My Jeep Compass Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
57 Posts
Discussion Starter #1 (Edited)
Well I bit the bullet and purchased a pedal enhancer. I went with the Sprint Booster brand, and I am glad I did.

First of all I works fantastic! No more delay in passing, (downshifts are much more crisper), getting into traffic, or just getting off the line (out of it's own way).

Real easy to install....about 15 minutes, and looks like it belongs on a small vehicle instrument panel, being all you have is the control head and not the whole unit, like in other brands.
I just have it set at what they call "sport mode" in the number 2 out of 9 sensitivities. It also has a "race" setting, bit it makes the vehicle a little Herky Jerky for traffic situations, for my taste....but fun to play with once in a while ;)

DSCN1375.JPG DSCN1377.JPG

If you want to wake up your buggy and not want a big box hanging on your dash, this is the way to go....its awesome!!

On a side note, make sure you let them know (got mine on eBay at a discounted price) that it is for the MP Compass (SBJE 1063S), the first one they sent fit the 1st gen. The confusion starts when the listing shows 07 - 19, which we all know they are two very different different animals.
 

·
Registered
2019 compass sport 4x4 6 speed manual
Joined
·
85 Posts
How dose this device work exactly? I have a manual transmission, would this do anything for me?
 

·
Registered
Joined
·
57 Posts
Discussion Starter #3
How dose this device work exactly? I have a manual transmission, would this do anything for me?
It has a setting for a manual transmission, so I imagine it would have the same effect the automatics have by making the throttle move with the slightest of input from your foot, then be able to dial how much sensitivity you want. Let me tell you, it is nice having the same throttle response as my other cabled throttle bodies and carbs.

If you Google Sprint Booster, their web site gives a nice tutorial on the operation of the unit
 

·
Registered
2018 Jeep Compass Trailhawk
Joined
·
40 Posts
How dose this device work exactly? I have a manual transmission, would this do anything for me?
It basically exaggerates the movement of your foot to the computer. If you don't have one, you can just push down further on the accelerator. Avoid using it off road or on slippery surfaces as you wont have as much fine throttle control.
 

·
Registered
Joined
·
1,083 Posts
It basically exaggerates the movement of your foot to the computer. If you don't have one, you can just push down further on the accelerator. Avoid using it off road or on slippery surfaces as you wont have as much fine throttle control.
Ehhhhhhhhhh.......... not really accurate, fairly misleading.

So what nobody is fully pointing out is that the gas pedal in these cars is an electronic unit. It simply sends an electronic signal to the ECU and the signal describes to the ECU how far you have pushed the pedal.

These types of modules go between the pedal and the ECU and alter the signal being sent. So you push the gas pedal maybe 20% and then this unit tells the ECU you have actually pushed it 40%, or 50%, etc causing a greater reaction than you normally get with 20% pedal down.

That is an oversimplification, though. Any "good" version of these signal modifiers is actually doing trickery far faster than your foot could ever replicate. More accurately a "good" pedal signal modifier would work more like: you push the pedal 20% and the unit tells the car 80-100% for 233ish microseconds and then drops it to that 40 or 50%, that split-second spike to almost full throttle is what gets the car to react better and then backs it off in the next heartbeat to something still double your actual physical input. This is not something you can recreate with your foot, as you simply can't move humanly fast enough.

There is also no real concern of using it on slippery surfaces as you simply learn the new version of the car's throttle response and drive accordingly, plus every version of this unit I have seen allows adjustment that goes all the way back to stock throttle response so if you really were having issues you'd press a button and go back to normal, no problem. They usually have a lot of adjustment so you can have it wild, mild, and you can change it any day any time.
 

·
Registered
2018 Jeep Compass Trailhawk
Joined
·
40 Posts
My understanding is that a lot of people desire these pedal boosters because they feel a sluggish throttle response. This implies to me that the throttle response is slower that human perception/reaction times or a human would not be able to detect it in the first place. If the engine cannot respond to the speed of a human foot, it certainly wont be able to respond any faster to an electronic circuit. Now it is possible as @arudlang pointed out that the output may not be a purely linear response but instead some fancy non-linear trickery, but I doubt that these devices are that sophisticated. The device above claims it boosts the response by 3-6% for each number setting 1-9 for a total of 30-60% boost. This sounds perfectly linear.
Now I went for a drive to experiment with the throttle (what better to do on a Friday night :)) Going to full throttle for 233 milliseconds then back to 50% throttle did not seem to produce any different results than just going straight to 50% throttle. In fact I noticed that the vehicle had little reaction to full throttle until it was held there for more than about 750 milliseconds. This is not surprising as the engine is a large rotating mass that simply takes time to increase its RPM's.
 

