Sprint Booster settings..?

My '09 2.9L PDK came with a Sprint Booster installed. I can't remember what the setting on it was when I bought the car, but for about 2.5 years I've been driving it around at "red-3"... About a week ago, I decided to try and see if I'd like it a bit more aggressive, so I switched to "red-4".. I ran it that way for about a week, and today went back to red-3. I found the engine felt somewhat lumpy in red-4, acceleration wasn't that smooth and it balked at times when giving it pedal. I also usually run in Sport mode, which changes the pedal and the PDK responses. Much of the driving was in traffic. Only a little bit was highway. I noticed tonight when I gave the car its usual once around in the garage that the exhaust pipes looked sooty on the bottom edge, and there was actually some soot in the license plate recess. I know part of the action of the Booster is not only making the throttle response more relative to throttle position, but it also increases the speed of the throttle opening (shown pretty dramatically in some videos Sprint produced.) I'm wondering if this setting Red-4 combined with Sport mode might be the reason for the soot and lumpy acceleration feeling, especially if the throttle opens quickly in slow traffic. I can imagine a scenario where the throttle opens faster than the ECU tells the injectors to increase output.. leading to a temporary lean condition the ECU tries to compensate for - and perhaps overshoots. I've got to get out in it and find some open roads where I can make use of the sport mode and the throttle and see if it relearns how I like it to feel... just curious where other people might be running theirs.

Silly question... are you sure that the SB is set to auto and not manual transmission..? It does make a difference after reading a few articles about these. My 2.9 manual is set to Sport 9 as i've not noticed a huge difference in Race mode apart from perhaps a little oversensitive on the throttle. There's a small switch on the side of the controller unit that allows to be switched between manual and auto and i'm led to believe it has to match the transmission of the car it's fitted too..? Hope that is of some help..? Si.

I guess I have to get the book out and see.. dunno is my answer. I'll do some research - from memory I can't recall mention of an auto/manual switch when I glanced over the booklet when I got the car, but it obviously deserves re-reading. Thanks!

I have a PDK and like it in Green 7 or 8. I tied Red 3 and found it a bit too twitchy. I’m a big fan of the improved throttle response. Shawn in VA (USA)

Shawn, do you have Sport/Sport-Plus?

Only sport. And 98% of the time I’m in that mode (and mood). Shawn in VA (USA)

Checked - AT mode was selected with the switch. Also - it's been in GREEN-3. Not red. My mistake (red LED numeric display confused my easily addled brain..) Still seems lumpy, but we'll see what it feels like later today when I get to drive it over 25mph.. for some distance.

Crank it up [emoji3595]. Shawn in VA (USA)

I keep my Sprint Booster set around Green-4 or 5. I found anything in the "race" (red) category to be really too twitchy and not well suited for the street. Maybe in a track situation it might have a valid use. It's all personal preference, though.

Not to confuse anyone I have a 987.1 S MT 6 speed which is a port injected motor same as deilenberger's. The PDK may make a difference. I have used Red 5 since the Sprint Booster was installed about 4 months ago. I use very soft soled driving shoes to manage the throttle input. I have had a few bucking bronco effects from the MT6 speed when starting out in 1st gear. Usually due to not being careful with engine RPM due to thinking about other stuff. So, the Red 5 keeps me paying attention. I have a Softronic ECU Race package that includes a GT3 78 mm throttle body. I do admit that this combo on a 987.1 S really adds to the initial throttle response. My tail pipes are clean, even with the rapid throttle body response.

I have the SB V.3 in my 981 Cayman set at R3 + Sports Mode all the time. Any setting above R3 made the car too sensitive, even small bump in the road that shakes your foot slightly triggers throttle response. No major soot on the exhaust tips.