Another (Long) Pedal Box Review

[dsh135]

Before I begin let me start with a public service announcement: IF YOU ARE A DRIVING ENTHUSIAST GET A PEDALBOX

Now, I know this is going to be contentious because I've read all of the posts about Pedal Box/Sprint Booster on this site as well as many on other forums over the years. Hopefully this thread doesn't get locked.

I've been thinking about getting a SB or PB for quite some time now because the promise of it sounds enticing - better throttle response - and who doesn't want that? But like many here I was skeptical because it sounds a bit too good to be true from a fairly simplistic-looking device that plugs into your throttle connector in 5 minutes. There's been many forum members who have come on here explaining at length how devices like this can't possibly do what they claim to do (ie. significantly improve throttle responsiveness) and this is what always gave me pause. Many of these arguments seem very rational, particularly this comment from one member last summer:

It [engine responsiveness] has *nothing* to do with pressing the pedal harder. It has to do with your engine, your transmission, gravity and many other things. Not just your throttle pedal. So adding snakeoil to your throttle is not going to change anything. Reducing turbo lag, improving low-end torque, improved engine timing for optimal combustion - those things actually help reduce throttle lag. And that's what actual tunes are doing. ... Whatever the PedalBox does can indeed be achieved by pressing the pedal harder. Arguing anything different only means you have no clue about the electronics involved.

When I first read that I thought "Yeah, that's right. To get an engine to rev-up faster you need to add power/torque or reduce the load through things like a lighter flywheel, lighter rims etc. Simply pushing the pedal more (or reconfiguring it to give more throttle with less pedal press) still doesn't reduce the time it takes for the revs to build."

Still, the curiosity kept eating at me due to my desire to get better throttle response and the important fact that the vast majority of those who were negative on these throttle controllers never actually used one, while almost everyone who did have one loved it. Surely not all of these SB/PB owners could be clueless dupes? So finally (taking some additional confidence in the fact that the Pedal Box is made in Germany and they don't generally build useless crap over there, especially where cars are concerned) I ponied-up the $300 and ordered the unit. It arrived from TWM Performance in Montreal the very next day (I'm near Toronto), which was impressive, especially because the shipping was free.

So here's the bottom line:

It not only requires less throttle input to get to a given RPM but the revs do indeed build faster - absolutely no queston about it. This is not only confirmed via perception at all speeds and in all gears but also by the fact that rev matching on the downshift (ie. "heel and toe") is now very do-able without having to "set-up" for it (by that I mean anticipating the lag and jumping on it early to build the revs). The improvement is not subtle, it is as obvious as the difference between a car with stock programming and one that is "chipped".

So how can this simple device increase the speed at which our engines build revs? That's tough to understand unless we go back to the debated theory that the factory actually programs the throttle to attenuate the engine's inherent ability to accelerate. Said another way, our engines are capable of revving-up much faster than they do but BMW puts a leash on them to appeal to the masses (or avoid lawsuits from the Sunday-driving masses). I should clarify that I don't pretend to know if this is fact or not, and no one here does know, but I do know 100% that the car revs-up A LOT faster with the Pedal Box. So if it's not because it overcomes factory-induced lag, then I don't know what the answer is - but that doesn't change the fact that it works.

It should also be mentioned that because the revs build so much faster the car does feel like it has a lot more power. One member posted that "it feels like the car has 100 more hp". I don't know if that's the right number but if someone drove the same car without Pedal Box and then with Pedal Box, without being told anything, they would definitely say that the Pedal Box car had a lot more power. If you think about it it is easy to understand why. Our cars have a "fat spot" in the power curve and if the engine revs build faster we get to this fat spot a lot sooner. I haven't done any measurement of any kind but I'd love see some time differences for 0-60, 50-80 etc. I don't think there'd be any difference at all at the strip because guys generally launch from high revs in the fat spot, but if they started at idle I'm sure there would be a measurable difference, as demonstrated in this Youtube vid: h ttp://www.youtube.com/watch?v=MdafHRwAZeQ.

So there you have it. A skeptic took the plunge and now I'm a convert. I couldn't go back to the stock throttle because it's incredibly boring in comparison. Definitely worth $300. Let the nay-saying begin, I'm going out to drive my car.