·
Registered
Joined
·
1,083 Posts
The throttle response is artificially kept low mainly to allow poor-footed drivers to still be able to operate the car without snapping all their passenger's necks. It can react much faster its simply setup not to.

There is no way you can move your foot up and down as fast as an electronic circuit can change the signal. Everything you do that seems fast to you takes an eternity for a modern computer, it can measure the throttle position probably in the range of thousands of times per second or better and its simply impossible for us bags of meat to move that fast ( and repeatedly trying is a good way to bust your pedal, probably).

We already know from official Jeep literature that the car is tracking not just the pedal position but also how fast it is changing. This is described in the emergency braking feature notes, where they talk about how the car is set up that it can "notice" the difference of someone letting-off the gas normally vs someone who lets off the gas very quickly and when you let off the gas very quickly at speed the car "preps" for emergency braking, then if the brake pedal gets smashed a fraction of a second later it takes that as a confirmation that "yes there was a reason they suddenly let off the gas so fast" and the car accurately can predict emergency braking condition before you have even touched the brake pedal and be more ready to brake hard.

If it can do that it can also work the opposite way, and "notice" when the gas is being smashed down very rapidly vs being pressed down at a normal pace. Circling back to my earlier point, you cannot humanly push the pedal down faster than an electronic circuit can spike the signal to 100%. So it is possible for pedal signal amplifiers to do things you can't replicate. Whether the car's ECU cares is unclear, I've never seen anybody post about any of these devices and say it didn't work though.

There are other possible ways that the pedal signal amplifier could be tricking the car into being more responsive. It might, for instance, never return fully to a 0% signal when you let completely off the pedal. Instead of going to 0% it could conceivably drop down to 1-2%. Not enough to be noticeable like the car is fighting the brakes any harder than normal but it might still be significant in tricking the car to go with more gusto. Again, the car "knows" how fast you are switching from gas to brakes and vice versa, and it seems to use that information. When you are sitting at a two-way stop intersection waiting for a gap in traffic, the car definitely appears to "notice" when you finally get that gap an average driver will let off the brakes and get foot down on the gas pedal much more quickly in that scenario than they would normally (if there was no traffic), so shortening the gap of how long between letting off the brake and getting foot down on the gas seems to impact how hard the car launches from a stop (based on my personal experience) and if the pedal signal modifier is not going to full 0 then every time you let off the brake the car thinks you have magically, instantly swept your foot directly from the brake to the gas so fast that it causes it to launch more firmly.

Now the above is just an example theory but again, its not something you can really test yourself. Everyone thinks they are pretty good at modulating their throttle but in reality there is no way for you to hold the gas pedal exactly 1%, you will be at 10% or something and not steady you will be wavering 5-15% most likely even if you think you are holding very still.

Like I said before I have no idea if these commercial pedal products use any of the techniques I describe I'm just saying I can clearly see how they can do things that we physically can't, therefore I believe they can work if they are designed properly and that they truly can do something we can't recreate with our feet.
 

·
Registered
Joined
·
57 Posts
Discussion Starter #8
Well after the first week of use, this pedal enhancer is the cats a**....... meow . It works great. As far as how it works, I believe since all a throttle mimics is a potentiometer, usually 0-5 volts...maybe 12.
The actual module, which is smaller than a small pack of small cigs ( Chesterfields) and bigger than a Zippo ( sorry that is all the physical sizes I can think of, lol). Not sure if the youngsters know what those are either! Anyway.... there cannot be too much to it. I'm thinking some capacitors in a circuit of some sort, storing energy, so when you apply the voltage it gives the ECU a stronger signal to the throttle body, so it responds much faster. Like I mentioned in my earlier post, the example shown on the Sprint Booster site gives a pretty good explanation on what is going on. Making it one to one (or better) from the pedal to throttle body (not, one to...l'll get there in a sec).

