the ones I deal with for service), but I do notice at times the lag is a good 2-3 count.

One question Boostbumps do you know if the MTUNE map is like the COBB for that feature?
 


BoostBumps

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#17
[MENTION=241]One question Boostbumps do you know if the MTUNE map is like the COBB for that feature?
Assuming your going though Randy with MTune I would think he should have full access to all tables and maps to make necessary changes...
 


CanadianGuy

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Assuming your going though Randy with MTune I would think he should have full access to all tables and maps to make necessary changes...
Assumption wrong(sorta). I was talking about the basic MP215 Ford authorized map not a custom. But ya I guess I will get a hold of him once I have it to discuss.
 


BoostBumps

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Assumption wrong(sorta). I was talking about the basic MP215 Ford authorized map not a custom. But ya I guess I will get a hold of him once I have it to discuss.
LOL...OIC..your doing the OTS MP215-tune thing...thats a question for Randy then!
 


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