[RnmEvo9]

Lets see some before and after dragstrip results.

[dsh135]

I'd be interested in seeing them too, but I don't do quarter mile. And as I said,

I don't think there'd be any difference at all at the strip because guys generally launch from high revs in the fat spot

But driving isn't always about quarter mile launches. Its also about driving on deserted backroads and passing slow drivers with a lot of oncoming traffic.

[Stohlen]

Originally Posted by RnmEvo9

Lets see some before and after dragstrip results.

They would be exactly identical because this "pedal box" doesn't magically give you more throttle... All this box does is make the 50% throttle position actually 75% throttle. It just tricks the car into thinking your pressing the throttle down more than it actually is... 100% throttle is still 100%. This box just tricks the user into thinking he has more throttle response.

Also, if you so desire, you can do this with Cobb's Accessport.

[tracer bullet]

Originally Posted by Stohlen

100% throttle is still 100%.

Here's what it does, right from the manufacturer no less:



If someone thinks the car feels livelier, great, if that turns you on. Some people prefer linear throttle response so as to be able to ride an edge during an autocross, highway ramp, etc. and not have it twitch out from under them, and understand that when they want to "drive on back roads and pass slow drivers", they just have to push the pedal a little more to do so. Because in the end it's the exact same thing.

[dsh135]

Some people prefer linear throttle response so as to be able to ride an edge during an autocross, highway ramp, etc. and not have it twitch out from under them

What makes you believe that the stock throttle response curve is linear? It sure doesn't feel that way to me when I get on it and it lags before building the revs. As for not being able to "ride an edge", by that logic a Toyota Yaris might be preferable to an M3 in those situations because it has a much more docile build of power that is easier to handle. The Pedal Box doesn't make throttle response unpredictable, just sharper, and you get used to the quickened delivery after a few minutes of driving.

when they want to "drive on back roads and pass slow drivers", they just have to push the pedal a little more to do so. Because in the end it's the exact same thing.

"Just push the pedal more" is the standard comment from the very first post I've ever read on these devices and always comes from people that have never used one. I always found it interesting that no one ever seemed to say that if they actually had one, and now I know why from firsthand experience. There is no way that pushing the accelerator down faster/further gets the same response as what the Pedal Box is doing to the throttle input. The best practical measure of this I can think of is when rev-matching. Without Pedal Box, pushing down on the accelerator harder doesn't bring your revs up any faster, the only thing you can do is wait the second or so longer to get the rpm you need before disengaging the clutch. With PB you're revs are up much more quickly with just a blip. As I said in my original post, my only explanation is that the PB's signal amplification is getting around some sort of purposeful delay the factory has programmed in to keep the engine from revving to its full capability. This is in fact what the manufacturers of these devices claim and I can't see any other plausible explanation.

[Stohlen]

I'm sorry, you can believe that your car is somehow enhanced by this mod, but essentially you spent money something you could do with your right foot. There is no performance benefit from this what so ever that you couldn't do by pressing the pedal further... And while you may like it better, you didnt really help make anything perform better.

Note: These vehicles do not come with a linear throttle path, they come with a progressive throttle which increases exponentially as you push the pedal (more or less). I have changed mine to linear with my accessport and have also tried a similar throttle path than this box does, but i prefer the linear because it is the most predictable.

[loesch]

Originally Posted by Stohlen

They would be exactly identical because this "pedal box" doesn't magically give you more throttle... All this box does is make the 50% throttle position actually 75% throttle. It just tricks the car into thinking your pressing the throttle down more than it actually is... 100% throttle is still 100%. This box just tricks the user into thinking he has more throttle response.

Also, if you so desire, you can do this with Cobb's Accessport.

Or a JB4. I read to the 3rd paragraph before I got the sales pitch glaze over. No thanks. I'd rather just tune my car to do that, plus throw in an extra 8psi of boost. If anyone is considering this please do some more research first.

[dsh135]

I'm sorry, you can believe that your car is somehow enhanced by this mod, but essentially you spent money something you could do with your right foot. There is no performance benefit from this what so ever that you couldn't do by pressing the pedal further... And while you may like it better, you didnt really help make anything perform better.

