HellsAngel

couple days ago, someone recommended me to buy a sprint booster, after 5mins of research on this forum, i was gooing to order it when i found this pdf...
its a repost, but im sure not everybody saw this !

and as for the guy who posted this, im sorry for not quoting him ((decided to create this thread after i closed his thread and i dont feel like doing the research again...))

i totally agree with the author, it finally make sense why on the sprint booster website, they tell u "sprint booster does not change ur 0-60", while users tell u "it feels its faster"....
they r both right, it just feels that way, enjoy the analysis...

Klinh

This is old news and the excuses that some people said you can achieved the same feel of the sprint booster if you drive your car aggressive all the time, use manual shifting when passing..etc. Yes, all of what they said is true but why need to go throught all that to get te car to excelerate at it peak when with the sprint booster, you will get 100% of peak exceleration every time you step on the gas paddle. The problem with Mercedes (not just Mercedes) wire-drive by throttle is the delay in throttle response when you floor it in an emergency passing situation. With the sprint booster, the delay throttle response is non-exist. Btw, these feature are now came with my car from factory. Take the new M3 for example, the "SPORT" on the console, it pretty much does the exact same thing as the sprint booster.

Midnight Koop

quoting pdf...

From Throttle Response Measurements:

He basically shows us that the responsiveness is a function of the speed at which the pedal is pressed.

Pressing Slower --> More lag / Less throttle response
Pressing Faster --> Less Lag / More throttle response

From Sprint Booster Measurements:

"It is important to note that any accelerator signal into the ECU using a Sprint
Booster can be duplicated exactly by a driver without a Sprint Booster, merely by pressing the accelerator pedal a greater distance."

-pressing the acelerator a greater distance takes more time

"Basically, the Sprint Booster makes the accelerator pedal
about 30% more sensitive. A side effect, ... is that the accelerator pedal becomes dead beyond about two thirds travel with Sprint Booster."

-being more sensitive early on results in a faster initial response
-even if it is "dead" for the last 2/3rd's of pressing the pedal, you reach the throttle response threshold earlier and this allows you to maximize the total responsiveness of the car earlier on (i.e. reduces lag)
**note: "last 2/3'rds dead" only applies to pressing it steadily/slowly, later he shows that when you press it quickly, only the last 1/3rd of pressing the accelerator is dead

From Sprint Booster and Throttle Response:

"Here, we see that initially the throttle response is virtually identical to that with no Sprint Booster connected. However, at the top 1/3 of accelerator pedal travel, where the pedal has now become 'dead', the throttle response catches up to the accelerator"

-This is what I just said in the note above: when pressing it fast, the first 2/3rds respond very similar to stock, and last 1/3rd is dead

"It directly affects only this one parameter, signal amplitude. It, in and of
itself, doesn't really do anything faster. The speed at which things get done
depends upon how fast the driver presses the accelerator pedal."

-The pure responsiveness of the throttle is a function of the speed and distance the pedal is pressed (human dependent)
-assuming when the accelerator becomes "dead", that the ECU is controlling the throttle response (ECU dependent): therefore they would perform the same stock vs sprint booster
-The distance and speed of pressing the pedal can be changed whether or not you have a sprint booster: less work required to get a full response with a sprint booster

"...as a driver I can duplicate the Sprint Booster result simply by pressing on the pedal a bit faster. The only time that the Sprint Booster can make anything happen faster is if I absolutely mash the pedal to the floor."

**Pressing pedal faster mimicks Sprint Booster
-for driving in the city, it would be entirely uncomfortable to "mash" the accelerator to get a sporty response for day to day driving.

**Pressing pedal slower is aided by Sprint Boster
-this involves the majority of natural city driving which is the most fun in my opinion, and here's where you benefit

"In theory, that would translate into a faster 0-60 acceleration figure of something less than 0.035 second. In actuality, the increase is so small
that it is not measurable."

-this only applies when comparing it to "mashing"/flooring it: see above "**"

SickSpeedMonte

I have to respectfully disagree with you here. The data presented in that .pdf shows that the TPS reacts no quicker with the Sprint Booster than it does without it. All it does is amplify the signal, and make the throttle pedal more sensitive. So in reality, you can get a slightly quicker throttle opening, but its only due to the limitations on one's ability to mash the pedal as quickly as possible. So the only place that the 'booster is giving you any extra capability is when you are putting maximum effort (i.e. throwing your weight) into hitting the throttle, something I dont think I have ever done.

