PeterUbers

So I've been annoyed by the throttle lag... Which is clearly NOT turbo lag... It's a drive by wire trait in that the engine doesn't begin to accelerate until you have the throttle depressed a certain depth and this leaves me a bit uneasy when in the middle of an intersection and turning left against oncoming traffic.

So I didn't buy the sprintbooster for the performance as much as I wanted it for the practicality and day to day improvement in the throttle feel. I certainly know it provides no power gains.

Installation: took about 4 minutes, couldn't be easier. Need a wratchet, and a hand and a flashlight.

Two modes (green = moderate setting and red = aggressive)

The depth that I have to depress the throttle has not changed. I still have to depress about 20% before any acceleration begins, but when it does begin, it takes very little pedal movement to aggressively accelerate, and acceleration then comes on fast. In red mode this is very aggressive and not suitable for me for daily driving in S or S+, but red mode in C has made comfort much more aggressive and less annoying for daily driving. green mode is most suitable for S and S+

So did this solve my problem? Yes and no. First of all I never drank the koolaid on these devices from the preachers on this board. I shelled out cash to determine if it is worth it. And I can only advise that until you experience it for yourself on the MCT equipped Benz, you won't know for sure if you'll like it

I'm not sold that I'll be keeping this. It hasn't change the depth of travel issue for me.. I still have to push the pedal down a certain amount before the car even begins to accelerate, but in green and S/S+ Mode, since acceleration comes on more quickly it seems to compensate for that delay making turning against traffic more predictable.

It does make the mct a bit more clunky when doing stop and go driving under 40 mph... As the engagement of the wet clutch occurs faster. It's NOT more clunky in C mode.

I'll have to play with this for another week or so before I decide to keep it or return it. I have a feeling I'll be returning it but we shall see

I found a lack of reviews on this board of the sprintbooster with the mct based vehicles

vdubpower

is this a product that might also work for the issues u have

http://weistec.com/all/r/r63/2007-w2...u-upgrade.html

PaulE550

From an electrical engineering perspective, I think the reason the initial response remains the same (requiring the pedal to be depressed a certain percentage before there is any acceleration with or without the Sprintbooster) may be because Mercedes must have hard-coded an artificial minimal threshold into the ECU. In essence, the car's computer is programmed to ignore or delay the driver's request for acceleration until a secondary feedback sensor, tied to how far the gas pedal has been depressed, has reached a certain level. That would explain why you still have to depress the gas pedal the same amount before you get acceleration, but also why when acceleration does finally occur with the Sprintbooster, it is more aggressive. There have to be two electrical signals being compared in the ECU related to the driver's request for acceleration from the ECU.


This may just be an added piece of electrical engineering and software coding to the ECUs of AMG models to act as an artificial acceleration limiter for what Mercedes may view as safety reasons. On non-AMG vehicles, there may be no such secondary feedback loop designed into the ECUs. Which would explain why owners of non-AMG vehicles report acceleration is more immediate with a Sprintbooster installed. If I were designing a restriction circuit to limit acceleration responsiveness, that is what I would do.


In vehicles that are tuned, I would imagine the new software either partially or completely over-writes this part of the ECU, so pedal response becomes more linear. Just a thought.

mainly

that same situation is what bugged me the most in my cls63.. its just hard to believe that in such a vehicle as this, a model of the highest performance division of one of the highest brands, would have this issue.

i actually had people honk at me because i had cut them off, as a result of the car jutting out into traffic about a 1-2 seconds after i had pressed the accelerator. it makes you seem like a fool - like you were intentionally waiting to turn so you would cut the person off.


i dont remember however, there being a certain amount of pedal depression required for acceleration. as far as i know, any amount of pedal input will make the car go, just not right away. if you press the pedal down 15% and the car doesnt move - AT ALL, that sounds like a malfuction.

i actually found the more aggressive i tended to be with the pedal when turning left, the more lag there appeared to be! not sure if it was real or just my perception.

PeterUbers

I agree with everything you've mentioned here.

ucla95

subscribed

PeterUbers

I thought about what you said here and I agree with you... It's like there is a delay for the engine to accept any input for whatever depth of the throttle... So this sprintbooster does NOT remove that delay... And that's obviously what most of us are looking for

You're right it doesn't have to do with depth of the pedal

Perhaps this delay is built in to allow the wet clutch to engage. Additionally I did not have this delay with the 7g tronic in the e550. Nor is this delay in our 2008 g35x or my 2014 mdx... Both of course drive by wire systems

I find that once I'm in gear and holding a gear as in manual mode, the pedal response in stock mode is much more responsive .. A scenario where the wet clutch is engaged and no need for that delay

This sprintbooster may be worth the money just for what it does for comfort mode... We will see

joseyu

I wonder what this would do to a car that has been tuned by either Renntech or AMS. Both companies already claim improved throttle response. Would this make it faster?

PeterUbers

Sdg had a good review of his renntech tune and he says that while the throttle response is better it's not ideal.

I'm not sure if he meant the delay to engine response on initial pedal depress is LESS or that once that delay has passed it's more responsive like what the sprintbooster does

I also think that ideally one should do a simple tcu reset and allow the tcu to "re learn" the driver input for smoother shifting... As this changes everything about driver input.

DATURK

no it doesnt do jack....you know wht...

DATURK

This is a great feedback/review Peter, this is my exact review would be for the PedalBox, couldn't say it better myself, even with the Renntech it feels the same, I wish I could have better news for everyone but it really sucks that I don't, I didn't return my PedalBox, simply because I just really wanted to believe and convince myself it does work for me, but, answer is still no...

Nanook

Renntech tune has little to no effect on this condition...I just added the "pedalbox" device...similar to sprintbooster but with more adjustment settings and as I mentioned in my post this too has little to no effect in improving this annoying trait...and with it set in the most aggressive setting of which I run may actually "aggrevate" it at times..so frustrating having to wait for the transmission to respond before adding throttle input

Wow Daturk..beat me while I was typing

PeterUbers

So we are all in the same boat... The boat named "Throttle lag"

Nanook

Yep..and it's a real biatch..I'd be embarresed to let someone drive my expensive Mercedes..

DATURK

well...I wouldn't, but I just wouldn't let them drive....

SilveRT8

I got the habit of driving my car with a heavy foot on the gas and a light one on the CCB brake pedal. It should be the opposite !

ucla95

What does the PL say?

PeterUbers

I should post on there... Good call

Nanook

PL ?

joseyu

Private Lounge

Nanook

Ah..PL..got it..good idea

I surprised MB doesn't address this extremely annoying deficiency

PeterUbers

I am starting to believe it's there because of the inadequacy of the mct and the time it takes the wet clutch to engage ... If there was very or no lag ... We would be dropping a lot of torque onto a clutch that's not yet engaged ... And this wouldn't bode well for long term reliability

Having ridden a few days in green mode... I find that this is more suitable for me while in S and S+ modes and makes me feel more confident taking left turns against traffic

Nanook

You know the ultimate fail here tho is left turn..icy winter street..car coming at you..you try to beat it and in addition to the hesitation when torque finally arrives it throws the tc and the outcome delay could be disastrous..has nearly happened so many times

PeterUbers

Couldn't agree with you more

I think it's worth trying the booster and seeing, nanook, if this makes things better overall ... I think this will help my left turn situation

Nanook

I have the pedalbox in my ML..have the SB in my vette and would say PB is better only since it has more settings..irrelevant for me tho as I always run it in the most aggressive sport mode...and as I say..no real help to the stalling response