Note: These vehicles do not come with a linear throttle path, they come with a progressive throttle which increases exponentially as you push the pedal (more or less). I have changed mine to linear with my accessport and have also tried a similar throttle path than this box does, but i prefer the linear because it is the most predictable.

Do you not think that having the PB installed in my car and it being completely defeatable at the push of a button that I haven't compared "pushing the pedal more" to the active PB settings? Especially when the first thing every skeptic with no direct experience says is "push the pedal more"?
I'm not sure how many more ways I can say this: RPM builds faster with the PB controller. If this were not the case then it would do bugger-all to make heel-and-toe downshifting more immediate - and it does.

I have no experience with AP so if you can replicate or even improve upon what the Pedal Box does with that device then that is great. You say you have tried a setting with a similar throttle path to the PB but how do you know the empirical result was the same, did you have a PB car for immediate comparison? The fact that you say that pushing the pedal more is the same thing makes me quite certain that what you tried to mimic with your AP was not comparable to the Pedal Box.

And as far as the PB being less predictable, I don't think "predictable" is the right word, because as I said before the PB's response is exactly the same every time you press the pedal - there's nothing unpredictable about that and you get used to it very quickly. Where I could see some people objecting is that they might not like the power coming up that quickly. Apparently BMW feels the same way when building a car for the masses and so they dumb it down quite a bit. For myself, I like the immediacy of the response and I think that a lot of people on this board would.

Or a JB4. I read to the 3rd paragraph before I got the sales pitch glaze over. No thanks. I'd rather just tune my car to do that, plus throw in an extra 8psi of boost. If anyone is considering this please do some more research first.

Sorry if my original post sounds too sales pitchy for you. My only motivation for saying anything at all is that like most of us here I'm an enthusiast and if I find a mod that really makes a positive difference then I like to share that information. At the end of the day it won't change my life one bit whether you get one of these or not - hence my "public service announcement" quip. I know this device has been contentious, which is all the more reason for me to say "listen guys, I was skeptical like you but made the leap of faith with my 300 bucks and now I'm here to tell you that you will like what this thing does". Period. BTW I am running this on top of a JB4 and am unaware of any JB4 setting that will replicate what the PB does. If you're just referring to the JB's "lagfix" settings forget about it, that doesn't come remotely close to what the PB does.

[Indo Rider]

Not This Shit Again... Please Close Thread And Stop Wasting Peoples Time.

[Stohlen]

Originally Posted by dsh135

I'm not sure how many more ways I can say this: RPM builds faster with the PB controller.

And I dont know how many more ways I can say that IT DOES NOT.

The way your engine operates is in absolutely no way changed by this modification. All this box does is capture the signal produced by your throttle pedal, then modify it to increase the resistance of that signal before sending it along to the PCM. The PCM sees the increased resistance and opens the throttle more than it would had it been seeing the actual resistance value of the pedal. You could accomplish the same thing by pushing the throttle further.

Example:

Throttle imput to Box_____Box output to PCM_________Actual Throttle Pedal
3 ohms_________________4 ohms__________________15%
5 ohms_________________7 ohms__________________25%
7 ohms_________________10 ohms_________________35%
9 ohms_________________13 ohms_________________45%
11 ohms________________15 ohms_________________55%
13 ohms________________16 ohms_________________65%
15 ohms________________17 ohms_________________75%
17 ohms________________18 ohms_________________85%
19 omhs________________19 ohms_________________95%

Originally Posted by dsh135

I have no experience with AP so if you can replicate or even improve upon what the Pedal Box does with that device then that is great. You say you have tried a setting with a similar throttle path to the PB but how do you know the empirical result was the same, did you have a PB car for immediate comparison? The fact that you say that pushing the pedal more is the same thing makes me quite certain that what you tried to mimic with your AP was not comparable to the Pedal Box.

I dont heed to have owned a Pedal Box.... because i know exactly how it works and know that what I did is exactly the same thing, except that I changed the actual values in the PCM rather than putting a chip in between the pedal and the PCM to fool it into thinking the pedal was in a different place.