You dont have to manually downshift to achieve what the booster achieves. Simply push the pedal 30% further, and you will trigger the exact same kickdown event.

I think I noticed a couple of (what I think might be) mis-interpretations of the results, but it might just be the verbage confusing me. The data is very revealing.

Glyn M Ruck

Please read the previous - long winded thread in this regard. The Sprintbooster principle is dead simple - & frequently misunderstood or over complicated by people.

A competent tuning shop can reprogramme your ECU to achieve exactly the same thing.

Midnight Koop

I dont think the pdf./review over complicated it. i actually was happy someone could break it down scientifically.

the long winded thread is full of theories not supported by evidence. there are too many conflicting views. it was about time someone took the time to find out what was actually going on.

according to the review, the throttle response is a function of our accelerator reaction time (human response). mercedes has made it adaptable for comfort because it is a luxury car, but still the potential to give you response when you "mash" the pedal and need it.

there is a negative feedback for slower human responses (slowly accelerating) that result in slower throttle responses and a more "comfortable" driving experience. this comfort/slower reponse is eliminated by the sprint booster and mirrors the way our cars adapt with a faster human response ("mashing" the pedal).

i dont think its as simple as you think

SickSpeedMonte

The "lag" (time from pedal application to throttle responding) isnt affected by the sprint booster. The signal is just amplified. The "lag" is downstream of the booster in the signal path, in other words, this 'booster cannot predict what you are going to do before you do it, and send the signal any earlier than it would be sent without it. The delay of 0.1s is probably due to the ECM processor and the actuator on the throttle.

So press it faster?
The only time it increases your capability is at maximum effort throttle application, and VERY marginally at that (0.07s is about inperceiveable by a human, there are plenty of other factors that will overpower this perception of lag, such as the ability of the greater air volume to get from the throttle blade to the cylinder).

Re-read above, noting the bold. Its dead (unresponsive, constantly WOT) beyond 2/3 throttle, meaning the last 1/3 is dead, regardless of what condition you consider. It's simple, the signal amplitude is amplified, so it reaches its maximum value sooner in the pedal throw. It results in a more sensitive response. It's faster for a given throttle application speed, but if you want a faster response and you know how your car reacts, you will hit the throttle faster. With the sprint booster, you will adjust your driving habits and slow your pedal application for the same desired throtte opening speed.

When the pedal is "dead" its just not responding to any further throttle pedal application because the signal is already maxxed out. The ECU always controls the throttle, even when the pedal is not unresponsive. When the pedal is "dead", its just because the ECU reads full throttle, which, with the booster, it will do for the last 1/3 of normally responsive pedal travel, and render the last 1/3 of pedal travel useless.

Correct, at the expense of reduced controllability because the system is more sensitive. If you have a full pedal throw, why not use it? You can always just push the pedal in further if you want to accelerate harder. We're talking probably less than an inch of travel here... how much work is it really? I dont really consider driving, even spiritedly, my bone stock Benz to be "work" by a long shot. If you like the feel of a more sensitive throttle pedal, thats personal preference. It just doesnt make the car perform any better, period.

I really dont understand where you are coming from with this. How often are you quickly on and off the throttle in the city? Thats all the booster is doing, reducing the distance you have to push the pedal to achieve the same throttle angle change, and in the end making the car less controllable by the same factor. When you push the throttle slower in the city, the booster makes it feel like you pushed it 30% faster, not any quicker. When I'm in the city and applying throttle slowly, its because I want the car to respond gently, and the booster makes this 30% more difficult.


If you like this product, then by all means, use it and enjoy it. But it is what it is, its shortening the total effective throttle pedal throw, thats all. It's not adding any capability to the car, and its not telling the trans to shift any differently (in response to having to manually shift to duplicate the effects of the booster).

IMO, its the placibo of the aftermarket.

Glyn M Ruck

It's as simple as smaller pedal movement creates larger throttle plate movement.

(I wanted to say logarithmic but that complicates the issue)

SickSpeedMonte

lol, its a signal amplifier. V_out = 1.3 * V_in (or close enough to it... im sure its not perfectly linear, but its close enough that nobody would know any different if it were)

Pretty simple. The adaptive drive still functions as it did before, you are just scaling all curves by 1.3.