You cannot replicate what it is doing with your foot, because the ECU does not keep up with the speed of your foot. And like Arudlang mentioned, going a little less than full throttle makes the 2.4 and trans respond much better. My theory is going at that percentage, it leaves the trans in first gear much longer. So the motor utilize it's whopping 180 hp power band much better. I was told (not sure it is fact) but when you go full throttle, it keeps the running gear in 4wd, and robs some of the power, or maybe hold it back, as to not damage the drive line.
Going at a slower pace,( like half throttle) it hits second gear much faster, and of course loses momentum. Driving normally, first gear is only good for about, maybe 5 feet or so of movement....if that!

The fun thing with this gadget, is I actually got some rubber off the line, (be it not much), but at about 3/4 throttle and the faster response time, she gets up and go's a whole lot nicer. Also, much needed downshifts are a LOT more responsive, especially while passing.
 

·
Registered
Joined
·
1,083 Posts
Anyway.... there cannot be too much to it.
I wouldn't count out a complicated circuit just because of its size. We have things like Apple watches that have full-color touch screens, days of battery life, and still room enough for cellular radios and run complex programs. They could fit a computer powerful enough to run this entire website in a box of matches these days.

I don't know about your brand but the ones by pedal commander and madness autoworks have bluetooth options and a huge range of tuning and tweaking for various modes so we know, for a fact, that these are very complicated devices running at least a 16 MHz type of microcontroller at the very least. I again wager that its extremely unlikely that these devices are doing something as simple as a linear ramp. Most likely spiking and then backing off in the range of a few milliseconds and possibly no full return to "zero" when foot off the pedal.

They could also be oscillating rapidly back and forth between 0 and 50% repeatedly, I mean like lightening fast 5-10 milliseconds per interval as a potential way to defeat the lag. We know sometimes it feels like when you put your foot down if you brain is going very fast that day it can feel like the car is almost "waiting" to see if you really meant to put your foot down and lets some time pass (100-300ish milliseconds?) before it takes it as a confirmation that you really do mean to move forward. If a pedal circuit were to strobe the ECU between 0 and some % really fast the computer might be tricked into reducing or eliminating the delay we normally experience when we get on the pedal.

At this point I've put forth at least 3 possible strategies an inexpensive 16 MHz microcontroller could easily employ to trick the ECU into being more responsive to input, and none of them are anything you could humanly do yourself with a slow moving meaty foot. I'm pretty confident they have to be using one or more of these strategies as a linear ramp alone simply would not be enough to get the results that are advertised and that reviewers rave about.

These theories could be easily confirmed by anyone who has both a pedal enhancer and AlfaOBD or similar data logger. All you would need to do is log the throttle signal reported at the ECU/PCM and compare the signal the car is seeing with and without the pedal enhancer hooked up. Graph it out (which AlfaOBD can do natively) and you'd easily see what the pedal enhancer is or isn't doing.

I intend to buy one of these pedal gizmos someday but I'd be perfectly happy if someone else would beat me to the experiment.
 

·
Registered
2018 Jeep Compass Trailhawk
Joined
·
40 Posts
These theories could be easily confirmed by anyone who has both a pedal enhancer and AlfaOBD or similar data logger. All you would need to do is log the throttle signal reported at the ECU/PCM and compare the signal the car is seeing with and without the pedal enhancer hooked up. Graph it out (which AlfaOBD can do natively) and you'd easily see what the pedal enhancer is or isn't doing.

I still think it is just giving the perception of better performance. It would be interesting if someone connected an oscilloscope to the output to actually see if it is doing anything clever or non-linear.
 

·
Registered
Joined
·
57 Posts
Discussion Starter #11
Well as this video is informative, but it did not record how quick the throttle body responded. Since the voltage is increased at the performance settings, obviously it should respond a bit quicker. Seems it does open the throttle a bit more also, as the setting is increased.

All I know, is the seat of the pants tests is a positive one, a purchase I do not regret.

The version (brand) I have does not have bluetooth. I figure that is one more distraction I do not need. My control head is mounted close by and very small, and easy to adjust (which is not very often). Once you pick a setting, it usually stays for the long term.
 
1 - 11 of 11 Posts
Top