I know that you're much too deep into this mod for me to change your mind. But hopefully I can just warn others before they go out and spend $300 on a box of resistors in clever packaging. The engine operates exactly as it did before, the box has just fooled you into thinking your car suddenly got more "peppy" because you suddenly don't have to push your right foot as far to accelerate briskly.

[dsh135]

And I dont know how many more ways I can say that IT DOES NOT.

YES, IT DOES.

This tennis match can go on indefinitely if we let it. You're showing a lot of numbers which may or may not be accurate, but regardless, the power comes on a lot harder and faster, as evidenced by the effortless rev-matching, the chirping tires off an assertive low-speed tip-in, and the big smile on my face every time I get in the car. This whole perception versus reality thing is kind of suspect in any event. I drive my car for enjoyment of the responses I feel from it, be they engine responses, suspension responses, or just the feel of the door closing. In short, I drive it for the things I perceive, and unless all you do is race, I'm not sure what else it is we drive for recreationally? The feel of this car on PB is dramatically different than the feel of the stock throttle and it is immensely more involving for the driving enthusiast. When you say you hope to "warn" people against devices like this what exactly do you believe you are warning them against? It's frustrating from my perspective because you are warning them against something that makes driving the car significantly more satisfying - whether your mathematical models are correct or not. In any event, I don't want to get argumentative over this because I know you have good intentions in what you think is the truth. If you lived close by I'd let you take her for a spin yourself - no question. At this point however, I've said my piece and now I'll move on to enjoy my new mod in silence as everyone else on this forum has done who bought one and posted-up into a barrage of doubt. For anyone who is on the fence about this mod and has any real questions that I might be able to help answer I'm happy to be pm'd about it.

[Stohlen]

Originally Posted by dsh135

YES, IT DOES.

This tennis match can go on indefinitely if we let it. You're showing a lot of numbers which may or may not be accurate, but regardless, the power comes on a lot harder and faster, as evidenced by the effortless rev-matching, the chirping tires off an assertive low-speed tip-in, and the big smile on my face every time I get in the car. This whole perception versus reality thing is kind of suspect in any event.

I am sorry that you refuse to see my science, and the fact that the graph shown above (by the PedalBox) supports my numbers. But there are countless numbers of people who've bought products like this thinking there car was improved when it actually does nothing... I'd be willing to put my entire career as an automotive engineer on the line to say that this product does not affect the engine one damn bit, and that your car is not at all improved by the use of this product.

You can believe what you "feel" and judge things by the smile on your face, but that your device is magic.

[Stohlen]

For those of you interested in this product, look at the following install image. The only wires effected by this device are those running to the pedal. Its just a box, with resistors in it, changing how much pedal the PCM sees in relation to reality. Nothing else.

[tracer bullet]

Originally Posted by dsh135

What makes you believe that the stock throttle response curve is linear?

Fine let me rephrase that - closer to linear. Certainly not twitchy like Pedalbox's own graph shows.

Originally Posted by dsh135

There is no way that pushing the accelerator down faster/further gets the same response as what the Pedal Box is doing to the throttle input.

Again refer to the chart directly from them showing that 100% is 100%.

Originally Posted by dsh135

my only explanation is that the PB's signal amplification is getting around some sort of purposeful delay the factory has programmed in to keep the engine from revving to its full capability.

Your only explanation doesn't make it a fact. Pretty slick how the pedalbox was able to reflash the car's ECU, to do what you think it does. I wonder if the Pedalbox company claims any of these things? Let's see...

"The PedalBox is located between the accelerator pedal sensor and the control module and works by capturing the accelerator pedal signal and transforms it. Lots of manufacturers offer similar functions via standard "sports buttons". The PedalBox reduces the pedal travel necessary in order to reach a "throttle wide open" state (full throttle response)."

Hmm, nope. No magic, just does what the chart says, the same thing you can do with your right foot.

[PeteA]

So to summarize, this mod does only the following:
- Allows you to heel toe more easily as the throttle is more sensitive so doesn't need to be depressed as much to rev up.
- Added sensitivity reduces the "physical time" it takes for the users foot to go from throttle %-age position a to throttle %-age position b. Because of this;
- Makes the user perceive a more responsive throttle due to increased pedal sensitivity.

