Throttle response improvement : Steeda throttle body spacer or BBK Throttle body ?

[Bluemustang]

Great information @jbird60 - as my grandpa once said, "You learn something new everyday". What I hear you saying is that this idea of throttle angle commanded vs. throttle angle actual isn't a thing. The ECU interprets the throttle angle actual to determine a final torque delivered by the engine, in combination with many other factors.

I can actually understand the appeal of devices like these. But I still feel it makes situations worse by making throttle modulation, or in the case more accurately to say torque modulation less and less. I am betting my tune does something similar by modifying the driver demanded torque model some to increase responsiveness, but it also does a lot of other things such as actually increasing power and torque the engine can deliver and has the ability to modify parameters of the transmission settings which also plays into the actual torque going to the wheels.

I still don't know if this driver demanded torque is the same thing as this "torque limiting" I've been hearing about. Would still love to know more but great information.

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[5LITERV8]

Race Tune = Best

 

[NoVaGT]

Just do a good tune and CAI, and be done with it.

Everything else is just smoke and mirrors.

 

[NoVaGT]

Race Tune = Best

I need to fix this for you.

In the voice of a Russian KGB agent; "Race tune is best tune."

 

[Bluemustang]

Ugh. IMO should never put 87 octane. You're down peak hp, but mostly midrange torque suffers a lot. 93 octane, 91 at minimum for a $30-$40k sports car. I think I used 87 the first month I owned the car LOL. When I didn't know any better.

If you need an 87 octane tune you should just give up LOL.

 

[jbird60]

Ok, time for clarifications and corrections.

If that device plugs directly between the pedal and the PCM, then it cannot directly change shift points or shift quality. But that's not to say you won't feel a difference in how an A6 or A10 changes gears. The transmission calibration relies on a large number of inputs, but some of the big ones are engine speed and torque demand (for simplicity's sake, let's say this is just the torque demand from your right foot). As you demand more and more torque, the PCM alters the transmission controls to be more "aggressive". So with a pedal modification device, you're simply "spoofing" the transmission control algorithms by telling it you want gobs of torque with very little pedal travel. Basically what I'm getting at is you'd feel the exact same shift quality and shift points if you just pushed the pedal down farther without a modification device.

As for downshifts, since most occur in off-pedal conditions, any noticed "improvement" is likely a placebo effect from the perceived upshift quality. If you're still on the pedal and request a downshift with a paddle, then bear in mind you're still demanding gobs of torque with little pedal input, so then the same principle mentioned above would apply.

While possible, this is largely irrelevant. Mass air flow vs. throttle opening, especially with butterfly valves, tends to be non-linear, and more importantly, engine torque is a function of air mass and fuel mass. What's more relevant is the PCM's requested torque from the engine as a function of the pedal input (as this is how the command structure is set up; the throttle angle is just one piece of the puzzle). Bear in mind that a change in your pedal input will change fueling, VCT position, CMCV position, etc... all of which influence torque. And torque is the only thing that matters

Edit: one note to add to my point above - the race car I used to work on achieved maximum mass air flow and maximum torque at ~90% throttle angle. Again, more reason why throttle angle is not relevant unless other factors are considered.

What I hear you saying is that this idea of throttle angle commanded vs. throttle angle actual isn't a thing. The ECU interprets the throttle angle actual to determine a final torque delivered by the engine, in combination with many other factors.

Close! I'm gonna get into semantics again because I'm neurotic It's "pedal angle vs. throttle angle" that's not really a thing. But yes, the ECU will interpret the pedal angle along with other modifying factors to determine the final output torque demanded from the engine. Then, any number of items will be modulated to achieve that torque.

 

[Bluemustang]

Maybe what I should've said (and what I meant) was pedal position. I'm not sure I get where the throttle angle actual comes in. Maybe that's the just final value arrived at by the ECU based on the calibration. For instance, when I am WOT I see 85.13 throttle angle actual.

 

[BmacIL]

Alternative facts. Enjoy them.

 

[Bluemustang]

It's not really a piece of the puzzle as much as it is an unintended effect. What he's telling you is that the "throttle enhancement" device isn't doing anything by itself to the transmission behavior.. The stock tune will do the same thing. You've just commanded more torque. The transmission will shift differently because you've commanded more torque. If you push the pedal down more in the stock tune it does the same thing. It just interprets torque demand. The term throttle response isn't really a thing. It's just commanded torque.

The throttle enhancement device is something you don't need. A tune does the same thing and also increases actual power and can modify transmission settings in addition to the torque model.

Where I think the term throttle response comes in - as @jbird60 said, it's about the mass airflow and injecting the fuel required for the engine to increase torque. The feeling of the car taking off as you put your foot down on the accelerator. That takes time for the air to accumulate and the fuel being injected. You're not increasing the speed of the signal from the PCM to the throttle body, so anything else related to that is incorrect or irrelevant. Real modifications to the intake, fuel delivery or the PCM calibration can effect those things.

A CAI + a tune probably helps this feeling because you're able to bring more air in faster and can improve the calibration of the engine.

Furthermore, if the torque model is being changed, I would personally rather have that done in a tune where other parameters of the engine/transmission can be optimized for these changes.

 

[Bluemustang]

Well I can't argue with you there because opinions are always subjective. My opinion differs from yours but that's all good. To each his own and more power to you, literally lol.

I do think that some of this info from jbird60 should be a sticky. A lot of people, myself included, did not know that it is all torque model based. This knowledge might disqualify a lot of the misinformation about the throttle response in these cars and how it relates to an old cable throttle. I for one find it extremely interesting. It might also help those who are trying to decide on which tuner to go with. I presume different tuners take different approaches as far as changes made to the driver demand torque tables.

 

[Livernois Motorsports]

Hey guys just wanted to agree with you guys on the throttle body spacer. You will see no gains from this and it will be a long time until the TB is your restricting point. Now as for throttle response a custom tune can also increase throttle response. We can make your normal driving mode have the same throttle response as your sport mode. Also on your vehicle we offer a flex fuel tune and after months of research and development we now have a e85 tune on the 18 10 speed transmissions. Soon we will have a flex fuel tune for that also but we do have e85 capable now. If you want to datalog this will also have the capability to do so. 620$ to your door suction cup and shipping to lower 48 states. Feel free to call me at 313-561-5500 ext 126 my name is Jake.

 

[Nagare]

Now as for throttle response a custom tune can also increase throttle response. We can make your normal driving mode have the same throttle response as your sport mode.

Which brings up another question, how do the Normal, Sport+, and Track modes affect all of this? I haven't looked it up yet so I'm sure some of the answers are out there. Do tuners need to adjust each of these when tuning or do they apply additional modification on top of what the tuner would do?

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