Glyn M Ruck

+1 - but that's complicating the issue for boneheads I stick to my basic definition

Midnight Koop

i only said it isn't as simple because of the adaptive drive and that makes the overall car response as a function of both the person driving AND the adaptive drive.. so its not a direct relationship. i wasn't, however, referring to the actual sprint booster. i meant the entire system with/without it.

i made a mistake with the 2/3rds vs 1/3rd because i think i read it too quickly. thanks for pointing that out. but everything else stands.

you have some good points, but it is not placebo of aftermarket because it does affect responsiveness.

Midnight Koop

i disagree: the sprint booster does exactly this. by making it more sensitive, it opens the throttle earlier/faster. so it reduces the time. it does this by amplifying the signal.

SickSpeedMonte

Agreed, it does affect responsiveness, so there is some value if you prefer a more sensitive throttle pedal. I just dont think it gives you the ability to do anything that you couldn't do before, or makes things much easier, and it doesnt make the throttle respond to your input any faster, just more pronounced. It makes certain things easier like being aggressive with throttle application, but you are trading off controlability of low throttle applications by the same amount.

I feel that its more of a tuning parameter than an upgrade.

Midnight Koop

is your car manual?

Midnight Koop

thats a good way to word it. i've had mine for about a year now and like to describe it as allowing my car better perform to its true potential.

SickSpeedMonte

The Benz, no.

The Monte has a 6 speed with pretty much strait cut gears, so maybe I'm a bit biased about driver effort. Still, the drive by wire throttle is VERY VERY easy to apply and I dont mind going the extra inch.

Midnight Koop

yeah well, once you get going then it doesn't really affect you. mine is 6-speed, and every time i shift/accelerate or rev-match it makes a big difference. its a must have for manual drivers, but unnecessary for auto IMO.

SickSpeedMonte

Maybe we are just defining the lag differently.

To me, its the time difference between applying the throttle and getting a response to that application. For example, if I pass 10% throttle on my way to 25%, its the time from 10% pedal to 10% throttle opening, and similarly 25% pedal to 25% throttle. The sprint booster only makes 25% pedal move to, say 20%. So if you consider the new total pedal throw, your 25% throttle pedal application is in a different position, but the time it takes for your throttle blade to react to the same 25% signal is no different. You reach 25% faster for the same input speed on the pedal, but like I said, that can be overcome by simply pushing the pedal faster (unless you are talking max effort application)

The driver will adjust to this change anyway and slow throttle application to achieve the same results as pre-booster during normal driving.

Glyn M Ruck

It opens the throttle plate (butterfly) by a greater amount for a given pedal input!

Midnight Koop

we were defining it differently...

i gotta get some actual work done this morning so i gotta peace out..

HellsAngel

+1



If the last 1/3 is dead, you feel that your pressing only 2/3 of the pedal, you want to accelerate since you think you can, but you cant... imagine that happening in a crirical situation
So the sprint booster is faking your feeling.. and you dont know anymore, how much of the available power your using !
And of course, amplifying the signal by 30% === reducing your maximum mpg by 30%

Glyn M Ruck

Nonesense! here we go down the BS slide again which destroyed the last thread.

gregr09

acr2001

Some of you guys are so thick headed its unbelievable. The simple facts that came out of that white paper are that a sprint booster does nothing more than REDUCE YOUR PEDAL TRAVEL by compressing the response into less distance out of the pedal. That is *ALL* that it does. You might as well put a wood block under the pedal adjusted so that the gas pedal can only be pushed down 70% of the way, because the other 30% is now useless! All this does is makes your vehicle HARDER to control (acceleration wise). If you feel like this makes your car faster or more responsive than you are sadly mistaken. You could just press the pedal down further and you would *EXACTLY* match the "improvements" from a sprint booster. This is not opinion, it's fact. I said this from the beginning in the huge sprint booster thread. I'm glad this white paper was posted!

gregr09

I agree partly, but you fail to mention any reference to the lag that is experienced from pedal mashing. It doesn't matter if you mash the pedal to the floor, that lag will be there.

The only reason I picked up an SB was to remove that lag entirely and allow the car to kickdown instantaneously.

So no, you can not match the improvements of an SB, exactly.

EDIT:
Before anyone asks, Yes, I have read the paper. I have performed my own tests without the SB installed and prefer the SB to stock. Simple as that.