[tuj]

does anyone have a graph of the stock 'exponential' throttle response map?

There seems to be a definite soft-spot on the throttle up to about 30 or 40%, then it seems to go more linear. What I'm really curious about is the 'make-up' to the linear line...does that occur? Or goes the BMW throttle map look more like what I have drawn here:



I guess what I'm asking is: is the stock BMW thottle map holding us back from being at full linear power?

[alex_d_22]

Im with OP on this one. I have a tune AND the pedalbox and both units complement themselves perfectly. Its very hard to understand, but it works and feels amazing!

As soon as your right foot gets near the pedal, you feel the engine power is right there instantly available. When you put the PB off, you can actually feel that here is a "lag" between your foot position and the engine reacting, and the PB makes that lag go away and makes the car drive like a drive-by-cable, much more responsive. This is simply not something that your "right foot can fix". The PB is adjustable, so yes you can set it for 50% pedal is 100% pedal, but no need. I like having it in the regular sport mode, this gives a more dynamic throttle pedal mapping along with the reduced lag and makes the pedal very controllable and lots of fun! I bet any technical driver would really appreciate the drive-by-cable feel.

[infinitekidM2C]

pedalbox....hahahahahahahahahaha

[tracer bullet]

Let's reiterate this - the pedalbox is not changing the car's ECU in any way whatsoever. It is only changing the signal from your accelerator pedal. No more, no less. This amplified signal coming out of the pedalbox mimics you pressing the pedal further, and that is ALL that it does. So get this whole nonsense about it fixing or changing anything related to the programming of the ECU out of your heads. It doesn't work that way.

When the ECU picks up that amplified signal, and it is fooled into thinking that your foot is deeper into the accelerator pedal than it actually is, then at that point yes the results you guys speak of do happen. Revs build faster, the ECU gives boost sooner, all the results you like do in fact happen. And that is because the ECU thinks you've "stepped on it", and it acts accordingly. But all you have done is made these things happen with less foot travel. A car without this device only needs to press the pedal down further, which results in sending the exact same signal to the ECU, and results in the exact same things happening.

While you guys are correct on some of these results, you are completely off base as to why, and you are filling in the blanks as to what it is doing incorrectly. If you can't understand how this device works then you know little about cars and / or electronics. You have probably skipped through my explanation with little thought so that you could get to the end and make a reply saying "yeah huh, it does so do all these great things". If you like the pedalbox, that is fine. No one has a problem with that. But please understand how it works and stop making stuff up.

(And by the way, not owning a pedalbox doesn't mean that those who don't own them don't know what they are talking about. Not any more than those without a dozen yellow Type R stickers on their car aren't capable of knowing that those stickers won't actually add 15hp. So as we learn what the pedalbox actually does, maybe we can also skip the logical fallacies?)

[tracer bullet]

Originally Posted by tuj

I guess what I'm asking is: is the stock BMW throttle map holding us back from being at full linear power?

Pretty much all cars are like your blue line because in normal day-day driving when you are leaving an intersection, navigating stop & go traffic, or trying to go 40 instead of 45 you need that lower portion of the curve to be a little flat. This is a good thing, it keeps the car from being a pain in the ass to drive and keeps you from rear ending the car in front of you. This is especially true the more power the car has. As you get deeper and deeper into the throttle it ramps up quickly, because at that point you just want power and want to get moving. There's little need for nuances there and so the curve gets much steeper. Evan pedalbox's own graph is misleading, it gives you an idea of how it works which is fine, but don't consider its "off" (aka stock) line to necessarily be correct.

[tuj]

tracer-bullet. I understand that DBW cars generally have a throttle map that is 'progressive' if that's the right word. The first 0-30% is below linear.

My question is, where does the stock BMW pedal transition to being linear and is it ever on a STEEPER curve than linear (which by definition it has to be at some point if it starts out slower than linear and is going to finish at 100% throttle)?

It seems to me that when you are performance driving, you would want a curve much more like the one the pedalbox is claiming to give you; more control over the 70-100% range. If the BMW map is like the one I drew, you are actually getting less control over that critical last 30% because the BMW map has to go steeper than linear to get to 100%.