Info on sprint booster.

Ivoidwarranty

I've noticed this sprint booster come up in conversations before and I have ran across the Sprint Booster before in a number of other forums. The first I heard of them was for the Mercedes and then the Chrysler LX platform. A lot of guys love this thing but they have no idea what it does or how it does it. A lot of other guys know what it does and hate it. If you have a programmer that can adjust throttle sensitivity (among other things) you can do the same thing.

Most of these electronic throttles work off a 5 volt reading. Someone tried to argue with me the other day that it's millivolts but I think it's volts (I may be wrong, it's happened before). When the accelerator is not depressed, a 0 volt reading is sent to the computer from the sensor. When the accelerator is pushed down, a signal is sent to the computer from the accelerator sensor. This signal is maxed out at 5 volts when the accelerator pedal is completely depressed. I believe the signal is completely linear, meaning at half throttle there is 2.5v. Now, when the signal gets to the computer either magic happens or hell breaks loose. Just because you have the throttle pushed down half way doesn’t mean the throttle is open half way. The computer totally takes control and decides what to do with the throttle blades based on a number of inputs and your right foot is only one of them.

This Sprint Booster just intercepts the signal from the accelerator and “boosts” it. They call it “boost”, I call it a signal multiplier. Well, it can’t go over 5 volts but it can get you to 5 volts a lot sooner. So, whether it multiplies the original signal by 1.5 or by 2 or whatever, all it really does is take away your full length of peddle travel. Why would anyone want to do that?

Some other things of note:

My Dodge uses a redundant signal (backup) that goes from 0-2.5v and the computer compares the two inputs to make sure the sensor and signal is not messed up (safety stuff). I'm sure all makes have something similar to this.

Don’t call this sensor on the back of the peddle TPS (throttle position sensor) that’s totally something else. This is called APPS (Accelerator Pedal Position Sensor) by some manufactures including Nissan.

Another one of those inputs to the computer is how “fast” you push the accelerator down (more on that next post).

Ivoidwarranty

Here is another post I did a while ago on pushing the throttle pedal:

I got the following information from the shop manual. Just wanted to share some cool info and get your thoughts.


The accelerator pedal position sensor is installed on the upper end of the accelerator pedal assembly. The sensor detects the accelerator position and sends a signal to the ECM.
Accelerator pedal position sensor has two sensors. These sensors are a kind of potentiometers which transform the accelerator pedal position into output voltage, and emit the voltage signal to the ECM. In addition, these sensors detect the opening and closing speed of the accelerator pedal and feed the voltage signals to the ECM. The ECM judges the current opening angle of the accelerator pedal from these signals and controls the throttle control motor based on these signals.
Idle position of the accelerator pedal is determined by the ECM receiving the signal from the accelerator pedal position sensor. The ECM uses this signal for the engine operation such as fuel cut.


Does this mean that pressing the gas pedal faster yields different results than easing into the throttle fully?

m4a1mustang

A tune can tweak throttle response too.

__________________
- Steve

Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!)
LIKE us on Facebook!

ChrisSlicks

The throttle position sensor, also called accelerator pedal position sensor (yes it's the same thing) measures purely the position of the pedal. Like you stated it sends a varying voltage to the ECU, likely between 0 and 5V but the scale is irrelevant. There are 2 sensors for redundancy and safely but they are named the same thing, even though the redundant sensor may be on a different voltage scale (e.g. 0 - 2.5V).

The ECU samples the position sensor voltage somewhere between 50 and 100 times a second (depending on exact vehicle). From this it not only determines the position but can also determine aggressive movement by abrupt changes in voltage. How the car reacts to these inputs depends on the original programming of the ECU and the loaded tune. The signal is also forwarded to the TCM (Transmission Control Module) so it can decide whether your throttle input warrants a new gear selection, and holding gears.

As already stated, a tune is the best way to "remap" how your throttle input behaves.

Ivoidwarranty

I like how you worded everything. It looks like you know what you are talking about. I only have one issue with all you posted and that is calling the APPS the same thing as a TPS. On a lot of cars the TPS is mounted on or to the throttle body and tells the computer how far the throttle blade is open. This was a lot more common back when the throttle was still cable driven and the computer didn't have any other input. For example, my brothers Ram has a cable controlling the tb and a TPS while my Ram (one year newer) is drive by wire and has a APPS. I have the FSM for both and mine specifically talks about how it does not have a TPS.

I wonder if the domestics and imports differ in this???

Zsteve

Ive heard of these before too, and the question everyone always asked was how long does it take to push your gas pedal all the way down to get the 5 volts? As you said it doesnt go over 5 volts so it brings no extra power. The only advantage I can see is like a very minimal amount of time quicker to the 5 volts.

__________________
2010 LS3 C6 Silver coupe corvette

ChrisSlicks

APPS is pretty clear, the sensor is mounted to the pedal itself. However I've seen the term TPS used when the sensor is mounted on either the pedal or the throttle body, it depends on the semantics that the manufacturer uses.

The Japanese and European cars were first to move to a drive by wire system, where as the American cars held onto the mechanically operated throttle body for a long time and simply mount the sensor to the throttle body itself (retrofit rather than redesign).

Note that the Nissan sensor uses a typical voltage range of 0.4 to 4.8V. Because the actual voltages vary slightly between vehicles, they have a feature that learns the up pedal voltage for your specific car. For down pedal anything beyond 4.0V is interpreted as WOT.

Ivoidwarranty

Good info. I have not tapped into the G37 yet (no need to yet) but my truck was measured at 0.40v to 4.82v.